Modeling and controlling gas cycle power plant operations using variant control characteristic diagrams

Abstract

Embodiments of the present disclosure provide a method for operating a combined cycle power plant (CCPP) (12). The method may include creating a variant control characteristic map of the CCPP (12) for a power plant model (68) of the CCPP (12). The method may include modifying the variant control characteristic map in response to the variant control characteristic map not reducing fuel consumption or not satisfying a quality threshold (228). The method may also include adjusting the CCPP (12) to use the variant control characteristic map in response to the variant control characteristic map reducing fuel consumption and satisfying the quality threshold (228). A turbine section inlet temperature schedule or an exhaust temperature schedule of the CCPP (12) is adjusted using the variant control characteristic map.

Description

Background Art

[0001] The present disclosure generally relates to modeling and controlling power plants. More specifically, embodiments of the present disclosure provide an operational method of modeling and controlling a power plant by modeling and analyzing variant control characteristic maps of the power plant.

[0002] Power plants typically include a variety of different turbines and / or systems for generating electrical output. Two conventional power systems for generating electricity include gas turbine systems and combined cycle power plants, which typically include gas turbine systems. Conventional combined cycle power plants employ one or more gas turbine systems 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 electrical output. The steam turbine system includes a high pressure (HP) turbine section, which is operably coupled to an intermediate pressure (IP) turbine section, which in turn is 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). In a typical combined cycle power plant, the exhaust gas from the gas turbine is transmitted to a heat recovery steam generator (HRSG), which can be used to generate steam to supply various turbines of the steam turbine system and reheat the steam to improve the efficiency of the system and / or power plant. Downstream of the HRSG, the exhaust gas is released into the atmosphere through a chimney.

[0003] The increased availability of alternative energy sources, such as various forms of renewable energy, has also increased the complexity of operating combined cycle power plants. Fluctuations in the demand for power generation at a combined cycle power plant typically require the system to shift between different load conditions, thereby changing the amount of electricity generated over time. The operation of a power plant at different load levels can affect several properties of the power plant, including the internal temperature and / or fuel consumption of various components. In some cases, prolonged operation at varying loads can adversely affect the efficiency or service life of some components. Summary of the invention

[0004] A first aspect of the present disclosure provides a method for operating a combined cycle power plant (CCPP), the method comprising: operating the CCPP under certain environmental conditions and certain load conditions; generating a power plant model for the CCPP operating under the environmental conditions and the load conditions; modeling fuel consumption using a baseline control characteristic map and the power plant model of the CCPP under the environmental conditions and the load conditions; creating a variant control characteristic map of the CCPP; using the power plant model to determine whether the variant control characteristic map meets a quality threshold of the CCPP, the quality threshold including at least the fuel efficiency of the CCPP; modifying the variant control characteristic map in response to the variant control characteristic map not meeting the quality threshold; and adjusting the CCPP to use the variant control characteristic map in response to the variant control characteristic map meeting the quality threshold, wherein the variant control characteristic map adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule of the CCPP.

[0005] A second aspect of the present disclosure provides a program product for operating a combined cycle power plant (CCPP) stored on a computer-readable storage medium, the computer-readable storage medium having program code for causing a computer system to perform actions, the actions including: operating the CCPP under certain environmental conditions and certain load conditions; generating a power plant model for the CCPP operating under the environmental conditions and the load conditions; modeling fuel consumption using a baseline control characteristic diagram and a power plant model of the CCPP under the environmental conditions and the load conditions; creating a variant control characteristic diagram of the CCPP; using the power plant model to determine whether the variant control characteristic diagram meets a quality threshold of the CCPP, the quality threshold including at least the fuel efficiency of the CCPP; modifying the variant control characteristic diagram in response to the variant control characteristic diagram not meeting the quality threshold; and adjusting the CCPP to use the variant control characteristic diagram in response to the variant control characteristic diagram meeting the quality threshold, wherein the variant control characteristic diagram adjusts the turbine section inlet temperature schedule or the exhaust temperature schedule of the CCPP.

