Abstract: The present application provides a method of optimizing fan usage in a cooling water system having a number of fans with a heat exchanger to cool a cooling fluid for use with a number of gas turbine subsystems. The method may include the steps of running all of the fans at base load, calculating a heat transfer capability of each fan at base load, calculating a temperature difference between an actual temperature and a target temperature of the cooling fluid, selecting a minimum target temperature of the cooling fluid, calculating a target thermal energy of the cooling fluid for the minimum target temperature, calculating a number of the fans to be turned on or off by dividing the target thermal energy with the heat transfer capability of each fan, and turn on or off the calculated number of fans in a predetermined manner with an objective of balancing the running hours of each fan.

Abstract: The present application provides a method of optimizing fan usage in a cooling water system having a number of fans with a heat exchanger to cool a cooling fluid for use with a number of gas turbine subsystems. The method may include the steps of running all of the fans at base load, calculating a heat transfer capability of each fan at base load, calculating a temperature difference between an actual temperature and a target temperature of the cooling fluid, selecting a minimum target temperature of the cooling fluid, calculating a target thermal energy of the cooling fluid for the minimum target temperature, calculating a number of the fans to be turned on or off by dividing the target thermal energy with the heat transfer capability of each fan, and turn on or off the calculated number of fans in a predetermined manner with an objective of balancing the running hours of each fan.

Abstract: A steam turbine has a rotor-stress reducing steam system coupled to the rotor bore of the rotor shaft so as to introduce steam in the rotor bore. The rotor-stress reducing steam system has a radial steam supply device in which steam is introduced via radial channels through the rotor core, or alternatively, an axial steam supply device has a steam supply tube coaxially disposed within the rotor bore. The surface of the rotor core that is the boundary of the rotor bore typically has rifled grooves so that condensate from the warming steam is collected and directed to a bore condensate drain apparatus coupled to the rotor bore.

Abstract: A method of minimizing undesirable emissions from and acoustic pressure oscillations in a gas turbine includes the step of coordinating modulation of turbine fuel and air supply signals to maintain the fuel air ration (FAR) within a selected range. Coordination of the modulation of fuel and air supply signals includes the steps of producing a turbine fuel supply control signal in correspondence with a turbine speed error signal, generating a coordinated turbine exhaust temperature error signal by modifying a preliminary turbine exhaust temperature error signal in correspondence with the speed error signal, and producing a turbine air supply control signal from the coordinated turbine exhaust temperature error signal; the coordinated turbine exhaust temperature error signal provides coordination between the turbine fuel supply signal and the turbine air supply signal so as to maintain the fuel-air ratio of the combustible mixture being fed to the turbine within the selected range.

Abstract: A method and apparatus are disclosed for inherent, reliable control of real time systems. The technique is based on asynchronously scheduling a plurality of sensor sampling cycles over a suitable sampling interval. The corresponding plurality of sampling signals so obtained are temporally redundant and out of phase with respect to one another. This plurality of sampling signals is processed by a corresponding plurality of controllers. Thereafter, a multiplexor means is used to alternately and asynchronously receive from each controller a subinterval portion of each of the plurality of signals corresponding to each of the plurality of controllers. In this way the sampling interval is responsively partitioned into subintervals wherein each controller of the plurality effectively controls the system for each respective subinterval. Concurrent multiple control of each interval inherently masks and compensates for faults or failures.