雷击输电线路上行先导起始与发展特性模拟试验研究  

Simulating Experiment Based on the Initiation and Propagation Characteristics of Upward Leader from Transmission Lines

作　　者：李志钊[1] 曾嵘[1] 庄池杰[1] 陈赦[1] 廖永力 高超 

机构地区：[1]清华大学电机工程与应用电子技术系,北京100084 [2]南方电网科学研究院有限责任公司,广州510080

出　　处：《高电压技术》2012年第8期2076-2082,共7页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2011CB209403);国家自然科学基金(50777035)~~

摘　　要：上行先导是分析雷电绕击输电线路的关键因素之一,由于雷电放电的随机性,鲜有输电线路上行先导的直接影像资料,因而上行先导是否存在是电力系统防雷研究的一个热点。现有的上行先导仿真计算模型主要由棒-板及热力学的结论间接推导所得,缺乏实际输电线路的实验依据。在昆明国家特高压实验基地对输电线路上行先导起始及其发展特性开展了模拟试验研究,经过仿真分析,设计并采用5～8m的板棒-线间隙进行模拟试验,施加最高达3.6MV、200/2 000μs波前的冲击电压,利用最高拍摄速度为106帧/s的高速摄像机对放电过程的放电形态进行观测,利用3dB带宽范围为0～6.5MHz的同轴分流器进行了电流测量。通过500余次试验及其结果分析,发现在该试验条件下,导线和地线上明显有上行先导产生,其发展速度约为1.2～3cm/μs,与正极性操作波下棒-板间隙放电的先导速度基本一致。仿真分析发现,大多数自然雷情况下,输电线路临界半径处场强高于上行先导起始场强的时间比该文试验工况中更长,因此推断自然雷击输电线的过程中上行先导是很有可能存在的。Upward leader is one of the key factors for analyzing the shielding failure of lightning,but a number of questions remain to be unanswered because it is difficult to observe the upward leader from transmission lines.In order to research whether the upward leader can incept from the transmission lines,it is necessary to study the characteristics of upward leader.Therefore,models of upward leader are established to calculate the rate of shielding failure by the breakdown voltage of rod-plane gap or theory of thermodynamics,but it is proved that these models are not completely suitable for analyzing the shielding failure of lightning.We presented results from the ultra high voltage laboratory in Kunming.Measurements were conducted in a rod-conductor gap of 5～8min length under maximum voltage of 3.6MV,200/2 000μs impulses,discharge was observed with high speed camera,the current was measured using a current shunt with frequency response of 0～6.5 MHz,and upward leader was observed in the process of discharge.The velocity of upward leader is found to be 1.2～3cm/μs,which is in accordance with the velocity of leader observed in rod-plane gap discharge under positive impulse.The duration of field strength when critical radius of conductors exceeds the critical value is longer than that in the experimental conditions,so the existence of upward leader in the process of shielding failure of lightning is reasonable.

关 键 词：绕击 上行先导 长间隙放电 观测平台 输电线路场强 先导发展法 

分 类 号：TM863[电气工程—高电压与绝缘技术]