Void Partial Discharge Simulation Under a Repetitive Frequency Square Wave with Different Overshoot Rates

Long-term partial discharge (PD) erosion is an important factor causing insulation failure. With the rapid development of power electronics and the widespread application of inverters, more insulation is subjected to repetitive frequency square wave signals. To understand the void PD characteristics of insulation subjected to repetitive frequency square wave signals, a finite element simulation model of void PD is established based on the ABC model. A time-domain waveform and a phase-resolved partial discharge (PRPD) plot of void PD under repetitive frequency square wave with different overshoot rates are simulated. Then, void PD is measured under different overshoot rates and compared with the simulation results. Finally, the influence of overshoot voltage on internal discharge is analyzed. The simulation and experimental results show that the overshoot rate positively correlates with statistical characteristics, such as the average PD number and maximum PD quantity. Void PD events mainly occur in the overshoot portion of the repetitive frequency square wave. Therefore, the overshoot portion of the repetitive frequency square wave is one of the key factors contributing to severe PD in insulation.