Determination of Lightning Response of Transmission Lines by Means or Geometrical Models

The voltages produced across the tower insulators of transmission lines struck by lightning can be determined both by measurements on geometrical models and by calculations. Measurements which have been made on geometrical models of the Ohio Valley Electric Corporation´s (OVEC) 345-kv transmission towers agree well with the calculations of Lundholm, Finn, and Price.1 A simplified theory has been developed, using electromagnetic field concepts and the distributed constants of transmission lines, which explains the relationships between insulator voltages and lightning voltages and lightning stroke currents. This theory includes the effects of the magnetic field produced by the return stroke and the changing electric fields produced by neutralization of the charged column of the leader.