高压直流GIL环氧绝缘子气固界面电场分布智能调控机理与方法研究

Epoxy resin casted post and disc insulators are widely used as insulation supports for HVDC gas insulated transmission pipelines (GIL). The electrical field along gas-solid interface is seriously distorted under the combined effects of electrical-thermal stresses and transient overvoltage, which easily leads to surface flashover and interface breakdown. Traditional electrical field homogenization methods through structure optimization and material modification show more and more limitations. The steady-state electrical field distribution along the gas-solid interface under electrical-thermal stresses and its evolution process under transient conditions such as switch on-off operation and lightning overvoltage in DC GIL will be first analyzed in this project. The surface flashover mechanism of the epoxy insulator and its key influencing factors are investigated, during which the intrinsic relationship between the electric field distribution along the gas-solid interface and the surface flashover will be explored. By optimizing the nonlinear conductivity parameters of the epoxy insulator, an intelligent regulation method for DC GIL interface electrical field distribution will be proposed. The research of this project can provide experimental basis for improving the electrical strength and operational reliability of DC GIL insulators, and also has important theoretical significance for the development of HVDC gas insulated transmission pipelines.

环氧树脂浇注支柱和盆式绝缘子作为高压直流气体绝缘输电管道（GIL）绝缘支撑件，在电、热以及暂态过电压复合场作用下其气固界面电场会发生严重畸变，极易导致沿面闪络和界面击穿，而传统结构优化及材料改性均压方法局限性越发突出。本项目首先研究直流GIL电、热复合场作用下的气固界面稳态电场分布规律和通断操作、雷电过电压等暂态条件下的电场分布演变过程；分析电、热和过电压复合场下环氧绝缘子沿面闪络机理及关键影响因素，探究气固界面电场分布与沿面闪络的内在联系；通过优化环氧树脂绝缘子非线性电导参数范围，提出基于非线性电导特性的直流GIL气固界面电场分布智能调控方法。本项目研究可为提高直流GIL绝缘子沿面耐电强度和运行可靠性提供实验依据，对高压直流气体绝缘管道输电发展具有重要的理论意义。

环氧树脂绝缘子作为高压直流气体绝缘输电管道（GIL）绝缘支撑件，在电、热以及暂态过电压复合场作用下其气固界面电场会发生严重畸变，极易导致沿面闪络和界面击穿，而传统结构优化及材料改性均压方法局限性越发突出。本项目首先研究了直流GIL电、热复合场作用下的气固界面稳态电场分布规律和暂态条件下的电场分布演变过程；通过优化环氧树脂绝缘子非线性电导参数范围，提出基于非线性电导特性的直流GIL气固界面电场分布智能调控方法；采用SiC控制复合材料的制备条件实现大范围准确地调控环氧树脂复合材料的非线性系数和电场阈值。本项目研究成果在相同直流电压等级下降低气体绝缘输电管道绝缘子模型件初始表面电荷密度15%；提升长时预压后管道输电绝缘子模型件直流闪络电压20%；制备±160kV盆式绝缘子满足气密性和水压出厂测试条件。本项目研究可为提高直流GIL绝缘子沿面耐电强度和运行可靠性提供实验依据，对高压直流气体绝缘管道输电发展具有重要的理论意义。