Lightning performance of transmission lines — III

THE purpose herein is to present a simplified method of calculating the voltage across the line insulation for a stroke terminating on the tower top and zero tower footing resistance based on the theory and equations derived in two previous papers. For purposes of analysis, the stroke has been resolved into two components: (1) a linear-front flat-top wave of positive charge and associated current that flows upward along the axis of the downward leader at a constant velocity less than that of light, and (2) a linear-front flat-top wave of negative charge and current which is fed into the tower and ground-wire combination.