Field breaker tripping options for generator static excitation systems with AC field circuit breakers - A case study

Short circuit contributions from synchronous generators can persist for several seconds even after the field circuit breaker is opened. Delayed tripping of an AC field circuit breaker can allow faster reduction of generator field current in some circumstances. Faster reduction of generator field current will reduce the energy in a short circuit and consequently reduce the damage caused by the short circuit. This paper describes a case study examining the issues associated with the decision to delay tripping of AC field circuit breakers.