Controlled Switching of Shunt Capacitor Banks with Vacuum Circuit Breaker

Controlled switching has been used extensively throughout the whole world for shunt capacitor banks. By precisely controlling where on the voltage waveform the contacts touch, it is possible to greatly reduce the magnitudes of the switching electrical transients. This paper presents the basic principle and the software algorithms of controlled switching for three-phase shunt capacitor banks with ungrounded neutral. The stringent performance requirement of the controlled vacuum circuit breaker with independent-pole-operated permanent magnetic actuator (PMA) and the synchronous controller based on the digital signal processor TMS320LF2407A that switching target tolerances should be within plusmn1ms was achieved. Numerous successful switching experiments on the 12kV voltage system demonstrated the well performance of the controlled switching system