Index Terms— Coupling models, lightning-induced voltage,
lossy ground.
I. INTRODUCTION
DUE to technical difficulties associated with measuring
the characteristics of lightning induced overvoltages in
power lines, many researchers have resorted to numerical
models to derive the features of overvoltages produced by
lightning. The main steps in these numerical models are
as follows [1]–[3]: 1) find a reliable return stroke model
capable of generating fields similar to those generated by
lightning return strokes; 2) estimate the distortions introduced
into these fields as they propagate over finitely conducting
ground and then obtain the vertical and horizontal electric
fields at ground level and at line height; 3) use a reliable
coupling model to simulate the interaction of electromagnetic
(EM) fields with power lines; and 4) include the effects of