Steam turbine fuzzy logic cyclic control method and apparatus therefor

A method for controlling a turbine in a steam plant using fuzzy logic such that future projected load demand is considered in determining current turbine control action so as to respond to cycling loads in an optimal fashion, the method comprising the steps of:

• comparing current turbine loading with selected composite electrical-load cycle profiles to generate a load error signal, each of said electrical cycle profiles comprising multiple sequential load stages corresponding to phases of a predicted turbine loading profile;
• generating weighted operating constraints by means of a fuzzy inference calculation in correspondence with selected ones of said electrical cycle profiles;
• producing control signals for selected steam plant regulatory functions by applying said weighted operating constraints and said load error signal so as to optimize turbine load-following efficacy, steam plant efficiency, and machinery stress reduction;
• and
• applying the steam plant regulatory control signals to respective regulatory function actuators in said steam plant.

A steam plant controller for controlling cyclic operation of the steam plant in response to changes in electrical load demand on a turbine generator unit in said plant, comprising:

• a boiler controller comprising means for selectively adjusting the steam pressure delivered to said turbine generator unit;
• a steam supply control apparatus coupled to said turbine generator unit so as to selectively control the amount of steam admitted into the turbine;
• and
• a steam plant cyclic controller coupled to said boiler controller and said steam supply control apparatus, said steam plant cyclic controller comprising means for generating control signals for said boiler controller and said steam supply control apparatus so that selected steam plant operation parameters are optimized with respect to an anticipated load profile by means of a fuzzy inference calculation.