Lightning-Induced Overvoltages on Overhead Medium-Voltage Lines

Lightning is one of the most important causes of failures of overhead power distribution networks. Overvoltages can be caused by both direct and indirect strokes, and the main protective measures consist of the increase of the line insulation level, the application of line arresters, and the use of a shield wire. The overvoltages associated with nearby strokes have usually a significant impact on the lightning performance of overhead distribution lines, especially of those with rated voltage lower than 36 kV. These overvoltages depend on several line and lightning parameters, as well as on the characteristics of the soil. Based on calculations performed using the Extended Rusck Model - ERM, this paper discusses the effects of various parameters on the amplitudes and waveshapes of lightning-induced voltages on overhead medium-voltage distribution lines.