Adaptive fuzzy control of combined cycle plant start up

Greater thermal efficiency and flexibility of operation of combined cycle plant (CCP) have made their use more wide spread. A CCP makes use of one or more gas turbines, associated special boilers known as heat recovery steam generators and a steam turbine. The steam, for the steam turbine, is formed through utilisation of the waste heat from gas turbine(s) in the heat recovery steam generator(s). The start up and shut down of CCP require the scheduling of gas turbines and the steam turbine to achieve the rated output in the shortest period of time. The most important variable to affect the start up time is the physical constraint of thermal stress. This paper suggests the use of adaptive fuzzy logic in an attempt to optimise the start up and shut down times whilst keeping within thermal stress limits