A two-stage DC thyristor circuit breaker

Conventional thyristor circuit breaker (TCB) devices absorb virtually all the inductive energy stored in circuits during short-circuit current interruption in a single switching operation. A novel TCB device, involving two switching stages, which produces significantly lower switching overvoltage, is presented and analysed. Results of tests taken on a low voltage model and high power prototype and design criteria are examined and discussed together with cost comparisons and applications