长间隙正极性先导放电通道电场计算方法  

A Simplified Model for Estimation of Electric Field of Positive Leader in Long Air Gaps

作　　者：黄煜彬 陈维江 贺恒鑫[1] 程晨 张宛霞 吴雨桐 车俊儒 HUANG Yubin;CHEN Weijiang;HE Hengxin;CHENG Chen;ZHANG Wanxia;WU Yutong;CHE Junru(State Key Laboratory of Advanced Electromagnetic Engineering and Technology(School of Electrical and Electronic Engineering,Huazhong University of Science and Technology),Wuhan 430074,Hubei Province,China;State Grid Corporation of China,Xicheng District,Beijing 100031,China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学电气与电子工程学院),湖北省武汉市430074 [2]国家电网有限公司,北京市西城区100031

出　　处：《中国电机工程学报》2023年第22期8977-8986,共10页PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING

基　　金：国家自然科学基金项目(51977090)。

摘　　要：正极性长空气间隙先导放电是特高压交、直流输电工程外绝缘设计以及雷电放电物理研究关注的重点。而其中连续先导通道电场特性十分关键,现有正先导通道电场工程计算方法均基于局部热力学平衡假设,不能准确计算先导通道等离子体特性。为此,该文构建连续正先导通道电离过程计算方法,结合3.0m棒–板间隙正先导通道电流数据进行仿真计算,获取先导通道半径膨胀过程。相比Gallimberti提出的经典模型,该文模型计算得到的半径扩张过程与实验测量结果更加接近。通过开展大量仿真研究,获取先导通道内约化电场与气体温度的关系,并通过添加振动–平动动能弛豫过程配分系数以及热传导损耗项修正了能量守恒方程。由此建立适用于工程计算的先导通道电场计算模型,并与经典模型进行对比。结果表明,在操作冲击与雷电冲击电压下,该文模型计算的先导通道电场值与实验结果更为接近,显著大于经典模型结果。在工程上继续沿用经典模型,将使预测的间隙50%击穿电压偏低。所作工作对于完善长空气间隙放电击穿过程和雷电上行先导过程仿真模型具有重要的参考价值。The characteristics of positive leader discharge are the primary concern of the external insulation design of the UHV AC and DC transmission systems as well as the lightning physics.The existing empirical models for the estimation of the electric field of the leader channel fail to consider the non-local thermal equilibrium(non-LTE)effect which can cause transient changes of the electric field.Aiming to consider the non-LTE effect,a numerical model is proposed in this paper.The simulated expansion process of leader radius is more consistent with the experimental results compared with the classical model.Based on a large number of simulation results,the relationship between the reduced electric field and the gas temperature of the leader channel is derived.Moreover,the transitional energy conservation equation of the leader channel is revised by adding the partition coefficient of the vibrational-translational relaxation and the conduction loss term.The proposed model is compared with the classical model.The simulation results of our model are consistent with the electric field inferred from experimental results under both switching impulses and lightning impulses.It is found that the classical model over-estimates the gas heating effect of the injected leader current,thereby leading to smaller electric field strength.Our model can be used to improve the existing leader propagation model.

关 键 词：先导放电 电场 非局部热力学平衡态 气体温度 计算模型 

分 类 号：TM855[电气工程—高电压与绝缘技术]