Analysis of correlation between Internal discharge in GIS and SF6 decomposition products

Gas-insulated metal-enclosed switchgear (GIS) has been widely used in high voltage power grid. At present, the most common fault of GIS equipment is internal discharge, which will bring harm to its insulation. The internal discharge of GIS equipment will cause the decomposition of SF6 gas. Therefore, in this paper, the research on the relationship between the GIS internal discharge and the SF6 decomposition products has been conducted, which is of great engineering value. Firstly, the principle of SF6 decomposition during the internal discharge of GIS equipment was analyzed, and the influence of trace moisture and oxygen in SF6 gas on gas decomposition was pointed out. GIS internal discharge model test platform was set up. Then, the detection experiments of SF6 decomposition products were carried out under different discharge quantities. The relationship between the dynamic change of the SF6 decomposition product and the discharge is obtained. The early diagnosis and prediction of sudden fault caused by discharge of GIS equipment can be realized effectively.