New mode-domain representation of transmission line for power systems studies

This paper presents a new model to represent multiphase transmission lines in transient studies, including the frequency dependence of longitudinal parameters. The frequency dependence is represented with synthetic circuits, with one pi-circuit for each mode. The transformation matrix used for the entire frequency range is the Clarke one and as it is a real matrix it is modeled through ideal transformers. The model is described for three-phase lines. An application of the methodology is presented for a 440 kV single three-phase transmission line. The simulations are performed in EMTP. This line model can be implemented in any digital program with R, L, C and transformer components.