Lightning-induced voltages on distribution lines with shield wires

One of the methods that can be applied to improve the lightning performance of overhead power distribution lines is the use of shield wires. Although the effectiveness of this measure against direct strokes is quite limited unless the shield wire is grounded at every pole, the ground resistances are low, and the line has sufficient CFO between the ground lead and the phase conductors, the line performance against indirect strokes can be improved. In this paper an analysis is presented of the effectiveness of shield wires in reducing the magnitudes of lightning-induced voltages on medium-voltage distribution lines considering various realistic situations.