A physical model for nanosecond partial discharge

Using an ultra-wideband detection system, the characteristics of partial discharge are studied. The new detection results are different from traditional experimental results in time-domain. Based on collision ionization theory, a new physical model is put forward for analyzing the new detecting results in this paper. In new model, the second emission resulted from ion impacting cathode and photoelectron radiation is considered. The electron current and positive ion current of first ionization, electron current resulting form ion impacting cathode and photoelectron radiation in nanosecond discharge process are computed in this paper. The each generation discharge current is obtained, and a computing discharge waveform is get. The theoretical computed current waveform is no difference from the measured nanosecond discharge waveform. It is proved that the new model can interpret the detecting results better.