The basic investigation of the high-speed VCB and its application for the DC power system

The fundamental phenomena and applications of the high-speed vacuum circuit breakers, which forced the fault current to zero, in a DC power system for railways were investigated experimentally and through simulations. The results showed the necessary performance of high-speed VCBs for DC power systems. The test circuit breaker consisted of a vacuum interrupter, a high frequency current source and a high-speed driving mechanism. The vacuum interrupter, which had the axial magnetic field electrode, was tested. The arcing period of high-speed vacuum circuit breakers is much shorter than that of conventional circuit breakers. The arc behavior between the contacts immediately after the contact separation was observed by a high-speed video camera. The effect of varying the current waveform just before current interruption was investigated and its effect on the interruption ability was quantified. The results demonstrate the interruption ability and the arc behavior of the high-speed vacuum circuit breaker. These results were applied to high-speed circuit breakers for DC power systems of railways.