Investigation of Inherent Transient Recovery Voltage for Generator Circuit Breakers

The transient recovery voltage (TRV) for generator circuit breakers is investigated. The TRV for fault currents from the generator as well as from the system through the generator step-up transformers is calculated. A generalized expression for the TRV is developed and dimensionless plots made. Test results on two generating units are presented, showing good agreement with calculated values. A basis of rating for generator breaker TRV is also presented. TRV waveshapes and TRV parameters are suggested as part of the basis of rating.