Dielectric Strength Recovery After Gas Arcs of Low-Voltage DC Hybrid Interruption

Investigating the post-arc dielectric strength recovery characteristics is essential for dc hybrid interruption, because a successful interruption in a hybrid dc switch is determined by the competition between the power system recovery voltage and post-arc dielectric strength recovery voltage. Based on a review of previous studies, related research is inadequate in the recovery of gas dielectric strength and research on the contact opening process is lacking. In order to investigate the influence of the rate of current reduction d i dt , arcing time, and electrode material on the breaking capacity of low-voltage dc hybrid switches, the dielectric strength recovery was measured after the quenching of gas arc. An experimental circuit and a pulse voltage generator were used to measure the post-arc dielectric strength recovery characteristics. The experimental results indicate that decreasing di/d t or the arcing time increases the dielectric strength recovery speed. However, there is a critical arcing time in the contact opening process that results in the fastest dielectric strength recovery speed. The optimal range of recovery time is proposed, which is an important parameter for the design of low-voltage dc hybrid switches.