Numerical Electromagnetic Analysis on Current Distribution in Building Directly Hit by Lightning

Abstract

Lightning current distribution in a directly hit building is studied by using a simple equivalent circuit and an electromagnetic model. Numerical Electromagnetic Code (NEC-4) is employed for numerical electromagnetic analysis. Error in portion of lightning current into wiring, which is calculate by the electromagnetic model, is estimated to be less than 4%. Portions of lightning current into wiring on the top floor and the first floor are largest. Although they are larger for a higher building, they are almost constant if the number of floors of the stricken building is more than five. They are smaller when there are more vertical conductors, or length of wiring is longer.