Comparative Analysis of Lightning-Generated Electromagnetic Field Propagation in Mountainous Terrain: a Study Using 2D Axisymmetric and 3D Models

The lightning strike is one of the major causes of power system failures. Investigating the propagation characteristics of electromagnetic waves generated by lightning is important for improving lightning localization accuracy. We conducted numerical simulations comparing a 2D axisymmetric model with a 3D model to analyze scenarios where the propagation path of lightning-generated electromagnetic waves was partially intersected by an isolated mountain in the 2D axisymmetric model and 3D model. The Finite Element Time Domain (FETD) Method was used. The simulation results obtained from both models were compared. The results show that the arrival time and amplitude of electromagnetic waves are consistent between the two models at the observation point in front of the mountain. At the observation point behind the mountain, increases in waveform arrival time delays and decreases in electric field amplitude are observed with increasing the mountain height. In the most extreme scenario, deviations in estimated waveform arrival time delays and electric field amplitudes between the two models reach <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{8 2. 2 \%}$</tex> and 40.0 %, respectively. Spatiotemporal analysis of vertical electric field distribution reveals that the 2 D axisymmetric model overestimates the terrain-induced scattering effects compared to the 3D model.