Metal particle contamination in gas-insulated switchgears/gas-insulated transmission lines

Metal particle contamination in a gas-insulated switchgear (GIS) or a gas-insulated transmission line (GIL) is an important factor leading to the decline of insulation performance. Exploring the deterioration mechanism and suppression measures of metal particles on insulation is a key technical problem in enhancing the dielectric strength of GIS/GIL equipment. In this paper, the charge and motion characteristics of metal particles are first introduced. The gas gap breakdown caused by free metal particles and the surface flashover caused by metal particles near or adsorbed on the insulator are then analyzed according to different particle motion patterns and spatial locations. Subsequently in terms of operation managements, the existing methods of particle detection are analyzed. In addition, the main inhibition methods of metal particles are introduced from three aspects: particle trap, insulator surface treatment and electrode coating. Finally, the prospects in the future research on particle pollution in GIS/GIL are also pointed out.