Flashover characteristics over solid/liquid interfaces under repetitive nanosecond-pulsed voltage

Abstract

The incipient experimental results, flashover on the surface of PMMA (polymethyl methacrylate) and nylon in transformer oil under repetitive nanosecond pulse voltage, are presented here. During lower frequency of applied pulse voltage, both FST (flashover stressing time) and flashover field strength decline nonlinearly in according with the increase of pulse frequency applied. Then as applied pulse frequency surpasses some threshold value, the declining trends of both are slowed. FST is curtailed and distributes more regularly for statistics. It is inferred that, in different experimental conditions, flashover field strength is lower under repetitive pulse voltage than under simple pulse voltage, and both decrease nonlinearly with applied pulse frequency increasing, furthermore the declining extent is bated with the continuous increase of applied pulse frequency. The longer FST is, the easier surface flashover is, which is indicated by the event that flashover field strength declines with repetitive pulse frequency, as a result the stressing time not the magnitude of applied repetitive pulse voltage is, to some extend, an essential element of flashover.