Abstract: A method and a system for limiting steam flow entering a steam turbine are provided. The method and system may intentionally unbalance the steam flow apportioned between sections of the steam turbine. The steam turbine comprises at least: a first section, a second section, and a rotor disposed within each section. The method may receive a speed/load command, or the like, which provides reference strokes for a first valve, associated with the first section; and a second valve, associated with the second section. The method may also determine an operational parameter that may limit the reference strokes relative to the speed/load command. The operational parameter may determine the allowable steam flow for each section of steam turbine, independent of the speed/load command.

Abstract: A method for increasing the operational flexibility of a turbomachine during a startup phase is provided. The turbomachine may include a first section, a second section, and a rotor disposed within the first section and the second section. The method may determine an allowable range of a physical parameter associated with the first section and/or the second section. The method may modulate a first valve and/or a second valve to allow steam flow into the first section and the second section respectively, wherein the modulation is based on the allowable range of the physical parameter. In addition, the physical parameter allows the method to independently apportion steam flow between the first section and the second section of the turbomachine, during the startup phase.

Abstract: Systems and methods for loading a steam turbine are provided. A method may include: receiving a turbine loading factor; receiving a current steam turbine exhaust temperature; determining a steam flow ramping rate parameter and a steam temperature ramping rate parameter based at least in part on the turbine loading factor and the current steam turbine exhaust temperature, wherein the steam flow ramping rate parameter and the steam temperature ramping rate parameter are determined based at least in part on an inverse relationship between the steam flow ramping rate parameter and the steam temperature ramping rate parameter. The method may further include controlling at least one of: (a) steam flow to the steam turbine based at least in part on the steam flow ramping rate parameter; or (b) steam temperature to the steam turbine based at least in part on the steam temperature ramping rate parameter.

Abstract: A method for increasing the operational flexibility of a turbomachine during a shutdown phase is provided. The turbomachine may include a first section, a second section, and a rotor disposed within the first section and the second section. The method may determine an allowable range of a physical parameter associated with the first section and/or the second section. The method may modulate a first valve and/or a second valve to allow steam flow into the first section and the second section respectively, wherein the modulation is based on the allowable range of the physical parameter. In addition, the physical parameter allows the method to independently apportion steam flow between the first section and the second section of the turbomachine, during the shutdown phase.

Abstract: A method for increasing the operational flexibility of a turbomachine during a shutdown phase is provided. The turbomachine may include a first section, a second section, and a rotor disposed within the first section and the second section. The method may determine an allowable range of a physical parameter associated with the first section and/or the second section. The method may modulate a first valve and/or a second valve to allow steam flow into the first section and the second section respectively, wherein the modulation is based on the allowable range of the physical parameter. In addition, the physical parameter allows the method to independently apportion steam flow between the first section and the second section of the turbomachine, during the shutdown phase.

Abstract: A method for increasing the operational flexibility of a turbomachine is provided. The turbomachine may include a first section, a second section, and a rotor disposed within the first section and the second section. The method may determine an allowable range of a physical parameter associated with the first section and/or the second section. The method may modulate a first valve and/or a second valve to allow steam flow into the first section and the second section respectively, wherein the modulation is based on the allowable range of the physical parameter. In addition, the physical parameter allows the method to independently apportion steam flow between the first section and the second section of the turbomachine, during the loading process.

Abstract: A method and a system for limiting steam flow entering a steam turbine are provided. The method and system may intentionally unbalance the steam flow apportioned between sections of the steam turbine. The steam turbine comprises at least: a first section, a second section, and a rotor disposed within each section. The method may receive a speed/load command, or the like, which provides reference strokes for a first valve, associated with the first section; and a second valve, associated with the second section. The method may also determine an operational parameter that may limit the reference strokes relative to the speed/load command. The operational parameter may determine the allowable steam flow for each section of steam turbine, independent of the speed/load command.

Abstract: A method for increasing the operational flexibility of a turbomachine during a startup phase is provided. The turbomachine may include a first section, a second section, and a rotor disposed within the first section and the second section. The method may determine an allowable range of a physical parameter associated with the first section and/or the second section. The method may modulate a first valve and/or a second valve to allow steam flow into the first section and the second section respectively, wherein the modulation is based on the allowable range of the physical parameter. In addition, the physical parameter allows the method to independently apportion steam flow between the first section and the second section of the turbomachine, during the startup phase.

