Magnetic field distribution inside metallic grid-like buildings struck by lightning based on finite element method

This paper dealt with the evaluation of magnetic field in a lightning protection system (LPS) of a metallic grid-like building. The finite element method was used, based on the numerical solution of Maxwell´s equations in frequency domain. The presented method takes into account electromagnetic coupling of the reinforced steel bars automatically. The verification structure under study comprises a cubic cage of 10 m side length having grid-like spatial shields with square meshes of 2 m width. In order to reduce the amount of calculation, a scaled model has been built up and the results are extrapolated using the similarity relations theory. Validation of the proposed method was performed by comparing the results with those computed available in IEC62305-4 equations.