Localization with Phase Resolved Partial Discharge Measured with High Frequency Current Transformer

Non-intrusive localization of partial discharge (PD) is an important step in the process of condition monitoring (CM) work. Localization aims to minimize the interruption to the supply grid network security, while performing the investigation and confirmation of the PD source. SP PowerGrid (SPPG) has the medium voltage (MV) network of metal-clad gas-insulated switchgears (GIS) with underground cables. With the provision of GIS individual phase cables accessible, high frequency current transformer (HFCT) is clamped to the split core cable to measure the PD conducted currents in the high frequency (HF) range and below. This paper demonstrates with case studies how CM engineers can apply HFCT at GIS and understand the basic of phase-resolved PD (PRPD) information, to narrow down the asset with the single or multiple PD sources. The localization method is simple yet practical by fully utilizing the propagation and cross-talk characteristics of PD.