III. RESULTS AND DISCUSSION
To illustrate the effects of different assumptions on the
calculated induced overvoltages, consider a 5-km-long line
at a height of 10 m and terminated with it’s characteristic
impedance. The ground is assumed to be finitely conducting
with conductivity of 0.002 S/m and the relative dielectric
constant of the ground is assumed to be five. The geometry
relevant to this situation is shown in Fig. 2(c). The induced
voltage and its derivative at the termination B, calculated by
using different approximations when the lightning strikes at
P1, are depicted in Figs. 3(a), 4(a), and 5(a). The correspond-