Transient Recovery Voltage Failures of Two 15 kV Indoor Oilles Circuit Breakers

Two recent cases of sequential failures of indoor oilless circuit breakers in power plant electrical distribution systems have demonstrated the need to establish transient recovery voltage (TRV) performance standards for such circuit breakers and to incorporate TRV analyses into the design basis of power plant electrical distribution systems. Current industry standards do not require breaker manufacturers to demonstrate or state TRV capability. Users must, therefore, establish the TRV parameters for their systems and include these data in their breaker specifications to ensure that the breakers will provide the required system protection.