Review on accelerated degradation mechanisms of electrical insulation in power electronic equipment under the pulsed electric field

Due to prolonged exposure to pulsed voltage during operation, the insulation systems of power electronic equipment are susceptible to premature degradation and failure, which seriously affect the operation of the power system. Therefore, it is important to explore the accelerated degradation mechanisms of electrical insulation under the pulsed electric field. In this paper, the influence of different pulse voltage parameters on insulation degradation characteristics is first summarized. Then, the research progress of the degradation mechanisms of insulation under a pulsed electric field is explored from microscopic and macroscopic perspectives. Three degradation mechanisms, including the dynamic behavior of charges, electromechanical stress and air gap discharge, are revealed, whose microscopic essence is the difference in the response time of charged particles of different scales under a pulsed electric field. In addition, the weaknesses of the current research are also identified and discussed. This review provides a theoretical reference and guidance for the optimal design of insulation materials.