Steam turbine fuzzy logic cyclic control method and apparatus therefor

Abstract

A method for automated control of a steam turbine during cyclic operation includes the steps of comparing current turbine loading with an anticipated load profile to generate a load error signal. Anticipated electrical load profiles correspond to the time of day, day of the week, month of the year, and historical data; operator input can vary such historical profiles as appropriate for unusual situations. The predicted load profile is categorized with respect to selected composite electrical load cycle profiles; weighted operating constraints are generated by means of a fuzzy inference calculation using electrical cycle profiles selected to correspond to the anticipated electrical load profile. Control signals for selected steam plant regulatory functions, such as steam supply valve position and boiler pressure, are produced by applying the fuzzy logic-generated weighted operating constraints and the load error signal so as to optimize turbine load-following efficacy, steam plant efficiency, and machinery stress reduction. These control signals are then applied to respective regulatory function actuators in the steam plant to implement the desired trajectory of steam plant operation.