Increasing Partial Discharge Inception Voltage at Low Pressures Using Electrets

Electrets, which are dielectric materials capable of generating electric fields without an external voltage source, have been extensively studied in our previous research. These studies have focused on the design, fabrication, and utilization of electrets to counteract locally concentrated high electric fields and mitigate partial discharge (PD) in power electronics systems. Notably, our prior work using polymer-based electrets has shown promising results in reducing both the magnitude and frequency of PD occurrences under recurring, steep voltage transients encountered at elevated operating temperatures. However, the effectiveness of electrets in mitigating partial discharges under low-pressure conditions has remained unexplored. In our latest investigation, we present findings indicating that Parylene electrets exhibit notable efficacy in PD mitigation at low pressures. Our study involves measuring PD occurrences under steep square voltage pulses with slew rates reaching up to 75 V/ns, specifically within the pressure range of 28 kPa to 101 kPa. The results conclusively demonstrate that Parylene electrets are capable of elevating the partial discharge inception voltage (PDIV) under low-pressure circumstances.