Báo Cáo Analysis of series impedance matrix models and induced magnetic field of transmission lines above lo

ABSTRACT
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This paper considers the influence of earth complex resistivity and sag to magnitude of the
induced magnetic field of transmission lines above lossy ground. We first analyze and compare series
impedance matrix calculation methods. We secondly propose a simple formula for calculating a height
of overhead distribution lines in a span. Finally, we present new theoretical analysis of the induced
magnetic field computation of power lines in a span based on the earth-return impedance formulae
which proposed by Taku Noda [5]. These analytical formulae are more accuracy about mathematics
and physics because, in which, the correction of earth resistivity and the line height are taken into
account. Results are presented by means of graphs that are shown that all values of inductances
(impedances) and induced magnetic fields always vary with complex resistivity and the height of the
line in a span.

Keywords: Transmission lines, induced magnetic field, complex resistivity, line sag.