Control of rotor stresses in turbines during startup operations

Abstract

Embodiments of the present disclosure provide a method for controlling a turbine during startup. The method includes calculating a predicted stress on a rotor (26) of a turbine component (48), and determining whether the predicted stress exceeds a threshold value. If the predicted stress exceeds the threshold value, the inlet valve (104) is adjusted to a warming position with an opening degree less than a minimum load position. When the steam in the discharge passage (112) reaches a target pressure, the discharge valve (110) is partially closed. If a safety parameter of the turbine component (48) violates a boundary while maintaining the warming position of the inlet valve (104), the discharge valve (110) is partially opened while maintaining the warming position of the inlet valve (104). The predicted stress on the rotor (26) is recalculated when the inlet valve (104) is in the warming position. If the predicted stress does not exceed the threshold value, the inlet valve (104) is opened to at least the minimum load position.

Description

Background Art

[0001] The present disclosure relates generally to the operation of a turbomachine. More specifically, embodiments of the present disclosure provide a method for controlling rotor stresses within a portion of a turbomachine system during startup operations, wherein the turbomachine may experience backpressure on or within a turbine element.

[0002] A power generation system (also referred to as a power plant) generally includes a variety of different systems (e.g., turbines, generators, and / or other interconnected components) for producing a power output. Such a power plant may include a power source (e.g., a turbine, a solar panel, a nuclear reactor, etc.), a prime mover (e.g., a rotatable shaft or similar element) for coupling the power source to the generator, and / or various components of the generator. For example, a power generation system may include a gas turbine assembly having a compressor coupled to a gas turbine. The gas turbine, in turn, may be coupled to and drive a generator mounted on the same shaft. The generator produces a power output.

[0003] Power generation systems typically include various turbines and / or systems for generating power output. Examples of such power systems may include gas turbine systems and / or combined cycle power plants that typically include one or more gas turbine systems. Conventional combined cycle power plants employ one or more gas turbine systems that are operably coupled to one or more steam turbine systems. The gas turbine system includes a compressor coupled to a gas turbine. The gas turbine is typically coupled to and drives an external component, such as a generator, for generating a load or power output. The steam turbine system typically includes a high pressure (HP) turbine section that is operably coupled to an intermediate pressure (IP) turbine section that is in turn coupled to a low pressure (LP) turbine. Similar to the gas turbine of the gas turbine system, the HP turbine, the IP turbine, and the LP turbine are used to drive external components (e.g., a generator).

[0004] In a typical combined cycle power plant, the exhaust gases from the gas turbine are transmitted to a heat recovery steam generator (HRSG), which can be used to reheat steam and provide steam to various turbine sections of the steam turbine system to improve the efficiency of the system and / or the power plant. Downstream of the HRSG, the exhaust gases are released to the atmosphere through a chimney. The technical challenges associated with steam turbine (ST) operation are to ensure that the steam turbine components operate safely and reliably during startup, and to maintain various parameters within their target boundaries. In addition to affecting the power output from the ST system, the increase in temperature and pressure from their non-operating values ​​throughout the turbine can also affect the health and life of the ST components. Summary of the invention

[0005] Aspects of the present disclosure provide a method for controlling steam pressure within a turbine component during a startup operation, the turbine component being fluidly coupled between an inlet and a discharge port, the inlet having an inlet valve for controlling steam flow into the turbine component, the discharge port having a discharge valve for controlling steam flow to a discharge passage, the method comprising: adjusting the discharge valve to a fully open position and adjusting the inlet valve to a fully closed position; calculating a predicted stress on a rotor of the turbine component based on a predicted steam flow, a rotor surface temperature, and an inlet steam temperature with the inlet valve in a minimum load position; determining whether the predicted stress exceeds a threshold; and in response to the predicted stress exceeding a threshold, calculating a predicted stress on a rotor of the turbine component; determining whether the predicted stress exceeds a threshold; and ... threshold, adjusting the inlet valve to a warming position that is less open than a minimum load position so that the steam flow through the turbine component pressurizes the exhaust passage; in response to the steam in the exhaust passage reaching a target pressure, partially closing the exhaust valve while maintaining the warming position of the inlet valve; determining whether a safety parameter of the turbine component violates a boundary while maintaining the warming position of the inlet valve; in response to the safety parameter of the turbine component violating the boundary, partially opening the exhaust valve while maintaining the warming position of the inlet valve; recalculating the predicted stress on the rotor when the inlet valve is in the warming position; and in response to the predicted stress not exceeding the threshold, opening the inlet valve to at least the minimum load position.

[0006] Another aspect of the present disclosure provides a program product stored on a computer-readable storage medium for controlling steam pressure within a turbine component during a startup operation, the turbine component being fluidly coupled between an inlet and a discharge port, the inlet having an inlet valve for controlling steam flow into the turbine component, the discharge port having a discharge valve for controlling steam flow to a discharge passage, the computer-readable storage medium including program code for causing a computer system to perform actions including: adjusting the discharge valve to a fully open position and adjusting the inlet valve to a fully closed position; calculating predicted stress on a rotor of the turbine component based on predicted steam flow, rotor surface temperature, and inlet steam temperature with the inlet valve in a minimum load position ; determining whether the predicted stress exceeds a threshold; in response to the predicted stress exceeding the threshold, adjusting the inlet valve to a warming position that is less open than a minimum load position so that the steam flow through the turbine component pressurizes the exhaust passage; in response to the steam in the exhaust passage reaching a target pressure, partially closing the exhaust valve while maintaining the warming position of the inlet valve; determining whether a safety parameter of the turbine component violates a boundary while maintaining the warming position of the inlet valve; in response to the safety parameter of the turbine component violating the boundary, partially opening the exhaust valve while maintaining the warming position of the inlet valve; recalculating the predicted stress on the rotor when the inlet valve is in the warming position; and in response to the predicted stress not exceeding the threshold, opening the inlet valve to at least the minimum load position.

[0007] An additional aspect of the present disclosure provides a turbine system, the turbine system comprising: a turbine component, the turbine component being fluidly coupled between an inlet and an exhaust port, the inlet having an inlet valve for controlling a flow of steam into the turbine component, the exhaust port having a exhaust valve for controlling a flow of steam to an exhaust passage; a control system, the control system being operably coupled to the inlet valve and the exhaust valve of the turbine component, wherein the control system performs an action, the action comprising: adjusting the exhaust valve to a fully open position and adjusting the inlet valve to a fully closed position; calculating a predicted stress on a rotor of the turbine component based on a predicted steam flow, a rotor surface temperature, and an inlet steam temperature when the inlet valve is in a minimum load position; determining the predicted stress whether the stress exceeds a threshold; in response to the predicted stress exceeding the threshold, adjusting the inlet valve to a warming position with an opening degree less than the minimum load position so that the steam flow through the turbine component pressurizes the exhaust passage; in response to the steam in the exhaust passage reaching a target pressure, partially closing the exhaust valve while maintaining the warming position of the inlet valve; determining whether a safety parameter of the turbine component violates a boundary while maintaining the warming position of the inlet valve; in response to the safety parameter of the turbine component violating the boundary, partially opening the exhaust valve while maintaining the warming position of the inlet valve; recalculating the predicted stress on the rotor when the inlet valve is in the warming position; and in response to the predicted stress not exceeding the threshold, opening the inlet valve to at least the minimum load position.

[0008] The illustrative aspects of the present disclosure are designed to solve the problems described herein and / or other problems not discussed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] These and other features of the present disclosure will be more readily understood from the following detailed description of various aspects of the present disclosure taken in conjunction with the accompanying drawings which depict various embodiments of the present disclosure, wherein:

[0010] Figure 1 is a schematic diagram of a control system, a combined cycle power generation system, and other components configured for use in a method according to an embodiment of the present disclosure.

[0011] Figure 2 is an enlarged schematic diagram of a portion of a turbine in the form of a steam turbine (ST) system and a control system according to an embodiment of the present disclosure.

