Lightning strokes to power transmission lines and lightning protection systems

A method, based on the electromagnetic field concepts, for prediction of the expected strokes to HV power transmission systems is presented. This method also makes it possible to determine the probable striking points in the system and study the efficiency of the shielding effects of overhead ground wires. The covered area and probable strokes to a HV transmission line are studied as an example. The theoretical calculations are compared with field data. These calculations show that by studying the various striking points in the system, a better shielding can be designed. The shielding angles vary not only from one configuration to another, but even within the same tower from one phase wire to another. Thus, the number of required overhead ground wires and their locations can be determined more accurately