Development of the dynamic equivalent model for large power system

This paper presents a procedure to construct an equivalent model of a large power system based on nonlinear time simulation responses. It consists of coherency identification, generator aggregation and network reduction. A coherency index that can be directly implemented to this procedure is proposed. Generator aggregation based on the detailed model is performed. This procedure can be used to construct an equivalent model in PSS/E. It is also possible to reduce the large power system directly from the nonlinear time responses. This procedure is applied to the transient stability analysis of the Korea power system that is now experiencing rapid changes. The equivalent model is compared with the original model in terms of its size, accuracy, speed and performance. This paper shows that the developed equivalent model is a good estimate of the original system.