Accurate simulation of lightning-induced overvoltage for overhead distribution lines is helpful to prevent lightning trip accidents. An electromagnetic return-stroke model was used to represent lightning and then a 3D finite-difference time-domain (FDTD) method was adopted to simulate the lightning-induced overvoltage on a distribution line without a field-line coupling model. How lightning-induced overvoltage behave for different ground conductivity and varying distance between the distribution line and the lightning channel was analysed. The results showed that the overvoltage waveforms at the centre point of the line corresponding to lightning strikes on the lossy ground and an ideal ground (σ = ∞) were similar; however, the peak amplitudes of the waveform were affected by soil conductivity at a close distance. The relationship between magnitude of the overvoltage and distance can be described by a second-order exponential decay equation. Finally, the overvoltage calculated using the proposed model was compared with those obtained based on Agrawal's model and measurements made using the newly developed intelligent insulator on site. From these comparisons, it could be concluded that the FDTD method with the electromagnetic return-stroke model produces reasonably accurate results of the attenuated oscillation waveform, which can better reproduce the overvoltage on operational distribution lines.

中文翻译：

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基于时域有限差分电磁回击模型的10 kV配电线路雷电过电压评估

准确模拟架空配电线路雷电过电压，有助于预防雷击跳闸事故。采用电磁回击模型来表示雷电，然后采用三维时域有限差分（FDTD）方法在没有场线耦合模型的情况下模拟配电线路上的雷电过电压。分析了不同接地电导率以及配电线与雷电通道之间距离不同时雷电感应过电压的表现。结果表明，有损接地和理想接地（ σ =∞）雷击对应的线路中心点过电压波形 相似；然而，波形的峰值幅度受到近距离土壤电导率的影响。过电压的大小与距离之间的关系可以用二阶指数衰减方程来描述。最后，将使用所提出的模型计算出的过电压与基于 Agrawal 模型和使用新开发的智能绝缘子现场测量得到的过电压进行了比较。从这些比较中可以得出结论，采用电磁回程模型的 FDTD 方法可以产生相当准确的衰减振荡波形结果，可以更好地再现运行配电线路上的过电压。