[0012] Figure 3 An illustrative environment of a control system and subcomponents configured to interact with portions of a turbomachine is shown according to an embodiment of the present disclosure.

[0013] Figure 4 An illustrative flow chart of a method for controlling steam temperature within a turbine during startup operations according to an embodiment of the present disclosure is provided.

[0014] Figure 5 An expanded flow chart of a process for controlling steam temperature within a turbine during startup operations according to an embodiment of the present disclosure is provided.

[0015] It should be noted that the drawings of the present disclosure are not drawn to scale. The drawings are intended to depict only typical aspects of the present disclosure and therefore should not be considered to limit the scope of the present disclosure. In the drawings, like numbers represent like elements between the drawings. DETAILED DESCRIPTION

[0016] First, in order to clearly describe the current technology, it will be necessary to select certain terms when referencing and describing the relevant machine parts within the various systems, components and other embodiments of the present disclosure. To the extent possible, common industry terms will be used and adopted in a manner consistent with the accepted meaning of the terms. Unless otherwise stated, such terms should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. Those of ordinary skill in the art will understand that several different or overlapping terms can generally be used to refer to specific parts. An object that may be described as a single part in this article may include multiple parts and be cited as consisting of multiple parts in another context. Alternatively, an object that may be described as including multiple parts in this article may be referred to as a single part elsewhere.

[0017] In addition, several descriptive terms may be used regularly herein, as described below. The terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of individual components.

[0018] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "a kind of" and "the" are intended to also include plural forms, unless the context clearly indicates otherwise. It will be further understood that when used in the specification, the terms "include" and / or "comprise" specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups. "Optional" or "optionally" means that the event or situation described subsequently may or may not occur, and the description includes instances where the event occurs and instances where the event does not occur.

[0019] Where an element or layer is referred to as being "on," "engaged to," "connected to," or "coupled to" another element or layer, it may be directly on, engaged to, connected to, or coupled to another element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to," there may be no intervening elements or layers. Other words used to describe relationships between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0020] Embodiments of the present disclosure provide methods, program products, and systems for controlling rotor stresses within a portion of a turbine. According to one example, the present disclosure can be effectively used to manage high pressure (HP) components of a steam turbine (ST) system during startup operations. In such an example, the present disclosure provides a method for operating an ST system having an HP component, the HP component being fluidly coupled between an inlet and a discharge port, the inlet having an inlet valve for controlling the flow of steam entering the HP component, and the discharge port having a discharge valve for controlling the flow of steam entering the condenser from the HP component. During startup operations, steam may flow through the intermediate pressure (IP) and / or low pressure (LP) sections of the ST system until conditions are met that allow steam to enter the HP component. Embodiments of the present disclosure predict the amount of stress that the initial steam flow will impose on the rotor. If the predicted stress is too high, the method may direct a steam flow less than a minimum load to warm the turbine (e.g., in one example, within the HP component) and pressurize the fluid interconnected components.

[0021] In an embodiment of the present disclosure, an operator of a turbine may initially adjust the discharge valve to a fully open position and the inlet valve to a fully closed position. In this state, no steam flows through the turbine components of the turbine, but any existing fluid may pass through the discharge valve. At this point, the method includes calculating a predicted stress on the rotor of the turbine. "Predicted stress" refers to the stress applied to the rotor at the moment when the minimum operating steam flow begins to pass through the turbine components. Therefore, in addition to the measured values ​​of the rotor surface temperature and the inlet steam temperature, the predicted steam flow is also based on the inlet valve in the minimum load position. In the case where the predicted stress exceeds a stress threshold (hereinafter referred to as the "threshold"), the inlet valve is adjusted to a "warming position" that is less open than the minimum load position, but not completely closed. In this state, the steam flow pressurizes the discharge passage of the condenser and can drive the rotation of the rotor and generate power output. Once the steam in the discharge passage reaches the target pressure, the discharge valve position is reduced while the inlet valve is maintained in the warming position. At this point, the turbine components begin to be pressurized, and the warming of the turbine elements is accelerated. During the warm-up of the turbine components, one or more safety parameters may be monitored and the discharge valve may be partially opened to prevent violations of the boundaries of the safety parameters. The predicted stress at the minimum load position with the inlet valve still in the warm-up position is then recalculated until it is below a threshold. Once the predicted stress is less than the threshold, the inlet valve is opened to at least the minimum load position and the discharge valve is completely closed. In some embodiments, the resulting stress on the rotor is input to a predictive model that adjusts future calculations of the predicted stresses. These adjusted calculations of the predicted stresses may affect the opening and closing of the inlet and discharge valves in future startup operations.

[0022] Reference below Figures 1 to 5 These and other embodiments are discussed. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for illustration purposes only and should not be construed as limiting.

[0023] Figure 1 A schematic diagram of a system 10 according to various embodiments of the present disclosure is shown. In one exemplary implementation, the system 10 may include a combined cycle power generation system 12 (hereinafter referred to as "power generation system 12"), which includes a steam turbine (ST) system 18, which ST system may include a low pressure (LP) component 20, an intermediate pressure (IP) component 22, and a high pressure (HP) component 24, as is known in the art. The LP component 20, IP component 22, and HP component 24 of the ST system 18 may be coupled and / or positioned on a rotor 26 and / or configured to rotate the rotor to produce mechanical work and / or drive additional components of the ST system 18. The various components of the system 10 need not be mounted on only one rotor 26, but may be mounted on and / or operably coupled to multiple corresponding rotors. As shown in FIG. Figure 1 As shown, the rotor 26 of the ST system 18 may be coupled to and / or may drive an external component, and more specifically, the external component is a generator 28 configured to generate electricity and / or produce an electrical load. Although the system 10 is shown and described as a combined cycle power generation system having multiple rotors and / or generators 28, 30, it should be understood that the system 10 may include only the ST system 18, only one rotor 26, and / or any other currently known or later developed type of ST system and / or configuration.

[0024] The power generation system 12 may also include a gas turbine (GT) system 30. The GT system 30 may include a compressor 32. As an incoming fluid flow 34 (e.g., air) flows through the compressor 32, the compressor 32 compresses the incoming fluid flow. The compressor 32 may include multiple stages of stator vanes (not shown) and rotating blades (not shown) positioned within the compressor 32. The stator vanes and rotating blades positioned within the compressor 32 may be configured to help move and / or convey the fluid 34 through the compressor 32. The compressor 32 delivers a compressed fluid flow 38 (e.g., compressed air) to a combustor 40. The combustor 40 mixes the compressed fluid flow 38 with a pressurized fuel flow 42 provided by a fuel source 44, and ignites the mixture to produce a combustion gas flow 46. The combustion gas flow 46 is then delivered to a turbine component 48, which typically includes multiple stages of stator vanes (not shown) and turbine blades (not shown), similar to the compressor 32. The combustion gas flow 46 drives the turbine component 48 to produce mechanical work. The mechanical work generated in turbine component 48 drives compressor 32 via shaft 50 and may be used to drive a generator 52 (eg, an external component) configured to generate electricity and / or a load.

[0025] Although the power generation system 12 is Figure 1 1 and 12. Although the power generation system 12 is shown as including a dual-shaft configuration in which two separate generators 28, 52 are used, it should be understood that in other non-limiting examples, the ST system 18 and the GT system 30 may share a single shaft and, in turn, a single generator. Additionally, while the power generation system 12 is shown as including only a single ST system 18 and a single GT system 30, it should be understood that the power generation system 12 may include multiple ST systems 18 and / or GT systems 30 that may be configured to produce an operating load and / or power output.

