Investigations on control tactics of phasing vacuum switches when synchronized closing capacitor banks

Capacitor banks are usually used for reactive power compensation in power system energized by a vacuum switch which often results in a surge current and overvoltage in the system. The phasing vacuum switch is an intelligent switch with electronic driver system based on permanent magnetic actuators, that means their interrupter closing at the voltage zero point and energizing the capacitor banks synchronized with the AC system. Interaction of the phasing switch with the system when energizing the capacitor banks was discussed first. Based on an ungrounded neutral capacitor bank system, the optimal closing opportunity was proposed. Simulation gives the allowed control scattering. Based on a separated-phase vacuum switch with permanent magnetic actuators, experimental results showed the effectiveness of the control tactics, and also proved the system can energize the capacitor banks synchronized with AC system.