建筑物LPS对雷击暂态磁场屏蔽效应分析

雷电放电现象发生在建筑物附近时,泄流通道周围会产生功率较强的雷电电磁脉冲(LEMP)。该脉冲极易通过耦合或者电磁辐射等方式干扰或者损坏敏感电子设备。针对建筑物LPS自然连接而构成的金属网栅屏蔽结构,在求得电流分布的基础上,推导出空间磁场强度表达式,分析了金属网栅屏蔽效应的影响因素。其中具体涉及了接地点的情况、网孔大小以及双层网结构对于屏蔽效果的影响,并与单层网及无屏蔽网进行了对比,最后给出了提高屏蔽效应的相关建议。该方法为大型保护框架内部空间的电磁环境的评估提供了一种量化手段。

Analysis on the Influence of Building LPS on Transient Magnetic Field Shielding Effect During Lightning Strike

When lightning discharge occurs near the building, the strong power lightning electromagnetic pulse(LEMP)will be generated around the discharge channel. The pulse can easily interfere with or damage sensitive electronic devices by coupling or electromagnetic radiation. In this paper, based on the calculation of the current distribution, the expression of the spatial magnetic field intensity is derived, and the influence factors of the shielding effect of the metal mesh screen are analyzed. The influence of ground conditions, mesh size and double network structure for shielding effect are analyzed respectively. Finally, some suggestions of improving the shielding effect are given. This method provides a means of quantifying the evaluation of the electromagnetic environment in the interior space of a large protective frame.