Reactor circuit breaker specification

[vidima]

Is a reactor circuit breaker specified in the same way as that of a Transformer or a line? If not what special features make a different? Please help me.I have lost now two 66kV circuit breakers on the reactor even when the breaking current was far much higher and fault level was considered.

 

[cuky2000]

IEEE STD C37.015-1993 “Application Guide for Shunt Reactor switching” covers the circuit breaker for shunt reactor switching. See also C57.21 for max. overvoltage that the reactors are able to withstand.

Switching shunt reactors are associated often with current chopping that could create severe transient voltage across the Reactor and Circuit Breakers.

Current chopping is circuit breaker dependent. Typical chopping number is as follow:

- SF6 Breaker…………..15 to 25x10⁴
- Minimum Oil Bkr……….7 to10x10⁴
- Air Blast Breaker………15-25x10⁴​

Suggested strategies for reduction of the switching overvoltage and stresses are:
a- Implement synchronous switching operation.
b- Limit the TRV with parallel surge arrester with SIPL & SIWL margin >32%.
c- Avoid breaker re-ignitions during opening operation.

Good luck.

 

[scottf]

Further to what cuky said, you could also apply a TRV capacitor on the breaker to help with the TRV. Be aware of the issues associated with capacitors in parallel with reactors, especially if it is an iron core reactor.