An efficient method of identifying coherent generators using Taylor series expansion

A novel method of identifying the coherency of a group of generators is presented. The method requires values of generator rotor angles at three distinct instants of time in the early part of the transients. Also, a measure of the degree of electrical coupling between the generators is required. The angles are calculated during the faulted and part of the postfault period through Taylor-series expansions. The degree of coupling is calculated from an admittance distance measure. The proposed method has been tested on five different power systems of varying sizes. It is concluded that the results obtained by the proposed method match perfectly those obtained through simulation of the total system dynamics