基于触发闪电的共用地网雷电流分布观测及分析

Observation and Analysis of Lightning Current Distribution in the Common Ground Network Based on Triggered Lightning

对于雷电流在地网上分布的研究大多是基于理论分析,为此,通过野外试验并结合ATP-EMTP仿真分析了雷击共用地网时雷电流的分布情况。研究结果表明：共用地网模型中连接地网的2条扁钢分流到远端地网电流5次回击幅值和电量平均值分别为-1.2 k A和-0.24 C,分别占注入触发闪电的7.8%和27.0%;波前时间平均值和波尾时间平均值分别为22.0μs和149.2μs,分别是注入触发闪电的44倍和16倍;触发闪电电流中的一次幅值为-19.3 k A的M分量分流到远端地网时波形和注入闪电电流相似,与回击分流到此的电流也较为相似。仿真与实测结果对比发现：回击过程分流的幅值和波前时间与实测结果相符合,但波尾时间模拟结果有明显的差异;M分量模拟结果与实测整体波形都比较符合,效果优于对回击过程的模拟。触发闪电电流注入后,共用地网远端M分量电流幅值衰减比例要远小于回击过程,而其波形与回击类似,M分量对远端地网分流和地电位升高的危害应值得关注。

The analysis on characteristics of lightning current distributed in the common ground network is usually based on theory studies. Wer analyze the problem though field experiment and ATP-EMTP simulation,and have drawn the following conclusions. The average amplitude and quantity of the 5 return strokes in the flats which are used to connect the two independent ground networks are-1.2 k A and-0.24 C, respectively, and the ratios to lightning current are 7.8% and 27.0%, respectively. The average front time and the time of wave tail in the flat1 are 22.0 μs and 149.2 μs, which are 44 times and 16 times of the lightning,respectively. During a lightning process, the parameters of the M-component of which value is-19.3 k A in flat2 are similar to those of flat1 s and are also similar to those of return stroke. According to the comparison of simulation and experiment, we find that the front time of return stroke agrees well with that of experiments when the wave tail is distinctly different in the flats. The simulation M-component agrees well with lightning current in the flats. The attenuation ratio between the lightning current and M-component caused by the network is larger compared to the return stroke, due to the transient effect of ground network the current distributed in the ground network and the ground potential rise（GPR） caused by M-component deserve more attention.