Calculation of magnetic fields from electric power transmission lines

The conventional method is applied for computation of magnetic fields aroun d multi-phase AC lines where each subconductor is represented by a filament current extending along its axis. The method is checked against a more acc urate efficient method based on the simulation technique. In this technique , each subconductor current is simulated by a finite number of filamentary line currents distributed within the subconductor. The number and coordinat es of the simulation currents are not arbitrary but dependent on the number oi subconductors and their arrangement in space. The ground-level magnetic -field profile is almost the same whatever it is calculated by the simulati on technique or by the conventional method. However, the distribution of th e magnetic-field intensity around thr phase conductors calculated using the simulation technique is symmetrical around the periphery of the outer phas e conductors in comparison with the asymmetrical one obtained by the conven tional method. The present calculated components of the magnetic flux densi ty agreed satisfactorily with those measured and calculated before undernea th three-phase single- and double-circuit transmission lines. (C) 1999 Else vier Science S.A. All rights reserved.