Electric Filed Simulation and Structure Optimization for 40.5kV GIS Based on Finite Element Method

The electric field distribution in the Gas insulated switchgear (GIS) gas chamber is an important factor for the design of GIS structure. The electric field distribution in the GIS gas chamber should be uniform as far as possible, to avoid excessive concentration of the electric field causing the occurrence of flashover and discharge in GIS. The electric field intensity in the gas chamber is higher than its dielectric's isolating strength when SF6/N2 mixed gas is used as the insulation dielectric of the gas chamber to reduce the consumption of pure SF6, and the research in this paper aim to solve this problem. Electric-filed numerical analysis and optimal design of GIS gas chamber structure have been done in this paper. The GIS gas chamber 3D model is built in Solidworks, and finite element analysis of the model is calculated in ANSYS. Electric field numerical calculation for the gas chamber model is calculated based on the theory of electrostatic field. The calculation results show that the electric field intensities of isolated switch, earthing switch and insulation rod are excessive high, and the optimizations for its internal structure are necessarily followed, then calibrating calculations of electric field are carried on the optimized model. The calculating results convey that the electric field intensity in gas chamber decreased significantly, and the maximum value of electric field intensity is lower than the dielectric strength of alternative gas. It means that the alternative gas can meet the insulation requirements for the gas chamber after optimization.