Effect of thermally stimulated discharges on partial discharges and tree growth in PMMA

Abstract

Treeing is an important aging process, which leads to electrical breakdown of solid dielectrics. A study of literature indicates that trapped charges play a significant role in the initiation and propagation of electrical tree channels. Experiments have been conducted in which charges have been modified by subjecting the samples aged by Partial Discharges (PD) to thermally stimulated discharging (TSD) procedure. Our earlier results have indicated that treeing could be characterized by PDs. The parameters of Weibull distribution are affected by the removal of charges by TSD. The parameters of Weibull distribution are correlated to one another and with time of aging. The parameters also respond to TSDs. Several Weibull plots, TSD curves and a number of microphotographs have been studied. In this work, the variation of bush growth with respect to aging time and variation of charge input with respect to aging time have been investigated.