An Experimental Test of the Theory of Lightning Induced Voltages on Power Line

An analysis of the relation between measured and calculated voltages induced by lightning on an unenergized power line has been studied. The experiment, performed at the NASA Kennedy Space Center involved the simultaneous measurement of the voltages induced on a power line and the two perpendicular components of the lightning horizontal magnetic field. The calculation of induced voltage has been performed using a time-domain transmission line coupling model as proposed by Agrawal et al. The inputs of this model are the incident vertical electric field and the incident horizontal electric field both derived via theory from the measured magnetic fields. Experiments were performed for both ends of the power line opencircuited and for the left-end terminated in 500 f t or 600 i l with the right end open. Comparison of the peak amplitude of the induced voltage showed that the differences between the measurement and the calculation are typically less than 35%. The waveshapes of the measured and calculated voltage are also in reasonably good agreement. Reasons for the observed discrepancies between experiment and theory are discussed.