1 The Utility Breaker Tim Heard DDC Engineer AEP Texas SWEDE 2006

2 Introduction A Utility Breaker is a spare breaker that can be used as a: Feeder replacement breaker Totalizing breaker Bus tie breaker

3 History Mid 1960’s-CPL began installing utility breakers 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)

4 SCADA 1-LINE OUT OF SERVICE

5 SCADA 1-LINE AS FDR REPLACEMENT

6 SCADA 1-LINE AS TOTALIZER

7 SCADA 1-LINE AS BUS TIE

8 PICTURE OF SWITCHES

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10 PICTURE OF SWITCHES

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13 PICTURE OF CONTROL PANEL

14 PICTURE OF SELECTOR SWITCH

15 Relay Transfer Switch

16 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.

17 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.

18 Relay Transfer Switch Operations Utility Breaker CT secondaries are shorted. Utility Breaker overcurrent relay trips remain switched to Utility Breaker trip coil.

19 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 amps  More cable work for CT and trip circuits

20 BENEFITS Huge impact on SAIDI/ CAIDI when dealing with Substation related outages Time/ Labor savings in switching for routine maintenance

21 Questions?