[0026] The power generation system 12 may also include a heat recovery steam generator (HRSG) 54 fluidly connected to the ST system 18 (eg, to the HP component 24, the IP component 22, and / or the LP component 20) and the GT system 30. Figure 1As shown in the non-limiting example of , the HRSG 54 may be fluidly connected and / or coupled to the ST system 18 to receive exhaust fluid (e.g., steam) from the ST system 18, and may be coupled via a supply conduit 58 to provide steam to portions of the ST system 18 via the supply conduit 58. Figure 1 In a non-limiting example, the HRSG 54 may be fluidly connected and / or coupled to the GT system 30 via an exhaust passage 59 that is coupled to and / or in fluid communication with the turbine component 48. The exhaust passage 59 may provide exhaust fluid 60 (e.g., gas) from the GT system 30 to the HRSG 54 for use in generating and / or heating steam for the ST system 18. A stack 61 of the HRSG 54 may exhaust or release gases (e.g., exhaust fluid 60) and / or fluids from the HRSG 54 into the atmosphere and / or outside of the power generation system 12.

[0027] The power generation system 12 may also include a condenser 62. The condenser 62 may be in fluid communication with and / or may be fluidly coupled to various components of the power generation system 12. In a non-limiting example, the condenser 62 may be fluidly connected to and / or coupled to the LP component 24 of the ST system 18 via a steam discharge conduit 64. The condenser 62 may be configured to condense a discharge stream and / or a bypass stream (not shown) from the ST system 18 and / or the HRSG 54, and provide a condensed fluid (e.g., condensed water) to the HRSG 54, as is known in the art.

[0028] like Figure 1 As shown, the system 10 may include at least one computing device 66 configured to control the power generation system 12 during any phase of its operation, including startup operation (i.e., the period between inactivity and operation at a target load when the power output from the ST system 18 is transient). The computing device 66 may be hardwired and / or wirelessly connected to and / or in communication with the power generation system 12 and its various components (e.g., the ST system 18, the GT system 30, and / or the HRSG 54, etc.) via any suitable electronic and / or mechanical communication components or techniques. The computing device 66 and its various components discussed herein may be a single independent system that functions separately from another power plant control system (e.g., a computing device) (not shown), which power plant control system may control and / or adjust the operation and / or function of the power generation system 12 and its various components (e.g., the ST system 18, the GT system 30, and / or others). Alternatively, the computing device 66 and its components may be integrated within, connected to and / or formed as a part of a larger power plant control system (not shown) which may control and / or adjust the operation and / or function of the power generation system 12 and its various components (e.g., the ST system 18, the GT system 30 and / or others).

[0029] In various embodiments, computing device 66 may include control system 68 and one or more sensors 70, as described herein, for controlling the operation of power generation system 12. As discussed herein, control system 68 may control power generation system 12 and its various components to affect the operation of power generation system 12. For example, and as discussed herein, control system 68 may use various types of data and / or operating characteristics of HP component 24 and / or other components of system 10 determined by sensor 70 to control the operation of system 10 and / or affect various properties thereof. In some cases, control system 68 may generate and / or otherwise provide a predictive model (e.g., in Figure 3 244, shown in FIG. 1 and discussed elsewhere herein, that uses operating conditions and / or other characteristics of the system 10 to predict how the HP component 24 may respond to a particular situation (e.g., it may predict stress on the rotor 26). In addition, embodiments of the present disclosure may adjust the predictive model based on, for example, measurements obtained using the sensors 70. Embodiments of the control system 68 may be configured or operated in part by a technician, a computing device 66, and / or a combination of a technician and a computing device 66. Where applicable, the predictive model of the controller 68 may include a bias constant for intentionally overestimating the predicted stress on the rotor 26. The bias constant may take the form of, for example, a multiplier, a predetermined amount of stress to be added to the preliminary calculation, and / or other mathematical modifications to the initial output. In some specific implementations, embodiments of the present disclosure may include changing the bias constant in future startup operations (e.g., reducing it to reduce the amount of overestimation) to account for the behavior of the system 10 under particular conditions. The bias constant may be calculated from data obtained using the sensors 70, pre-recorded data for multiple systems 10, and / or may be derived from these and / or other data sources.

[0030] like Figure 1 As shown, the computing device 66 may include and / or be in electrical and / or mechanical communication with the sensor 70 and numerous other additional and / or intermediate components such as valves, solenoids, actuators, transducers, etc. (not shown) positioned throughout the system 10. Figure 1As shown in the non-limiting example of and as discussed herein, at least one sensor 70 of the computing device 66 and / or at least one sensor connected to the computing device may be positioned within the HP component 24 and / or one or more of its various subcomponents, as discussed elsewhere herein. The sensor 70 in communication with the computing device 66 of the system 10 may be any suitable sensor or device configured to detect and / or determine data, information, and / or operating characteristics associated with the power generation system 12 during operation. For example and as discussed herein, the sensor 70 positioned within the HRSG 54 of the power generation system 12 may be any suitable sensor configured to detect and / or determine a characteristic of a working fluid (e.g., steam, exhaust fluid 60). Such characteristics may include a portion of the HP component 24 and / or a temperature of a working fluid within a component, a temperature of a turbine component (such as the HP component 24 of the ST system 18), and / or a steam flow measurement of steam flowing through all or a portion of the turbine (such as the HP component 24). In non-limiting examples, the sensors 70 may be configured as, but are not limited to, thermometers, thermistors, thermocouples, and / or any other mechanical / electrical temperature sensors. In some cases, the computing device 66 may aggregate multiple measurements (e.g., temperature, pressure, etc.) of multiple portions of the ST system 18 and / or its subcomponents to generate a temperature distribution, pressure distribution, stress distribution, etc. of the ST system 18 and / or any of its components (e.g., the HP component 24). Although two sensors 70 are shown, it should be understood that the system 10 may include more sensors 70 (e.g., Figure 2 ), these sensors may be configured to provide computing device 66, and specifically control system 68, with information or data related to the temperature of fluids and components included within HP component 24, and / or fluid flow measurements. Figure 1 The number of sensors 70 shown is merely illustrative and not limiting. Thus, the system 10 may include more than Figure 1 Or more or fewer sensors 70 as depicted in other figures.

[0031] Figure 2 Shows Figure 1 1 is an enlarged schematic diagram of the HP component 24 and the interconnected portions of the system 10. Specifically, Figure 2 A schematic diagram of the HP component 24 is shown along with its inlet connection from the HRSG 54 and the outlet connection to the condenser 62. It should be understood that similarly numbered and / or named components may function in a substantially similar manner. Redundant explanations of these components and illustrations of other components within the system 10 are omitted solely for the sake of clarity.

[0032] Figure 2The HP component 24 of the ST system 18 is depicted, which is mounted on a portion of the rotor 26 and mechanically coupled to a portion of the rotor, as discussed elsewhere herein. Steam output from the HRSG 54 may be in fluid communication with a supply conduit 58, which in turn is coupled to an inlet 102 of the HP component 24 through an inlet valve 104. The inlet 102 may fluidly couple the supply conduit 58 to a bowl 106 within the HP component 24. The bowl 106 represents an interior portion of the HP component 24 that is located upstream of the energy extraction elements (e.g., rotating blades) and is therefore the highest temperature and highest pressure region within the HP component 24 during operation. Steam may flow through the HP component 24, where the rotating blades extract thermal energy from the steam before the steam is delivered to the outlet 108. The outlet 108 may include an outlet valve 110 that is adjustable to control fluid flow to a discharge passage 112 of the condenser 62. The discharge passage 112 may take the form of any pressure-sensitive component for reducing the pressure of the steam before the steam reaches the condenser 62. According to one example, the discharge passage 112 may take the form of a "dump tube," i.e., a mechanical assembly welded to the steam pipe downstream of the outlet 108 that reduces the steam pressure to the pressure of the condenser. A check valve 114 may also be coupled to the outlet 108, for example to direct excess steam to a reheater or other heat transfer component (not shown). The check valve 114 may allow such excess steam to be directed from the outlet 108 to reheat the steam flow elsewhere in the ST system 18 and / or the HRSG 54. The check valve 114 may be configured such that any steam passing therethrough cannot return to the outlet 108 (e.g., due to back pressure), and thus may be embodied as any currently known or later developed valve structure for allowing fluid to flow in only one direction.

