Induced voltages on transmission lines

ABOUT the year 1929 it first became appreciated that the lightning discharge is not instantaneous. The recognition of this fact had a profound influence upon the theories of lightning protection, the emphasis being diverted from induced to direct strokes¹ as the agent to be guarded against. With the meager information then available the calculations indicated that induced voltages were unimportant when the finite time of discharge was taken into account.² The more accurate information available today calls for a critical analysis of this subject, which is the purpose of the present paper.