[0006] A third aspect of the present disclosure provides a system comprising: a combined cycle power plant (CCPP) having at least a gas turbine, a heat recovery steam generator (HRSG), a steam turbine (ST), and a condenser; and a system controller in communication with the gas turbine and the HRSG of the CCPP, the system controller being operable to perform the following operations: operate the CCPP under certain ambient conditions and certain load conditions; generate a power plant model for the CCPP operating under the ambient conditions and the load conditions; model fuel consumption using a baseline control characteristic map and a power plant model of the CCPP under the ambient conditions and the load conditions; create a variant control characteristic map of the CCPP; use the power plant model to determine whether the variant control characteristic map meets a quality threshold of the CCPP, the quality threshold including at least the fuel efficiency of the CCPP; modify the variant control characteristic map in response to the variant control characteristic map not meeting the quality threshold; and adjust the CCPP to use the variant control characteristic map in response to the variant control characteristic map meeting the quality threshold, wherein the variant control characteristic map adjusts the turbine section inlet temperature schedule or the exhaust temperature schedule of the CCPP.

[0007] The exemplary aspects of the present disclosure are designed to solve the problems described herein and / or other problems not discussed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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:

[0009] Figure 1 is a schematic diagram of a system having a combined cycle power plant (CCPP) according to various embodiments of the present disclosure.

[0010] Figure 2 is an expanded schematic diagram of a system and a CCPP according to various embodiments of the present disclosure.

[0011] Figure 3 An exemplary computer environment operable to control a CCPP according to embodiments of the present disclosure is shown.

[0012] Figure 4 An illustrative flow chart of a method for operating a CCPP according to an embodiment of the present disclosure is provided.

[0013] Figure 5 Exemplary graphs of gas turbine inlet (alternatively, "fired") temperature versus load in a CCPP according to embodiments of the present disclosure are provided.

[0014] Figure 6 Exemplary curves of gas turbine outlet (alternatively, "exhaust gas") temperature versus load in a CCPP according to embodiments of the present disclosure are provided.

[0015] Figure 7 The inlet guide vane angle (θ) in a CCPP according to an embodiment of the present disclosure is provided. IGV ) versus load.

[0016] Figure 8 A thermostat fluid flow rate (Q) in a CCPP according to an embodiment of the present disclosure is provided. Att ) versus load.

[0017] Fig. 9 A heat rate change (Δ HR ) versus load.

[0018] 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

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] Embodiments of the present disclosure provide methods, program products, and systems for controlling various attributes of a combined cycle power plant (CCPP) to compensate for transient load operation, i.e., changes in power output from the CCPP relative to time. Embodiments of the present disclosure may include, for example, generating a power plant model of the CCPP for operation under certain environmental conditions and certain load conditions. The generation of such a model may include validating the accuracy of the model based on current operating data and / or historical operating data of the CCPP. The method may include using a model to model the fuel consumption of the CCPP using a baseline control characteristic map, and then creating a variant control characteristic map that defines alternative operation and / or control settings for several loads. The method may include determining whether the variant control characteristic map meets one or more quality thresholds of the CCPP, and adjusting the CCPP to use the variant control characteristic map if these requirements are met. Adjustment of the CCPP may include adjusting variables such as turbine inlet temperature (also referred to as "firing temperature" in the art), exhaust temperature, and / or other variables that affect the power output and operating characteristics of the CCPP.

[0024] Figure 1A schematic diagram of a system 10 according to various embodiments of the present disclosure is shown. As shown, the system 10 may include a combined cycle power plant 12 (hereinafter referred to as "CCPP 12"), which includes a steam turbine (ST) system 18, which ST system may include a high pressure (HP) portion 24, an intermediate pressure (IP) portion 20, and a low pressure (LP) portion 22, as is known in the art. The HP portion 24, the IP portion 20, and the LP portion 22 of the ST system 18 may be coupled and / or positioned on a shaft 26 and / or may be configured to rotate the shaft to produce mechanical work and / or drive additional components of the ST system 18. Figure 1 As shown, the shaft 26 of the ST system 18 may be coupled to and / or may drive an external component, and more specifically, a generator 28 configured to generate electricity and / or produce a load.

[0025] The CCPP 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 may include a set of inlet guide vanes (IGVs) 36. The IGV 36 is a vane specifically configured to guide the incoming working fluid flow to the rotating blades of the compressor 32. The IGV 36 can be adjusted between several positions to affect the flow rate, angle of incidence, and / or other characteristics of the fluid entering the compressor 32. The IGV 36 can therefore affect the temperature of the compressor 32, the power output from the GT system 30, and / or other characteristics. The compressor 32 delivers a compressed fluid flow 38 (e.g., compressed air) to the 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 generally 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 produced in the turbine component 48 drives the compressor 32 via a shaft 50 and can be used to drive a generator 52 (e.g., an external component) that is configured to generate electricity and / or a load.

