Mixed Numerical Methodology for Evaluation of Low-Frequency Electric and Magnetic Fields Near Power Facilities

Abstract

This paper develops a mixed finite-element, analytical solutions, equivalent surface impedance methodology for the computation of electric and magnetic field distributions near power facilities. The proposed method enables efficient consideration of conductor sag, ground surface irregularities, proximity effects of metallic components such as transmission line towers, and transformer tank walls as well as human presence. Application examples of this methodology are given, illustrating that under a single-circuit 400 kV transmission line, the maximum electric field intensity at 1.5 m height from the ground is generated at a distance of 10 m from the line center while the maximum current density induced in a human standing on the ground is developed in the ankle; the computed values are practically half of the admissible limits of 5 kV/m and 2 mA/m2, respectively, foreseen for general public exposure by international standards.