A Method of Evaluating a Circuit Breaker for a Capacitor Bank and Suppression of Restriking Overvoltage

The difference was defined between two methods of evaluating a circuit breaker for switching a capacitor bank, i.e. 3-phase actual load testing and single- phase equivalent testing. New items which should be added to the equivalent testing were also determined. Next, the relations were discussed among the impulse withstand voltage specified by IEC, switching surge withstand voltage and overvoltage in the event of restriking. If there is a possibility of restriking occurring in the circuit breaker, it is necessary to reinforce the insulation level or add surge suppression for a certain circuit breaker voltage class. Finally, the capacitance-resistance (CR) suppressor was examined as a means to suppress overvoltage from restriking and optimum CR constants were obtained.