固有過渡回復電圧測定時の電流零点

抄録

The prospective transient recovery voltage (TRV) at current interruption for circuit breakers should be measured by using ideal circuit breaker. But, it is very difficult to measure the prospective TRV because there is no ideal circuit breaker. It is often used a vacuum circuit breaker or a diode to measure the TRV. It is difficult to decide the current zero by the arc voltage or the forward voltage drop. This paper shows the new method to decide the current zero for breaker terminal fault (BTF) interrupting condition at low voltage measurements using diode. It was found that the SiC diode is suitable to use the TRV measurement. The forward voltage drop of the SiC diode is nearly constant. The terminal voltage of the diode in BTF circuit during the current flowing is nearly constant regardless of the interrupting current. But, the terminal voltage after current interruption is varied with the amplitude of the current. The current zero is a border between the voltage constant region and varied region. We can find the current zero from the voltage waveforms by plural measurements.