Field Testing – Commissioning & Routine Tests II– tests made in the development phase & prior to...
Transcript of Field Testing – Commissioning & Routine Tests II– tests made in the development phase & prior to...
Diagnostics of Cable Systems
Field Testing ndash Commissioning amp Routine
Tests II
Bruce Olson amp Nigel Hampton
Diagnostics of Cable Systems
Nigel Hampton
2
Diagnostics of Cable Systems
Outline
bull Diagnostic Techniques
bull Purpose of Diagnostics
bull Accuracies
bull Diagnostic Outputs
3
Diagnostics of Cable Systems
4
Test Types
Testing
Development ndash tests made in the development phase amp prior to approval tests
Approval ndash tests made on a design before commercial supply
to show satisfactory performance
Routine ndash tests made on every component
Field ndash tests made on a complete system
Diagnostics of Cable Systems
Field Tests
Field Testing
Commissioning
Diagnostic
Return to Service
Normal Work
After Failure
Diagnostics of Cable Systems
Commissioning
Tests carried out with a known chain of custody ndash we know what has
happened to the system
Diagnostics of Cable Systems
Commissioning Tests- HV amp EHV
HV ndash mainly Proof Test with a resonant system only some PD
EHV ndash Proof Test with a resonant system and PD
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Nigel Hampton
2
Diagnostics of Cable Systems
Outline
bull Diagnostic Techniques
bull Purpose of Diagnostics
bull Accuracies
bull Diagnostic Outputs
3
Diagnostics of Cable Systems
4
Test Types
Testing
Development ndash tests made in the development phase amp prior to approval tests
Approval ndash tests made on a design before commercial supply
to show satisfactory performance
Routine ndash tests made on every component
Field ndash tests made on a complete system
Diagnostics of Cable Systems
Field Tests
Field Testing
Commissioning
Diagnostic
Return to Service
Normal Work
After Failure
Diagnostics of Cable Systems
Commissioning
Tests carried out with a known chain of custody ndash we know what has
happened to the system
Diagnostics of Cable Systems
Commissioning Tests- HV amp EHV
HV ndash mainly Proof Test with a resonant system only some PD
EHV ndash Proof Test with a resonant system and PD
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Outline
bull Diagnostic Techniques
bull Purpose of Diagnostics
bull Accuracies
bull Diagnostic Outputs
3
Diagnostics of Cable Systems
4
Test Types
Testing
Development ndash tests made in the development phase amp prior to approval tests
Approval ndash tests made on a design before commercial supply
to show satisfactory performance
Routine ndash tests made on every component
Field ndash tests made on a complete system
Diagnostics of Cable Systems
Field Tests
Field Testing
Commissioning
Diagnostic
Return to Service
Normal Work
After Failure
Diagnostics of Cable Systems
Commissioning
Tests carried out with a known chain of custody ndash we know what has
happened to the system
Diagnostics of Cable Systems
Commissioning Tests- HV amp EHV
HV ndash mainly Proof Test with a resonant system only some PD
EHV ndash Proof Test with a resonant system and PD
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
4
Test Types
Testing
Development ndash tests made in the development phase amp prior to approval tests
Approval ndash tests made on a design before commercial supply
to show satisfactory performance
Routine ndash tests made on every component
Field ndash tests made on a complete system
Diagnostics of Cable Systems
Field Tests
Field Testing
Commissioning
Diagnostic
Return to Service
Normal Work
After Failure
Diagnostics of Cable Systems
Commissioning
Tests carried out with a known chain of custody ndash we know what has
happened to the system
Diagnostics of Cable Systems
Commissioning Tests- HV amp EHV
HV ndash mainly Proof Test with a resonant system only some PD
EHV ndash Proof Test with a resonant system and PD
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Field Tests
Field Testing
Commissioning
Diagnostic
Return to Service
Normal Work
After Failure
Diagnostics of Cable Systems
Commissioning
Tests carried out with a known chain of custody ndash we know what has
happened to the system
Diagnostics of Cable Systems
Commissioning Tests- HV amp EHV
HV ndash mainly Proof Test with a resonant system only some PD
EHV ndash Proof Test with a resonant system and PD
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Commissioning
Tests carried out with a known chain of custody ndash we know what has
happened to the system
Diagnostics of Cable Systems
Commissioning Tests- HV amp EHV
HV ndash mainly Proof Test with a resonant system only some PD
EHV ndash Proof Test with a resonant system and PD
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Commissioning Tests- HV amp EHV
HV ndash mainly Proof Test with a resonant system only some PD
