New multiphase mode domain transmission line model

This article presents a new model to represent transmission lines including the frequency dependence of longitudinal parameters. The model uses exact modes, for ideally transposed lines, and "quasi-modes" for non-transposed lines. The line is represented through a cascade of pi-circuits, with one pi-circuit for each mode. The transformation matrix used is real and it is modeled with ideal transformers. The model is described for three-phase lines, dc lines, double three-phase lines and six-phase lines. An ATP-EMTP implementation of a 440 kV three-phase transmission line is performed to illustrate the model and a comparison with two frequency dependent ATP line models are made, the Semlyen and JMarti ones. (C) 1999 Elsevier Science Ltd. All rights reserved.