Polarization and depolarization current study in polymeric insulation containing voids

Abstract

PDC testing is one of the dielectric diagnostic techniques based on time domain measurement. It is a non-destructive dielectric testing which is used to determine the conductivity of insulation. Voids are inevitable in HV insulations which can occur during manufacturing. Numerous studies have been carried out to assess the condition of solid and liquid insulations using PDC. However, such studies on voids have been found lacking. This project presents PDC studies on insulations containing voids. PDC measurements were conducted on new Silicone Rubbers (SiR) samples containing various sizes of voids as well as multiple number of voids. DC conductivity of the samples were calculated by using PDC Analyzer via LabVIEW program and the PDC curves were plotted by using MATLAB. Result from this study showed that different sizes and numbers of void affected the conductivity of SiR samples. Increasing sizes of void as well as increasing number of voids resulted in increase in polarization and depolarization currents as well as the conductivity of the SiR samples. Thus study suggests that PDC measurement can be a tool in analysing and detecting voids in solid insulation.