Partial discharge modeling: an improved capacitive model and associated transients along medium voltage distribution cables

The presence of partial discharges is one of the most prominent indicators of defects and ongoing degradation processes of electrical insulation. As a high percentage of failures are associated with partial discharges, the need for the classification, extraction and evaluation of partial discharge signals is essential. Consequently, an electrical model of a breakdown void, modeled as part of the power system, is more than a necessity. In this paper an improved capacitive model of void based on streamer concepts is proposed for the study of the transients generated at the void location. Further, the high frequency model of the cable is employed in order to examine the propagated partial discharge simulated transients of the improved capacitive model. The simulated transients of both models are compared and discussed on a theoretical basis.