Lightning overvoltage due to first strokes considering a realistic current representation

Lightning overvoltages due to direct strikes over a 138-kV transmission line and voltages induced on a single-conductor overhead line by nearby strikes were simulated using a realistic representation for the first-stroke current waveform that includes a pronounced initial concavity followed by a sharp rise at the half peak and the double peaks, in addition to the median time parameters taken from traditional database of instrumented towers. The results were compared to those yielded by a single-peaked current given by two Heidler functions, which is commonly used in simulations. Significant differences were found on the amplitude of the resultant overvoltages. The elaborate waveform is responsible for higher direct-strike overvoltages and lower lightning-induced voltages in relation to those yielded by simplified single-peaked waveform.