Magnetic Fields Around a Transmission Line Tower

The magnetic fields produced around a transmission line tower by the passage of lightning current down the tower have been investigated by the use of geometrical models. The results show that former measurements of tower currents with magnetic links must be reappraised. The equivalent cylinder that represents a transmission tower has been determined experimentally, and the effective tower inductance and surge impedance derived. A new and more accurate method for interpreting tower magnetic-link measurements of lightning surges is described.