Partial Discharge Characteristics of MV Switchgear Using TEV and HFCT Sensors

This paper presents partial discharge (PD) experiments for a medium voltage (MV) switchgear. Various types of defects were simulated i.e., corona discharge, surface discharge, and floating discharge inside the simulated MV switchgear. The transient earth voltage (TEV) was employed as a PD sensor to acquire the PD signals generated by the simulated PD defects. The TEV sensors were installed on the simulated metal enclosures MV switchgear to detect electromagnetic (EM) pulse radiated through such metal housing. Besides, high-frequency current transformer (HFCT) sensors were also used for a purpose similar to that of a TEV. Based on laboratory test results, it was found that when the external structural material and internal partition wall of the MV switchgear have greater insulation properties, some of the PD signals detected by the TEV sensor tend to exhibit a significant decrease in signal magnitude. The detected PD results of the simulating PD sources inside the MV switchgear will be presented in this paper. Moreover, the field test PD experiment for the MV switch gear is also reported.