10 kV配电线路雷电感应过电压分布特性计算研究

Research on Characteristics of Lightning-Induced Overvoltage Along 10 kV Distribution Line

配电线路的绝缘水平较低,线路易受雷击影响产生雷电过电压进而导致闪络等故障,由雷电感应过电压导致的故障占线路故障总数的90%以上.本文研究了一种仿真计算配电线路雷电感应过电压的方法并分析了6种不同因素对配电线路雷电感应过电压的影响.为计算雷电感应过电压,本文选择TL模型作为雷电通道模型,选择Agrawal模型作为场线耦合模型,根据所选数学模型在ATP-EMTP中搭建出仿真模型对雷电感应过电压进行仿真计算,结果表明:雷击点距线路中点最近时线路中点雷电感应过电压是线路最大雷电感应过电压.通过仿真时改变影响因素的数值得到,雷电感应过电压幅值随雷电流幅值的增大而增大,随雷电回击速度的增大而增大,随雷击点到线路距离的增大而减小,随雷电流波头时间的增大而减小,随线路高度的增大而增大,随土壤电导率的增大而减小.研究结果对配网雷电防护具有实际工程意义.

The insulation level of the distribution line is low,and the line is easy to be affected by lightning,resulting in lightning overvoltage,which leads to flashover and other faults.The fault caused by thelightning-induced overvoltage accounts for more than 90%of the total number of line faults.A simulation method to calculate the lightning-induced overvoltage of distribution lines is studied,and the influence of six different factors on the lightning-induced overvoltage of distribution lines is analyzed.To calculate the lightning-induced overvoltage,the TL model is selected as the lightning channel model andthe Agrawal model is selected as the coupling model.According to the mathematical model,a simulation model is built in ATP-EMTP to simulate the lightning-induced overvoltage.The result shows that the midpoint overvoltage of line is maximum,which occurs when the lightening point on the ground is closest to the line midpoint.It's known that through changing the number of influence factors in simulation that thelightning-induced overvoltage amplitude increases with increasing amplitude of lightning current,with increasing lightning return stroke speed and with increasing line height,and while itdecreases with increasing distance from lightning point to line,with increasing wave front time and with increasing soil conductivity.The research results have practical significance for lightning protection of distribution grid.