550kV GIS盆式绝缘子小型化设计(二)——介电分布优化

Compact Design of 550kV Basin-Type Spacer in Gas Insulated Switchgear(Part Ⅱ) -- Dielectric Distribution Optimization

为缩小气体绝缘金属封闭开关设备(GIS)的体积、简化生产制造工艺、降低原材料与SF_(6)气体消耗,在《550kV GIS盆式绝缘子小型化设计(一)——几何形状优化》(简称论文1)的基础上,引入介电功能梯度材料的理念,开展盆式绝缘子材料介电分布优化设计。针对接地法兰附近盆体表面电场畸变严重的问题,以均化接地法兰处电场为目标,基于拓扑优化方法构建了盆式绝缘子材料介电常数空间分布优化模型,并讨论了密度函数因子、梯度惩罚权重、介电常数上限等算法参数对于介电梯度形式及电场优化效果的影响。仿真结果表明,优化后绝缘子外法兰附近凸面一侧出现高介电常数区域,呈近似菱形的几何轮廓。此时,即使绝缘距离较原始结构减小15%,接地法兰处的电场集中现象仍可得到大幅改善。因此,该文提出的介电梯度材料,有望代替外壳倒角处的“R弧”形金属屏蔽以及绝缘子内嵌金属屏蔽环等方法进行电场分布调控,在GIS小型化改造、减少材料用量、优化工艺流程方面具有广阔前景。此外,提出了3D打印+浇注固化的小型化介电梯度盆式绝缘子制造方案,为后续研究与应用提供支撑。

To downsize the gas insulated metal enclosed switchgear(GIS),simplify manufacturing techniques,and reduce consumption in raw materials and SF_(6) 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.