Investigation and Experimental Verification of Decomposition Components of GIS Gas Mixture under Partial Discharge Defects

The mixed gas technology of sulfur hexafluoride (SF6) gas and nitrogen (N2) gas for gas insulated switchgear (GIS) has been proven to be an effective method to the traditional GIS with single sulfur hexafluoride (SF
6
) gas, which can effectively reduce carbon emissions. However, for GIS equipment using mixed gas technology, the characteristic components of internal decomposition products under different partial discharge types are not clear. A rapid diagnosis and analysis method of internal decomposition products after partial discharge in GIS field is proposed, and four typical partial discharge defects of GIS equipment, namely metal protrusions, metal contamination on insulator surface, air gap between metal and insulator, and suspension discharge, are investigated by building a test platform, respectively. Characteristic components and the trend of discharge voltage and discharge amount, which provide a potential solution for accurate and rapid evaluation and diagnosis of equipment defects.