大地电导率和线路长度对10kV架空线路雷电感应电压的影响

Effect of Earth Conductivity and Length of Line on Lightning Induced Voltage of 10kV Overhead Distribution Lines

为了对架空线雷电感应电压特性进行系统深入的研究,以10kV单/双回架空线为研究对象进行了数值计算。分析大地电导率(σ)、导线排布方式和线路长度(L_l)3个因素对雷电感应电压峰值沿线分布和时域波形的影响。计算结果表明,感应电压脉冲极性改变的位置随L_l增大明显向导线中部移动,电压最高峰值并非位于距回击通道最近杆塔。感应电压幅值和波形整体受σ影响明显,但距回击通道越近,受影响越弱。相同条件时,σ越低、导线数越多,电压波形"畸变"越严重。感应电压脉冲幅值和上升时间随L_l增大呈不同的非线性增长,但均在L_l≤6km范围内存在明显"饱和"现象,半峰值宽度在L_l整个取值区间内有较明显地增长。排除架设高度因素,导线排布方式对感应电压影响很弱。

In order to systematic and thoroughly study the characteristics of lightning induced voltage on overhead lines,the lightning induced voltages on 10 kV overhead distribution lines were calculated by numerical calculation.This work investigated the effects of the earth conductivity(σ),the wire arrangement and the length of line(L_l)on the characteristics of induced voltage waveform and the induced voltage peak distribution on line.Results show that,the position of the induced voltage pulse polarity change moving to the middle of the line obviously with the increase of L_l.The highest peak of induced voltage is not located at the tower closest to the return-stroke channel.The amplitude and waveform of induced voltage are obviously affected byσ,however the closer to the return-stroke channel,the weaker the influence is.The decrease ofσand the increases of conductors can aggravate the distortion of induced voltage waveforms under the same conditions.The pulse amplitude and rise time of lightning induced voltages increases different nonlinear respectively with the increase of L_l,and both of them have obvious‘saturation’phenomenon in the range of L_l≤6 km.The half peak width increases obviously in the whole range of L_l in this paper.The wire arrangement has a weak effect on lightning induced voltages if the erection height factor is excluded.