online aggregation of coherent generators based on electrical parameters of synchronous generators

this paper proposes a novel approach for coherent generators online clustering in a large power system following a wide area disturbance. an interconnected power system may become unstable due to severe contingency when it is operated close to the stability boundaries. hence, the bulk power system controlled islanding is the last resort to prevent catastrophic cascading outages and wide area blackout. meanwhile, the aggregation of the coherent generators is the most important step in large power grids intentional defensive splitting to guarantee the dynamic stability of the created islands and reduce the computational burden of the huge initial search space. the proposed method of this paper determines the coherent machines based on the electrical parameters of the synchronous generators instead of the dynamical parameters such as rotor angle or speed curves, speed participation factors, etc. the stator and excitation windings flux, excitation voltage and current have been proposed as coherency indices. the proposed coherency based aggregation has been carried out on new england 39-bus test system. the time-domain simulation results demonstrate the effectiveness and capability of the proposed method to identify the coherent machines following a severe contingency.