Analysis of shielding failure in transmission lines considering both first and subsequent strokes

Abstract

This work asses the shielding failure of transmission lines by applying the Electrogeometric Model, notably considering the influence of both first and subsequent strokes and also channel angles different from 0° (vertical channel). Considering different tower geometries, it is shown that the shielding failure rate of transmission lines is much more significant for subsequent strokes than for first stroke currents. Furthermore, it is shown that considering channel angles different from 0° leads to an increase of the number of strokes hitting phase conductors. Such increase can be very significant depending on the tower geometry, for instance, in case of EHV double circuit lines.