A Stochastic Model for Evaluating the Lightning Performance of a −400 kV HVDC Overhead Line

A stochastic lightning attachment model for evaluating the lightning performance of overhead transmission lines is introduced. The proposed model considers the stochastic nature of lightning attachment by taking into account the lightning discharge branched and tortuous behavior. It integrates physical criteria on leader inception by adopting the Petrov and Waters model, as well as leader discharge progression considering also the competing interaction of multiple upward leaders. A generalized methodology combining stochastic modeling of lightning incidence with an electromagnetic transients (EMT) simulation model is proposed so as to estimate the backflashover and shielding failure flashover rates of HVDC overhead lines; an application to a monopolar −400 kV line sheds light on the basic parameters that affect the lightning performance of HVDC lines. The probability of shielding failure is higher than that obtained by the deterministic lightning attachment models. The stochastic nature of lightning attachment and the effect of lightning peak current distribution should be considered for the design and evaluation of the lightning performance of the emerging HVDC systems.