[0026] Although CCPP 12 Figure 11 and 12 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 CCPP 12 is illustrated as including only a single ST system 18 and a single GT system 30, it should be understood that the CCPP 12 may include multiple ST systems 18 and / or GT systems 30 that may be configured to produce an operating load and / or electrical output.

[0027] CCPP 12 may also include a heat recovery steam generator (HRSG) 54 fluidly connected to ST system 18 (eg, to HP section 24 and / or IP section 20 and / or LP section 22) and GT system 30. Figure 1 As shown in the non-limiting example of , the HRSG 54 may be fluidly connected and / or coupled to the ST system 18 via a supply conduit 58 to provide steam to various 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 waste 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 (excess or used) gas (e.g., waste fluid 60) and / or fluid from the HRSG 54 to the atmosphere and / or externally from the CCPP 12.

[0028] The CCPP 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 CCPP 12. In a non-limiting example, the condenser 62 may be fluidly connected to and / or coupled to the LP portion 22 of the ST system 18 via a steam discharge conduit 64. The condenser 62 may be configured to condense a bleed stream and / or a bypass stream (e.g., a line connecting the HP 24 to the condenser 62) 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.

[0029] like Figure 1As shown, the system 10 may include at least one computing device 66 configured to generate (i.e., create and validate) a power plant model and / or directly control the operation of the CCPP 12. The computing device 66 may be hardwired and / or wirelessly connected to and / or in communication with the CCPP 12 and its various components (e.g., ST system 18, GT system 30, HRSG 54, etc.) via any suitable electrical communication 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., computing device) (not shown), which may control and / or regulate the operation and / or function of the CCPP 12 and its various components (e.g., ST system 18, GT system 30, etc.). Alternatively, computing device 66 and components thereof may be integrally formed within, communicate with, and / or form a part of a larger power plant control system (e.g., computing device) (not shown) that may control and / or regulate the operation and / or functionality of CCPP 12 and various components thereof (e.g., ST system 18, GT system 30, etc.).

[0030] In various embodiments, the computing device 66 may generate (i.e., create and / or validate) a power plant model 68 of the CCPP 12. The power plant model 68 may model or otherwise simulate many aspects of the operation of the CCPP 12, including performance, economic variables, environmental data, and / or other attributes of the CCPP 12. In some cases, the power plant model 68 may be referred to or referred to as a "digital twin" or "digital model," and such terms should be understood as a specific form of the power plant model 68 in various embodiments. The computing device 66 may be communicatively coupled to one or more sensors 70, as described herein, to provide input data for modeling and / or controlling the CCPP 12. As described herein, the computing device 66 may generate and / or modify the power plant model 68. The computing device 66 may rely on analysis and / or output from the power plant model 68, as described below, to control the CCPP 12 and / or its various components to affect the operation of the CCPP 12. For example and as described herein, power plant model 68 may simulate various operating characteristics and / or settings of CCPP 12 (including ST system 18 , GT system 30 , HRSG 54 , etc.) and components included therein to control operation of system 10 and / or affect various properties thereof.

[0031] In some cases, computing device 66 may include an operations control program ("operation control program") 72 for interacting with and / or controlling various aspects of system 12. Operation control program 72 may take the form of any currently known or later developed control system suitable for managing power plant operations, such as, for example, a proportional-integral-derivative (PID) controller for managing transient operation of CCPP 12. Additionally or alternatively, operation control program 72 may include a PID subsystem configured to selectively operate during various power generation modes of CCPP 12. A PID controller or subsystem refers to a system that is configured to continuously calculate an error value as a difference between a desired target value and one or more predetermined variables. In the case of a PID controller, operation control program 72 may operate by detecting a variance between one or more variables and a corresponding target (e.g., a corresponding target in power plant model 68) and applying a corrective adjustment, i.e., an instruction to change one or more characteristics of CCPP 12 such as component temperature, valve position, and / or other adjustable operating parameters. According to one example, the corrective adjustment made by the operational control program 72 may modify an instruction of the computing device 66, such as to adjust a valve controlling fuel flow to a 90% capacity position, to a corrective instruction to adjust the valve to a 70% capacity position to reduce the firing temperature and / or firing rate of the GT system 30. The operational control program 72 may thus amplify or mitigate corrective actions output from other algorithms and / or controllers of the CCPP 12, and / or may modify the CCPP 12 to use settings in the power plant model 68. Regardless of implementation, the corrective adjustment made by the operational control program 72 may be calculated from the variables and targets based on proportional, integral, and derivative terms using variables within the power plant model 68, variables measured by the sensors 70, and / or other information within the computing device 66 and / or other devices in communication therewith.

