特高压GIS用单支撑绝缘子绝缘结构优化设计

Optimization Design of Insulation Structure for Post Insulator in UHVAC GIS

单支撑绝缘子是气体绝缘金属封闭开关设备(GIS)中重要的绝缘支撑结构,其性能优劣影响着GIS运行的可靠性和稳定性。该文开展了1100kV GIS用单支撑绝缘子的结构优化研究,选取绝缘子表面合成电场强度、绝缘子表面切向电场强度、金属嵌件表面合成电场强度作为性能指标,分析绝缘子伞裙和金属嵌件各自的关键结构参数对性能指标的影响规律,采用自适应变异的粒子群算法进行整体优化。在此基础上,提出了基于贝塞尔曲线的绝缘子表面轮廓描述方法,选取整体优化后电场畸变严重的绝缘子伞裙底部圆角结构开展局部精细化优化。优化结果与原始结构相比,金属嵌件表面电场强度下降24.2%,绝缘子表面合成电场强度下降25.6%,绝缘子表面切向电场强度下降22.6%。该文提出的参数整体优化和贝塞尔曲线局部精细化优化的分步优化方法,使特高压GIS用单支撑绝缘子的绝缘性能得到了显著提高,优化结果能够为GIS单支撑绝缘子的结构设计提供参考。

With the gradual promotion of“peak carbon dioxide emissions”and“carbon neutrality”,the demand for long-distance and high-voltage power transmission is also growing.The safe and reliable operation of gas insulated switchgear(GIS)equipment is an important factor to ensure the stable transmission of power.Post insulator is an important insulation structure support for GIS,the performance affected the reliability and stability of GIS in operation.Its structural characteristics make it not only have complex contours tangent to multiple circular arcs,but also needs to consider its insulator umbrella skirt which may bring about various optimized structural forms,many parameters to be optimized,and difficulties in overall optimization.To address these issues,this paper proposes a method to optimize the design of insulation structure for the post insulator used in UHVAC GIS.The insulation performance of post insulators for UHVAC GIS is significantly improved by a multi-step optimization method of total parameter optimization and local refinement optimization of the Bessel curve.Firstly,the finite element simulation calculation model of the 1100kV UHVAC GIS post insulator is established,and the insulator electric field distribution under lightning surge voltage can be calculated and obtained.According to the actual structure of the post support insulator,the outer contour of the post insulator and the outer contour of the metal inserts are parameterized.The maximum value of the total and tangential electric field of the post insulator surface as well as the electric field strength of the metal insert surface are defined as optimization indexes,and the influence law of different structural parameters on the performance indicators is analyzed.Particle swarm optimization with adaptive mutation is used to optimize the parameters.After calculating the insulator’s electric field distribution after the total parameter optimization,optimization indexes are reduced by more than 10%compared with the original structure.Based on this,local refinement optimization of the Bessel curve is used to carry out local optimization for the rounded bottom of the insulator umbrella skirt,where the field distortion is more serious.Compared with the original structure,the total and tangential electric field strength on the insulator surface of the optimized structure has been reduced by 25.6%and 22.6%.The insulation performance of post support insulators for UHVAC GIS has been significantly improved after the total parameter optimization and local refinement optimization.The following conclusions can be drawn from the simulation analysis and structure optimization:①the maximum value of the electric field strength of the existing post insulator appears at the rounded corner of the bottom of the umbrella skirt;the maximum value of the electric field strength on the surface of the metal inserts appears at the rounded corner of its edge.②The study of the law of insulator structure parameters on each electric field strength maximum found that the metal insert structure parameters not only affect its surface electric field strength maximum,but also will change the insulator surface electric field distribution;adjusting the insulator skirt distance from the high-voltage conductor,the tangential distance of the umbrella skirt,and the bottom rounded corner basically only change the insulator surface electric field strength,and the rest parameters have different degrees of influence on each performance index.③Using the multi-step optimization methods of total parameter optimization using particle swarm optimization with adaptive mutation and local refinement optimization of the Bessel curve,the improved structure of the post insulator of UHVAC GIS is obtained.Compared with the original structure,each electric field strength index of the optimized insulator is reduced by more than 20%.