传输线耦合雷电电磁波过程的分析方法

Analysis Method of Lightning Electromagnetic Wave Process Coupled by Transmission Line

针对传输线耦合雷电电磁波形成过电压对电子设备造成干扰及损坏的问题,将雷电闪电通道等效为辐射线天线,建立雷电回击通道、传输线、大地一体化模型,利用传输线模型所得理论推导公式与试验相结合的方法,对传输线耦合自然界雷电与模拟雷电进行对比分析,并计算了传输线耦合雷电电磁波形成过电压波形的幅值及能量。得出:当雷电回击通道中雷电流在5 kA^45 kA范围时,传输线耦合雷电电磁波形成的过电压幅值与雷电流大小呈较好的线性关系,耦合的能量与雷电流大小呈幂函数关系;雷电过电压在传输线传输过程中激励出高频分量电压,并对其特性进行分析。试验结果和理论分析结论相吻合,研究结果对传输线雷电防护具有一定的指导意义。

According to the interference and damage problem of electronic equipment caused by overvoltage from the lightning electromagnetic coupled by transmission line, the lightning tunnel is equivalent to a radiant antenna, a model integrated with lightning return stroke tunnel, transmission line and ground is founded. And the method combined the derived formula with the experimental is used to analysis the voltage coupled by transmission line. The voltages caused by natural and simulated lightning coupled by transmission line are also compared, and the amplitude and energy of the coupled voltage wave were calculated respectively. Upon these experimental results, we can draw several conclusions as follows： when the amplitude of the lightning current in the tunnel is between 5 kA to 45 kA , it takes on a excellent linear relation between the amplitude of overvohage and the magnitude of the lightning current, the relation between coupling energy and magnitude of the lightning current takes on an exponential trend. When lightning wave transmits on the transmission line, the high frequency components will be excited. Through analysis on the high order mode＇s characteristics, we find the theoretical analysis is consistent with the experimental results, which has a certain reference value to the protection on transmission line.