Metodologia para representação da influência de meios externos nos parâmetros unitários de cabos subterrâneos e submarinos

Abstract

Proposes a methodology for an accurate inclusion of the influence of external media in the per unit length parameters of underground and submarine cables. The per unit length expressions for the impedance and admittance were obtained using a full-wave model and then simplified considering a quasi-TEM (Transverse Electromagnetic) approximation. The accuracy of the proposed approximation lies in the range of a few MHz, thus being suitable for most of the power system transient analysis. The quasi-TEM approximations are used to derive a transient model for several cable configurations comprising: single-core, pipe-type and a cable system. The Numerical Laplace Transform is used to obtain the timedomain responses of distinct mode excitations. A modification of a previously developed approximation of the full-wave model, named quasi-full-wave, is also presented. This formulation might be useful when accurate evaluation of electromagnetic field in the surroundings of a conductor is needed.