Study on the characteristics of insulation recovery of the repetitive-rate gas spark gap

The characteristics of insulation recovery were tested by using a two-pulse circuit technique, in which, the first pulse breaks down the gap, and the second pulse determines the recovery of switch. The recovery of the spark gap is defined as a ratio of the second pulse average breakdown voltage to the first pulse average breakdown voltage for each two-pulse burst. It was found that (1) under static condition (no gas blown), the hydrogen gas allows the recovery time to be an order-of-magnitude shorter than that of nitrogen gas; (2) under the condition of gas flow, significant improvement in gas insulation recovery was observed when the velocity of gas flow increases to 4m/s.