A tutorial about tower transmission models for the analyses and prediction of backflashovers

Lightning is one of a main causes of sudden outages in the power systems. When a lightning strikes the ground wires or directly to transmission tower, a backflashover may occur. It consists of an electric arc from the tower structure to the line phase conductors, causing transient voltage surges in the transmission line and may cause an outage. In this context, an electric parameter named tower surge impedance plays a key role for the prediction and estimation of backflashovers. Several authors have proposed models representing the transmission tower in order to estimate its surge impedance and measure overvoltages caused by the lightning on transmission lines. In this article, a brief historical survey on transmission towers modelling proposed by diverse authors, a description of the backflashover and the most common models for representing towers are presented.