Synchronized energization of shunt capacitor banks based on statistical characteristics of vacuum circuit breakers

Operation of switching capacitor banks always produce over voltages and inrush currents, which may be harmful not only to the capacitor hanks themselves but also to other adjacent components of the system. Synchronized closing has been proved an efficient solution to reduce switching surge. In the present study, a l2kV vacuum circuit breaker (VCB) with permanent magnet actuator for each pole is used as the shunt capacitor switch. The influences on synchronized energization of circuit breaker's statistical characteristics, like contact operation time scatter, and the rate of decrease of dielectric strength (RDDS) of the electrode gap are discussed. The optimum closing instant is calculated according to these characteristics of VCB. Based on above analysis, a controlled closing system for shunt capacitor banks has been developed. A series of experiments demonstrate the excellent performance of this system.