[0032] 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 described 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 ST system 18, the GT system 30, the HRSG 54, and / or one or more subcomponents of the system 10, as described 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 CCPP 12 during operation. For example, and as described herein, the sensor 70 positioned within the HRSG 54 of the CCPP 12 may be any suitable sensor configured to detect and / or determine characteristics of the working fluid (e.g., steam, waste fluid 60). Such characteristics may include the temperature of the working fluid within portions and / or components of the HRSG 54 (including the ST system 18 and / or the GT system 30), the temperature of components of the HRSG 54 of the CCPP 12, and / or steam flow measurements of steam flowing through the HRSG 54. In non-limiting examples, the sensor 70 may be configured as, but not limited to, a thermometer, a thermistor, a thermocouple, and / or any other mechanical / electrical temperature sensor.

[0033] Although three sets of sensors 70 are shown, it should be understood that the system 10 may include more sensors 70 (e.g., Figure 2 and Figure 3 ), these sensors may be configured to provide computing device 66 (and specifically operational control program 72) with information or data related to temperature or pressure of fluids and components included within HRSG 54, and / or fluid flow measurements. Figure 1 The number of sensors 70 shown is merely illustrative and non-limiting. Thus, the system 10 may include more than Figure 1 Or more or fewer sensors 70 as shown in other figures.

[0034] See also Figure 2 , showing the system 10( Figure 1) to further illustrate various embodiments of the present disclosure. The system 10 may include, for example, an ST system 18 and a GT system 30 mounted together on an axis 26. Embodiments of the present disclosure provide operating methods and related program products and systems for operating the CCPP 12 under various load amounts (i.e., "load conditions") and various environmental conditions. In some cases, the CCPP 12 may operate at a continuous load and within predetermined power generation boundaries determined based on the design specifications of the CCPP 12, and the continuous load provides a constant power output to meet all or a portion of the customer's demand. In other cases, the CCPP 12 may operate at a non-continuous load amount under conditions that are different from the operating specifications of the CCPP 12 for at least a threshold period of time. The varying load conditions may be selected to meet the varying needs of the customer for the CCPP 12.

[0035] As the electric grid diversifies to include a wider variety of power sources, it becomes less common to operate the CCPP 12 or other systems under fixed load conditions. However, conventional implementations of the CCPP 12 may not be configured to operate in such settings for extended periods of time. In some cases, the CCPP 12 may operate primarily in a transient operating setting when used in the same electric grid as alternative power sources such as solar, wind, geothermal, etc. Embodiments of the present disclosure provide a method for modeling and controlling the operation of the CCPP 12 to maintain desired parameters and / or efficiency levels when operating under conditions different from those contemplated by its design specifications.

[0036] Embodiments of the present disclosure also take into account differences in the operation of the CCPP 12 under different "ambient conditions," i.e., differences in the temperature, pressure, and / or other properties of the settings in which the CCPP 12 is operated. For example, the CCPP 12 may operate in a region where the temperature is between about 15 degrees Celsius (° C.) and 25° C. Embodiments of the present disclosure may distinguish between different ambient conditions based on a predetermined temperature range (e.g., a predetermined temperature range of about 5° C.) above or below another ambient condition. Thus, "ambient conditions" refer to characteristics of external variables (temperature, pressure, etc.) within a particular embodiment rather than within user control. In various subcomponents of the CCPP 12, higher temperatures may affect variables such as inlet temperature, exhaust temperature, fluid flow, heat rate, and the like. Similar changes in the above and / or other variables of the CCPP 12 may be caused by higher or lower operating pressures. In any case, the changes caused by the ambient conditions of the CCPP 12 may be independent of the load conditions of the CCPP 12.

[0037] According to an embodiment, the system 10 may include a CCPP 12 operating with varying load conditions and / or ambient conditions. As the power output of the CCPP 12 varies under operating conditions, the CCPP may produce its maximum output, reduced output, etc. In such cases, the power generated by the systems 18, 30 may cause the subcomponents of each system 18, 30 to exhibit sustained temperatures, pressures, flow rates, etc. that are significantly different from their expected values. In an exemplary embodiment, the exhaust temperature of the turbine component 48 may be significantly greater than the upper limit of the target exhaust temperature range. This situation may be associated with undesirable consequences, such as being greater than the expected temperature of the fluid flowing through the HRSG 54. In a conventional setting, one or more attemperators 74 divert water from the HRSG 54 to cool the fluid herein. Water diverted to the HRSG 54 by the attemperator 74 may produce inefficient operation because the diverted water becomes unavailable for steam production in the HRSG 54, or more generally, unavailable in the CCPP 12.

