Abstract: Systems and methods for controlling exhaust steam temperatures from a finishing superheater are provided. In certain embodiments, the system includes a controller which includes control logic for predicting an exhaust temperature of steam from the finishing superheater using model-based predictive techniques (e.g., based on empirical data or thermodynamic calculations). Based on the predicted exhaust temperature of steam, the control logic may use feed-forward control techniques to control the operation of an inter-stage attemperation system upstream of the finishing superheater. The control logic may determine if attemperation is required based on whether the predicted exhaust temperature of steam from the finishing superheater exceeds a set point temperature as well as whether the inlet temperature of steam into the finishing superheater drops below a set point temperature of steam.

Abstract: A control system for a combined cycle power generation system including a gas turbine engine (GT), a heat recovery steam generator (HRSG), and a steam turbine (ST) includes a display wherein an operator may observe information about predicted operating parameters; a user interface wherein an operator may provide additional operating constraints; and a controller configured to generate input profiles of the GT, the HRSG, and the ST that satisfy the nominal constraints and any additional constraints and to generate the information about the predicted operating parameters. The controller may be configured to detect a stage transition of power generation system operation and update the input profiles. The controller may be configured to generate alternative operating scenarios by mapping alternative control actions to an operating constraint of at least one of the system components.

Abstract: Methods and apparatus for controlling load on a machine are provided. The method includes determining a maximum value of a process variable using a predictive model of the machine while holding a control output associated with the process variable substantially constant over a prediction period, incrementing the control output if the determined maximum value of the process variable is within an allowable limit range, and setting the control output to the last value of the process variable that did not cause the process value to exceed the allowable range.

Abstract: Block loading may occur during the process of restoring an electrical grid after a blackout. A method and system for coordinating the loading of a combined cycle power plant to support block loading is provided. The power plant may include a gas turbine and a steam turbine. The method and system may provide load control loops, for the gas and steam turbine, which support block loading.

Abstract: In an integrated gasification power plant a steam recovery system is provided. The system enables power generation equipment designed for a predominant fuel and operating condition to efficiently utilize additional steam generation by syngas coolers when heat transfer surface condition or fuel characteristics enable additional steam generation. The system can detect excess steam generation, integrate it with the syngas cleaning process and transmit it to the power generation equipment. The system results in a low cost power generation system which is capable of efficiently operating with a wide range of fuels and a wide rang of operating conditions.

Abstract: Systems and methods for controlling exhaust steam temperatures from a finishing superheater are provided. In certain embodiments, the system includes a controller which includes control logic for predicting an exhaust temperature of steam from the finishing superheater using model-based predictive techniques (e.g., based on empirical data or thermodynamic calculations). Based on the predicted exhaust temperature of steam, the control logic may use feed-forward control techniques to control the operation of an inter-stage attemperation system upstream of the finishing superheater. The control logic may determine if attemperation is required based on whether the predicted exhaust temperature of steam from the finishing superheater exceeds a set point temperature as well as whether the inlet temperature of steam into the finishing superheater drops below a set point temperature of steam.

Abstract: A control system for a combined cycle power generation system including a gas turbine engine (GT), a heat recovery steam generator (HRSG), and a steam turbine (ST) includes a display wherein an operator may observe information about predicted operating parameters; a user interface wherein an operator may provide additional operating constraints; and a controller configured to generate input profiles of the GT, the HRSG, and the ST that satisfy the nominal constraints and any additional constraints and to generate the information about the predicted operating parameters. The controller may be configured to detect a stage transition of power generation system operation and update the input profiles. The controller may be configured to generate alternative operating scenarios by mapping alternative control actions to an operating constraint of at least one of the system components.

Abstract: An actuation pressure control system effects actuation of adjustable seal segments between stationary and rotating turbomachinery members. At least one actuator is coupled with each of the adjustable seal segments and controls a position of the seal segments, respectively. A pressure system is disposed within the turbomachinery that measures or estimates ambient pressure representing an actuator back pressure acting against the actuator. A pressure regulator via a controller pressurizes the actuator to a level sufficient for a desired seal operation and controls actuator pressure based on the actuator back pressure.

Abstract: Block loading may occur during the process of restoring an electrical grid after a blackout. A method and system for coordinating the loading of a combined cycle power plant to support block loading is provided. The power plant may include a gas turbine and a steam turbine. The method and system may provide load control loops, for the gas and steam turbine, which support block loading.

Abstract: A method and system for determining a limit exceedance of an operating parameter in a steam turbine system. Measurement data associated with the operating parameter is received, and a limit exceedance is determined when the rate of change in the received data over a predefined period of time exceeds a predefined limit. A control action is taken when a limit exceedance has been determined.

Abstract: An actuation pressure control system effects actuation of adjustable seal segments between stationary and rotating turbomachinery members. At least one actuator is coupled with each of the adjustable seal segments and controls a position of the seal segments, respectively. A pressure system is disposed within the turbomachinery that measures or estimates ambient pressure representing an actuator back pressure acting against the actuator. A pressure regulator via a controller pressurizes the actuator to a level sufficient for a desired seal operation and controls actuator pressure based on the actuator back pressure.

Abstract: Methods and apparatus for controlling load on a machine are provided. The method includes determining a maximum value of a process variable using a predictive model of the machine while holding a control output associated with the process variable substantially constant over a prediction period, incrementing the control output if the determined maximum value of the process variable is within an allowable limit range, and setting the control output to the last value of the process variable that did not cause the process value to exceed the allowable range.

Abstract: In a method of controlling steam flow through a steam turbine having a turbine rotor, a maximum heat transfer rate is determined based on thermal stress calculations in the turbine rotor. A maximum steam flow rate can be calculated based on the maximum heat transfer rate. An actual steam flow rate through the steam turbine is determined, and a turbine inlet valve is controlled based on a difference between the actual steam flow rate and the maximum steam flow rate. In this manner, steam flow can be controlled to the steam turbine in such a way as to limit thermal stress to an acceptable level while minimizing start times and maximizing operability.