Influence of accurate soil representation for transmission-line parameters: Analyses based on Carson's modified formulations

Abstract

In this paper the influence of earth's conductivity and permittivity frequency dependence are evaluated when calculating transversal and longitudinal transmission lines' parameters directly from numerical integration of Carson's modified expressions. As an example of the importance of properly considering the frequency-dependent soil model, an actual 440 kV single three-phase transmission-line was represented, comparing the longitudinal and transversal parameters considering the earth's conductivity and permittivity frequency dependence soil model in relation to the common soil representation with a constant conductivity and permittivity that can be neglected assuming a low frequency approximation.