Effects of conductor sag on spatial distribution of power line magnetic field

Abstract

Traditional extremely low frequency (ELF) magnetic field computation techniques assume that the current carrying power line conductors are straight horizontal wires. This assumption results in a model whose magnetic fields are distorted from those produced in reality.An exact solution and an approximation are proposed for modeling magnetic fields produced by the sagged conductors of power lines, by taking advantage of the fact that the equation of the catenary exactly describes the line sag. The proposed approaches differ in the required computational burden and in the precision of the results. A field mapping measurement example illustrates the applicability and the need for this analysis. The relative importance of the catenary effect is discussed.

Influence of Environmental Conditions on Emf Levels in a Span of Overhead Transmission Lines

“…Moreover, the accuracy of the equation for the catenary and parabola is almost the same [5]. Therefore, while the mechanical wire calculations in practice are performed with the parabola; the catenary is recommended to use for very long spans (700-1000 m).…”

“…Nevertheless, it is possible to obtain satisfactory accuracy of calculated results by means of two-dimensional approaches with the height variation along the span, demonstrated in [5,7]. Based on these approaches, in order to obtain the distribution of EMFs in the span, it is necessary to use Equations (11) or (12) for computing the height of wire H at every calculation point.…”

“…For instance, in papers [1][2][3][4], an OTL was represented as straight horizontal conductors, allocated at the given constant height. The authors of a paper [5] proposed an exact solution and an approximate equation of the catenary for MF calculations. It was shown that the approximation, which assumes a wire as a straight and horizontal conductor with the height varied at each point and equaled to the height of the catenary or the parabola, provides satisfactory accuracy (5%).…”

Voltage induced by currents in power-line sagged conductors in nearby circuits of arbitrary configuration

“…A sagging power line conductor has a form of a catenary curve. The approximating equation of the catenary can be written in the form [11,16,17]:…”

“…The effect of the catenary on the amplitude of the magnetic field can be significant in some cases [11][12][13][14][15][16][17].…”