Identification, Prioritization, and Placement of Automatic Sectionalizing Devices
July 27th, 2015
John Reid, Joseph Viglietta
PECO Reliability Programs
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Overview
• Reclosers at PECO
• Recloser Program Overview
• Cost per ACI per Year
• Circuit Section Prioritization Method
• Circuit Section Analysis Process
• Recloser Saves Analysis
• Latest Developments
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Reclosers at PECO • Overcurrent and loss-of-potential based loop schemes
• 1,600+ reclosers across 4kV, 13kV, and 34kV distribution
• 3-phase trip and lockout
• 3-phase auto-transfer without load checking – Transfer capacity must be available under peak load conditions
• No “fuse saving”—slow trips only
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Reclosers at PECO
Various controller types utilize standardized recloser settings
• Standard Recloser (R) – Trip on fault current, switch to alternate trip setting on loss of voltage to coordinate with ties
• Modified Recloser (RM) – Trip on fault current, open on loss of voltage
• Sectionalizer (S) – Do nothing for fault current, open on loss of voltage
• Tie Recloser (T) – Normally open, close on loss of voltage. Circuit transfers are designed with peak loads in mind
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RM1 680A
R1 480A/240A
S
S1 T111 340A
Distribution Sectionalizing Program • Annual reliability program to install reclosers
o Reclosers also installed under Capacity Expansion, New Business, Top Priority Circuit program, and various reliability projects
• Primary goal is improving system SAIFI
• Secondary goals include:
o Enhancing reliability for customers experiencing multiple interruptions (CEMI)
o Controlling circuit section size (ideal size is 500-750 customers)
o Improving operational flexibility
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Cost per Avoided Customer Interruption
• Proposed installation – 5 faults over 3 years
• Scheme above would save 2800 (3x800, 2x200) customer interruptions over 3 years, or 933 CI per year
• Cost per ACI per Year:
$/𝐴𝐶𝐼 = 𝐶𝑆𝑃%×𝐶𝑜𝑠𝑡 𝑜𝑓 𝐼𝑛𝑠𝑡𝑎𝑙𝑙𝑎𝑡𝑖𝑜𝑛
𝐴𝑣𝑜𝑖𝑑𝑒𝑑 𝐶𝑢𝑠𝑡𝑜𝑚𝑒𝑟 𝐼𝑛𝑡𝑒𝑟𝑟𝑢𝑝𝑡𝑖𝑜𝑛𝑠 𝑌𝑒𝑎𝑟𝑠 𝐴𝑛𝑎𝑙𝑦𝑧𝑒𝑑
• Customer Save Percentage: 93.3% in 2014
– Sum of Actual Customer Saves divided by Possible Customer Saves
• Cost per ACI is used to prioritize installations and optimize placements
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131
600A
SUBSTATION
RM1 480A
T1 280A
OTHER_CIRCUIT 800 CUSTOMERS 200 CUSTOMERS
Circuit Section Ranking Score
A “circuit section” is a segment of a circuit bounded by 3-phase recloser devices
Rank all circuit sections using 3-year reliability history
• 3 weighted components contribute to score
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SUBSTATION
T163 340A
CIRCUIT_A
T104 340A
CIRCUIT_X
UNIT_SUB
960A R1 680A/240A
T108 340A
CIRCUIT_Y
RM2 480A
T105 340A
CIRCUIT_Z
340A
New RM3 480A
240A
Circuit Section Scores
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0.00
500.00
1000.00
1500.00
2000.00
2500.00
3000.00
3500.00
4000.00
4500.00
SAIFI Score CI Score CEMI Score
Solid Portion SAIFI
• Entire section is experiencing multiple events
Customer Interruptions per Year
• System SAIFI Contributor
Customer Frequency Factor (CEMI)
• Pocket reliability issues
Circuit Section Analysis – Outage History
• Examine 3-5 years of fault history on the circuit to determine optimal recloser placement
• Precise fault location is determined by reading outage comments in conjunction with isolation device information
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Circuit Section Analysis – Topology & Density
• Considerations include alternate supply points, circuit topology, and customer density
• GIS trace determines upstream and downstream customer counts
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Yellow: 4kV
Blue: 13kV
Green: 34kV
Red: Circuit highlighted
Recloser Saves / Metrics
• All recloser operations are analyzed to evaluate system performance
• Mis-operations are investigated
• Correct Operating Percentage vs. Customer Saves Percentage • 2014 COP: 98.9%
• 2014 CSP: 93.3%
• Customer Saves Percentage is a more accurate predictor of future SAIFI benefit
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Recloser Process Overview
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Reliability Metrics SAIFI, CI, CEMI
Section Selection
Circuit DA Scheme & Topology
Outage History
Proposed Placement
Cost per ACI, including
Customer Saves %
Prioritization
Monitor Performance
Installation
Latest Developments
• Advanced Sectionalizing Strategies
o Load checking prior to performing circuit transfers
o FLISR: Fault Location, Isolation, Service Restoration Device logic controlled by Distribution Management System – designed to
work with existing time-overcurrent schemes
o Single-phase trip, lockout, and auto-transfer
o Expanded loss of potential monitoring capabilities Legacy devices only monitor B-phase with source transformers
o Fast Trip / No Reclose at circuit section level (rather than circuit breaker)
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In Conclusion
• PECO uses a three-pronged approach to drive SAIFI benefit from recloser installations without losing sight of the customer experience.
• PECO measures the performance of existing reclosers and utilizes this data as a means of predicting future reliability return on investment more accurately
• PECO welcomes opportunities to cooperate in the development of common measures of effectiveness of distribution automation, and to share practices and results with other utilities.
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Thank You!
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