MEASUREMENTS OF THE VOLTAGE INDUCED ON AN OVERHEAD POWER-LINE 20-M FROM TRIGGERED LIGHTNING

Voltage induced on a 448-m power distribution line by eleven return st rokes in three lightning flashes artificially initiated 20 m from one end of the distribution line and the corresponding vertical electric f ields at 500 m have been measured. Two types of induced-voltage wavefo rms were recorded: oscillatory and impulsive. The former exhibit peak values that range from tens of kilovolts to about 100 kV; the latter s how peak voltages nearly an order of magnitude larger. Both types of i nduced voltage waveforms were observed to occur for different strokes within a single flash. Relatively successful modeling of the oscillato ry voltage waveforms is presented. Modeling of the impulsive waveforms proved unsuccessful, probably due to those waveforms being in part as sociated with a failure, perhaps an unexpected flashover, in the measu ring system.