EHV ndash Proof Test with a resonant system and PD
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Voltage Time Profile for HV amp EHV Commissioning
8
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Commissioning Tests - MV
bull Soak System Voltage bull Very Low Frequency (VLF) Proof Tests bull Partial Discharge (PD)
bull These do not replicate Factory Tests as generally only
PD or Proof tests are done bull Factory Test criteria can be relevant in decision making
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Bruce Olson
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Diagnostics
Tests carried out without a known chain of custody ndash we really donrsquot know
what has happened to the system
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Diagnostic Tests - MV
Technologies currently discussed bull Time Domain Reflectometry (TDR) bull Simple Dielectric Withstand bull Dielectric Loss (Tan δ amp Dielectric Spectroscopy) bull Online Partial Discharge (PD) bull Offline Partial Discharge (PD) bull Isothermal Relaxation Current (IRC) bull Recovery Voltage (RV) bull Damped AC (DAC) - currently not used in North America
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Time Domain Reflectometry
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
TDR Equipment
Accessed 9302009 httpwwwbauratenproductscable-fault-locationirg-2000html
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Time Domain Reflectometry (TDR) Test Description bull Measures changes in the cable impedance as a function of
circuit length by observing the pattern of wave reflections bull Used to identify locations of accessories faults etc
Field Application bull Offline test that uses a low voltage high frequency pulse
generator bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
TDR Principles
Near End TDR Equipment
Far End
Joint L
Joint
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
TDR can be Feature Rich
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Simple Dielectric Withstand
18
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
28kV
60kV 34kV
56kV WPD amp TD
60kV
60kV
28kV
54kV
30kV
60kV
VLF MODELS FROM VARIOUS VENDORS
34kV
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
VLF Waveforms
SEBAKMT VLF40 5kv RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
Volta
ge (k
V)
HVA30 5kV RMS with 280feet XLPE Load
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Volta
ge (k
V)
Sinusoidal
Cosine-Rectangular
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Simple Dielectric Withstand Test Description bull Application of voltage above normal operating voltage for a
prescribed duration bull Attempts to drive weakest location(s) within cable segment to
failure while segment is not in service
Field Application bull Offline test that may use
ndash DC ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Setup
22
VLF DUT
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
23
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Withstand Test Process
HOLD EARLY
Time
oltage
t = 0 tTest
Voltages and Times for VLF covered in IEEE Std 4002
The goal is to have circuit out of service test it such that ldquoimminentrdquo service failures are made to occur on the test and not in service
Hold Entry
Ramp Entry
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
25
Dielectric Loss (Tan δ)
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
TD Assesment
26
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Tan δ Equipment
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Dielectric Loss (Tan δ) Test Description bull Measures total cable system loss (cable elbows splices amp terminations) bull May be performed at one or more frequencies (dielectric spectroscopy) bull May be performed at multiple voltage levels bull Monitoring may be conducted for long durations
Field Application bull Offline test that may use
ndash 60 Hz AC ndash VLF AC ndash Damped AC
bull Testing may be performed by a service provider or utility crew bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Setup
29
VLF DUT Tan Delta
Data
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Cable System Equivalent
T C S C T
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Cable System Equivalent
T C S C TCable system (cable splices and terminations) is reduced to simple circuit
Tan δ
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
SIMPLIFIED CABLE MODEL AND PHASOR Tan Delta = IRIC = 1(2πfCR)
The tangent of this angle is calculated
δ
I
V
IC
IR
IR IC
= tangent of δ
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Dielectric Loss Test Process
Time
Voltage
Loss measurement
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
34
Tan δ Ramp Test Data
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
Mean
could be used)Standard Deviation - IQRScatter (represented by
Tip Up
