FDTD Simulation of LEMPs Considering Ground Geometry and Grounded Structure

摘要

Radiation components of vertical electric field and azimuthal magnetic field, generated by a vertical lightning return stroke attached to a flat, well-conducting ground, are inversely proportional to the horizontal distance from the lightning return-stroke channel. Field magnitudes at far distances are reduced by a low-conducting ground, while they are enhanced by the presence of a tall grounded strike object. In this paper, vertical electric and azimuthal magnetic fields generated by a lightning strike to the top of a mountain, those due to a lightning strike to the top of a tall grounded object on the top of a mountain, are computed using the finite-difference time-domain (FDTD) method in the two-dimensional (2D) cylindrical coordinate system. Computed results for these cases are then compared with corresponding results computed for a lightning strike to flat ground.