Identification of coherent generators considering the electrical proximity for drastic dynamic equivalents

This paper describes an application of the coherency-based dynamic equivalent methodology to determine drastic reductions in the representation of power systems. This condition is necessary for real time power system simulator studies. The paper demonstrates that the exclusion of electrically distant generators from the coherent groups solves the convergence problems that may appear in the power flow algorithm during the calculation of drastic dynamic equivalents. This paper also demonstrates that for each fault neither the strongly coherent generators are always electrically close, nor the approximately coherent generators are always electrically distant. The New England system and two simplified configurations of the Brazilian interconnected power system are considered in the studies.