不同布设方式下平行线缆雷电感应耦合特性

Lightning inductive coupling characteristics of parallel cables under different cable layouts

针对不同线缆布设下线缆雷电感应耦合特性的问题,搭建由干扰线缆和受扰线缆组成的平行线缆雷电感应耦合仿真模型,研究干扰线缆注入8/20μs、10/1 000μs及0.5μs/100 kHz等雷电浪涌电流时,线缆间水平距离、受扰线缆相对高度和受扰线缆长度对受扰线缆端口负载感应电压的影响规律。结果发现:随两线缆间水平距离的增大,线缆感应电压呈指数衰减;当受扰线缆距地高度由零开始增加时,线缆感应电压近似呈线性快速增加,在两线缆高度相同时达到最大值,之后感应电压随线缆高度的继续增加近似呈线性缓慢减小;受扰线缆感应电压在受扰线缆长度等于干扰线缆长度时达到最大值,在此基础上,减小或增大受扰线缆长度,受扰线缆感应电压均近似呈线性缓慢减小。针对水平间距和相对高度的仿真结果开展验证性试验,试验与仿真结果基本吻合,波形幅值偏差小于5%。

A simulation model is established here for studying the lightning inductive coupling effect between parallel cables comprising of an interfering cable and a disturbed cable, both located above the ground surface. Various effects, including the horizontal distance between cables, the relative heights between cables, and the lengths of disturbed cable, are investigated for the induced voltage of the resistive load connected to one terminal of the disturbed cable, when different lightning surge currents(8/20 μs, 10/1 000 μs and 0.5 μs/100 kHz) are injected into the interfering cable. Results show that the cable induced voltage decreases exponentially with the increase of the horizontal distance between two cables. Moreover, as the height of the disturbed cable increases from the ground surface, the cable induced voltage increases approximately linearly, reaching the maximum when the two cables are at the same height, and then decreases almost linearly with a much slower rate than the previous increasing rate. Furthermore, with the increase of the disturbed cable length, the cable induced voltage increases more or less linearly, reaching, again, the maximum when the lengths of two cables are equal, and then decreases slowly and linearly. Verification experiment are finally carried out for the simulation results of the influence of horizontal distance. Experimental results are found to agree moderately well with their simulative counterparts, since the waveform amplitude deviations are smaller than 5% between two.