Electret Based Partial Discharge Mitigation in High Switching Frequency PWM Voltage Systems

Electret based electric field neutralization has been reported as a novel approach to mitigate PD caused by triple points and cavities. In this study, the electret-based PD mitigation approach is assessed under the PWM voltage waveform of higher switching frequencies and higher slew rates. A set of PD experiments are conducted under high dv/dt sinusoidal PWM (SPWM) voltage stresses with an uncharged PVDF and an electret (charged PVDF). Surface discharge caused by triple points and cavity discharge caused by voids in solid insulators are measured to observe the PD mitigation performance of electret. From the PD signals recorded through a high-frequency current transformer (HFCT), PD magnitudes and repetition rates are determined, and these are compared to assess the PD mitigation performance of electrets. The PD mitigation performance of electrets under PWM voltage with high switching frequency and high dv/dt suggests that the electret-based PD mitigation approach is a potential solution to dielectric challenges in future power applications including the electrification of transportation.