Analysis of Internal Discharge and Burn in 750kV HGIS Disconnector Switches

HGIS is a new type of integrated electrical equipment, structurally similar to GIS but without the inclusion of bus equipment. It has the advantage of having the bus not installed in an SF6 gas chamber but exposed, thus offering clear and concise connections, convenient installation and maintenance, flexible modular design, and high operational reliability. This paper deeply analyzes an internal fault of a 750kV HGIS disconnector switch that led to the tripping of related protection within the station. Through rigorous analysis, the root cause of the fault was accurately identified, and effective solutions and preventive measures were proposed to significantly enhance the operational reliability of the HGIS equipment within the station.