Transient recovery voltage considerations in the application of medium-voltage circuit breakers

Medium-voltage circuit breakers can fail to interrupt three-phase fault currents when power systems have transient recovery voltage (TRV) characteristics which exceed the rating of the circuit breaker. This paper examines the application of 13.8-kV generation and load switchgear for an oil refinery in which circuit parameters as originally designed would have exceeded the 13.8-kV circuit breakers' TRV ratings had corrective measures not been taken. This paper illustrates this case and discusses the basis of TRV, how TRV is assessed, and alternative actions taken to bring circuits to within the 13.8-kV circuit breaker ratings.