通道高度对斜向通道雷电电磁场影响研究

Effect of Channel Height Parameters on Oblique Channel Lightning Electromagnetic Field

由于雷电的突发性和瞬时性,导致其产生的强电磁脉冲场难以直接测量,给雷电电磁场的研究带来了很大的难度。将斜向通道电流微元分解为垂直和平行于大地的分量,利用脉冲函数表示通道底部电流并结合雷电电磁场的TL模型,根据偶极子法求解Maxwell方程组,得到斜向通道电磁场的解析表达式;基于斜向通道模型,研究了雷电通道高度对不同场区地表回击电磁场的影响。结果表明,通道高度对电磁场的影响随着水平距离的增加而增加,在回击电流达到通道顶部之前,电磁场波形基本完全重合。

Due to the sudden and transient of lightning, the strong electromagnetic pulse field of lightning is difficult to be directly measured, resulting in that it takes great difficulty to the research of lightning electromagnetic field. This paper decomposes the micro dipole into the one perpendicular to the earth and the other one parallel to the earth, using pulse function to express channel bottom current and combining with the TL model for lightning electromagnetic field, then the analytical expressions of electromagnetic field which is generated by oblique channel is obtained based on the dipole method to solve the Maxwell＇s equations. The effects of channel height on lightning electromagnetic fields at ground surface based on oblique discharge channel model in different areas are researched. The results show that the impact of electromagnetic fields by channel height will increase with the increasing of the horizontal distance and the waveform of electromagnetic fields will overlap before the return stroke current reach the top of the channel.