Abstract: Systems and methods for loading a steam turbine are provided. A method may include: receiving a turbine loading factor; receiving a current steam turbine exhaust temperature; determining a steam flow ramping rate parameter and a steam temperature ramping rate parameter based at least in part on the turbine loading factor and the current steam turbine exhaust temperature, wherein the steam flow ramping rate parameter and the steam temperature ramping rate parameter are determined based at least in part on an inverse relationship between the steam flow ramping rate parameter and the steam temperature ramping rate parameter. The method may further include controlling at least one of: (a) steam flow to the steam turbine based at least in part on the steam flow ramping rate parameter; or (b) steam temperature to the steam turbine based at least in part on the steam temperature ramping rate parameter.

Abstract: An external steam turbine main steam startup control valve bypass loop is provided to facilitate a full pressure combined cycle rapid response/fast start powerplant. The main steam startup bypass control loop particularly includes a main steam startup bypass control valve, which allows for the implementation of high efficiency, low pressure drop main steam control valve that otherwise would not be able to handle the severe throttling duty during a full pressure steam turbine startup and enhances the controllability of the steam turbine allowing for the high fidelity controls necessary to minimize steam turbine rotor stresses.

Abstract: The present invention has the technical effect of reducing the start-up time associated with starting a steam turbine. Embodiments of the present invention provide a new methodology for reducing the steam-to-metal temperature mismatch present during the start-up of a steam turbine. Essentially, embodiments of the invention may raise the pressure of the steam upstream of an admission valve associated with a High Pressure (HP) section of a steam turbine. The initial high pressure of the steam may reduce the enthalpy of steam, reducing temperature of the steam admitted to the HP section.

Abstract: A method controls at least a portion of a combined cycle power plant having at least one gas turbine, at least one heat recovery steam generator, and at least one steam turbine. The method includes developing an actual operating curve of a steam characteristic of the at least one heat recovery steam generator versus an amount of steam provided to the at least one steam turbine from the at least one heat recovery steam generator. The method also includes determining the steam characteristic of the at least one heat recovery steam generator at a point in time during operation of the combined cycle power plant. The method further includes providing an amount of the steam from the at least one heat recovery steam generator to the at least one steam turbine depending upon the determined steam characteristic of the at least one heat recovery steam generator at the point in time.

Abstract: A method of facilitating a probabilistic lifting process is provided. The method includes obtaining operational data for at least one turbine engine, defining a plurality of cool-down curves for the at least one turbine engine, identifying a plurality of different start types of the at least one turbine engine, and developing a formula for the at least one turbine engine. The method also includes determining an operating strategy and establishing a design useful life for the at least one turbine engine, developing at least one histogram and a probabilistic model using the operational data, and determining a mission mix for the operating strategy by performing a simulation of the probabilistic model combined with cyclic life expenditure data of the at least one turbine engine.

Abstract: An external steam turbine main steam startup control valve bypass loop is provided to facilitate a full pressure combined cycle rapid response/fast start powerplant. The main steam startup bypass control loop particularly includes a main steam startup bypass control valve, which allows for the implementation of high efficiency, low pressure drop main steam control valve that otherwise would not be able to handle the severe throttling duty during a full pressure steam turbine startup and enhances the controllability of the steam turbine allowing for the high fidelity controls necessary to minimize steam turbine rotor stresses.

Abstract: A method of facilitating a probabilistic lifting process is provided. The method includes obtaining operational data for at least one turbine engine, defining a plurality of cool-down curves for the at least one turbine engine, identifying a plurality of different start types of the at least one turbine engine, and developing a formula for the at least one turbine engine. The method also includes determining an operating strategy and establishing a design useful life for the at least one turbine engine, developing at least one histogram and a probabilistic model using the operational data, and determining a mission mix for the operating strategy by performing a simulation of the probabilistic model combined with cyclic life expenditure data of the at least one turbine engine.