Dielectric Recovery Characteristics after High Frequency Current Interruption in Vacuum Circuit Breaker

Abstract

When the contacts of circuit breaker are opened just before current zero, the gap between contacts will still be very short. Therefore, it cannot withstand recovery voltage between the contacts. In such a case, multiple re-ignition is likely to take place. Many investigators had tried clarify this phenomenon, and many reports have been published. However, high frequency current interruption and dielectric recovery characteristics are relates to some parameters (value of current, arc time etc). In addition, arc phenomenon also has been implicated. Hence, it is difficult to understand this phenomenon accurately. In this paper, we conducted dielectric recovery test and high frequency current interruption test. Further, we conducted observation experiment using vacuum chamber in order to investigate the effect of small DC current. At the end, we calculated plasma density in the electrodes after high frequency current interruption by considering the result of observation experiment and dielectric recovery test.