Field and Analytical Studies of Transmission Line Shielding: Part

An analytical model for the shielding of transmission lines against lightning is extended to the case of partially effective shielding, including the effect of possible leader approach angle distributions. Results of the Pathfinder projects are brought up to date, and the data are shown to be consistent with the model. An index number is developed to aid in classifying line performance, and suggestions are made regarding the study of the backflash problem.