Time [min]
Tan-
delt
a [1
e-3]
543210
100
90
80
70
60
50
40
30
20
10
05101517
[pu]Voltage
MeanTip Up
30 Cycles
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Tan δ Monitored Withstand
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Monitored Withstand Test Protocol
HOLD Tan δ Ramp
Time
Voltage
Focus in this section is on the Hold Phase
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Ways Not to Pass a Monitored Withstand
Failure ndash Insulation puncture
OR
High Dielectric Loss
OR
High Instability ndash Measured by standard deviation in consecutive measurements at one voltage level
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Tan δ - MV Test Protocol
38
Voltage [U0]
025 050 075 10 125 150 175 20 225 25
Frequency [Hz]
002
005
010
Features bull Stability 01 Hz amp U0 bull Tip Up 01 Hz amp between 15 U0 amp 05 U0 bull Mean Tan δ 01 Hz amp U0
Ramp Withstand
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
If this had been a Simple Withstand
Length Tested (miles)1086420
18 Segments Tested
No Failures On Test
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
60 min test
30 min test
Monitored Withstand - Stability
Sequence of Lengths Tested (miles)1086420
Pass - Un Stable Loss
Pass - Stable Loss
18 Segments Tested
60 min test
30 min test
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
41
Offline Partial Discharge
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Offline PD Equipment for MV or HV
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Offline Partial Discharge Test Description bull Measurement and interpretation of partial discharge signals
above normal operating voltages bull Signal reflections (combined with TDR information) allows
location to be identified within cable segment
Field Application bull Offline test that may use
ndash 60 Hz AC service provider ndash VLF AC utility crew ndash Damped AC utility crew
bull Step voltage up to pre determined level with post test analysis
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
PD Setup and Calibration
bull Cable Map bull TDR
ndash Length ndash Splices ndash Propagation velocity
bull Calibration ndash Inject 05 1 or 2 nC signal ndash Verify TDR info
Jicablersquo11 19 - 23 June 2011 - Versailles - France
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
PD Interpretation
ndash Voltage ndash PD Level ndash Frequency ndash Location ndash Discharge Pattern (phase resolved) ndash Phase to phase ndash Year to year
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Setup
46
VLF DUT
PD SENSORS
FILTER
Data
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
47
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Differences for PD Tests
Laboratory Field Calibrated ndash how many mV = pC
X
Sensitivity Check ndash can a PD like signal be seen
X
PD Technique Defined IEC
Variable Wide
Bandwidth
Criteria Defined Depends upon
situation
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Offline PD Test Process
Time
oltage
Discharge measurement
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
PD Pulse
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Offline PD (60 amp 01Hz) Outcome Sequences
No PD
PD
A
B
C
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
52
Online Partial Discharge
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Setup
53
DUT
PD SENSORS Data
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Online PD Equipment
httpwwwutilxcompdfsCableWISE_Generation_Sample_Reportpdf
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Online Partial Discharge Test Description bull Measurement and interpretation of discharge and signals on
cable segments andor accessories bull Signals captured over minutes hours bull Monitoring may be conducted for long durations
Field Application bull Online test that does not require external voltage supply (no
customer outage required) bull Testing performed by a service provider bull Assessment criteria are unique to each embodiment of the
technology bull Measurements require sensor placement at multiple locations
along cable circuit
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Online PD Test Process
Time
U0
oltage
Continuous measurement
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Distribution of PD along Lengths bull 5000 ft portion of sample feeder
bull Mixture of different PD levels for different sections and accessories
Cable Section Accessory
No PD
PD
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Nigel Hampton
58
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Current Use of Diagnostics
59
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
60
Safe
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
61
Effective
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
62
Useful
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
63
Valuable
