输电线路走廊雷电流幅值分布统计方法

Statistical Method of Lightning Current Amplitude Distribution Along Transmission Line Corridor

雷电参数沿线路呈现显著的差异性,单一的雷电流幅值累积概率分布公式不足以准确反映长线路走廊的实际情况。为进一步提高线路耐雷性能分析的精细化程度,提出一种精细化雷电流幅值累积概率分布统计方法。该方法在"网格法"基础上,根据网格雷电地闪次数逐步合并网格形成不同统计区段,分别统计拟合得出各区段内的雷电流幅值累积概率分布公式。研究结果显示以地闪2 000次为阀值划分统计区段较合理。采用分区段的雷电流幅值分布公式和全线路单一的分布公式相比较,两者造成110 kV杆塔反击跳闸率的差异达–0.093~0.181次/(100 km·a),而220 kV和500 kV杆塔的反击跳闸率差异较小;对500 kV杆塔的绕击跳闸率,在地面倾角不足10°时影响可忽略不计,在地面倾角为30°时差异达–13.2%~6.2%。

Since lightning parameter behaves remarkable difference along power lines, an onefold formula of accumula- tive probability distribution（APD） of lightning current amplitude（LCA） is not able to characterize the actual situation for a long power line. We put forward a detailed statistical method of APD of LCA for multiple sections to refine lightning protection analysis. The method is based on ＂grid method＂ and merges grids into a statistical section according to ground flash number in grid, further respectively obtains a formula for each section, and 2 000 is suggested to be an appropriate threshold for division of sections by case study. A comparison between onefold and multiple APD formulas of LCA indi- cates that they bring about a difference of-0.093 to 0.181 times/（100 km.a） in back stroke trip-out rate（BSTOR） to 110 kV transmission tower, while a slight differencer to 220 kV and 500 kV transmission tower. As to the shielding failure trip-out rate（SFTOR） of 500 kV transmission tower, they produce negligible differences if ground elevation is less than 10° while difference is about -13.2% to 6.2% when it is 30°.