Research on the Factors Influencing the Post-arc Current in Vacuum DC Interruption

As a research hotspot of power switches in recent years, DC circuit breaker will be widely applied in DC and AC/DC systems in future. The post-arc current, as a main characteristic of the post-arc zero zone, can reflect the breaking capacity of the circuit breaker. In this paper, a 60kV DC syntheic circuit platform was set up, and the DC breaking test was performed by the method of artificial current zero. Based on the principle of current transferring, the method for measuring the post-arc current was designed. The factors such as zero-zone parameters, opening speed and arcing time influencing the post-arc current in vacuum DC interruption were investigated. Based on the experimental results, this paper considers that the first peak of the post-arc current traces the change trend of di/dt, and the second peak appears when dv/dt reaches a certain value. The larger the dv/dt, the more obvious the second peak. At the same time, the post-arc current decreases with the increase of the opening speed of the circuit breaker, and increases when the arcing time gets shorter.