[0033] like Figure 2 As shown and as herein with respect to Figure 1

[0063] Similarly discussed, the computing device 66, and more specifically, the control system 68 of the computing device 66, may be operably coupled to and / or in electronic communication with various components of the ST system 18. For example, the computing device 66, and more specifically, the control system 68 of the computing device 66, may be operably coupled to and / or in electronic communication with the valves 104, 110 of the ST system 18. The control system 68 of the computing device 66 may be configured to activate and / or control the operation of the valves 104, 110. The control system 68 may activate and / or control the position of the regulating valves 104, 110 for actively controlling the flow of steam through the HP components 24 during operation of the ST system 18, as discussed herein. The valves 104, 110 may be adjustable between positions such as a fully open position, a fully closed position, and one or more partially open positions. Such control of the valves 104, 110 using the computing device 66 and / or the control system 68 and / or the like may be accomplished via mechanical coupling, electrical coupling, and / or switches (collectively represented via dashed lines) between the computing device 66 and the valves 104, 110. The position of the regulating valves 104, 110 as discussed herein may affect the temperature and pressure of the steam within the HP components 24 to control stresses and / or other characteristics on the rotor 26 during startup operations.

[0034] To assist in the activation and / or control of valves 104, 110, control system 68 may also use a plurality of control modules located within portions of ST system 18 and / or system 10 ( Figure 1 ) in other places in the sensor 70 to obtain information. As the present invention relates to Figure 1 As discussed, the system 10 including the various portions of the ST system 18 may include a sensor 70 of a computing device 66 positioned therein. Figure 2 In the non-limiting example shown, the sensors 70 may be positioned within various portions of the ST system 18 for obtaining various information and / or operating characteristics of the components of the HRSG 54. For example, the sensors 70 may be positioned within the supply conduit 58, the bowl 106, and / or the outlet 108 of the HP component 24. The sensors 70 may additionally or alternatively be positioned at other locations within the ST system 18, such as on the surface of the rotor 26, within other portions of the HP component 24, within the exhaust passage 112, within the inlet 102 to the HP component 24, and / or any other location where a characteristic (e.g., fluid temperature, fluid pressure, surface temperature, velocity, etc.) is to be measured. Such sensors 70 may additionally or alternatively be distributed throughout other components of the system 10, such as the HRSG 54, the LP and / or IP components 20, 22 of the ST system 18, the generator 28, etc., to measure various properties of such components (e.g., temperature, pressure, stress, etc.) for use by the control system 68.

[0035] As discussed herein, the system 10 ( Figure 1) and / or the sensors 70 within the ST system 18 may be configured to detect and / or determine fluid temperature, fluid pressure, mass flow, component temperature, component pressure, and / or other properties of components and / or fluid flow. Figure 2 In the non-limiting example shown, various sensors 70 positioned within the HP components 24 and / or interconnected components may determine characteristics of steam or other characteristics (e.g., rotor 26 temperature) within the ST system 18. That is, the sensors 70 may determine and / or detect the temperature, pressure, mass flow rate, etc. of the fluid, such as the temperature of the steam at multiple locations as the steam flows from the supply conduit 58 to the inlet 102, through the HP components 24, through the outlet 108, and into the exhaust passage 112 and / or the check valve 114. As described elsewhere herein, in non-limiting examples, the sensors 70 may be configured as, but not limited to, thermometers, thermistors, thermocouples, and / or any other mechanical / electrical temperature sensors. In various specific implementations, the computing device 66 may represent data from the sensors 70 in the form of a "profile" for the ST system 18 and / or its components, i.e., values ​​of temperature, stress, etc. indexed by the sensors measuring these values.

[0036] Additionally, in a non-limiting example, the sensors 70 may directly or indirectly measure a mass flow rate (e.g., a volume flow rate in cubic meters per second) at the location where each sensor 70 is located. Additional sensors 70 in communication with the computing device 66 may be configured to detect or determine a duration of operation of the ST system 18 during a startup phase, measured relative to an initial state in which the ST system 18 is inactive or in a dormant phase of operation. Temperatures (e.g., steam, components), fluid flow measurements, and / or durations of operation detected by the various sensors 70 positioned within the ST system 18 may be provided to the computing device 66, and specifically to the control system 68. Using the detected and / or measured temperatures, fluid flow measurements, durations of operation, etc., the control system 68 may activate and / or adjust the operation or position of the valves 104, 110 to predict stresses on the rotor 26 and ensure that stresses are not too high when steam flow through the HP components 24 is at its minimum load level, as discussed herein.

[0037] It should be understood that Figure 2 The number of sensors 70 shown as being positioned within the ST system 18 is merely exemplary. Thus, the computing device 66 may include more or fewer sensors 70 positioned within the ST system 18 to help control the flow of steam through the HP components 24, as discussed herein. Additionally, although a portion of the plurality of sensors 70 are not depicted as being in communication with the computing device 66, it should be understood that Figure 2All sensors 70 shown are in communication with the computing device 66 and / or are capable of providing thereto sensing data relating to operating characteristics of components of the ST system 18, as discussed herein. Furthermore, although the computing device 66, control system 68, and sensors 70 are only in Figure 2 6, but it should be understood that computing device 66, control system 68, and sensor 70 may be included in any of the non-limiting examples discussed herein.

[0038] Characteristics of the ST system 18 operating in a startup mode are generally discussed to further illustrate their effects on and / or within the HP components 24. During startup operation of the power generation system 12, and specifically when the HRSG 54 initially begins to produce steam, each component 20 ( Figure 1 ),twenty two( Figure 1 ), 24 may be at a reduced temperature or pre-startup temperature (e.g., at least about thirty-eight degrees Celsius (°C) / one hundred degrees Fahrenheit (°F), but if steam flow is allowed to enter each component 20, 22, 24, it will be immediately exposed to heated, high-temperature steam (generated by the exhaust fluid 60). In this case, any component 20, 22, 24 that receives the steam flow will experience rapid temperature changes and / or increases in temperature, pressure, and / or surface stresses due to exposure to the heated, high-temperature steam. Subcomponents such as check valves 114 can help reduce thermal fatigue and / or stress experienced by portions of the HP component 24, the rotor 26, and / or the ST system 18. If the incoming heated steam is not managed, for example using embodiments of the present disclosure, its initial temperature may initially overstress the rotor 26 and / or other portions of the ST system 18. Therefore , a method according to the present disclosure may initially allow steam to be directed to the LP component 20 and / or the IP component 22 before the inlet valve 104 allows steam to enter the HP component 24. Embodiments of the present disclosure may enable the control system 68 to predict the stress that will be applied to the rotor 26 when the inlet valve 104 is opened to its minimum load position, and may control the volume of steam initially directed through the HP component 24 to warm and pressurize its interconnected components. At this point, the HP component 24 extracts significantly less energy from the steam passing therethrough than the amount of energy extracted at the "minimum load" flow. Once the predicted stress is below a threshold, the inlet valve 104 is opened to its minimum load position. With the steam flow to the HP component 24 in its minimum load position, the HP component 24 mechanically drives the rotor 26 to further extract energy from the steam.

[0039] See also Figure 3 , a schematic diagram of computing device 66 and its subcomponents is shown as part of system 10. Figure 3 In the illustration of FIG. 1 , only one ST system 18 is shown in detail, and for the sake of clarity of the illustration, Figure 3The computing device 66 and Figure 1 The computing device 66 may include a memory 202 and a control system 68 operating thereon. The control system 68 may be a software system that is integrated with a portion of the ST system 18 (e.g., valves 104, 110) or otherwise operably communicates therewith. The control system 68 may include, for example, a steam turbine (ST) control program 212. The turbine control program may enable the computing device 66 to act on the ST system 18 and / or modify the ST system, and / or may modify an existing operating method of the computing device 66 for use in operating the ST system 18. As shown in the figure, the computing device 66 may include a memory 202 and a control system 68 operating thereon. The control system 68 may be a software system that is integrated with a portion of the ST system 18 (e.g., valves 104, 110) or otherwise operably communicates therewith. The control system 68 may include, for example, a steam turbine (ST) control program 212. The turbine control program may enable the computing device 66 to act on the ST system 18 and / or modify the ST system, and / or may modify an existing operating method of the computing device 66 for use in operating the ST system 18. Figure 3 The illustrated computing device 66 represents one type of hardware for interacting with and / or controlling the ST system 18. As discussed herein, the computing device 66 may react to various monitored attributes of the ST system 18 to ensure safe and reliable operation of the system 10 during startup operations. Within the computing device 66, the turbine control program may monitor and / or interact with, and in some cases override, other actions taken by the computing device 66 to control the ST system 18 during startup operations (e.g., regulating valves 104, 110, modifying the amount of steam directed through the supply conduit 58, etc.).

