Characteristic of SF6 decomposition under surface defect in GIS

The detection of gas decomposition products is an effective method to diagnose the partial discharge in SF6 insulated electric power equipment for its anti-interference ability and high sensitivity. However, surface defect is usually generated on the disc type insulator, which will menace the operation of apparatus and grid. A discharge chamber with Teflon coating inside was designed, with adjustable defect parameters and the volume nearly the same as real ones. With the assistance of gas chromatography detection system, this paper studied the decomposition characteristics of surface defects. Experimental results show that typical products include SOF2, SO2, CS2, CF4, CO2, CO, among which CS2 and CF4 are specific product. And CS2 could also be an important feature components for diagnosing…