The most important points we have gathered from this
exercise are as follows. First, simulation of the ground effects
by a constant resistance leads to an overestimation of derivatives
and an underestimation of the risetimes of the induced
voltages. Second, the magnitude of the resistance that gives the
correct results for the peak of the induced voltage depends on
the point of strike and probably on the length of the line. The
reason for this is that the frequency content of the induced
voltages changes in different ways depending on the strike