雷击石油化工装置电磁脉冲危害研究

Research into the electromagnetic pulse risk of a petrochemical plant struck by lightning

为了分析雷击石油化工装置产生的雷电电磁脉冲危害,基于电流线性衰减的传输线雷电模型,采用时域有限差分法仿真计算了100kA强雷电雷击石油化工装置产生的电磁脉冲。结果表明,水平电场在地面以上受地面反射影响波形变化很大,而地面以下波形变化不大,主要是幅值的变化;垂直电场地面上下的幅值差别非常大,地上的波形随高度的增大差别不大,地下的波形第一个峰值随深度的增大而减小,由于反射的影响,第二个峰值随深度的增大反而有所增大;水平磁场的变化比较规则,地上的水平磁场受高度的影响较小,仅随与通道距离的增大而减小,地下的水平磁场随深度的增大,幅度有所衰减,波形趋向平滑;在地上5m,距离雷电通道10m处的水平电场峰值达到了110kV/m以上,垂直电场峰值达到了240kV/m以上,水平磁场峰值达到了2300A/m以上,如此强大的电磁脉冲对石化企业的防雷设计是一种严峻考验。

We analyzed the possible lightning electromagnetic pulse(LEMP)caused by a lightning strike on a petrochemical plant,based on the modified transmission line model with linear current decay with height. The LEMP caused by a lightning strike with a 100 kA lightning current was calculated using the finite-difference time-domain(FDTD)method. The results indicate that the overground waveform of the horizontal electric field varies greatly because of the influence of ground reflection,while the underground waveform changes slightly,primarily a change in magnitude. The difference of the vertical electric field amplitude between above the ground and below the ground is very large,and the overground waveform change slightly with height,and the first peak of the underground waveform reduces with an increment of depth,but the second peak increases with an increment of depth because of the influence of ground reflection. The horizontal magnetic field changes regularly,which below ground changes slightly with height and decreases with the increment of distance to the lightning channel,but the underground horizontal magnetic field decays smoothly with an increment of depth. At a height of 10 m above ground,the peak of the horizontal electric reaches more than 110 kV/m at 10 m away from the lightning channel,the vertical electric field reaches 240 kV/m,the horizontal magnetic field reaches 230 0 A/m,and the powerful LEMP is a severe test to lightning protection design of petrochemical enterprises.