基于表层梯度电导调控的直流三支柱绝缘子界面电场优化方法  

Interfacial Electric Field Optimization of DC Tri-Post Insulator Based on Gradient Surface Conductance Regulation

作　　者：胡琦 李庆民 刘智鹏 刘衡 AManu Haddad Hu Qi;Li Qingmin;Liu Zhipeng;Liu Heng;AManu Haddad(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing,102206,China;Beijing Key Lab of HV and EMC,North China Electric Power University,Beijing,102206,China;Advanced High Voltage Engineering Research Centre,Cardiff University,Cardiff,CF243AA,UK)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206 [2]北京市高电压与电磁兼容重点实验室(华北电力大学),北京102206 [3]先进高压工程研究中心(卡迪夫大学),卡迪夫CF243AA

出　　处：《电工技术学报》2022年第7期1856-1865,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51737005,51807060);北京市自然科学基金(3202031)资助项目。

摘　　要：气-固界面和嵌件-环氧界面的电场强度集中效应被认为是导致直流三支柱绝缘子发生沿面闪络和支腿炸裂的重要原因,传统的结构优化难以同时有效调控两个界面的电场分布,迫切需要更合理的调控手段。通过电-热-流多物理场仿真,研究直流三支柱绝缘子界面电场分布特性,指出电荷积聚是造成界面处场强集中的主要原因。据此提出基于“类U型”梯度电导的绝缘子双界面电场联合调控策略,通过嵌件-环氧界面高电导涂层和气-固界面非线性电导涂层的协同使用,使得三支柱绝缘子体电导和表面电导呈“类U型”梯度分布,可降低绝缘子内部及表面电荷积聚程度,从而优化界面电场分布。进一步研究双界面涂层对直流三支柱绝缘子界面电场的调控作用,并针对电场调节与损耗控制目标,实现对涂层电导参数的优化。研究结果表明:当嵌件-环氧界面涂覆材料电导率不小于10^(-12)S/m、气-固界面非线性电导材料参数处于“临界饱和线”上时,支柱绝缘子嵌件-环氧界面最大电场强度可从4.48kV/mm降至0.04kV/mm,气-固界面最大切向电场强度从2.47kV/mm降至1.73kV/mm。参数优化后的双界面梯度电导涂层,可使界面电场集中效应得到有效抑制,同时将绝缘子最大电场与功率损耗控制在允许范围内,为高压直流三支柱绝缘子的优化设计提供了基础依据。Electric field concentration at the gas-solid interface and the insert-epoxy interface is considered to be the principal culprit that leads to surface flashover and outrigger burst of the DC tri-post insulator.Previously available structure optimization encounters difficulty in effectively addressing the electric field distribution of the two interfaces simultaneously,which poses imperative challenge for practical solutions.In the proposed research of this paper,the electric field distribution characteristics of the DC tri-post insulator interfaces were studied by electric-thermal-fluid multiphysics simulations,which indicated interfacial charge accumulation contributed most of the electric field concentration.A joint control strategy of electric field for dual-interfaces of the tri-post insulators based on"U-shaped"gradient conductance was proposed.Through synergistic utilization of high-conductivity coating for the insert-epoxy interface and non-linear conductivity coating for the gas-solid interface,the bulk conductance and surface conductance of the tri-post insulator present a"U-shaped"gradient distribution,which will reduce the internal and surface charge accumulation of the insulator,thereby optimizing the interfacial electric field distribution.The regulation effect of the dual interfacial coatings on electric field concentration was then studied,and the conductivity parameters of the coatings were optimized based on hybrid regulation targets for both electric field and power loss control.The presented research showed that,if the insert-epoxy interface coating conductivity was controlled less than 10^(-12)S/m and the nonlinear gas-solid interface coating conductivity was well above the"saturation critical line",the maximum e-field strength of the insertepoxy interface decreased from 4.48kV/mm to 0.04kV/mm,while the maximum tangential field strength of the gas-solid interface decreased from 2.47kV/mm to 1.73kV/mm.Parameter-optimized dual interfacial gradient conductance coatings can effectively suppress th

关 键 词：直流气体绝缘金属封闭输电线路(GIL) 三支柱绝缘子 界面涂层 梯度电导 界面电场优化 

分 类 号：TM216[一般工业技术—材料科学与工程]