Abstract:

Scholars have demonstrated the necessity of installing generator circuit breaker （GCB） in large capacity generator terminal, but they did not make in depth study on whether GCB should be installed in small capacity generator （≤30   MW） terminal or feeder line. So in this paper, transient recovery voltage （TRV） of circuit breaker in small capacity generator（12-30  MW）terminal and feeder line was researched with using electromagnetic transient program PSCAD/EMTDC, under three-phase short circuit fault in the worst breaking condition. Then, this paper determined whether distribution circuit breaker could replace GCB to be installed at generator terminal or feeder line. The calculation results show that when three-phase short circuit fault occurs in generator terminal or feeder line, respectively, the TRV rising rate of circuit breaker is no more than 0.34   kV / μs, thus distribution circuit breaker can replace GCB to be installed at generator terminal and feeder line.

Key words: small capacity generator, feeder, distribution circuit breaker, generator circuit breaker, three-phase short circuit fault, transient recovery voltage