Breakdown characteristics of helium and nitrogen at kHz frequency range in partial vacuum for point-to-point electrode configuration

Power devices operating in partial vacuum, such as aerospace systems or space environment are susceptible to partial discharges, corona, or volume discharges due to the partial vacuum conditions. These power systems also operate under frequencies and waveforms quite different from those studied and developed for earthbound power distribution systems. In this paper, we present our studies on the breakdown characteristics of helium and nitrogen gases under positive square-pulsed voltage at frequencies varying from 50 kHz to 200 kHz in partial vacuum, for a point-to-point electrode configuration. It is observed that high frequency breakdown voltage is lower than the dc breakdown voltage under the same experimental conditions and electrode geometry. Also, breakdown voltage versus pressure curves exhibited a Pashcen like behavior. Breakdown voltages of helium and nitrogen as a function of signal frequency are also presented.