地闪密度按杆塔画圆差异化统计分析

Statistical Method of CG Lightning Density by Circling Tower

国网武汉高压研究院在2007年提出用网格法对地闪密度进行统计,这种方法可形成直观的、高精度的密度空间分布图。但是在进行防雷计算的过程中,当某一杆塔处于地闪密度变化剧烈的网格分界处时,不易于确定地闪密度的值。笔者提出地闪密度按每基杆塔为中心画圆的方法进行统计,可以更直观和精确的反映出杆塔所处地的综合地闪密度值。并以500 kV葛岗线为例,用按杆塔画圆方法得到的地闪密度值对线路耐雷水平进行计算,并进行了风险评估,计算结果显示,文中方法能够较好地反映线路地闪密度变化对耐雷水平的影响。

Wuhan High Voltage Research Institute of SGCC proposed a statistical method of CG lightning density, named grid method, which can form a intuitive and high-precision spatial distribution map of CG lightning density. However, the lightning protection calculation becomes in difficulty because the CG lightning density around a tower is not easy to be determined when the tower is located at the boundary of grid with sharp variation of CG lightning density. The authors propose a statistical method of CG lightning density by circling the tower to intuitively and precisely reflect the comprehensive value of CG lightning density around the tower. Taking Ge-Gang 500 kV transmission line for example, its lightning withstand level is calculated and the risk assessment is performed by using the proposed method, and the results illustrate the relation between lightning withstand level of the line and CG lightning density.