Modeling the auxiliary switch of a high-voltage SF6 circuit breaker

The close-open time of extra-high voltage circuit breaker reclosing is an important parameter to ensure the second contact separation breaking capacity of “Close-Open” operation. According to statistics, the average close-open time of existing extra-high voltage SF6 breakers is about 23∼35ms, which is less than the standard time 50ms. The close and open commands are issued by auxiliary switch equipped by the operating mechanism, so the auxiliary switch is an ideal and reliable mechanism to control the close-open time. Based on theoretical mechanics and system dynamics, this paper proposes a close-open time control method using auxiliary switch, then establishes a mathematical model describing operation characteristics of auxiliary switch and optimizes its parameters. At last, the research results are verified by experiments.