Electrets: A Remedy for Partial Discharge Caused by Power Electronics Switching

In this article, a novel approach that mitigates partial discharge (PD) by neutralizing local electric fields with the incorporation of electrets is presented. The surface charge density requirement of electret films that enable electric field neutralization is derived and numerical analysis is performed to validate them. The fabrication process of electrets is introduced, and we experimentally demonstrate the electret films reducing PD caused by the high
dv/dt
of power electronics switching voltage stimuli for the first time. The PD measurements of an uncharged polyvinylidene fluoride (PVDF) film and a charged PVDF (electret) film are compared as a function of the rise time of square voltage stimuli. In addition, we compare the PD inception voltage of the two films while maintaining
dv/dt
at a constant value to regulate the impact of capacitive current pulses falsely being detected as PD. The results show great promise in the electret-based approach and suggest that further development of the technology may be able to completely solve PD that has been both chronic and emerging issues in the power industry.