Accurate representation of soil behaviour for transient studies

A paper representation of soil behaviour for transient studies is presented. Such representation is more accurate than the most common procedures of engineering practice and, in several conditions, lead to results with important differences. The proposed model takes into account the earth´s conductivity and permittivity frequency dependence, which normally are not considered. One of the aspects covered in the paper is the importance of properly considering the Earth´s electromagnetic behaviour when calculating transmission line parameters. Some comparisons are presented for an actual 440 kV three-phase transmission line in which the soil behaviour is represented through a unique real value of conductance (the normal approach) and through the proposed model.