一种雷电感应过电压的快速算法及其精度检验

A Fast Algorithm for Lightning-Induced Voltages and Its Accuracy Validation

本文基于B-P方程、Rusck方程和Agrwal耦合模型,开发出一种架空线雷电感应过电压的时域快速算法。利用该算法研究了不同参数对雷电感应过电压的影响,并利用2-D FDTD算法对其计算精度进行全面检验。结果表明:(1)首次回击电流产生的感应过电压的峰值较大,波头陡度小;继后回击电流产生的感应过电压的峰值较小,而波头陡度更大。(2)地面电导率σ对感应过电压的幅值和极性影响较大。架空线路中点处的感应过电压峰值与地面电导率呈负相关,而端点处的感应过电压峰值与地面电导率呈正相关,并且在电导率较低(σ=0.001 S/m)时波形表现出双极性特征。(3)架空线路中点和端点处的感应过电压峰值均随线路高度h增大而增大。(4)在闪电通道50~1000 m范围内,本文算法模拟出的感应过电压波形与2-D FDTD的结果基本一致,且峰值计算误差均小于5%。综上,由于本文算法计算时间仅需10 s并具有较高的计算精度,有利于在防雷工程中推广应用。

Based on the B-P formula,Rusck formula and the Agrawal coupling model,we developed a time-domain method for lightning-induced voltages in overhead lines.Using this method,we studied the effects of different parameters on lightning-induced voltages and validated its accuracy using the 2-D FDTD method.The results show that:(1)The induced overvoltage generated by the first return current had a larger peak value and smaller wave head steepness.However,the induced overvoltage generated by the subsequent return current had a smaller peak value and larger wave head steepness.(2)Ground conductivity greatly influenced the amplitude and polarity of induced overvoltage.The peak value of induced overvoltage at the line centre negatively was correlated with ground conductivity.However,at the line end,the peak value of induced overvoltage positively was correlated with ground conductivity,and the waveform showed bipolar characteristics at poor ground conductivity condition(σ=0.001 S/m).(3)Both at the line centre and ends,the peak value of induced overvoltage increased with the line height.(4)Within distances from 50 to 1000 m from the lightning channel,the voltage waveforms calculated by our method were consistent with the 2-D FDTD results and the calculation error was less than 5%.In conclusion,because the calculation time of our method only needs 10 s with high calculation precision,it is very beneficial to be applied in lightning protection engineering.