AN INNOVATIVE METHOD OF PROVIDING TOTAL BREAKER FAILURE PROTECTION

Breaker failure relaying has been generally achieved through the use o f a current monitoring relay to determine whether current continues to flow into a fault after a breaker has been instructed to interrupt th e circuit. If current continues to flow after a predefined period of t ime, the circuit breaker is considered to have failed. Steps must then be taken to trip the next set of upstream breakers in the power syste m to remove the faulted circuit and prevent system damage. However, wi th industrial power systems, this may be the utility's breakers on the feeding transmission line. Regardless, breaker failure schemes must b e designed to isolate both the faulted circuit and the failed circuit breaker. This paper discusses a new and innovative method of protectin g a circuit breaker from the failure described above, plus other failu res that go unprotected with conventional schemes, thus providing ''to tal'' breaker failure protection.