Analysis of lightning electromagnetic fields with metal layer surrounding the lightning rod system

In this paper, we set a metal layer to surround the lightning rod system to reduce the lightning electromagnetic fields when lightning strokes to the lightning rod All the underground fields amplitude decrease with the metal layer existing. Three influence factors are considered including metal layer height and grounding depth and distance between metal layer and lightning channel. The effect of metal layer height on underground electromagnetic fields is more notable than two other factors and mainly for electric fields. The metal layer grounding depth only affects the vertical electric field amplitude for the time more than 2 μs. The distance between metal layer and lightning channel can affect the vertical electric field slightly and hardly on two other kinds of fields. The horizontal electric field underground appears to be little affected by the metal layer. For comparison, we also discuss the effect of metal layer on the field aboveground and the results show that the reducing effect of metal layer on the fields aboveground is a little more obvious than that on underground fields.