Novel method for analyzing the transient behavior of grounding systems based on the finite-difference time-domain method

When lightning strikes bulk transmission lines or electric substations, large currents flow through towers or in substations and equipment structures before dissipating in the ground through the grounding systems. The electromagnetic fields generated by such lightning surges cause large currents and voltages, which may result in damage to equipment and serious accidents, such as failure of electrical transmission, and furthermore may be dangerous to personnel working nearby. Moreover, the immunity level of electronic equipment that contains semiconductors and LSI devices is low, and such equipment is sensitive to various types of electromagnetic stimuli. Therefore, it is important to analyze the transient behavior of grounding systems of power systems in order to study lightning protection and improve human safety. However, the transient behavior of grounding systems has so far been difficult to evaluate. In this paper, we propose a novel method in which the transient behavior is analyzed based on the finite-difference time-domain method, and confirm its validity through comparison between experimental results of the transient behavior and analytical results.