[0038] To improve operation under varying ambient and / or load conditions, a computing device 66 and / or an operational control system 72 coupled to the system 18, 30 may rely on the power plant model 68 to adjust the control profile of the GT system 30 to vary parameters such as firing temperature, exhaust temperature, etc. during its operation. Where applicable, the variant control profile may be achieved, for example, by direct cooling of the turbine component 48, reduction of the firing temperature of the combustor 40, and / or other operations discussed herein for reducing exhaust temperature while maintaining similar or identical electrical output. Generation and validation of the power plant model 68 may then be based on monitoring and modeling the firing rate, exhaust temperature, and / or heat rate within the turbine component 48 (based on load and ambient conditions), and also based on modeling other parameters of the GT system 30 (based on modeled variables). In various embodiments, the operational control system 72 may modify additional operational parameters, such as IGV 36 position, fluid flow through the inlet blow-off heat (IBH) line 76 , and / or other operational parameters to further improve CCPP 12 efficiency and / or align CCPP 12 with operation of the power plant model 68 .

[0039] See together Figure 2 and Figure 3, an illustrative environment 150 for operating the system 10 and its subcomponents is shown, in which the CCPP 12 is simplified. As shown, the environment 150 may include a computing device 66, which may include a memory 152 and a CCPP system 154 operating thereon. The CCPP system 154 may be a software system that integrates features of the power plant model 68 and / or the operation control program 72 as its subsystems. In other examples, the power plant model 68 and / or the operation control program 72 may be independent of each other and / or implemented using different computing devices 66. The computing device 66 may be a separate component as shown, or may be included as part of the power plant model 68, as previously described. Figure 3 The illustrated environment 150 represents one type of configuration for controlling the CCPP 12. As described herein, the power plant model 68 of the computing device 66 may simulate the operation of the CCPP 12 when operating under a set of environmental and load conditions. The operational control program 72 may include components for modifying the operation of the CCPP 12, such as by providing and implementing variant control profiles output from the power plant model 68. Embodiments of the present disclosure may be constructed 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 CCPP system 154.

[0040] The computing device 66 may include a processor unit (PU) 158, an input / output (I / O) interface 160, a memory 152, and a bus 164. In addition, the computing device 66 is shown as being in communication with an external I / O device 166 and a storage system 168. The CCPP system 154 may provide a power plant model 68, which in turn may operate using various modules 202 (e.g., calculators, determiners, comparators, etc.) to implement various functions and / or logical steps. In addition or alternatively, the CCPP system 154 may provide the operation control program 72 with its own set of modules 212 (e.g., calculators, determiners, comparators, etc.) to implement the corresponding functions and / or steps of the operation control program 72. The various modules 202, 212 may use algorithm-based calculations, lookup tables, and similar tools stored in the memory 152 for processing, analyzing, and operating on data to perform their respective functions. Generally, the PU 158 may execute computer program code to run software, such as the CCPP system 154, which may be stored in the memory 152 and / or the storage system 168. While executing the computer program code, the PU 158 may read and / or write data to or from the memory 152, the storage system 168, and / or the I / O interface 160. The bus 164 may provide a communication link between each of the components in the computing device 66. The I / O devices 166 may include any device that enables a user to interact with the computing device 66 or any device that enables the computing device 66 to communicate with the equipment described herein and / or other computing devices. The I / O devices 166 (including but not limited to keyboards, displays, pointing devices, etc.) may be coupled to the controller 160 directly or through an intermediate I / O controller (not shown).

