Modelling partial discharges in an insulation material at very low frequency

As very low frequency high-voltage testing is becoming more popular, it is essential to simulate partial discharges in an insulation material at such frequency to investigate physical activities. In this study, measurement data of partial discharges in a cylindrical void bounded by an insulation material were recorded under both 50 Hz and 0.1 Hz excitation for fitting the simulation model. The developed model was based on several physical parameters such as electron surface emission rate, electron volume ionization rate and surface charge decay constant. Simulation results show that differences of discharge characteristics at both frequencies might be due to effects of charge decay constant. Charge decay plays a significant influence on partial discharge patterns at 0.1 Hz whilst it hardly affects discharge pulses at power frequency.