An Indirect Test Circuit for Testing Vacuum Interrupters for Capacitor Switching Duty

This paper describes an indirect test circuit that was developed to test vacuum interrupter prototypes for capacitor switching duty. The test circuit consists of an 80kJ capacitor bank and an 85 mH inductor. It can supply test currents up to 900A rms followed by recovery voltages up to 90kV peak. This circuit is used to test primarily for delayed restrikes. Single phase and three phase experiments at other test laboratories on these interrupters verified the test technique for the synthetic test circuit. It is concluded that a low cost flexible synthetic test circuit can be used for developmental testing of vacuum interrupters for capacitor switching duty.