摘要
随着海拔的升高,空气密度逐渐降低,导致空气间隙绝缘强度降低,研究高海拔低气压条件下的空气间隙放电特性,对高海拔地区输电线路及输变电设备的设计和运行有着重要的意义。为此,采用光电倍增管、光电集成电场传感器搭建光电联合检测系统,分别在西藏羊八井(海拔4300 m)、北京(海拔50 m)特高压试验基地开展了3m球–板间隙的正极性操作冲击放电试验,试验结果表明:海拔4300 m地区长间隙放电仍具有初始流注、流注–先导转化、先导发展等典型长间隙放电阶段,而高海拔流注起始升压时延均值53.53μs、有效电子形成的统计时延均值18.74μs均小于低海拔地区。临界体积、负离子密度、负离子寿命是统计时延的主要影响因素。当间隙施加相同操作波时,高海拔临界体积增长率为6.92 dm^(3)/μs,低海拔临界体积增长率为3.32 dm^(3)/μs,高海拔下临界体积增长速率显著增加。同时高海拔地区紫外线强度增加导致负离子密度增加,且高海拔下负离子寿命较短,更易电离出自由电子,因此高海拔统计时延均值显著降低。
With the increase of altitude,the air density decreases gradually,which leads to the decrease of air gap insulation strength.It is of great significance to study the air gap characteristics under high altitude for the design and operation of transmission lines and transformation equipment at high altitudes.In this paper,a photo multiplier tube and a photoelectric integrated electric field sensor were used to build a combined photoelectric detecting system,and a discharge test of 3m sphere-plane gap under positive switching impulse voltage was carried out at the Yangbajing(altitude 4300 m)and Beijing(altitude 50 m)UHV test bases,respectively.The test results show that the long gap discharge at an altitude of 4300m still has typical discharge stages such as initial streamer,streamer-to-leader transition and leader development.The mean value of the initial streamer voltage rise of high altitude is 53.53μs,and the mean statistical time delay of effective free electron is 18.74μs,which is lower than that in low altitude area.Critical volume,negative ion density and negative ion lifetime are the main influencing factors of statistical time delay.When the same switching impulse voltage is applied to the gap,the critical volume growth rate is 6.92 dm^(3)/μs at the high altitude and 3.32 dm^(3)/μs at the low altitude.The critical volume growth rate increases significantly at the high altitude.At the same time,the density of negative ions increases with the increase of ultraviolet intensity at high altitudes,and the lifetime of negative ions is shorter at high altitudes,which may facilitate the ionization of free electrons.Therefore,the mean statistical time delay at high altitudes decreases significantly.
作者
王平
肖智勇
汪鑫宇
陈雅茜
丁玉剑
耿江海
WANG Ping;XIAO Zhiyong;WANG Xinyu;CHEN Yaxi;DING Yujian;GENG Jianghai(Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense,North China Electric Power University,Baoding 071003,China;China Electric Power Research Institute,Beijing 100192,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2022年第3期857-864,共8页
High Voltage Engineering
基金
国家自然科学基金(52007064)。
关键词
高海拔
正极性操作冲击电压
长空气间隙放电
流注
起始时延
临界体积模型
high altitude
positive switching impulse voltage
long air-gap discharge
streamer
inception delay time
critical volume model
