Modeling combined-cycle power plant for simulation of frequency excursions

The maximum continuous power output of a combined-cycle power plant depends on the system frequency and the ambient temperature. The temperature control of a gas turbine limits the exhaust temperature by reducing the fuel flow as the airflow decreases with the shaft speed. In this paper, a simple model of a combined-cycle power plant is derived from a detailed design model for an example plant. The model is suitable for long-term simulation of power system dynamic performance involving abnormal frequency conditions.