High-efficiency condition-based maintenance of MV switchgears via an improved PD location technique

Abstract

Insulation faults on medium voltage (MV) switchgears can lead to power outages, disrupting daily domestic activities and economies. An acknowledged solution is to conduct partial discharge (PD) evaluation of MV switchgears. However, the existed PD measurement instruments difficultly identify the PD-affected switchgear in a row of switchgears, causing PD diagnosis laborious and time-consuming. Therefore, this paper develops an improved PD location technique for fast identification of the PD-affected MV switchgears. The technique is based on the time of flight (TOF) method, which detects the orientation of PD source by identifying the difference of time of arrival between the PD signals arriving at the two enabled sensors. Particularly, a time-sharing mechanism is developed to ensure the TOF method to be available for multiple sensors in order to automatically identify the exact PD-affected switchgear in a row of switchgears. The efficiency of the proposed technique was validated in three 10 kV metal-clad switchgears in laboratory.