A Novel Method to identify Coherent Generators using Graph Theory and Clustering

Power system stability, control, and design studies are time-consuming due to the formation of large size and heavy interconnection networks. Reduced ordered dynamic equivalent methods are thus so desirable for performing these studies. Simple equivalents are obtained by converting large and complex networks into smaller networks. One of the approaches to the problem of model reduction is to find coherency-based generator grouping and aggregation. In this method, first, based on network characteristics, each group of coherent generators is replaced with a dynamic equivalent, and then the dynamic equivalent of the generators is used in the studies of power networks. In this regard, in this article, using graph theory and clustering quality index, a novel method for finding coherent generators in a power network is presented. The proposed method is simple and the network admittance matrix is the only information required by this approach. The IEEE 39-bus network is used to show the effectiveness of the proposed approach. The comparison of the results with other research shows that the proposed method identifies the coherent generators with an acceptable approximation.