Determination of Harmonic Interference Voltages Induced in Paired-Cable Communicatioins Circuits by Harmonic Currents in Adjacent Power Lines

Magnetic field patterns under typical configurations ions of distribution lines due to harmonic currents are analyzed. Laboratory measurements of differential voltages induced in a section of twisted-pair telephone hone cable in the presence of known magnetic fields at harmonic frequencies are reported. These data are used to predict induced voltages in communications circuits as functions of harmonic current and distances ances over which the power and communications cables run parallel. Such results permit much closer estimates ates of the likelihood of harmful interference for specific circuit configurations than use of the Telephone hone Influence Factor method.