Plane-Wave Coupling Analysis of a Distribution Line With a Multipoint Grounded Shield Wire and Surge Arresters Using the Three-Dimensional FDTD Method

A high-frequency electromagnetic plane wave arises owing to a high-altitude electromagnetic pulse (HEMP), which may cause overvoltages in distribution lines and insulation failure. To protect distribution lines from such overvoltages properly, it is necessary to evaluate the effectiveness of countermeasures. Nowadays, the finite-difference time-domain (FDTD) method, which is one of the full-wave numerical approaches, has become a powerful tool for analyzing electromagnetic transient phenomena. In this article, first, we propose a simplified approach to modeling an impinging plane wave by taking into account homogeneous soil parameters in the three-dimensional FDTD method on the basis of a total field/scattered field technique for the analysis of HEMP-based plane-wave coupling. Second, using the proposed technique, we carry out the statistical analysis of overvoltages in a three-phase distribution line and evaluate the effectiveness of a multipoint grounded overhead shield wire and surge arresters, which are commonly used as lightning protection measures, while modeling the reinforcing bars of concrete utility poles, earth electrodes, and vertical grounding wires to simulate a realistic condition.