Critical separation and dielectric recovery of phasing vacuum switches when synchronized breaking short-circuit current

The phasing switch is one of the intelligent techniques for vacuum switches, that means their interrupters closing at the voltage zero point and opening at the current zero point of AC system. The electronic driver system based on permanent magnetic actuators ensures the switch keeps synchronism with the AC voltage or current. A fast permanent magnet actuator designed for phasing vacuum switch was introduced firstly in the paper, some measurement results were given for maximum initial opening speed and operation time scattering. Based on the characteristics of phasing switch, the dielectric recovery characteristic for short gap vacuum arc were discussed, a vapor density model was proposed under the special boundary conditions. Short-circuit current breaking tests showed the meaningful parameters of phasing switch and gave out the region of critical separation under certain system voltage and current, that provides some theoretic and experimental proofs for the design of control system of phasing switches.