10kV架空配电线路感应雷过电压暂态特性分析

Analysis on Transient Characteristic of Induction Thunder Overvoltage in 10 kV Overhead Distribution Lines

研究架空配电线路的感应雷过电压特性对分析配网雷击风险有重要意义。基于传输线模型和电磁场理论,计算了回击过程产生的空间电磁场,先导发展过程产生的静电感应影响了线路上的过电压波形。采用Agrawal场线耦合模型和时域有限差分法(FDTD)求得导线上产生的散射电压。通过与文献实测结果对比,验证了方法的有效性。针对典型的10kV架空配电线路,分析了先导发展速度、雷击点与导线间的水平距离、导线高度和雷电流幅值不同时的感应过电压波形特性。结果表明:先导发展速度越快,感应雷过电压波前时间越短,过电压幅值越大,越容易造成线路绝缘闪络。

the study on the characteristics of induction thunder overvoltage in overhead distribution lines has considerable significance to the analysis of the risks of distribution network lightning. On the model of transmission line and the theory of the electromagnetic field, the space electromagnetic field produced during return stroke is calculated, and the electrostatic induction induced during guide development process influences overvoltage waveform in line. Scattering voltage generated in the line is also calculated by using Agrawal field line coupling model and finite difference time domain method （FDTD）.And through the comparison between the empirical results in documents and the result in the paper, the effectiveness of the method is verified. Based on the typical 10 kV overhead distribution lines,the guide development speed and the horizontal distance between the lightning stroke point and wire is analyzed as well as the characteristics of induced voltage waveform when wires height is different with the lightning current amplitude. The results show that ：the faster the guide development speed, ,the less the time before induction thunder overvoltage wave, the bigger the voltages, and it＇s more likely to induce line insulation flashover.