Influence of Supply Voltage Frequency on Cavity Partial Discharge Parameters: Simulation Results

This paper presents simulation results on the influence of supply voltage frequency on cavity partial discharges (PD) parameters. The capacitance equivalent model is implemented in MATLAB® Simulink^® to achieve the results. Frequency dependent mechanisms responsible for this influence are the statistical time lag, surface and bulk conductivity, and surface charge decay and electron de-trapping. Only the first two of these mechanisms are implemented in the model to get their effect on partial discharge inception voltage (PDIV) as well as the phase-resolved partial discharge patterns. PDIV and PD magnitude increase as the supply voltage frequency is increased. Pulse repetition rate (PRR) has two trends whereby for frequencies between very low frequency to 50 Hz it increases whereas for frequencies above 50 Hz it decreases. More analysis is required to understand why these two trends behave the way they do. Modeling of the surface charge decay and electron de-trapping factor, and experimental results is recommended to validate and give more confidence and reliability to the simulation results.