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Utility Use of MV Diagnostics
VLF DC Tan Delta
PD On PD Off TDR
IRC DAC
No UseOccasionalStandardTesting
Category
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
65
Lengths Tested
Cable Length - log (ft)
Perc
ent
100
75
50
25
00100000100001000100
100000100001000100
100
75
50
25
00
PD Tan D
VLF Withstand
Panel variable Technique
Median 814 ftMedian 485 ft
Median 3500 ft
Based on diagnostic data supplied to CDFI Measurements made with TDR
TDR
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Distribution of Causes for MV Failures
Unknown11Terminations
56
Splices371 Cable
562
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Locations of Failures differ between Utilities
Percentage
C1
16144
23137
1519241121
20106
173
229
121858
21
100806040200
5539CableUnknown SourceAccessories
Uti
lity
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Accuracy
68
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Objective of Diagnostic Tests The target population contains both ldquoGoodrdquo and ldquoBadrdquo components
ndash ldquoGoodrdquo ndash Will not fail within diagnostic time horizon ndash ldquoBadrdquo ndash Will fail within diagnostic time horizon
ldquoBadrdquo Components ldquoGoodrdquo Components Target Population
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Diagnostic Operation Applying the diagnostic will separate the population into bull No Action Required group bull Action Required group
No Action Required Action Required
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Accuracies
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action Accuracy
212019181716151413121110987654321
100
80
60
40
20
0212019181716151413121110987654321
No Action Accuracy
Dataset
Dia
gnos
tic
Acc
urac
y
Action AccuracyVariable time horizons of 1-8 years
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Group Sizes ndash Act vs Not Act
Not ActAct
100
80
60
40
20
0
Test
s [
of
Tota
l]
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
All Accuracies
Overall AccuracyAction AccuracyNo Action Accuracy
100
80
60
40
20
0
Dia
gnos
tic
Acc
urac
y
989
100
05
10
497
925
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Using Results from Diagnostics
74
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Outputs from Diagnostics
Numeric Survival
Pass Fail
Classification
Good Bad 1 2 3 4 5 NA FS AR
Replace Defer
Time Reflectometry (TDR) X X Simple Dielectric Withstand X Dielectric Loss (Tan δ) X X Online Partial Discharge (PD) X Offline Partial Discharge (PD) X Monitored Withstand X X X
Characteristics Transparent Repeatable Updatable
Unambiguous Opaque
Not Repeatable Not Updateable
75
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Route to Use Diagnostics
bull Field Tools bull Asset Health
bull Diagnostic Features
bull System Data
bull Numbers bull Pass Fail bull Classes
Test Data
Feature Extraction
Experience Library
Knowledge Rules
76
Data
Information
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Knowledge Rule - Age
77
GoodPoor
750
250 281
719
1000
1975 1979
1982
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Snohomish PUD Cable System
bull Two areas tested ndash Glenwood Mobile Homes (1976 amp 1981 vintage) ndash Evergreen Shopping Center (1986 vintage)
bull Homogeneous cable system ndash 15 kV voltage class (operated at 72 kV) ndash XLPE insulation ndash 10 conductor ndash Unjacketed concentric neutral ndash Installed in conduit ndash no splices ndash Terminated with elbows
78
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Testing Sites
79
Glenwood Mobile Homes
Evergreen Shopping Center
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Glenwood Mobile Estates
80
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05
U0 [10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required (Best 80 )
lt005 amp lt5 amp lt4
Further Study
005 to 05 Or
5 to 80 Or
4 to 50
Action Required
(Worst 5 ) gt05 gt80 gt50
Knowledge Rule
Field Tool Tan δ Criteria for PE-Based Insulation
81
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Tan δ Map (Tip Up amp Mean Tan δ)
82
10001001001
100000
10000
1000
100
010
00110001001001
Evergreen Shopping Center
TD Uo [E-3]
Tip
Up (
15U
o -
05U
o) [
E-3]
4 50Glenwood Mobile Homes
4 50
5
80
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Basic Assessment Summary
83
Evergreen Glenwood
No Action Required1000
Action Required133
Further Study267
No Action Required600
1986 Vintage12 Ckts
1976 amp 1981 Vintage15 Ckts
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Example - No Action Required
84
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Example - Further Study
85
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
TestTan δ Stability
Tip Up Mean Tan δ
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Wet Circuits
86
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Knowledge Rule Field Tool
