Re-strike and Breaker Failure Conditions for Circuit Breakers Connecting Capacitor Banks

This paper addresses re-strike conditions of breakers connecting capacitor banks. Field cases are presented as related to both breaker failure and breaker re-strike conditions. A method has been presented for detecting re-strike of a breaker connecting capacitor banks. The method has been implemented and tested using both field cases and by real time digital simulation. The re-strike detection function is a cost-efficient way to monitor a capacitor breaker for signs of degradation caused by aging, inappropriate ratings, internal problems or unexpected operating conditions. Raising re-strike alarms and collecting oscillographic records in a capacitor bank relay can prevent catastrophic failures of capacitor breakers, feed into an event-driven maintenance program, and extend the lifetime of the equipment. Lowering the number of re-strikes reduces over-voltage stress on the system. Triggering events and records when detecting re-strike allows better post-mortem analysis in the case of catastrophic events caused or preceded by re-strikes.