Numerical Analysis of Surface Discharge due to Particles Attached to the GIS spacer

GIS 스페이서에 파티클 부착시 연면방전과 전계해석

GIS is a typical power equipment with higher reliability. It is compact and safe because all the energized parts are enclosed by a sealed cylindrical tank which is filled with $SF_6$. Generally gas insulated power equipments like GIS are designed to have sufficient electrical strength to prevent partial discharges under normal operating condition. Despite of the careful processes in manufacturing, transporting and assembling, voids or particles can be created, resulting in partial discharges at electrically weak points. The key factors causing partial discharges in GIS are; particles, voids in solid insulation, protrusions, poor contact of metal components, etc. The particle can be attached on; spacers, electrodes, internal wall of the GIS tank. It also moves in GIS freely. Most of partial discharges are likely to occur when particles are attached to spacers. In this paper, the electrical characteristics of a surface discharge were investigated under various conditions by using simulation program of FEMLAB.