气固绝缘系统电场模型的建立与求解方法  

Electric Field Modeling and Solving for Gas/Solid Insulation System

作　　者：李乃一 彭宗仁[2] LI Naiyi;PENG Zongren(Institute of Electric Power Research,State Grid Zhejiang Electric Power Co. Ltd.,Hangzhou 310014,China;State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]国网浙江省电力有限公司电力科学研究院,杭州310014 [2]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《西安交通大学学报》2019年第6期151-160,168,共11页Journal of Xi'an Jiaotong University

基　　金：国家“863计划”资助项目(2014AA051800);国家电网公司科技资助项目(GY71-12-020)

摘　　要：针对目前气固绝缘系统直流电场计算所普遍采用的恒定电流场计算方法过于简化,尤其对于电流密度存在饱和现象的气体介质计算误差较大的问题,建立了基于介质内部和分界面上电荷驰豫过程的复合绝缘系统的电场模型,通过构建自由电荷密度方程并实时计算电荷产生的泊松场分布,获得了体电荷和界面电荷密度分布的暂态变化过程;建立了基于气体自然电离和离子迁移、扩散运动的弱电离气体的电导模型,准确表征了气体电流密度与场强的非线性关系。制作了常用于GIS/L的柱式绝缘子实验模型,测量了直流电压下绝缘子表面的电位分布,并与计算结果进行了对比,结果表明:计算得到的表面电位分布的整体变化趋势以及各电位峰位置均与测量结果吻合较好;发现弱电场下绝缘子配置嵌件时表面主要积聚同号电荷,强电场下则正好相反,同时负极性电压下的阴极发射电子过程将增大空气侧电流密度。The constant current field calculation method for calculating DC field of gas/solid insulation system is oversimplified, and especially the calculation error is larger for the gaseous media with saturated current density. An electric field model of composite insulation system based on charge relaxation processes in media and on interface is established in this paper. The transient bulk and interface charge distributions are obtained by constructing free charge density equations and real-time computing Poisson’s field. The conduction model of feebly ionized gas based on natural ionization and ion drift and diffusion is developed. The nonlinear relationship between gaseous current density and electric stress is accurately characterized. The GIS/L post insulator sample is prepared, and its surface DC potential distribution is measured. The results show that the computed potential distributions and peak locations agree well with the measured results. In the case of post insulator with an insert, homo-charge accumulates on the surface under weak electric fields, but contrary situation occurs under strong electric fields. The cathode electron emission process under negative voltage is able to increase the current density on air side.

关 键 词：气固绝缘 电荷驰豫 气体电导 表面电位测量 

分 类 号：TM216[一般工业技术—材料科学与工程]