考虑全雷击过程架空配电线路防雷性能计算分析

Calculation and Analysis of Lightning Protection Performance of Overhead Distribution Lines Considering Full Lightning Strike Process

架空配电线路分布广泛且线路绝缘水平低,易发生直击雷和感应雷闪络故障,为了考虑配电线路受直击雷和感应雷过电压的综合影响,建立了配电线路耐雷性能计算模型。首先基于ATP-EMTP建立线路直击雷和感应雷过电压模型对线路耐雷水平进行仿真计算,然后通过电气几何模型并结合线路感应雷耐雷水平关于雷击点至线路距离的拟合关系式,对线路直击雷和感应雷闪络区域进行划分,进而计算得到线路直击雷和感应雷跳闸率,最后,计算分析了杆塔高度和大地电导率对配电线路耐雷水平以及雷击跳闸率的影响规律。计算结果表明,杆塔高度与大地电导率均会不同程度的影响直击雷和感应雷跳闸率,进而影响总跳闸率,降低杆塔高度和增大大地电导率可降低配电线路雷击跳闸率以提高配电线路耐雷性能。

The overhead distribution lines are widely distributed and the line insulation level is low,which is prone to direct lightning and induced lightning flashover faults.In order to consider the comprehensive influence of direct lightning and induced lightning overvoltage on distribution lines,a lightning withstand performance calculation model of distribution lines is established.Firstly,the overvoltage models of line direct lightning and induced lightning are established based on ATP-EMTP to simulate and calculate the lightning withstand level of the line.Then,through the electrical geometric model and the fitting relationship between the lightning withstand level of line induced lightning and the distance from the lightning strike point to the line,the lightning flashover area of line direct lightning and induced lightning is divided,and the trip rate of line direct lightning and induced lightning is calculated.Finally,the influence of tower height and ground conductivity on the lightning withstand level and lightning trip rate of distribution lines is calculated and analyzed.The calculation results show that the tower height and the ground conductivity both affect the direct lightning trip-out rate and the induced lightning trip-out rate to varying degrees,thereby affecting the total trip-out rate.Reducing the tower height and increasing the ground conductivity can reduce the lightning trip-out rate of the distribution line and improve the lightning resistance of the distribution line.