Mitigating Space Charge Accumulation at Various Temperatures Using Electrets

Under medium and high voltage direct current (HVDC), space charge builds up near electrodes in insulating materials. Charge accumulation increases electric stress, alters electric field, shortens the usable life of insulating materials, and lowers partial discharge inception voltage, all of which negatively impact the dielectric integrity of power applications. In this study, we numerically demonstrate the effectiveness of electrets in mitigating space charge accumulation in dielectric materials by analyzing their steady-state responses. Additionally, the effects of temperature on space charge accumulation in dielectric materials with and without electrets have been investigated. All Models have been constructed in COMSOL Multiphysics for numerical analysis. To simulate space charge injection and accumulation in dielectric both with and without the use of electrets, a bipolar charge transport model has been utilized. To clearly visualize the validity of electrets, steady-state space charge analysis has been performed. The steady-state results show that electrets can prevent space charge accumulation and injection in dielectric materials. Furthermore, the temperature analysis results show that space charge injection and accumulation intensify with rising temperature.