Predicting molded-case circuit breaker let-through characteristicsin an electrical system under short-circuit conditions

摘要

The authors discuss the MCCB (molded-cased circuit breaker) as acircuit element and describe one method of calculating system behaviorwith the MCCB as an element. Circuit breaker behavior in a system isdetermined using six parameters of the circuit breaker's measuredbehavior. The proposed method satisfies any condition for power factorand closing angle of fault current level within the instantaneousoperating range of the circuit breaker. As verified by tests, the methodoutputs conservative estimates of key circuit parameters relative torecommended values for safe applications