Influence of the presence of grounded wires on the lightning performance of a medium-voltage line

The paper compares the effect that the shield wire, underbuilt grounded conductor, and surge arresters have on the direct and indirect lightning performance of medium voltage overhead lines and provides its quantitative assessment. The paper focuses on a line configuration characterized by the presence of both shield wire and underbuilt neutral wire. The presence of the grounded shield wire significantly reduces the voltages induced across the insulators. In case surge arresters are installed, the effect of the shield wire is shown to have a lower impact. The environmental shielding on the overall lightning performance is also accounted for by considering the effect of the buildings close to the line that reduce the frequency of direct events and increase the frequency of indirect ones.