Monitored Withstand Criteria (PE)
87
Condition Assessment
Change in Tan Delta between 0
and 10 mins (E-3)
VLF-TD Stability (standard
deviation) at Maintenance Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 and lt025 and lt5
Extend to 60 Mins gt17 or gt6 or gt45
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
88
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Stability15Uo=27E-3
TDUo=13Tip Up on Tip Up= 128Tip Up = 134StabilityUo = 0
Snopud Segment 6912
Monitored Withstand with Water
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud Segment 6912
0 to 10 mins
89
Difference between 10 amp 0 mins = -45
Change in Tan Delta
between 0 and 10
mins (E-3)
VLF-TD Stability
(standard deviation)
at Maintenance
Level [10-3]
Mean VLF-TD at
Maintenance Level [10-3]
Reduce to 15 Mins lt025 lt025 lt5
Extend to 60 Mins gt17 gt6 gt45
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
0 to 30 mins
90
302520151050-5
10
1
Test Time [min]
Tan
Del
ta [
E-3]
05101522
[Uo]Voltage
Test
Snopud 6912
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Final Classification - Retest
91
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]_2Voltage
TestTan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
302520151050
1000
100
10
1
Measurement Sequence []
Tan
Del
ta [
E-3]
051015
[Uo]Voltage
Test
Example ndash Action Required
92
Tan δ Stability Tip Up
Mean Tan δ
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Condition Assessment
VLF-TD Stability (standard deviation)
at U0 [10-3]
Differential TD TD 15 U0 ndash TD 05 U0
[10-3]
Mean VLF-TD
at U0 [10-3]
No Action
Required lt005 amp lt5 amp lt4
Further Study
005 to
05 Or
5 to 80 Or
4 to 50
Action Required gt05 gt80 gt50
Something for another day ndash Health Indices
93
05
50
0 1 2
Stability 0 Tip Up 614 Tan Delta 23
What is the classification
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
Nigel Hampton
Bruce Olson
94
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-
Diagnostics of Cable Systems
SUMMARY
bull Have the correct expectation ndash Diagnostics are useful ndash Diagnostics are not perfect
bull There is no ldquomagic bulletrdquo or ldquoone techniquerdquo bull Today the main goal of diagnostics is to indicate which
members of a target population are likely to have ldquogoodrdquo performance
bull A lot of work continues in this area
95
- Field Testing ndash Commissioning amp Routine Tests IIBruce Olson amp Nigel Hampton
- Slide Number 2
- Outline
- Test Types
- Field Tests
- Commissioning
- Commissioning Tests- HV amp EHV
- Voltage Time Profile for HV amp EHV Commissioning
- Commissioning Tests - MV
- Slide Number 10
- Diagnostics
- Diagnostic Tests - MV
- Time Domain Reflectometry
- TDR Equipment
- Time Domain Reflectometry (TDR)
- Slide Number 16
- TDR can be Feature Rich
- Simple Dielectric Withstand
- Slide Number 19
- VLF Waveforms
- Simple Dielectric Withstand
- Setup
- Slide Number 23
- Withstand Test Process
- Dielectric Loss (Tan δ)
- TD Assesment
- Tan δ Equipment
- Dielectric Loss (Tan δ)
- Setup
- Cable System Equivalent
- Cable System Equivalent
- Simplified Cable Model and PhasorTan Delta = IRIC = 1(2fCR)
- Dielectric Loss Test Process
- Tan d Ramp Test Data
- Tan δ Monitored Withstand
- Monitored Withstand Test Protocol
- Ways Not to Pass a Monitored Withstand
- Tan δ - MV Test Protocol
- If this had been a Simple Withstand
- Monitored Withstand - Stability
- Offline Partial Discharge
- Offline PD Equipment for MV or HV
- Offline Partial Discharge
- Slide Number 44
- Slide Number 45
- Setup
- Slide Number 47
- Differences for PD Tests
- Offline PD Test Process
- PD Pulse
- Offline PD (60 amp 01Hz) Outcome Sequences
- Online Partial Discharge
- Setup
- Online PD Equipment
- Online Partial Discharge
- Online PD Test Process
- Distribution of PD along Lengths
- Slide Number 58
- Current Use of Diagnostics
- Safe
- Effective
- Useful
- Valuable
- Utility Use of MV Diagnostics
- Lengths Tested
- Distribution of Causes for MV Failures
- Locations of Failures differ between Utilities
- Accuracy
- Objective of Diagnostic Tests
- Diagnostic Operation
- Accuracies
- Group Sizes ndash Act vs Not Act
- All Accuracies
- Using Results from Diagnostics
- Outputs from Diagnostics
- Route to Use Diagnostics
- Knowledge Rule - Age
- Snohomish PUD Cable System
- Testing Sites
- Glenwood Mobile Estates
- Knowledge RuleField ToolTan δ Criteria for PE-Based Insulation
- Tan δ Map (Tip Up amp Mean Tan δ)
- Basic Assessment Summary
- Example - No Action Required
- Example - Further Study
- Wet Circuits
- Knowledge RuleField ToolMonitored Withstand Criteria (PE)
- Monitored Withstand with Water
- 0 to 10 mins
- 0 to 30 mins
- Final Classification - Retest
- Example ndash Action Required
- Something for another day ndash Health Indices
- Slide Number 94
- SUMMARY
-