Regulation Problems of Combined Cycle Gas-Steam Turbine Power Plant in a Liberalized Market: Part II - Thermodynamic Analysis

This paper addresses the thermodynamic analysis performed with reference to a 760 MW Combined Cycle Gas-Steam Power Plant, built in Sparanise (Italy) and went into service in September 2007. The analysis is based on the experimental analysis already described in Part I of the work. The new Italian legislation revealed a number of technical and economic issues for Combined Cycle Power Plants designed to reach out their maximum efficiency in the operation at the nominal point, thus affecting its efficiency, operations and maintenance costs. In fact, this Plant does not operate at constant maximum load (Base Load) but it is forced to continuous load variations facing the problem of Frequency Regulation. For the evaluation of these aspects, thermodynamic analyses have been performed. This activity is used to identify the combinations of control parameters that maximize the overall performance and enable the evaluation of different system configurations. An application of the tool developed for the thermodynamic analysis has also been proposed to evaluate the effect of the Inlet Fogging Technique on the global efficiency and significant quantities.