Calculation of transient electric field inside the building struck by lightning

This paper proposes an efficient method for calculating transient electric field inside the building struck by lightning. The analytical description of transient electric field is given by the vector potential on the basis of Maxwell equations. The vector potential is further expressed by the lightning current traveling along an arbitrary branch of building´s lightning protection system. With a reasonable simplification made in consideration of the field components, an approximate formula is derived for evaluating transient electric field in terms of the lightning current. The numerical solution is then obtained by performing a discretization treatment to the approximate formula. Finally, an electric field distribution is illustrated for a tall building to confirm the capability of the proposed method.