南川地区10kV配网线路防雷分析

Lightning Protection Analysis of the 10 kV Transmission Lines in Nanchuan Region Based on Lightning Parameters

中国10 kV配电线路绝缘水平低,雷击引起的跳闸事故在配网故障中占据较大比例。根据实际雷电活动特征,分析线路跳闸原因、评估线路防护状况,从而有针对性地指导雷电防护。依托雷电定位系统(LLS)对重庆南川地区1999-2009年间雷电参数进行收集,拟合正负极性雷电流幅值的概率分布公式来分析不同情况下输电线路雷击闪络率。结果表明:该地区地面落雷密度达到0.077 7次/(km2.d),负极性雷占据94.84%,线路直击雷和感应雷的总闪络率均接近基于负极性雷的计算值,但不同极性雷电流的闪络率因各自雷电流幅值概率函数不同而差别较大,线路防雷计算和评估应充分考虑不同极性雷电流的影响。

In china the trip faults of 10 kV power distribution lines caused by lightning account for a large percentage of distribution network faults due to low insulation level. In this paper, the reasons why the trips occur are analyzed, and the lightning protection condition of 10 kV power distribution lines is evaluated according to the characteristics of lightning activity to improve the lightning protection. The lightning parameters of Nanchuan Region in Chongqing were collected from 1999 to 2009 via the lightning location system, then a probability distribution equation of positive and negative lightning current amplitudes is derived to analyze flashover rates of 10 kV transmission lines under direct lightning and induced lightning. The results show that： the ground lightning density is 0.077 7 time/（km2-d）, of which negative lightning accounts for 94,84%; both total flashover rates of direct lightning and induced lightning close to the values of their negative lightning; and the flashover rates induced by different polarity lightning current depend on their probability distribution equations of lightning current amplitude. The calculation and evaluation of lightning protection should consider the polarity effect of lightning current.