Voltages Induced on an Overhead Line by the Lightning Stepped Leader

We present the first correlated measurement of the voltage induced on an overhead line and the corresponding vertical electric field strength produced by a stepped leader in a lighting discharge to ground. These data were obtained in the Tampa Bay area of Florida during the summer of 1979. The voltage pulses were induced by individual leader steps separated in time by about 15 μs. The peak voltage induced on the overhead line by the largest stepped-leader pulse was about 10 percent of that induced by the following return stroke. It is suggested that the peak voltages induced on distribution lines by stepped leaders preceding a return stroke may impose an additional stress on lightning protection devices to that produced by the return stroke.