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The Utility Breaker Tim Heard DDC Engineer AEP Texas SWEDE 2006

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Introduction

A Utility Breaker is a spare breaker that can be used as a:

Feeder replacement breaker Totalizing breaker Bus tie breaker

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History

Mid 1960’s-CPL began installing utility breakers

1994- Utility breakers removed from substation design standard

Today- 41 Utility breakers available for service in TCC (old CPL)

0 Utility breakers in TNC (old WTU)

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SCADA 1-LINE OUT OF SERVICE

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SCADA 1-LINE AS FDR REPLACEMENT

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SCADA 1-LINE AS TOTALIZER

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SCADA 1-LINE AS BUS TIE

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PICTURE OF SWITCHES

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PICTURE OF SWITCHES

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PICTURE OF SWITCHES

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PICTURE OF CONTROL PANEL

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PICTURE OF SELECTOR SWITCH

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Relay Transfer Switch

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Relay Transfer Switch Operations

Utility Breaker CT secondaries are switched to Utility Breaker overcurrent relays.

Utility Breaker relay trips are switched to Utility Breaker trip coil.

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Relay Transfer Switch Operations

Utility Breaker CT secondaries are switched to #3 Transformer Differential Relays and #3 Transformer Totalizing relays.

#3 Differential trips and Totalizing trips are switched to Utility Breaker trip coil.

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Relay Transfer Switch Operations

Utility Breaker CT secondaries are shorted.

Utility Breaker overcurrent relay trips remain switched to Utility Breaker trip coil.

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Utility Breaker Cost

Installation costs is 40%-50% higher than feeder breaker due to: 1- Utility Breaker or 2- Feeder

Breakers can fit in standard 20’x20’ bay

Breaker, risers, and switches rated for 2000 amps vs. 1200 amps

More cable work for CT and trip circuits

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BENEFITS

Huge impact on SAIDI/ CAIDI when dealing with Substation related outages

Time/ Labor savings in switching for routine maintenance

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Questions?