Influence of Spatial Grid-like Shield Dimensions on Attenuation of Nearby Lightning Magnetic Field

Numerical analysis of spatial grid-like shields in the case of a nearby lightning strike is presented. Spatial shields of different dimensions and mesh density are analyzed. The significant influence of the shield outer dimensions on the magnetic field attenuation is presented, which is not considered in the IEC lightning protection standards. The IEC formulas for the shielding effectiveness take mostly the mesh width into account.