[0040] According to one example, the computing device 66 may control the ST system 18 during startup operations and continuously evaluate whether to move the valves 104, 110 to various positions based on data measured via the sensors 70 and / or additional values ​​calculated via the control system 68. The turbine control program may cause the computing device 66 to predict the stress on the rotor 26 when the inlet valve 104 is moved to the minimum load position, and direct a smaller amount of steam through the HP component 24 to adjust the temperature and pressure within the HP component 24, thereby reducing the predicted stress. Embodiments of the present disclosure may be configured or operated in part by a technician, the computing device 66, and / or a combination of a technician and the computing device 66. It should be understood that Figure 3 Some of the various components shown may be independently implemented, combined, and / or stored in memory for one or more separate computing devices included in computing device 66. In addition, it should be understood that some of the components and / or functions may not be implemented, or that additional schemes and / or functions may be included as part of control system 68.

[0041] The computing device 66 may include a processor unit (PU) 228, an input / output (I / O) interface 230, a memory 202, and a bus 234. In addition, the computing device 66 is shown as communicating with an external I / O device 236 and a storage system 238. The control system 68 may provide a turbine control program, which in turn may operate using various modules 242 (e.g., calculators, determiners, comparators, etc.) to implement various functions and / or logical steps. The various modules 242 may use algorithm-based calculations, lookup tables, and similar tools stored in the memory 202 for processing, analyzing, and operating on data to perform their respective functions. In general, the PU 228 may execute computer program code to run software, such as the control system 68, which may be stored in the memory 202 and / or the storage system 238. When executing the computer program code, the PU 228 may read and / or write data to or from the memory 202, the storage system 238, and / or the I / O interface 236. Bus 234 may provide a communication link between each of the components in computing device 66. I / O devices 230 may include any device that enables a user to interact with computing device 66 or any device that enables computing device 66 to communicate with the equipment described herein and / or other computing devices. I / O devices 230 (including but not limited to keyboards, displays, pointing devices, etc.) may be coupled to computing device 66 directly or through an intervening I / O controller (not shown).

[0042] The memory 202 may also include various forms of data 250 related to various components of the system 10, such as various forms of data and / or predetermined data that the computing device 66 may use as a reference to modify the operation of the system 10. The turbine control program may store and interact with the data 250 subdivided into various fields. For example, the sensor data field 252 may store any and all types of data (e.g., inlet temperature, outlet temperature, measured rotor stress, fluid flow, etc.) collected by the sensor 70 that may be used to monitor and control the flow of steam through the HP component 24. Where applicable, the sensor data field 252 may be divided into various subfields corresponding to specific types of data.

[0043] The data 250 may include one or more threshold values ​​for various parameters, and such threshold values ​​may be organized in a threshold value data field 254. The threshold value data field 254 may include, for example, one or more stress threshold values ​​representing the maximum allowable stress on the rotor 26. Calculating that the predicted stress on the rotor 26 is above the threshold value may cause the computing device 66 to control the amount of steam flow through the HP component 24. This, in turn, may reduce the predicted stress on the rotor 26. The prediction of the stress may occur before steam admission to the HP component 24 is increased (e.g., via the inlet valve 104) to provide a minimum load. The threshold stress in the threshold value data field 254 may be determined before the method of the present disclosure is initiated (e.g., in process P0.3( discussed below)). Figure 5 ) is calculated and may indicate the maximum allowable stress on the rotor 26 when the valve 104 is opened to the minimum load position. In some cases, the threshold in the threshold data field 254 may be calculated based on past operation of the ST system 18, the system 10, other similar ST systems and / or power generation systems, and / or may be analytical predictions. Whether calculated or derived, the threshold of the predicted stress may be stored in the threshold data field 254 for reference by the control system 68. The threshold data field 254 may additionally include boundaries for various safety parameters related to the operation of turbine components (such as the HP component 24). For example, the threshold data field 254 may include the maximum current stress on the rotor 26 during the warm-up phase of turbine component operation, the maximum temperature in the outlet 108 corresponding to the corresponding temperature in the bowl 106, and / or other data indicating safe turbine component operation.

[0044] The data 250 may include a valve position field 256 for storing various valve positions of each valve 104, 110 and / or other components of the system 10 for regulating fluid flow (e.g., the check valve 114) where applicable. The valve position field 256 may indicate a partially open position of the valve 104, 110 corresponding to a particular operating condition. For example, the valve position field 256 may include at least one partially open position of the inlet valve 104 that is less than the minimum load position of the inlet valve 104. Such a position of the inlet valve 104 may be designated as a "warming position" because it is used to increase the temperature within the HP component 24 before a higher steam flow is allowed through the inlet valve 104. The valve position field 256 may also include a plurality of partially open or fully open positions, including a minimum load position and / or a position that allows a greater fluid flow than the minimum load position. During operation, the control system 68 may adjust the inlet valve 104 between a plurality of warming positions that are less open than the minimum load position until the predicted stress is less than the corresponding threshold value in the threshold data field 254.

[0045] In various implementations, it may be desirable to overestimate the predicted stress on the rotor 26. Technical benefits of overestimating the predicted stress may include, for example, ensuring that opening the inlet valve 104 to a minimum load position does not cause significant damage to the rotor 26 or the HP component 24 during startup operation of the ST system 18. In order to intentionally overestimate the predicted stress, the data 250 may include a bias constant field 258 for storing a corrective adjustment to the predicted stress calculated via the prediction model 244. The bias constant field 258 may include an overcorrective adjustment to the calculated stress, such as in the form of a constant to be added to the predicted stress. In another example, the bias constant field 258 may take the form of a lookup table, an algorithm, etc., for changing an amount to increase the predicted stress by reference to the operation of the ST system 18 and / or the HP component 24. In such an example, the table in the bias constant field 258 may associate, for example, a minimum load of fifty megawatts (50 MW), a rotor surface temperature of three hundred degrees Celsius, an inlet fluid temperature of three hundred and fifty degrees Celsius, and a predicted steam flow rate of approximately forty kilograms per second (kg / s) with a bias constant of five megapascals (MPa). The associated bias constant (e.g., five MPa in this example) may then be added to the initially calculated predicted stress to produce a final value for the predicted stress. Whether organized, tabulated, etc., the bias constant values ​​in the bias constant field 258 may be user defined (e.g., via the I / O device 236), calculated via the prediction model 244, and / or generated using a combination of user input and / or via functionality implemented by the control system 68 or applicable subcomponents.

[0046] The computing device 66 may include any general purpose computing article of manufacture (e.g., a personal computer, server, handheld device, etc.) installed by a user for executing computer program code. However, it should be understood that the computing device 66 is merely representative of various possible equivalent computing devices and / or technicians that can perform the various process steps of the present disclosure. In addition, the computing device 66 may be part of a larger system architecture that is operable to model and / or control various aspects and elements of the ST system 18.

