Preventing Space Charge Accumulation by Incorporating Electrets

Abstract Space charge accumulates near electrodes in insulating materials under high voltage direct current. Electric stress created by charge accumulation distorts electric field, reduces the remaining useful life of insulating materials, and decreases partial discharge inception voltage that are critical for ensuring the dielectric integrity of power applications. In this article, a novel approach that mitigates space charge accumulation using electrets is presented. Electrets are used to reduce electric fields that cause charge injection and space charge accumulation in dielectric materials. The validity of using electrets for preventing space charge accumulation is numerically and experimentally demonstrated. Bipolar charge transport model is developed to simulate space charge injection and accumulation in silicone rubber without and with the incorporation of electret. Space charge experiments are performed to confirm the numerical results. The results show that electrets can effectively mitigate space charge accumulation in dielectric materials. The results also show that the incorrect use of electret such as reversing the polarity can lead to more substantial space charge accumulation.