Study on the mathematical model and primary frequency regulation characteristics of combined cycle plants

Combined cycle plants have significant impact on the primary frequency regulation stability of a power system. Because of the complexity and non-linearity of combined cycle plants, the modeling is very challenging. It is important to propose a simplified mathematical model for studying primary frequency regulation characteristics of combined cycle plants. In this paper, an appropriately simplified model is proposed based on classical model of a combined cycle plant. This model is suitable for power system analysis on primary frequency regulation stability. Parameters of the proposed model are identified by a method based on genetic algorithm. With all parameters identified, this dynamic model is applied to simulate a real 400MW combined cycle plant. The simulated results and the measured responses are in favorable agreements, indicating the feasibility of the proposed model. The results may be helpful for further studies on the primary frequency regulation of combined cycle plants.