On the connections between used models of power transmission lines

The dynamic structures of three usual models for power transmission lines are compared. It is shown that, from a systemic point of view, the so-called π-model is the reduction of the distributed parameters one. This complements the well known comparison of the trajectories provided by these models. This new view is useful for the analysis and simulation of power systems dynamic behavior. Indeed, this structural analysis allows one to better link the models used in simulation to the specific phenomena which have to be reproduced like, e.g., interarea oscillations, hyposynchronous oscillations. This leads to the unification and classification of some models actually used in different simulators which can thus be simplified and improved. The results have been obtained in a theoretical framework and, afterwards, checked by numeric simulations.