Abstract: Methods and apparatus for operating a combined-cycle power system are provided. The method includes operating the steam turbine, the combustion turbine, and the steam source at steady state operating conditions. Upon sensing a grid frequency deviation away from the standardized grid frequency value, determining a current thermal energy capacity of the steam source, determining a rate of frequency recovery available using the current thermal energy capacity of the steam source and a predetermined rate of change of the at least one steam turbine control valve, if the determined rate of frequency recovery available is greater than the grid frequency deviation, mitigating the frequency deviation using the current thermal energy capacity, if the determined rate of frequency recovery available is less than the grid frequency deviation then mitigating the frequency deviation using the current thermal energy capacity substantially simultaneously with a power level increase of the combustion turbine.

Abstract: Methods and apparatus for operating a combined-cycle power system are provided. The method includes operating the steam turbine, the combustion turbine, and the steam source at steady state operating conditions. Upon sensing a grid frequency deviation away from the standardized grid frequency value, determining a current thermal energy capacity of the steam source, determining a rate of frequency recovery available using the current thermal energy capacity of the steam source and a predetermined rate of change of the at least one steam turbine control valve, if the determined rate of frequency recovery available is greater than the grid frequency deviation, mitigating the frequency deviation using the current thermal energy capacity, if the determined rate of frequency recovery available is less than the grid frequency deviation then mitigating the frequency deviation using the current thermal energy capacity substantially simultaneously with a power level increase of the combustion turbine.

Abstract: A method and apparatus for operating a combined-cycle power system is provided. The system is coupled to an electric power grid. The system includes at least one electric power generator, at least one steam turbine coupled to the generator, at least one combustion turbine coupled to the generator, and at least one steam source that is in flow communication with the steam turbine. The method includes operating the system at a first power output level with the steam turbine and the combustion turbine being synchronized to an operating frequency of the grid, so that the steam turbine, the combustion turbine, and the grid are operating at a frequency substantially similar to a standardized grid frequency value. The method also includes sensing a grid frequency deviation away from the standardized grid frequency value.

Abstract: A method and apparatus for operating a combined-cycle power system is provided. The system is coupled to an electric power grid. The system includes at least one electric power generator, at least one steam turbine coupled to the generator, at least one combustion turbine coupled to the generator, and at least one steam source that is in flow communication with the steam turbine. The method includes operating the system at a first power output level with the steam turbine and the combustion turbine being synchronized to an operating frequency of the grid, so that the steam turbine, the combustion turbine, and the grid are operating at a frequency substantially similar to a standardized grid frequency value. The method also includes sensing a grid frequency deviation away from the standardized grid frequency value.

Abstract: A method to rapidly change a power output level of a steam turbine including the steps of: operating the steam turbine at a continuous power output level including regulating a steam temperature to a constant steam temperature set point; receiving a demand for a rapid change in the power output level of the steam turbine; adjusting the steam temperature set point to a temporary temperature excursion limit selected to achieve the demand for the rapid power change; regulating the steam temperature in the turbine to the temporary temperature excursion limit; operating the turbine at a temporary power output level achieved using the temporary excursion limit; generating power by the turbine using steam regulated to the temporary temperature limit, and changing the temperature used to regulate the turbine after a predetermined period.