An Improved Electrogeometric Model for Transmission Line Shielding Analysis

An improved electrogeometric model - intended for transmission line lightning shielding analysis - is presented, based upon previous empirical and analytical studies of the lightning striking process. In contrast to earlier approaches, the model provides a rational basis for taking account of the influence of structure height and is essentially independent of any assumptions regarding striking distances to ground. Sample applications of the model show comparatively good agreement with line experience, both in the estimation of shielding failure outage rates, and in the calculation of the requisite critical shielding angles.