[0047] In this regard, in other embodiments, the computing device 66 may include any dedicated computing product having hardware and / or computer program code for performing specific functions, any computing product including a combination of dedicated and general-purpose hardware / software, etc. In each case, the program code and the hardware may be created using standard programming and engineering techniques, respectively. In one embodiment, the computing device 66 may include a program product stored on a computer-readable storage device that is operable to automatically control other elements of the system 10 when executed. The computing device 66 may also take the form of, for example, a remote monitoring system that is part of a central monitoring system that in turn is responsible for monitoring several ST systems 18. In this case, the computing device 66 may represent a portion or subcomponent of the central control system.

[0048] Now let’s see Figure 3 and Figure 4 , an illustrative flow chart for implementing method M1 according to various embodiments of the present disclosure is provided. The embodiments of the methods described herein may be implemented, for example, using a control system 68 of a computing device 66, various modules and / or subcomponents of the computing device 66 and / or the control system 68. The method M1 according to the present disclosure may also rely on other components (such as sensors 70 communicatively coupled to the computing device 66 and / or the control system 68) to measure and / or otherwise determine various parameters to be used as the basis for the process discussed herein. As discussed herein, the control system 68 may adjust various operating parameters of the power generation system 12, for example, by opening, closing or otherwise adjusting the position of valves 104, 110 to control the predicted stress on the rotor 26. In other embodiments, the control system 68 may be operable to modify other instructions and / or actions taken via the computing device 66 and / or the control system 68, for example, by modifying a bias constant used to calculate the predicted stress on the rotor 26. Figure 4 The illustrative flowchart shown in has several processes organized in an exemplary process, but it should be understood that one or more processes can be implemented simultaneously and / or sequentially and / or performed in any alternative order while maintaining the various technical features described in the examples of this document.

[0049] Now let’s see Figure 1 , Figure 3 and Figure 4, embodiments of the present disclosure provide a method M1 for controlling steam flow through a turbine component during startup operation of a turbine system. For purposes of example, the various methods provided herein are discussed with reference to the ST system 18 and the HP component 24 therein. It should be understood that embodiments of the present disclosure may be implemented on other types of turbines and / or turbine components without substantially changing one or more of the methods described herein. The methods discussed herein may be initiated by a control system 68 of a computing device 66 under certain conditions (e.g., detecting that the HP component 24 has begun operation) and / or may be implemented as part of a more general method for controlling the HP component 24, as discussed elsewhere herein. In additional embodiments and / or as a different control method implementation process (i.e., determination D0.1 and process P2) in Figure 4 0 is shown as an example in FIG. 1 and described in more detail with respect to the other figures.

[0050] As described herein, embodiments of the present disclosure control steam pressure within the HP component 24 of the ST system 18 during startup operations. The method includes a process P1 of adjusting the inlet valve 104 to a fully closed position (e.g., via a mechanical coupling, an electrical coupling, a converter, etc., generally indicated by a dashed line between the computing device 66 and the inlet valve 104). In order to prevent steam flow from prematurely entering the HP component 24 and subsequently causing stress on the rotor 26, the control system 68 of the computing device 66 may implement a process P2 to adjust the exhaust valve 110 to a fully open position (e.g., via a mechanical coupling, an electrical coupling, a converter, etc., generally indicated by a dashed line between the computing device 66 and the exhaust valve 110). After processes P1 and P2 are completed and the valves 104, 110 are in their respective positions, existing fluid may be extracted from the HP component 24, while the incoming fluid must bypass the HP component 24 due to the closure of the inlet valve 104.

[0051] After process P1, P2, the method may proceed to process P3, where the module 242 of the turbine control program or in some cases the prediction model 244 calculates the predicted stress on the rotor 26. Process P3 can be the initial process of sub-method M1.1, which can be implemented in a loop until various technical conditions as discussed herein are met. Sub-method M1.1 may generally include a step for evaluating whether the predicted stress is below a threshold, and, where applicable, adjusting valves 104, 110 so that the predicted stress becomes less than the threshold. As described herein, the predicted stress calculated in process P3 does not involve the current stress on the rotor 26 or the future stress of the valve 104, 110 remaining in its current position. On the contrary, the predicted stress calculated in process P2 refers to the instantaneous stress (e.g., measured in MPa) of the steam allowed on the rotor 26 when the inlet valve 104 is opened to its minimum load position (as defined, for example, in the valve position field 256 of the data 250). In the event that the prediction model 244 intentionally overestimates the predicted stress, process P2 may include adding a bias constant to the predicted stress (as indicated, for example, in bias constant field 258). Regardless of implementation, process P2 may include calculating the predicted stress on rotor 26 using at least the surface temperature of rotor 26 and the steam temperature within inlet 102 (as measured or calculated using sensor 70, for example, and / or derived from data 250, such as the value in sensor data field 252).

[0052] After calculating the predicted stress on the rotor 26 in process P3, the method may proceed to decision D1 to determine (e.g., via module 242 of the turbine control program) whether the predicted stress exceeds a corresponding threshold value for the ST system 18 and / or its current operating conditions. Such a threshold value may be stored, for example, in a threshold field 254 of data 250. In various specific implementations, module 242 of the ST control program 212 may (e.g., based on user input, internal logic, a lookup table, and / or an algorithm) select one of several threshold values ​​to compare with the predicted stress calculated in process P3. In the event that the predicted stress does not exceed the threshold value (i.e., "No" at decision D1), method M1 may end and / or proceed to further operations (e.g., such as Figure 4 1 ). In the event that the predicted stress exceeds the threshold (ie, “yes” at decision D1 ), method M1 may proceed to subsequent operations for preparing HP component 24 to allow steam to enter therein.

[0053] In response to the predicted stress exceeding the threshold, sub-method M1.1 may include adjusting the inlet valve 104 to a warming position that is less than the minimum load position of the HP component 24. For example, the warming position of the inlet valve may be configured to allow, for example, ten percent of the available steam flow from the supply conduit 58, compared to the minimum load position that allows, for example, twenty-five percent of the available steam flow. In the warming position, the discharge valve 110 remains fully open, and the check valve 114 may allow excess steam to be directed away from the condenser 62, if desired and / or applicable. With the inlet valve 104 in the warming position, the incoming steam may exert some torque on the rotor 26 without extracting significant energy, while also increasing the pressure within the discharge passage 112.

[0054] After opening the inlet valve 104 to the warming position in process P4, process P5 of sub-method M1.1 may include allowing an admitted steam flow through the HP component 24 to pressurize the exhaust passage 112. Specifically, the admitted steam may apply pressure to the physical components of the exhaust passage 112 (including, for example, the discharge pipe to the condenser 62), thereby raising the total pressure. The admitted steam flow will also gradually raise the surface temperature of the rotor 26, making it less susceptible to stress from the incoming steam.

[0055] When the incoming steam flow is allowed to pressurize the exhaust passage 112, the method M1.1 may include a decision D2 to compare the pressure of the exhaust passage 112 with a target value. The target value may indicate that the pressure within the exhaust passage 112 is sufficient to allow pressurization of the HP component 24. The target value of the exhaust passage 112 pressure may be stored, for example, in the threshold field 252 or elsewhere in the data 250. The measured pressure within the exhaust passage 112 may be obtained directly via the sensor 70 and / or may be calculated from other data 250 via the module 242. The startup operation of the ST system 18 may require an increase in the pressure within the HP component 24 to further reduce the stress on the rotor 26. The pressurization of the HP component 24 may be more effectively performed after the exhaust passage 112 is first pressurized. In the event that the pressure of the exhaust passage 112 has not yet reached its target (i.e., "No" at the decision D2), the method may return to process P5 to allow further pressurization of the exhaust passage 112. The decision D2 may be repeated after a predetermined time delay, or may be implemented continuously. In the event that the pressure of the discharge passage 112 has reached its target (i.e., "yes" at decision D2), the method may proceed to process P6 of partially closing the discharge valve 110 while maintaining the inlet valve 104 in the warming position. Process P6 will keep the total steam flow through the HP section 24 substantially the same, but the upstream pressure (i.e., the pressure within the HP section 24) will increase.

