摘要
针对经典电气几何模型认为雷电先导对导线、避雷线、大地三者之间击距相等的不合理问题,提出了用击距系数来描述雷电先导对导线与大地击穿强度的差别;依据长间隙放电与雷击放电的相似性,开展了棒-板间隙实验以得到击中目的物概率为50%时雷电先导与地面、导线之间的位置关系。实验结果显示击距系数随线路高度的增加而减小,实验结果修正之后得到击距系数与线路高度之间的关系,并依据电磁场理论的知识推得雷电先导击中地面的临界场强为500kV/m;导线的临界击穿强度随线路高度变化满足一定关系时,计算分析所得的击距系数与实验所得的非常接近。实验所得的击距系数公式可用于线路绕击防雷计算中。
It is not reasonable that striking distances of lightning leader to phase conductor, ground line and the ground are equal in classical electric geometry method （EGM）. Striking distance factor is introduced to describe the difference of striking electric intensity between phase conductor and the ground. According to the comparability of lightning discharge and rod-plane gap discharge, a simulated experiment was carried out. Experimental data indicate that striking distance factor k decreases with the increase of the height of line h, The relation between k and h is concluded from experimental data. Based on the electromagnetic theory, if the critical electric intensity of lightning leader to the ground is 500 kV/m, and the electric intensity Ec and the height of phase conductor h satisfy the relationship presented in this paper, the striking distance factor is very close to the result concluded from the experiment. The expression from experiment can be used in the lightning protection calculation.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2008年第1期41-44,共4页
High Voltage Engineering
关键词
输电线路
绕击
击距系数
击距
电气几何模型
模拟实验
transmission line
shielding failure
striking distance factor
striking distance
electric geometry method
simulated experiment
