Identification, Prioritization, and Placement of Automatic Sectionalizing Devices

July 27th, 2015

John Reid, Joseph Viglietta

PECO Reliability Programs

1

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

3

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

9

Circuit Section Analysis – Topology & Density

• Considerations include alternate supply points, circuit topology, and customer density

• GIS trace determines upstream and downstream customer counts

10

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

12

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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