Comparative analysis on the part load performance of combined cycle plants considering design performance and power control strategy

The purpose of this study was to analyze the relationship between the part load performance and design performance of gas turbines and combined cycle plants. The effect of power control strategy on the part load performance of the combined cycle was also examined. The analysis was carried out using a proven cycle simulation program. Based upon the design performances of actual gas turbines, a consistent principle of design point selection was applied to four different gas turbines representing various technology levels. The part load control strategies considered were fuel-only control and IGV control. It has been observed that gas turbines with higher design performances exhibit superior part load performances. Since the average combined cycle performance is affected by the range of IGV control, as well as its temperature control principle, a control strategy appropriate for the load characteristics of the individual plant should be adopted.