Using EMTP for evaluation of surge current distribution in metallic gridlike structures

This work presents a study on the utilization of EMTP² in calculating the lightning current distribution in the metallic structure of a building. The structure is modeled as a network of Pi-circuits and represented by three parameter matrices, [R], [L] and [C]. With the modifications in EMTP, EMTP can compute the current distribution in the structure in either frequency domain or time domain during a direct stroke to a structure or an indirect stroke near a structure. Subsequently, the impulsive magnetic field inside the structure can be evaluated. The accuracy of this method is verified by a laboratory experiment. A 10m×10m×10m structure is also constructed in the paper for the illustration of both lightning current and magnetic field evaluations. The results show that EMTP is capable of analyzing lightning currents in the metallic gridlike structure of a building.