SHIELDING FORMULAS FOR WIRE-GRID STRUCTURES DURING AN INDIRECT LIGHTNING STRIKE

This paper investigated the shielding effect of a metallic wire- grid structure found in modern buildings du ring an indirect Iightning stroke. An equivalent circuit approach was employed to model the structure and nearby down conductor and to calculate the induced current in the structure. The resultant magnetic field inside the buildings was evaluated. It is revealed that the geometrie parameters of the building structure, such as structure length/width, grid length/width, and distance to nearby down conductors, have a great impact on its shielding effect. Empirical shielding formulas are provided for various situations. General conclusions of the shielding characterizes for wiregrid structures are presented finally.