Measurement and Analysis of partial discharges patterns in high voltage resin impregnated capacitors

The presence of defects in the insulating wall of high voltage capacitors can cause early deterioration of the insulating system and can lead to the degradation of electrical properties. The presence of partial discharges (PD) is considered to be one of the main causes of initiation of the degradation of the insulating wall. Accordingly, PD measurement is used as a non-destructive control test in order to assess the quality of a high voltage capacitor. It permits to ensure that the capacitors are free from defects and, in case PD are measured, it can help identifying the types of defects. In this context, the main objective of this work is the identification of Phase-Resolved Partial Discharge (PRPD) patterns and their correlation with the type of defect introduced in the dielectric wall of all-film capacitors impregnated with a thermosetting resin.