[0041] The memory 152 may also include various forms of data 220 related to the CCPP 12 (or more specifically, the systems 18, 30 of the CCPP 12). As described elsewhere herein, the power plant model 68 may simulate the operation of the CCPP 12 under specific environmental conditions and / or load conditions, and the operation control program 72 may adjust the exhaust temperature, firing temperature, relative load, and / or other operating parameters of the CCPP 12 to achieve one or more variant control characteristic maps output from the power plant model 68. In order to implement the method according to the present disclosure, the CCPP system 154 may store and interact with the data 220 that is subdivided into various fields. For example, the environmental condition field 222 may store data related to the environmental conditions of the CCPP at various temperatures, pressures, and / or other environmental variables that are not related to the specifications of the CCPP 12. The data 220 may also include a load condition field 224, which is used to catalog specification data for operating at various output levels (including fixed output and non-fixed output). A set of control characteristic maps for the CCPP 12 may be stored in a control characteristic map field 226, which may include one or more sets of operating parameters (e.g., temperature, pressure, flow rate) and / or ranges of such parameters that represent expected and / or safe operating settings for components of the CCPP 12 under various environmental conditions and / or load conditions. In some cases, the value of each parameter stored in the control characteristic map field 226 may be based on calibration data and / or simulated values ​​obtained from the power plant model 68 for one or more parameters during non-baseload operation. Thus, it should be understood that the data 220 may include a number of measured variables and / or calculated variables that may be applied and / or stored in the control characteristic map field 226 to control the operation of the CCPP 12. The data 220 may also include, for example, a quality threshold field 228 for cataloging quality thresholds, such as minimum improvements in CCPP 12 performance (e.g., heat rate reduction, power plant efficiency increase, fuel consumption reduction, power plant capacity increase, etc.), compliance with emission limits (e.g., NO X emissions, CO emissions, etc.), compliance with operational stability limits (e.g., compressor operability limits, combustion stability limits, gas turbine firing temperatures, gas turbine exhaust temperatures, turbine shaft torque limits for systems 18, 30, operational limits for HRSG 54, operational limits for ST system 18, condenser pressure limits, etc.), and / or other operational quality metrics of the CCPP 12. As noted herein, the quality threshold field 228 may define one or more parameters that the CCPP 12 must meet in order to shift from one control characteristic map to another.

[0042] 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 skilled persons that may perform the various process steps of the present disclosure. Furthermore, the computing device 66 may be part of a larger system architecture operable to model and / or control various aspects and elements of the CCPP 12.

[0043] In this regard, in other embodiments, the computing device 66 may include any special-purpose computing article of manufacture having hardware and / or computer program code for performing specific functions, any computing article of manufacture including a combination of special-purpose and general-purpose hardware / software, etc. In each case, the program code and 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 elements of the CCPP 12 (e.g., the system 18, the system 30, the HRSG 54, etc.) when executed.

[0044] See also Figures 2 to 4 , embodiments of the present disclosure provide methods for operating CCPP 12 using, for example, power plant model 68 and operation control program 72. According to a specific example, Figure 4 A flow chart is provided for controlling the operation of CCPP 12 in the exemplary configuration shown, but using Figure 4 Embodiments of the exemplary process flow shown may also control the CCPP 12 in other configurations. Embodiments of the methods described herein may be implemented, for example, using the power plant model 68 and the operating control system 72 of the computing device 66, and / or various modules and / or subcomponents of the computing device 66, the power plant model 68, or the operating control system 72. Methods 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 power plant model 68) to measure and / or otherwise determine various parameters to be used as the basis for the processes described herein. As described herein, the environment 150 may be operable to model and adjust various operating parameters of the CCPP 12, such as by modifying various operating parameters of the system 18, the system 30, the HRSG 54, etc., to control the flow of fluids therethrough. In additional embodiments, the power plant model 68 may be operable to modify other instructions and / or actions taken via the computing device 66 and / or the power plant model 68, such as by creating one or more variant control characteristic maps that modify the rate of change of various parameters over time and / or relative to the change of power output. Figure 4The 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.

[0045] To initiate a method according to the present disclosure, process P1 may include operating the CCPP 12 under specific load conditions and environmental conditions. Load conditions may refer to the power output from the CCPP 12 during operation, and may include fixed loads or non-fixed loads to accommodate changing conditions. For example, the load conditions of the CCPP 12 may include peak load operation, base load operation, reduced load operation, variable load operation, and / or extended transient operation of the CCPP 12. Environmental conditions for operating the CCPP 12 may refer to external temperature, pressure, and / or other external variables that affect the operation of the CCPP 12. Environmental conditions for the CCPP 12 may include, for example, specification temperature operation, elevated temperature operation, reduced temperature operation, transient temperature operation, and the like. Various load conditions, environmental conditions, and / or combinations thereof may cause the CCPP 12 to exhibit operating parameters (e.g., temperature, pressure, and flow rate) that are significantly different from its specification level. Additional processes according to the present disclosure may simulate the operation of the CCPP 12, and in some cases, modify the operation of the CCPP 12 to prevent inefficient operation, greater than the desired use of cooling fluids and / or components, and / or avoid negative consequences caused by operating outside of a specified range.

