Simulation of partial discharge under impulse voltage waveforms

A drift diffusion model is used to investigate a PD between spherical electrodes coated by a dielectric material. The model geometry is an axisymmetric analog of crossed wire experiments which have been used in the literature to investigate PD activity due to impulse voltage waveforms. The simulation shows that discharges in crossed wire arrangements are likely to form surface ionising waves over the dielectric material covering the wires. This may allows the initiation of discharges at other locations where the electric field is high along the wires. The peak apparent current of this PD was found to be highly dependent on the applied voltage and exhibited a different pulse shape to PD inside spherical voids. The results suggest a significant factor behind the high magnitude discharges observed in impulse voltage waveform experiments may be the higher triggering voltage of the PD due to the impulse waveform