Computation of transmission line magnetic field harmonics

Abstract

AbstractThis work presents an accurate procedure to evaluate low‐frequency magnetic fields produced by overhead power line distorted currents containing several harmonic orders. The analysis is conducted in the framework of quasi‐stationary regimes where wave‐propagation phenomena are of little relevance. Bearing in mind that international regulations for safe public exposure to electromagnetic fields establish increasingly stringent reference levels for the magnetic‐field intensity as the frequency increases, the key issue addressed here is whether the presence of higher order harmonics may cause those reference levels to be exceeded. Complying with standard power quality requirements, our analysis considers that the harmonics have prescribed small magnitudes. Computation examples, including balanced and non‐balanced loads, are presented. It is shown that the worst‐case scenario corresponds to the injection of harmonics produced by balanced loads whose order is a multiple of three. Copyright © 2006 John Wiley & Sons, Ltd.