Electret: A Method to Increase Critical Flashover Voltage in Power Dense Applications

Abstract

Surface flashover in medium to high voltage devices and in power-electronics-driven applications is a challenge that threatens the dielectric integrity of emerging technologies. The risk of surface flashover is increasing in many of the latest applications owing to their high voltage rating, high power density, and high dv/dt. Therefore, it is necessary to improve the critical flashover voltage (CFO) for enhanced dielectric robustness. In this study, a novel technique to increase insulator CFO with the incorporation of electret film on dielectric surfaces is proposed. The CFO of insulator with and without the incorporation of electret films is compared experimentally. The electret-based approach increases the CFO by either acting as a potential barrier that impedes surface charge migration or by reducing the local electric field near the triple point.