Partial Discharge Characteristics of Void Defects in Epoxy Insulation

A void in a GIS spacer can lead to serious dielectric breakdown during operation. There are significant differences in partial discharge (PD) characteristics depending on the size of voids. In this paper, we designed three different spherical voids in an epoxy insulation to evaluate PD characteristics, and analyzed partial discharge inception voltage (PDIV), partial discharge extinction voltage (PDEV), apparent charge (q), number of pulse (n), and PD patterns. From the experimental results, PDIV and PDEV increased rapidly as the diameter of void increased. The q and the n in the same electric field were larger and more frequent as the diameter of void increased. However, there were not significant differences in the PD patterns.