The influence of conductive passive parts on the magnetic flux density produced by overhead power lines

There has been apprehension about the possible adverse health effects resulting from exposure to power frequency magnetic field, especially in the overhead power lines vicinity. Research work on the biological effects of magnetic field has been substantial in recent decades. Various international regulations and safety guidelines, aimed at the protection of human beings, have been issued. Numerous measurements are performed and different numerical algorithms for computation of the magnetic field, based on the Biot- Savart law, are developed. In this paper, a previously developed 3D quasistatic numerical algorithm for computation of the magnetic field (i.e. magnetic flux density) produced by overhead power lines has been improved in such a way that cylindrical segments of passive conductors are also taken into account. These segments of passive conductors form the conductive passive contours, which can be natural or equivalent, and they substitute conductive passive parts of the overhead power lines and towers. Although, their influence on the magnetic flux density distribution and on the total effective values of magnetic flux density is small, it is quantified in a numerical example, based on a theoretical background that was developed and presented in this paper. nema