A fast algorithm for coherency identification and dynamic equivalencing of power systems

An analytical method to decompose a power system into a number of weakly interconnected areas and further to identify the coherent machine groups in each area is presented in this paper. The proposed method is based on a technique of grouping related elements of the network. The system decomposition and coherency groupings obtained is independent of the location of the faults to be simulated in the system. The first part of the algorithm of decomposing the system into weakly coupled areas uses only the information about the transfer admittances between the generator internal nodes. For the subsequent part of identifying the coherent groups of machines in each area, transfer admittances and moments of inertias of the machines are used.