Identification of dynamic equivalents preserving the internal modes

A methodology is presented to construct dynamic equivalents through matching modes associated to internal generators. The formulation is posed as an optimization problem with an objective function based on eigenvalues´ second order sensitivities. The external system is reduced to a few fictitious generators, whose parameters are to be estimated by the optimization procedure. Results show the feasibility of the methodology, able to preserves the modal structure associated with the study system.