The Application of High Frequency and Ultra High Frequency Partial Discharge Detection to Gas Insulated Switchgear

Partial discharge (PD) charged detection is one of the important means to determine the internal insulation condition of gas insulated switchgear (GIS) equipment in extra high voltage (EHV) substations. Through PD charged detection, equipment defects can be detected and warned in advance to avoid further development of PD leading to equipment and grid failure. This paper introduces a GIS arrester PD defect found by applying GIS online monitoring system, using high-frequency (HF) and ultra-high-frequency (UHF) methods to discover abnormal signals of GIS equipment, and tracing and analyzing the abnormal signals. Based on the traditional discharge type identification technology, a deep learning-based PD type identification technology is proposed. The PD type is identified using HF and UHF mapping features, and the location of PD is precisely located using sensor time delay characteristics. Finally, the disassembly analysis of GIS equipment verifies the effectiveness of the GIS online monitoring system, while avoiding the further development of PD leading to serious accidents of unscheduled bus outages. This paper also provides some reference and experience on GIS charged detection as well as operation and maintenance.