Analysis of Factors Influencing the Internal Insulation Performance of GIS Equipment Based on Multiphysics Coupling

Internal overheating and excessive micro-water content can lead to the degradation of insulation performance in gas insulated switchgear (GIS) air chamber and cause faults. In order to solve those problems, methods to detect the internal overheating fault and to reduce the micro-water content in GIS air chamber were discussed in this paper. With the finite element analysis software, a heat-fluid-solid multiphysics coupling simulation model of GIS equipment was built. The temperature rise distribution of GIS air chamber and its shell was calculated and thus a scheme of calculating the internal temperature rise from the shell temperature rise was proposed. According to the relationship between temperature rise and micro-water content in the air chamber, the influence of the micro-water content on the gas insulation performance was discussed. Based on that, a scheme to reduce micro-water content by the drying-treatment of nitrogen-washing and heating was proposed. Both schemes were verified by experiments. Finally, a joint maintenance program for GIS internal overheating faults detection and micro-water content control was raised.