On the Influence of Peak Current Distribution on the Lightning Incidence to Transmission Lines

This paper investigates the influence of the peak current distribution on the assessment of the average annual number of strokes to transmission lines (TLs). Three widely used lightning attachment models in TL performance studies are implemented, namely: i) electrogeometric model (EGM) considering the constants suggest in the IEEE Std. 1243; ii) the attractive width approach proposed by Eriksson; and iii) the average attractive width, suggested by IEEE and CIGRE guidelines for estimating the lightning incidence to TL shielding wires and implemented in the IEEE FLASH program. Also, two different peak current distributions are analyzed, namely the classical Berger's distribution and another one representative of tropical regions. It is shown that using the concept of average attractive width leads to an overestimation of the lightning incidence to the shield wires of around 50%, taking as reference Berger's distribution. The EGM and attractive width approaches agrees fairly well in predicting the annual number of strokes to TLs. Furthermore, the annual number of strokes to TLs increases with the median peak value of the current distribution.