Indirect lightning performance of a real distribution network with focus on transformer protection

The paper applies the Monte Carlo procedure proposed by the Authors to evaluate the indirect lightning performance of a real medium-voltage distribution network, which includes feeders and laterals, poles, secondary substations and surge protection devices. Such a procedure allows inferring the amplitude of lightning-induced voltages at any point and any phase of the network. The analysis presented in this paper aims at assessing the expected mean time between failures of each MV/LV transformer caused by indirect lightning strikes. A heuristic technique has been specifically developed to reduce the computational effort despite the non-linear response of the network enhanced by the presence of surge arresters.