FDTD-based lightning surge simulation of a microwave relay station

In electric power systems, microwave relay stations are employed to exchange information using electromagnetic radio waves to control the systems. Some microwave relay stations are built on tops of mountains, which causes a high incidence of lightning strikes to microwave towers, and the lightning strikes may result in disturbances of microwave radio equipment. To protect microwave radio equipment from lightning, it is required to analyze surge phenomena in microwave relay stations and evaluate the effectiveness of lightning protection methodologies. Nowadays, the finite-difference time-domain (FDTD) method to solve Maxwell's equations directly, has been widely and successfully applied to the surge analysis of three-dimensional structures and grounding structures. In this study, setting up a reduced-scale microwave relay station model with a microwave tower of 10 m height, we calculate the distribution of lightning impulse currents in the model and compare the calculated results with measured ones for validation. Secondly, we calculate the magnetic fields inside the microwave relay station in the case of direct lightning strikes to the microwave tower to study the effect of the layout of the microwave relay station and the effectiveness of the reinforcing bars used for grounding.