Optical emission characteristics of helium breakdown at partial vacuum for point to point geometry

In general, power devices and systems operating in vacuum or space environment are more susceptible to partial discharges, corona, or volume discharge due to the partial vacuum conditions. Partial discharge and breakdown measurements have been performed on electrical equipment operating in such environments for over decades. In spite of all the studies, fundamental understanding of partial discharge or corona initiation has not been understood completely. Various means of detection have been used over the years, including the detection of electromagnetic emissions using antennas or by observing the current through the ground cables to obtain a better understanding. The measurements are usually analyzed together with other techniques like visual inspection, transient voltage/current measurements and acoustic/optical characteristics. In this paper we present our work on optical emission characteristics of breakdown events at partial vacuum for point-to-point electrode configuration, operating at 20 kHz frequency in helium. A DC-offset-AC voltage source was used for the high frequency experiments. Preliminary data of voltage and current waveforms along with the light emission data are presented. Optical data collected by a video camera is analyzed and the R/G/B emission characteristics as a function of time are presented.