Thin wire representation in finite difference time domain surge simulation

Simulation of very fast surge phenomena in a three-dimensional (3-D) structure requires a method based on Maxwell’s equations, such as the finite difference time domain (FDTD) method or the method of moments (MoM), because circuit- equation-based methods cannot handle the phenomena. This paper presents a method of thin wire representation for the FDTD method which is suitable for the 3-D surge simulation. The thin wire representation is indispensable to simulate electromagnetic surges on wires or steel flames of which the radius is smaller than a discretized space step used in the FDTD simulation. Comparisons between calculated and laboratory test results are presented to show the accuracy of the proposed thin wire representation. The development of a general surge analysis program based on the FDTD method is also described in the present paper.