[0056] Further analysis may include a process P7 of monitoring one or more safety parameters of the turbine (e.g., HP component 24) to be compared to corresponding boundaries. As used herein, the term "safety parameter" refers to any quantity indicating the current operating state of a turbine component, and / or the likelihood that the HP component 24 will experience an adverse effect. As discussed herein, examples of safety parameters may include current or "actual" stress on the rotor 26 (as opposed to predicted stress), predicted temperature in the outlet 108 based on the actual temperature in the bowl 106, and / or similar characteristics. The predicted temperature in the outlet 108 may be particularly relevant, for example, because too low a steam flow through the HP component 24 may cause the rotating blades to apply energy to the steam, rather than vice versa, thereby raising the temperature at the turbine outlet to an unacceptable level. In decision D3, module 242 of the turbine control program 212 may compare one or more of the safety parameters monitored in process P7 with their corresponding boundaries. The boundaries of each safety parameter may be stored in a threshold field 254 of the data 250, or stored elsewhere in the memory 202. According to one example, determination D3 may include comparing the current stress on the rotor 26 (e.g., monitored by sensor 70) to the maximum allowable stress. In another example, determination D3 may include comparing the predicted temperature in the outlet 108 to its expected maximum value based on the current temperature in the bowl 106. In the event that the safety threshold does violate its boundary (i.e., "yes" at determination D3), the method may include process P8 of partially opening the discharge valve 110 to return the monitored safety parameter to the desired range. In the event that the safety parameter does not violate the boundary (i.e., "no" at determination D3), the method may proceed to further steps. In some cases, process P7 and the monitoring of the safety parameter in determination D3 may be performed as shown in the example. Figure 4 The process is implemented in the loop indicated by the dotted line.

[0057] The present disclosure may further include a determination D4 of whether a monitoring period (e.g., a desired time span, user confirmation, and / or a desired number of processing cycles) has occurred. If the monitoring period has passed (i.e., "yes" at determination D4), the method may return to process P3 to recalculate the predicted stress on the rotor. If further monitoring is required (i.e., "no" at determination D4), the method may return to process P5 to further pressurize the turbine component (e.g., HP component 24). If the predicted stress is now below the threshold (i.e., "yes" at process D1), sub-method M1.1 may end. If the predicted stress remains above the threshold (i.e., "no" at process D2), processes P5, P6, and determination D2 may be repeated with the inlet valve 104 in the warming position but with a higher target pressure applied to the exhaust passage 112 and / or HP component 24.

[0058] See now Figure 1 and Figures 3 to 5 , further operations may be performed with method M1 to provide further control of the ST system 18. Method M1 is performed via Figure 5 , and it should be understood that method M1 may include the method described herein with respect to Figure 4 Various Processes and Decisions Discussed. Although several processes are shown by way of example as occurring before or after implementation of method M1, it should be understood that in various alternative embodiments, several operations may be reordered and / or omitted.

[0059] In various embodiments, process P0.1 may include initiating operation of the ST system 18, for example, by initiating steam flow through the LP component 20 and the IP component 22 while preventing steam flow through the HP component 24 (e.g., by fully closing the inlet valve 104 thereto). Such a configuration may be limited to, for example, an ST system 18 configuration with a "cascade bypass" to control steam flow through the components 20, 22, 24. When process P0.1 ends, the HP component 24 may remain dormant and thus not drive motion of the rotor 26.

[0060] Process P0.2 of the present disclosure may include generating a prediction model 244 for the ST system 18. The prediction model 244 may be generated based on, for example, various information within the data 250, such as recorded data in the sensor data field 252, operating settings of the ST system 18, and / or other inputs. The prediction model 244 may take the form of a generalized formula, algorithm, lookup table, etc. for predicting stress on the rotor 26 based on operating conditions of the ST system 18. According to a specific example, the prediction model 244 may be configured to generate predicted stress on the rotor 26 using the surface temperature of the rotor 26, the steam temperature within the inlet 102 to the HP component 24, one or more bias constants (such as those recorded in the bias constant field 258 of the data 250), and / or any other data related to the operation of the system 10. The generation of the prediction model 244 in process P0.2 may be a single operation performed before, after, or simultaneously with the other processes discussed herein. In further examples, generation of the predictive model 244 may be continuous and may incorporate additional readings from the sensor 70 to calculate the predicted stress on the rotor 26 when the inlet valve 104 is adjusted to the minimum load position.

[0061] After or during the generation of the prediction model 244 in process P0.2, the method may include a process P0.3 of calculating a threshold value of the rotor stress for use in decision D1 ( Figure 4). The calculated threshold value may be stored, for example, in threshold value field 254 for future reference, and / or may be continuously updated as ST system 18 continues to operate. In any case, process P0.3 may include predictive model 244 of control system 68 using current operating conditions of system 10 (e.g., surface temperature of rotor 26, steam temperature within inlet 102 to HP component 24, one or more bias constants (such as those recorded in bias constant field 258 of data 250), and / or any other data related to operation of system 10) to generate a threshold value to be compared with the predicted stress in decision D1.

[0062] Embodiments of the present disclosure may continue by operating the ST system 18 with the HP component 24 not activated, i.e., no steam enters the HP component 24 because the inlet valve 104 remains closed. In this case, the LP component 20 and the IP component 22 will continue to operate and mechanically drive the rotation of the rotor 26. When the ST system 18 continues to operate with the HP component 24 not activated, the module 242 of the control system 68 may determine whether the steam flow to the LP component 20 and the IP component 22 has reached the target level. The target steam flow to the LP component 20 and the IP component 22 may be manually selected via a user of the control system 68, and / or may be stored in the data 250 (e.g., as part of the sensor data field 252 and / or alternatively as part of the threshold field 254). Decision D0.1 in embodiments of the present disclosure may evaluate whether the steam flow through the LP component 20 and the IP component 22 has reached its target. In the event that the steam flow through the LP section 20 and the IP section 22 is below the target (i.e., "No" at decision D0.1), the ST system 18 may continue to operate without allowing steam flow to enter the HP section 24 (i.e., the inlet valve 104 remains in the closed position). In the event that the steam flow through the LP section 20 and the IP section 22 is equal to or above the target (i.e., "Yes" at decision D0.1), the various processes of method M1 discussed elsewhere herein may be initiated. Figure 4 As shown, in an exemplary implementation, the process P1 of adjusting the exhaust valve 110 to the fully open position may follow the decision D0.1. The method M1 may thus be fully implemented, wherein the sub-method M1.1 determines, where applicable, whether the predicted stress on the rotor 26 is below an applicable threshold. Once it is determined that the predicted stress on the rotor 26 is less than the threshold (i.e., the method M1 ends), further operations may be implemented.

[0063] After the method M1 ends and the predicted stress is below the threshold, additional operations may include a process P2.1 of opening the inlet valve 104 to a minimum load position. The minimum load position may be defined in the valve position field 256 of the data 250. Through one or more operable couplings (e.g., electrical connections, mechanical transducers, etc.) between the computing device 66 and the inlet valve 104, the inlet valve 104 may be adjusted to at least the minimum load position, thereby allowing steam to enter the HP component 24 and mechanically drive the rotation of the rotor 26. The adjustment of the inlet valve 104 will apply stress to the rotor 26, but the applied stress will be significantly less than conventional operation omitting the method M1.

[0064] Continuing to process P2.2, the ST system 18 may continue to allow steam to enter the HP component 24 through the inlet valve 104. Once the inlet valve 104 is in its minimum load position, the control system 68 may adjust the discharge valve 110 to a closed position. Adjustment of the discharge valve 110 may be implemented, for example, via a mechanical connection between the computing device 66 and the discharge valve 110, a mechanical converter, etc. With the discharge valve 110 in the closed position, fluid within the outlet 108 may continue to flow through the check valve 114 to the reheater component, as discussed elsewhere herein. At this stage, the HP component 24 has ceased operating in the "start-up" mode and has begun to generate at least a minimum load via the rotor 26. In some cases, the method may end ("complete") after adjusting the discharge valve 110 to a fully closed position, such as Figure 5 In another example, the method may return to process P0.3 at any point in the system 10 to re-initiate a startup operation, such as by ceasing operation for a set period of time and / or switching to a different type of operating mode.

