Statistical evaluation of transferred voltages through transformers due to lightning induced overvoltages

This paper deals with the evaluation of the transferred voltages to the transformer low voltage side, due to lightning induced voltages on overhead distribution lines. The induced voltages calculations, taking into account the presence of electrical devices connected to the electric networks like transformers and surge arresters, is done by its implementation into the ATP/EMTP program. The frequency of certain voltage to be exceeded is evaluated using the Monte Carlo method in order to generate multiple simulation parameters randomly. As a result, it is shown that in some cases the protection devices used to attenuate the overvoltages are insufficient from the user´s point of view.