[0046] During operation of the CCPP 12, embodiments of the present disclosure may include generating a power plant model 68 of the CCPP 12. As used herein, the term "generating" may include one or more processes for simulating the operation of the CCPP 12 under specific load conditions and environmental conditions, changing an existing power plant model 68 to "run-time" conditions, correcting an existing power plant model 68 to "run-time" conditions, tuning an existing power plant model 68 to "run-time" conditions, calibrating an existing power plant model 68 to "run-time" conditions, and additionally or alternatively, verifying the accuracy of the power plant model 68 based on concurrent operating data of the CCPP 12 and / or other forms of data suitable for verifying the accuracy of the power plant model 68, additionally or alternatively, verifying the accuracy of the power plant model 68 based on concurrent operating data of the CCPP 12 and / or other forms of data suitable for verifying the accuracy of the power plant model 68. In the case of validation based on comparing the power plant model 68 to CCPP 12 operation, process P2 may include indicating whether the power plant model 68 is valid based on whether one or more modeled parameters of the CCPP 12 are similar to (i.e., equal to or within a predetermined error limit) the actual CCPP 12 parameters. Additionally or alternatively, such validation may include changing the power plant model 68 to account for differences between the model parameters and the actual CCPP 12 parameters, and then verifying whether the power plant model 68 is accurate after such adjustments have occurred. The terms "generating" and / or "changing" with respect to the power plant model 68 also encompass actions such as "correcting or calibrating or tuning or updating" the power plant model, as CCPP power plant performance changes over time, e.g., due to degradation, changes, upgrades, etc. In such cases, terms such as "operationally tuned power plant model" may refer to further modifying an existing model to obtain a desired control characteristic map. Process P2 may thus include, for example, determining whether the power plant model 68 is acceptably accurate based on meeting or exceeding a predetermined accuracy metric (e.g., a percentage of modeled parameters of the CCPP 12 being met, optionally within a predetermined time interval). Once validated, the power plant model 68 may represent a baseline set of operating parameters for the CCPP 12 .

[0047] Embodiments of the present disclosure may include modeling the fuel consumption of the CCPP 12 using the power plant model 68. The fuel consumption may be relative to a specific time interval for operating the CCPP 12, and relative to the above-mentioned environmental conditions and / or load conditions of the CCPP 12. The fuel consumption of the CCPP 12 may be expressed as, for example, the total amount of fuel expected to be consumed within a specific time interval under the modeled load conditions and environmental conditions. In addition or alternatively, the fuel consumption modeled in the process P3 may be expressed as an efficiency percentage, a percentage of fuel consumed relative to an expected level, other load conditions and / or environmental conditions. Thus, the fuel consumption modeled in the process P3 may include any conceivable metric for modeling the amount of fuel consumed by the CCPP 12.

[0048] Continuing with process P4, embodiments of the present disclosure may include using the power plant model 68 to create a variant control signature map for the CCPP 12. The variant control signature map may be created in process P4 by any conceivable modeling operation based on various operating parameters included within and / or modeled by the power plant model 68. The variant control signature map may include several operating parameters and / or operating parameter ranges that are different from their current values ​​in the power plant model 68. Such parameters may include one or more of a firing temperature, an inlet temperature, an outlet temperature, an inlet guide vane (IGV) pitch angle, an inlet heat release (IBH) volume, a firing rate, and the like. The variant control signature map may include, for example, a load path of the CCPP 12 that is different from an actual load path of the CCPP 12 during its operation. Such a variation of the load path of the CCPP 12 may be any modified load path that does not violate any specification boundary of the CCPP 12. The variant control signature map may be biased based on an operating schedule for the CCPP 12, for example, to bias the operation of the CCPP 12 and / or its subcomponents toward hotter or cooler values ​​of exhaust temperature, firing temperature, etc. The magnitude or direction of the parameter shift within the variant control signature map may be determined, for example, by randomly selecting a bias magnitude and / or direction and / or by applying predetermined logic to the variant control signature map that is more likely to improve the operation of the CCPP 12. Such logic may be based on the power plant model 68, actual parameters of the CCPP 12, and / or other variables or models associated with the CCPP 12.

