Calculation of magnetic fields from electric power transmission lines

摘要

The conventional method is applied for computation of magnetic fields around multi-phase AC lines where each subconductor is represented by a filament current extending along its axis. The method is checked against a more accurate 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 coordinates of the simulation currents are not arbitrary but dependent on the number of subconductors and their arrangement in space. The ground-level magnetic-field profile is almost the same whatever it is calculated by the simulation technique or by the conventional method. However, the distribution of the magnetic-field intensity around the phase conductors calculated using the simulation technique is symmetrical around the periphery of the outer phase conductors in comparisions with the asymmetrical one obtained by the coventional method. The present calculated components of the magnetic flux density agreed satisfactorily with those measured and calculated before underneath three-phase single- and double-circuit transmission lines.