A state-space combined-cycle power plant model and simulation with IAPWS IF-97 properties

This paper presents an extension of a state-space model for a combined cycle gas turbine (CCGT) power plant in order to include water and steam properties stated by the International Association for Properties of Water and Steam Industrial Formulation 1997 (IAPWS IF-97). The CCGT thermal cycles were implemented using MATLAB XSTEAM IF-97 functions, which provide an accurate steam and water properties within the thermodynamic states model. This model can be used in academia and training environments to test and validate different types of control systems, or even serve as an input for state-estimation methods. Steady state results for this model have been obtained for a generic 20 MW CCGT power plant, as well as a 133 MW steam generation plant in Ecuador. The results reveal that the model provides accurate values for steam flow, temperatures, and power outputs; moreover, the calculated thermodynamic states correspond to actual measurements.