The presence of free conductive particles in GIS is the greatest threat to GIS insulation. How to detect foreign matter defects in GIS

especially free conductive particles

is one of the problems to be urgently solved to improve the reliability of GIS equipment. Consequently

we established a research platform of partial discharge of free conductive particles in GIS

and analyzed the relationship between the partial discharge signal and the particle motion caused by free conductive particles. The theoretical phase resolved partial discharge pattern was deduced

which is in accordance with the experimental results. According to the model

the identification method for free conductive particle defects in GIS was proposed

and the effectiveness of free conducting particles defects in GIS was studied. The results show that the phase resolved partial discharge of free conducting particles in GIS is a sinusoidal envelope band. The pattern shows strong symmetry

low repetition rate and full phase distribution. The on-site power-frequency partial discharge tests can be performed to detect free aluminum particles less than 1 mm

and are highly effective in detecting the free conducting particles defects in GIS. This study provides theoretical support for the identification of free conductive particles defect in GIS.