Identification of the dynamic equivalent of a power system

This paper presents the identification of the dynamic equivalent of a power system from on-line measurements by using knowledge of coherent generators to determine the model structure. The knowledge of coherent generators is a crucial part of power system model reduction that could indicate how many equivalent generators should there be and how they are interconnected. By using the interpretation of coherency from the graph model of a power system, the coherent generators can be identified without the necessity of dynamic parameters. Test results of a small five bus system are presented and the feasibility of the proposed method is demonstrated. It is shown that the obtained dynamic equivalent is more reliable when the model structure is used.