[0065] In various implementations, the control system 68 may use the operating characteristics of the system 10 to modify the calculation of the threshold value in the process P0.3 in other implementations. For example, in the case where the prediction model 244 intentionally overestimates the predicted stress via the bias constant, the process P2.3 may calculate the difference between the actual stress on the rotor 26 and the predicted stress. The calculated difference may be expressed, for example, as a percentage, a MPa difference, etc. In some cases, the bias constant may be further adjusted based on, for example, the startup temperature of the HP component 24 (e.g., as measured with the sensor 70), the pressure distribution of the ST system 18 (e.g., the pressure within each component 20, 22, 24) when the inlet valve 104 is in the warming position, and / or other operating characteristics. The prediction model 244 may then use the difference to adjust the bias constant used to predict the stress, for example, by recalculating or adjusting various properties of the algorithm, lookup table, etc. The adjusted bias constant may be stored as data 250, for example, in the bias constant field 258. The method may then end ("Done"), or may return to process P0.3 of calculating a threshold value for predicted stress using the adjusted bias constant.

[0066] Technical effects of the embodiments described herein include predicting the stresses that incoming steam flow to a high pressure component of a steam turbine will cause to a rotor for driving a generator. When the predicted stress exceeds a desired level, the technical effects of the present disclosure ensure that the high pressure component is preheated and pre-pressurized before more steam is admitted to the high pressure component to drive the rotor. Additional technical effects of the embodiments discussed herein include using actual stresses on a rotor in a particular operation as training data to predict how future steam flow will stress the same rotor in future operations or similar rotors in other steam turbine systems.

[0067] As used throughout the specification and claims, approximate language may be used to modify any quantitative representation that may be permissibly varied without resulting in a change in the basic function to which it is related. Therefore, values ​​modified by one or more terms, such as "about," "approximately," and "substantially," are not limited to the precise values ​​specified. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. Here and throughout the specification and claims, range limitations may be combined and / or interchangeable; unless the context or language indicates otherwise, these ranges are identified and include all subranges contained therein. "Approximately" applied to a particular value of a range applies to both end values ​​and may indicate + / -10% of the value unless otherwise dependent on the precision of the instrument for measuring the value.

[0068] The corresponding structures, materials, actions and equivalents of all means or steps plus function elements in the following claims are intended to include any structure, material or action for performing functions in conjunction with other claimed elements specifically claimed. A description of the present disclosure has been given for the purpose of illustration and description, but it is not intended to be exhaustive or to limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and essence of the present disclosure. Embodiments have been selected and described in order to best explain the principles and practical applications of the present disclosure, and to enable other persons of ordinary skill in the art to understand the various embodiments of the present disclosure with various modifications suitable for the intended specific use.

Claims

1. A method for controlling steam pressure within a turbine component (48) during a startup operation, the turbine component (48) being fluidly coupled between an inlet (102) having an inlet valve (104) for controlling steam flow into the turbine component (48) and a discharge port having a discharge valve (110) for controlling steam flow to a discharge passage (112), the method comprising: adjusting the discharge valve (110) to a fully open position and adjusting the inlet valve (104) to a fully closed position; calculating predicted stresses on a rotor (26) of the turbine component (48) based on predicted steam flow with the inlet valve (104) in a minimum load position, a rotor (26) surface temperature, and an inlet (102) steam temperature; determining whether the predicted stress exceeds a threshold; In response to the predicted stress exceeding the threshold, adjusting the inlet valve (104) to a warming position that is less open than the minimum load position such that steam flow through the turbine component (48) pressurizes the exhaust passage (112); In response to the steam in the discharge passage (112) reaching a target pressure, partially closing the discharge valve (110) while maintaining the warming position of the inlet valve (104); determining whether a safety parameter of the turbine component (48) violates a boundary while maintaining the warming position of the inlet valve (104); In response to the safety parameter of the turbine component (48) violating the boundary, partially opening the discharge valve (110) while maintaining the warming position of the inlet valve (104); recalculating the predicted stress on the rotor (26) with the inlet valve (104) in the warming position; as well as In response to the predicted stress not exceeding the threshold, the inlet valve (104) is opened to at least the minimum load position.

2. The method of claim 1, wherein the safety parameter of the turbine component (48) comprises an actual stress on a rotor (26) when the inlet valve (104) is in the warming position, and wherein the boundary comprises a stress limit of the rotor (26).

3. The method of claim 1, wherein the safety parameter comprises a predicted steam temperature drop across the turbine component (48) based on an upstream steam temperature, and wherein the boundary comprises a minimum steam temperature at an outlet (108) from the turbine component (48).

4. The method of claim 1, wherein the turbine component (48) comprises a high pressure HP component (24) of a steam turbine ST system (18), and wherein the method further comprises: Prior to calculating the predicted stresses on the rotor (26), initiating steam flow through an intermediate pressure IP section (22) and a low pressure LP section (20) of the ST system (18), determining whether the steam flow through the IP section (22) and the LP section (20) of the ST system (18) reaches a target level; as well as In response to the steam flow through the IP section (22) and the LP section (20) reaching the target level, the predicted stress on the rotor (26) is calculated.

5. The method of claim 1, further comprising adjusting the discharge valve (110) to a fully closed position after opening the inlet valve (104) to at least the minimum load position.

6. The method of claim 1, further comprising generating a predictive model (244) for the turbine component (48) to calculate the predicted stress based on at least the rotor (26) surface temperature, the inlet (102) steam temperature, and a bias constant before adjusting the discharge valve (110) to the fully open position and adjusting the inlet valve (104) to the fully closed position.

7. The method of claim 6, further comprising adjusting the bias constant of the prediction model (244) based on a startup temperature of the turbine component (48) and a pressure distribution of the turbine component (48) with the inlet valve (104) of the turbine component (48) in the warming position after reducing the steam flow through the discharge valve (110).

8. A program product stored on a computer readable storage medium, the program product for controlling steam pressure within a turbine component (48) during a startup operation, the turbine component (48) being fluidly coupled between an inlet (102) having an inlet valve (104) for controlling steam flow into the turbine component (48) and a discharge port having a discharge valve (110) for controlling steam flow to a discharge passage (112), the computer readable storage medium comprising program code for causing a computer system to perform actions comprising: adjusting the discharge valve (110) to a fully open position and adjusting the inlet valve (104) to a fully closed position; calculating predicted stresses on a rotor (26) of the turbine component (48) based on predicted steam flow with the inlet valve (104) in a minimum load position, a rotor (26) surface temperature, and an inlet (102) steam temperature; determining whether the predicted stress exceeds a threshold; In response to the predicted stress exceeding the threshold, adjusting the inlet valve (104) to a warming position that is less open than the minimum load position such that steam flow through the turbine component (48) pressurizes the exhaust passage (112); In response to the steam in the discharge passage (112) reaching a target pressure, partially closing the discharge valve (110) while maintaining the warming position of the inlet valve (104); determining whether a safety parameter of the turbine component (48) violates a boundary while maintaining the warming position of the inlet valve (104); In response to the safety parameter of the turbine component (48) violating the boundary, partially opening the discharge valve (110) while maintaining the warming position of the inlet valve (104); recalculating the predicted stress on the rotor (26) with the inlet valve (104) in the warming position; as well as In response to the predicted stress not exceeding the threshold, the inlet valve (104) is opened to at least the minimum load position.

9. The program product of claim 8, wherein the safety parameter of the turbine component (48) comprises an actual stress on a rotor (26) with the inlet valve (104) in the warming position, and wherein the boundary comprises a stress limit of the rotor (26).

10. The program product of claim 8, wherein the safety parameter comprises a predicted steam temperature drop across the turbine component (48) based on an upstream steam temperature, and wherein the boundary comprises a minimum steam temperature at an outlet (108) from the turbine component (48).

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