Optimal Design of a Permittivity Graded Spacer Configuration in a Gas Insulated Switchgear

The relaxation of the electric field intensity can be expected when a functionally graded material (FGM) with various permittivity distributions is applied to the spacer of a gas insulated switchgear (GIS). We calculated the electric field strength in the FGM spacer model of a common GIS by using the finite element method (FEM). Based on the results in this paper, a rapid permittivity variation has a tendency to relax the electric field concentration near the anode and to improve the uniformity of the internal electric field distribution in the FGM spacer. In addition, the design of experiment (DOE) method was used to design an optimal spacer configuration where the electric field along the surface of the spacer was smaller and more uniform. Consequently, a FGM spacer is more efficient than a single permittivity spacer for improving insulation performance.