Partial Discharge Localization in Insulated Switchgears by Eigenfunction Expansion Method

Abstract

A partial discharge (PD) is a well-known phenomenon particularly important in medium-voltage (MV) and high-voltage (HV) electric devices, eventually leading to failure events. Hence, PD detection and localization are fundamental in order to monitor their evolution and eventually perform some maintenance. In this paper, a totally new PD localization approach is proposed, which includes a priori information coming directly from the physics of the phenomenon. By processing the a priori information, it is possible to locate the PD sources in small (order of meters) and not homogeneous closed volumes and, at the same time, reduce the complexity of the measurement system and improve its accuracy. Here, the focus is restricted on electrical devices, such as metal-enclosed insulated switchgears (ISs). The proposed approach is based on the measurements of the electromagnetic (EM) radiation due to PDs, picked-up by few probes inside the IS volume. The a priori information concerning the EM wave propagation physics is introduced and dealt with adopting a proper eigenfunction basis defined inside the IS volume.