Pre-Breakdown and Breakdown Phenomena in Liquid Nitrogen With a Tape–Plane Electrode Geometry

Abstract

Pre-breakdown and breakdown phenomena are investigated in liquid Nitrogen (LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) with a tape-plane electrode geometry. Different voltage waveforms are used: lightning and switching standard impulses, step impulse, and DC ramp. The influence of temperature is also investigated, by sub-cooling LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> down to 65 K. Breakdown voltage depends on polarity, gap distance, temperature, and HV waveform: the longer waveform, the lower breakdown voltage. Positive pre-breakdown streamers are about 3 decades faster than negative ones. With short duration lightning impulses, the propagation of slow negative streamers is quenched, resulting in higher breakdown voltage. In boiling conditions, slow negative streamers may propagate for long durations. Sub-cooling LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> induces a slight increase of streamer initiation voltage, and impedes the propagation of slow streamers due to condensation.