In many ancient mythologies, lightning and the associated thunder crash were seen as mechanisms for divine retribution. Though we are well beyond that view, the public still has many misconceptions about lightning. In fact, there is much that is not known about lightning initiation. It begins abruptly and is over in an instant, so for that reason it is difficult to pinpoint all the details.
It is an established fact, however, that lightning rods, properly known as air terminals, are effective in preventing lightning damage to buildings. Placed at correct intervals along the roof, they limit the risk of fire and electric shock.
在流行的叙述中，闪电螺栓在实际到达建筑物之前撞击了杆，然后将电能无害地转移到地面上。尽管可能会像这种后备机制一样发生这种情况，但这并不是应该工作的方式。
闪电的前奏是大气中不同区域之间静态电荷的积累。区域之间有很高的电压差。放电可能是点对点或点对点。空气是一种有效的绝缘体，可以防止放电，直到上升的电压达到一定水平，具体取决于带电位置与空气中的温度和水分量之间的距离。然后，像任何绝缘子一样，由于高电压应力而崩溃。两个区域之间突然建立了一个电离（导电）路径，并且遵循该路径的高电流。电离的量化性质的结果是，电弧特征在于曲折，有时是分支的途径。
通过低阻抗导体连接到地面电极系统的闪电棒旨在将电荷从屋顶上方的区域不断流向地面，因此没有突然的弧。使闪电棒起作用的是，杆的顶端是一个非常尖锐的点。电荷不断从周围地区流出，而不是高水平建造，将空气电离并突然冲动，如果闪电杆以朝上向上的平板形式形式发生。
设计和安装避雷针系统，尤其是对于具有大型电气服务和广泛数据电缆的高层建筑物，这是严格的工作，任何错误都可能昂贵。雷电保护设计和安装在大多数司法管辖区受到特定的闪电保护规定，尽管某些方面涵盖了国家电气代码。
中心要求是用于电源和光线以及所有数据和通信子系统的低阻抗接地电极系统。所有这些都必须相互关联，以防止任何危险的电压差。许多家庭和企业主会争辩说这是一种危险的做法，因为它将闪电称为主要电源系统，但实际上是正确的。
The ground electrode conductor should be run as straight as possible, without short-radius bends. Otherwise, the electrical energy may leave the conductor causing a fire hazard. Many people figure that the inability of electrical energy to navigate bends in conductors is due to centrifugal force, as when a train derails taking a curve too fast. That is not the case. Electrons have very little mass and do not necessarily tend to go straight.
The true explanation is that lightning energy has a fast rise time when it arcs and thus resembles a high-frequency wave. The bend in the conductor is like a part turn in an inductive coil, increasing the ac reactance. The fault current follows the path of least impedance, exiting the bent conductor. Air-gap lightning arrestors work in this way also.
帖子Lightning and its myths首先出现Test & Measurement Tips.
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