550kV GIS盆式绝缘子小型化设计(二)--介电分布优化

To downsize the gas insulated metal enclosed switchgear (GIS), simplify manufacturing techniques, and reduce consumption in raw materials and SF₆ gas, concept of functionally graded material was introduced, and the design of graded dielectric distribution for basin-type spacer was conducted based on the research "Compact Design of 550kV Gas Insulated Switchgear (Part one) -- Structure Optimization of Basin-type Spacer" (abbreviated to paper No. 1). Aiming at the problem of spacer's surface electric field distortion at flange side, a topology optimization model of spatial distribution in relative permittivity was built to relieve corresponding electric field intensification in and around the basin insulator. Moreover, influences of several algorithm parameters on the permittivity distribution and electric field optimization results were discussed, which includes the density function coefficient, the gradient penalization weighing factor and the permittivity's upper limit. Simulation results exhibited that a high permittivity area with a rhombus size was presented at the convex side of the outer flange region. Resultantly, the electric field distribution at the flange side is greatly improved even if the insulation distance is reduced by 15%.Therefore, the functionally graded material can replace "R" shape shielding corner added at the outer vessel and the metal shield ring embedded inside the spacer, which is potential in downsizing GIS devices, reducing materials/gas consumption and optimizing manufacture process. Moreover, a fabrication approach based on stereolithographic 3D printing and resin casting is proposed for the corresponding basin insulator, supporting the further experimental and industrial investigation.