Electrical endurance capability of vacuum circuit breakers: Standards and tests results for MV equipment

Electrical endurance capability of circuit breakers is mostly demanded for sound economic reasons in order to verify the cumulative energy that may be interrupted without maintenance during the lifetime of the equipment. Reliability of the vacuum circuit breakers has been proven by superior electrical endurance at short-circuits current. Standards, particularly IEC, ANSI, JT, GB, GOST, present various test programs relative to the electrical endurance E2 class ability, the differentiation between being done by the type and number of operating sequences, testing current and successful criteria to pass the test. The paper presents the electrical endurance results obtained in respect with different standard testing programs for MV circuit breaker 40kV/ 25kA.