Abstract: A method for automated control of a steam turbine prewarming procedure employs fuzzy logic to generate a control signal for a turbine regulatory function, such as steam supply. The method includes the steps of determining a plurality of turbine condition parameter signals; generating a plurality of regulatory control directions; generating a weighting factor to be assigned to each of said regulatory control directions by means of a fuzzy inference calculation in accordance with an operator-selected fuzzy logic profile, and applying the weighting factors to the regulatory control directions to produce the turbine regulatory function control signal. The turbine regulatory function control signal is applied to a respective function controller in the steam plant such that the selected turbine prewarming profile is implemented.

Abstract: In a steam turbine system including a high pressure turbine section, a reheat turbine section and a low pressure turbine section coupled to a generator, and wherein a boiler supplies steam to the high pressure turbine and wherein a condenser is arranged to receive spent steam from the low pressure turbine and to return the spent steam to the boiler, a process including the steps of: a) during cold start-up, bypassing a portion of the steam generated by the boiler around the high pressure turbine section, reheat turbine section and low pressure turbine section and feeding the bypass portion directly to the condenser, accelerating the turbine to a predetermined speed less than approximately 1000 rpm utilizing control valves at an inlet side of the high pressure turbine section while keeping closed a plurality of intercept valves at an inlet side of the reheat turbine section; and wherein steam pressure to the high pressure turbine section is controlled by a high pressure bypass valve; and b) upon reaching said

Abstract: A signal representing the electrical output power of a steam turbine-generator is fed back to a control system. A signal representing the boiler steam pressure is also fed to the control system. A control signal for controlling valves feeding steam to the steam turbine is gain controlled between one and zero in the presence of a negative rate of change of steam pressure less than a predetermined value. At other negative and all positive values of rate of change of steam pressure, the control signal is unaffected. In one embodiment, a linear relationship is employed for controlling the gain for increasingly negative values of the rate of change of steam pressure. At an extreme negative value, the gain is controlled to zero, whereby the a load reference signal remains unchanged.

Abstract: Improved method and apparatus for controlling thermal stress on component parts of a steam turbine while providing maximum loading and unloading rates during startup, shutdown, and other periods of load change. From monitored and derived quantities, a loading rate is calculated for each of a plurality of preselected turbine component parts and the lowest rate is selected for control. Simultaneously, and in concert with load change calculation and execution, the steam admission mode of the turbine is automatically directed to either the partial arc mode or the full arc mode as necessary to reduce stress as compared with a preselected and adaptive stress reference value.