Two methods of simulating corona current pulses in SF6 under negative DC voltage

This paper presents and compares the results of two simulation methods for negative corona current pulses in SF6 at 0.3 Mpa. A needle-plane electrode configuration is constructed in a 2D axisymmetric model using COMSOL Multiphysics®. The first model is constructed based on fluid dynamics and plasma chemical reactions. The second is a simplified fluid model which reduces the whole particles and reactions into three continuity equations of electrons, positive ions and negative ions. The results show that in the first simulation, the current pulse bears a close resemblance to that in experiment, with a magnitude of 1.31 mA and a pulse-width of 48.7 ns. The second simulation can also successfully simulate the current waveform, but there exists obvious deviation from experimental current pulses in numerical values. Based on the spatiotemporal distribution of mean electron energy and charged particles, the mechanism of pulse formation is analyzed.