Presentation Roizman Davydov Modified
-
Upload
israel-daniel -
Category
Documents
-
view
219 -
download
0
Transcript of Presentation Roizman Davydov Modified
-
8/9/2019 Presentation Roizman Davydov Modified
1/25
Temperature Rise Tests
Centre for Power Transformer Monitoring, Diagnostics
and Life Management (transformerLIFE)
Monash University, Australia
Oleg RoizmanIntellPower, Australia
Spring 2009 IEEE Transformers Committee Meeting
Miami FL, 21 April 2009
Valery DavydovMonash University
-
8/9/2019 Presentation Roizman Davydov Modified
2/25
Special Test Transformer Nameplate Data
Year of Manufacture 2006
Rated Power HV/MV for ONAN,
kVA
468/468
Rated Voltage HV/MV/LV, kV 22/4.5/0.415
Rated Current HV/MV Amp 12.3/60.0
Cooling Types ONAN, ONAF,
OFAF
Number of Phases 3
Vector Symbol YNyn0yn0
Mass Untanking, kg 2420
Mass Each Cooler (excluding oil), kg 115
Mass Total (including oil), kg 6850
Insulating Oil Each Cooler, l 43
Insulating Oil Total, litre 2650
Oil Circulation, l/min 1200
-
8/9/2019 Presentation Roizman Davydov Modified
3/25
Temperature Sensors and DAQ System
16 Fiber Optic sensors
24 Thermocouples, including magnetic and thermalribbon types
9 RTDs, including those of moisture/temperature
transmitters
More than 60 channels of information stored at 1 min
interval
-
8/9/2019 Presentation Roizman Davydov Modified
4/25
Location of Thermocouples and RTDs
in Test TransformerTop Oil Temperatures
Top Core Yoke Temperatures
Top Rings Temp
Top Radiator
Bottom Radiator
-
8/9/2019 Presentation Roizman Davydov Modified
5/25
Location of Fibre Optic Probes and Core
Thermocouples
-
8/9/2019 Presentation Roizman Davydov Modified
6/25
Fibre Optic Probe Installation
in MV Winding, Phase B
-
8/9/2019 Presentation Roizman Davydov Modified
7/25
Fibre Optic Probe Installation in HV Winding
-
8/9/2019 Presentation Roizman Davydov Modified
8/25
Effect of Measuring Instrumentation
In the following 4 slides, comparisons are made for
the two windings of Phase B (OFAF)
MV (layer type) HV (disc type)
The comparisons are made for results obtained during
the Temperature Rise Tests conducted at Monash
using two different instrumentation sets for windingresistance measurement
-
8/9/2019 Presentation Roizman Davydov Modified
9/25
Comparison of Tavr and FO for MV OFAFPhase B, 100A
30
35
40
45
50
55
60
65
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
t, min
T
,deg
C
FO12 MV top FO13 MV middle FO14 MV bottom wm(i) as measured w(i) as calculated
Avr wnd. T
Top wnd. temp
Mid wnd. temp
Bot wnd. T
1st set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
10/25
Comparison of Tavr and FO for HV OFAFPhase B, 100A
35
37
39
41
43
45
47
49
51
0 2 4 6 8 10 12 14 16
t, min
T,
deg
C
FO7 HV top FO9 HV middle FO11 HV bottom
Measured average winding temperature Calculated average winding temperature
Tawr
1st set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
11/25
OFAF (100A) HV Phase B
60
65
70
75
80
85
90
0:00:00 0:02:53 0:05:46 0:08:38 0:11:31 0:14:24 0:17:17 0:20:10 0:23:02
Twarm Twarm fitted IEC 20mins Twarm fitted IEC 15mins Twarm fitted IEC 5mins
Twarm fitted exp 5mins FO7 FO1 FO9
2nd set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
12/25
OFAF(100 A) MV Phase B
60
70
80
90
100
110
120
0:00:00 0:02:53 0:05:46 0:08:38 0:11:31 0:14:24 0:17:17 0:20:10 0:23:02Time since shu t down (mins)
T,
degC
Twarm Twarm fitted IEC 20mins Twarm fitted IEC 15mins Twarm fitted IEC 5mins
Twarm fitted exp 5mins FO13 FO12 FO14
It could be seen that depending on duration of test variations in Twnd (R) is ~10 C
2nd set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
13/25
Blocked Coolers: 60A
70
72
74
76
78
80
82
84
86
88
90
7:12 8:24 9:36 10:48 12:00 13:12 14:24 15:36 16:48 18:00 19:12
T,
degC
FO6 FO15 FO16
Blocked Coolers 60 A
Phase A Phase C Phase B
~4 hours!
