Induced voltage on an overhead line due to nearby lightning

Voltage waveshapes induced on an overhead line by nearby lightning return strokes are calculated numerically by solving the transmission-line equations using the time-domain approach of A.K. Agrawal et al. (1980) and a finite-difference technique. The traveling current source (TCS) model is used to calculate the return-stroke vertical and horizontal-electric fields (which are the sources for a line voltage) above a perfectly conducting ground plane. The effect of the striking-point distances and the return-stroke current waveshape on the induced voltages are illustrated. The exact location of the maximum voltage along the line depends not only on the closest distance from the striking point to the line but also on lightning-current parameters. In the case of a 2000-m-long line and a striking point a distance of 100 m from the line center, almost 90% of the induced voltage at the line terminations is due to the horizontal electric field coupling.<
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