Characteristics of low frequency electric and magnetic fields in the vicinity of electric power lines

Abstract

The authors describe the quasi-static and radiation fields of simple three-dimensional sources and proceed to a two-dimensional source. It is shown that the quasi-static approximations result in an error of 0.000002% for fields at 100 m or less from the power line. This is followed by a discussion of how the quasi-static fields are coupled together by Maxwell's equations. It is shown that the electric field of a power line can formally be determined from the magnetic fields, but this cannot be done practically. The electric and magnetic fields are assumed to be independent and are related respectively to voltage and current. The conditions under which electric and magnetic fields are related by the free space impedance are discussed. In general, they are not for power line fields. Poynting's theorem is applied to the power line fields to describe the bulk power transferred along the power line as a result of the quasi-static fields and to calculate the insignificant amount of power radiated laterally away from the power line.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>