-
8/9/2019 Presentation Roizman Davydov Modified
14/25
Blocked Coolers: 60 A
Blocked Cooling
68
70
72
74
76
78
80
82
84
0:00 2:24 4:48 7:12 9:36 12:00 14:24 16:48 19:12 21:36
T,
degC
Twarm A Twarm fitted IEC (A) Twarm C Twarm fitted IEC Twarm B Twarm fitted IEC (B)
Ph A
Ph C
Ph B
76.59+time*0.1618-4.331)exp(-time/*5.521=Tw
2nd set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
15/25
Blocked Coolers HV Phase B 60A
45
50
55
60
65
70
75
80
85
90
0:00 2:24 4:48 7:12 9:36 12:00 14:24 16:48 19:12 21:36
Time since shutdown (mins)
T,
degC
Twarm FO7 FO9 FO11 (TV4+TV5)/2
hottest measured temp mid measured temp
bottom measured tempWinding temp by
resistance
-
8/9/2019 Presentation Roizman Davydov Modified
16/25
ONAN(60A) HV phase B
45
50
55
60
65
70
0:00:00 0:02:53 0:05:46 0:08:38 0:11:31 0:14:24 0:17:17
Time since shutdown (mins)
T,
degC
Twarm Twarm fitted IEC 15mins Twarm fitted IEC 5mins Twarm fitted exp 5mins FO9 FO3 FO11
2nd set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
17/25
ONAN(60A) MV phase B
40
45
50
55
60
65
70
75
0:00:00 0:02:53 0:05:46 0:08:38 0:11:31 0:14:24 0:17:17
Time since shutdown (mins)
T,degC
Twarm Twarm fitted IEC 15mins Twarm fitted IEC 5mins Twarm fitted exp 5mins FO12 FO13 FO14
2nd set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
18/25
Comparison of FO Data for Phases A, B & C
In the following slide a comparison is made for Phases A, B
and C for the HV (disc type) winding for the OFAF cooling
mode
The comparison is made for the measurements obtained
during the Temperature Rise Tests conducted at Monash for
the FO probes installed in the 2nd top disc of Phases A, B & C
The differences in the FO measurement results wereobserved due to the following reasons:
Phase A is the most remote phase from the oil inlet pipe; the velocity
of oil flow through the winding ducts of Phase A is the lowest
Phase C is the closest phase to the oil inlet pipe; the velocity of oil flowthrough the winding ducts of Phase C is the highest
Phase B is in the middle between the inlet pipe and Phase A
-
8/9/2019 Presentation Roizman Davydov Modified
19/25
FO Sensors Data for Phases A, B and C
OFAF (100A)
55
60
65
70
75
80
85
90
95
8:24 9:36 10:48 12:00 13:12 14:24 15:36 16:48 18:00
Time, h:mm
Temperatu
re,
degC
FO6 FO15 FO16
Phase A
Phase B
Phase C
Cooling curves
-
8/9/2019 Presentation Roizman Davydov Modified
20/25
Cooling Curves for A, B and C Phases,
OFAF (100A), HV
60
65
70
75
80
85
90
0:00 2:24 4:48 7:12 9:36 12:00 14:24 16:48 19:12 21:36
Time since shutdown, min
Windingtempe
rautrebyR,
degC
Phase B Phase C Phase A
2nd set of winding resistance measurement instrumentation was used
-
8/9/2019 Presentation Roizman Davydov Modified
21/25
Effect of first valid time point for MV in OFAF
60
65
70
75
80
85
90
0:00:00 0:02:53 0:05:46 0:08:38 0:11:31 0:14:24 0:17:17 0:20:10 0:23:02
Time since shutdown (mins)
T,
deg
C
Twarm Twarm fitted IEC 20mins (from 1m45s) Twarm fitted IEC 20mins (from 4m)
1:45 min
4:00 min
-
8/9/2019 Presentation Roizman Davydov Modified
22/25
Factors Affecting Winding Temperature Rise
Winding resistance measuring equipment
Ambient temperature determination Inadequate calculation of the average oil
temperature (leads to wrong g factor)
Accuracy of Load Loss measurement Assumed total loss as sum of NL + LL
Effect of the Core temperature dynamics
Cold resistance measurement errors Not reaching steady state before shutdown
-
8/9/2019 Presentation Roizman Davydov Modified
23/25
Factors Affecting Winding Temperature Rise
(contd)
Connection circuit (two windings at a time) Time interval first and last data point resistance
measurement
Fitting curve method
Ambient oil temperature consideration
-
8/9/2019 Presentation Roizman Davydov Modified
24/25
Conclusions
Depending on winding time constant taking first
resistance measurement at 4 min may be too long wait
and could lead to significant error in determination of
winding temperature at shutdown
10 min cooling curve period could be well justified for
small and medium distribution transformers, but does not
seem to be adequate for large power transformers,where 20 min should be considered as more appropriate
15 sec acquisition rate was found to be easily
achievable with the modern acquisition systems and is
recommended, especially for a winding with a short time
constant
-
8/9/2019 Presentation Roizman Davydov Modified
25/25
Conclusions (Contd)
Considerations should be given to the followingrecommendations when FO sensors are used:
a. Number and locations of FO temperature probes should be determined
on the basis of analysis of heat and mass transfer with assistance ofnumerical methods such as FEM and CFD;
b. Hot-spot temperature should be continuously measured by FO sensorsinstalled in each winding of each phase and verified by calculations inaccordance with the latest relevant standards and/or more detailed in-house thermo-hydraulic models;
c. Average winding temperature rise by resistance should be measuredonly in the winding of the phase with the highest hot-spot temperaturefound in b) unless the difference between that temperature and theaverage of all phases exceeds agreed value (e.g. 3 C).