Effect of surface discharges on different polymer dielectric materials under high field stress

Abstract

Polymer insulation surface degradation is affected by various factors. Surface discharge is one of the factors, which occurs between an insulating material and a conductor subjected to high voltage stress, leading to quality reduction of the insulation surface. Thus, it is essential to monitor the insulation material quality. In this study, the effect of surface discharges on various polymer types was investigated, which include polypropylene (PP), low density polyethylene (LDPE) and high density polyethylene (HDPE). The characteristics of partial discharge (PD) patterns and tan delta values from each polymer type were analysed. Weibull distribution was plotted to determine the probability occurrence and to analyse PD inception voltage. A finite element model was also developed to deduce the connection between PD characteristics and the electric field distribution on each polymer type. From the simulation and measurement results in this work, a greater understanding on the effect of surface discharges on different polymer material types can be gained.