基于改进饱和电流密度法的气-固界面电荷分布特性仿真研究  

Simulation Study on Charge Distribution Characteristics of Gas-Solid Interface Based on Improved Saturation Current Density Method

作　　者：刘杉 姜喆 袁书文 李杨 谢更生 王青于 彭宗仁[2] LIU Shan;JIANG Zhe;YUAN Shuwen;LI Yang;XIE Gengsheng;WANG Qingyu;PENG Zongren(State Key Lab.of Advanced Power Transmission Technol.,Beijing 102209,China;State Key Lab.of Electrical Insulation and Power Equipment,Xi'an Jiaotong Univ.,Xi'an 710049,China)

机构地区：[1]先进输电技术国家重点实验室,北京102209 [2]西安交通大学电力设备电气绝缘国家重点实验室,陕西西安710049

出　　处：《工程科学与技术》2024年第5期117-126,共10页Advanced Engineering Sciences

基　　金：先进输电技术国家重点实验室开放基金项目(GEIRI-SKL-2021-011)。

摘　　要：直流电压下气-固界面存在自由电荷积聚现象,对沿面闪络等放电行为具有重要影响,与绝缘子的安全可靠性密切相关。国内外学者对此开展了大量实验和仿真研究,已有研究表明,气-固绝缘表面电荷的来源主要有3种:固体侧的体电流、气体侧的离子电流以及气-固表面的面电流。在气体绝缘开关设备(GIS)、气体绝缘金属封闭输电管廊(GIL)等电力设备中,各关键部件的控制场强较低,正常运行时不会发生局部放电,故气体侧电荷来源主要为气体分子的弱电离,但是气体场域的对流扩散方程离散形式会出现振荡解,直接求解易导致迭代不收敛。为了解决此难题,本文提出绝缘子气-固界面电荷积聚的改进饱和电流密度计算方法,并搭建柱式绝缘子表面电荷测量实验系统,测量了常温常压下空气中柱式绝缘子在直流电压下的表面电荷积聚特性,通过对比分析,验证了仿真计算方法的合理性和准确性。结果表明:支柱式绝缘子表面在直流电压下存在两个异极性电位峰、1个同极性电位峰,且随加压时间增大,电位峰位置不变。在试样下部,气体侧电流小于固体侧电流密度,表面积聚负电荷,在试样上部气体侧电流大于固体侧电流密度,表面同样积聚负电荷;在试样中部,绝缘子表面积聚正电荷,固体侧电荷占主导因素。研究结果可为直流输电设备的设计提供理论支持。Free charge accumulation on the surface of solid insulation under direct current(DC)voltage distorts the electric field distribution on the insulator's surface,affecting discharge behavior,such as creeping flashover.Numerous experiments and simulation studies have been conducted by scholars worldwide.Current research shows that there are three primary sources of surface charge on gas-solid insulation:bulk current on the solid side,ionic current on the gas side,and surface current on the gas-solid interface.In GIS,GIL,and other power equipment,the field strength of each critical component is low,and no partial discharge occurs during normal operation;hence,the source of gas-side charge is mainly the weak ionization of gas molecules.However,oscillating solutions occur in the discrete form of the convection-diffusion equation in the gas field,which leads to non-convergence of iteration.This study proposes,for the first time,an improved saturated current density calculation method for charge accumulation at the gas-solid interface of insulators.The surface charge accumulation characteristics of post-insulators in air under DC voltage at normal temperature and pressure are measured.The rationality and accuracy of the simulation calculation method are verified by comparing and analyzing the experimental results.The results indicate that there are two different polarity potential peaks and one homopolar potential peak on the surface of the post-insulator under DC voltage.The position of the potential peak remains unchanged with the increase in voltage application time.At the lower part of the sample,the gas-side current is less than the solid-side current density,resulting in the accumulation of negative charges on the surface.In contrast,at the upper part of the sample,the gas-side current exceeds the solid-side current density,and the surface also accumulates negative charges.In the middle part of the sample,the insulator surface area gathers positive charges,driven by the solid-side charge.This research can provide t

关 键 词：表面电荷 饱和电流 HVDC系统 柱式绝缘子 优化计算 

分 类 号：TM216[一般工业技术—材料科学与工程]