[0049] The variant control profile created in process P4 may include a suggested temperature increase and / or decrease within the load path of the CCPP 12. In some cases, one or more quality thresholds of the CCPP 12 may be improved by reducing the load path temperature within the CCPP 12. In such cases, the variant control profile may produce a reduced exhaust temperature / energy, thereby directing less fluid through the thermostat 74 and improving the efficiency of the CCPP 12 by reducing fuel consumption at a fixed load. Such conditions may include, for example, low loads, where the exhaust flow through the CCPP 12 is high, but the exhaust gas temperature within the ST system 10 and / or the GT system 30 is low. In other cases, the variant control profile may increase the temperature within the load path of the CCPP 12. Specifically, the variant control profile may result in higher temperatures within the inlet, exhaust, and / or other sections of the ST system 10 and / or the GT system 30. Such modifications may be desirable in the event that the CCPP 12 is operated at a load above specification. Although there may be several variant control profiles for improving efficiency, fuel consumption, system health, etc. at a particular time, process P4 may require that any variant control profile have a minimum predicted improvement before the power plant model is applied to control CCPP 12 .

[0050] After creating the variant control profile map from the power plant model 68 in process P4, the method according to the present disclosure may include several decisions for determining whether to modify the operation of the CCPP 12 based on the variant control profile map created in process P4. At decision D1, the module 212 of the operation control program 72 may evaluate whether applying the variant control profile map to the CCPP 12 will continue to meet the quality thresholds (e.g., maximum values ​​of temperature, pressure, temperature, fuel consumption, etc.) of the CCPP 12. According to one example, the quality threshold may be expressed as whether the fuel consumption of the CCPP 12 is reduced by at least a threshold amount. In this case, the reduction in fuel consumption may be defined as a percentage (e.g., a reduction in fuel consumption of at least about 1% over a specified time span). In other examples, the quality threshold may include additional threshold improvements in the operation of the CCPP 12, such as a reduction in the minimum heat rate of the CCPP 12, an increase in the minimum power plant efficiency, compliance with emission limits, and / or compliance with operational stability limits. "Emission limits" may refer to maximum allowable levels of carbon dioxide and / or nitrogen oxide emission levels of the CCPP 12. The “operational stability limit” may refer to the maximum amount by which a variant control feature map shortens the expected life and / or exceeds the specification limits of the CCPP 12 and / or its subcomponents. As noted herein, the quality thresholds evaluated in decision D1 and stored in the quality threshold field 228 may include various metrics, such as minimum improvement in CCPP 12 performance (e.g., heat rate reduction, power plant efficiency increase, fuel consumption reduction, power plant capacity increase, etc.), compliance with emission limits (e.g., NO Xemissions, CO emissions, etc.), compliance with operational stability limits (e.g., compressor operability limits, combustion stability limits, gas turbine firing temperatures, gas turbine exhaust temperatures, turbine shaft torque limits of systems 18, 30, operational limits of HRSG 54, operational limits of ST system 18, condenser pressure limits, etc.) and / or other operational quality metrics of CCPP 12.

[0051] In the event that the variant control signature map does not meet the quality threshold (i.e., “No” at decision D1), the method may proceed to process P5 to modify the variant control signature map. Such modifications may be random changes, and / or may be based on a schedule of possible changes managed by logic within the power plant model 68, and / or may be based on results of experimental and / or calculated power plant models (e.g., “digital twins”). In the event that the quality threshold is met (i.e., “Yes” at decision D1), the method may proceed with further operations for applying the variant control signature map to the CCPP 12. In some cases, methods according to the present disclosure may test only a predetermined number of variant control signature maps (e.g., five, ten, fifty, or one hundred or more variant control signature maps). In such examples, the method may end (“Complete”) after decision D1 indicates that none of the tested variant control signature maps meet the relevant quality threshold.

[0052] In the event that the variant control profile map satisfies the quality threshold, a method according to the present disclosure may include process P6 in which the operating control system 72 adjusts the CCPP 12 to use the variant control profile map. Process P6 may involve the operating control system 72 applying one or more modifications to the existing control profile map of the CCPP 12 to change one or more parameters (e.g., temperatures such as firing temperature, inlet temperature, exhaust temperature, etc.) as defined in the variant control profile map. In some cases, the operating control system 72 may adjust and / or otherwise modify the parameters of the variation based on one or more characteristics of the particular CCPP 12 unit being controlled. In any case, the modified parameters (e.g., temperatures) may be offset substantially in real time as the CCPP 12 continues to operate. After adjusting the CCPP 12 in process P6, the method may end ("complete") and the CCPP 12 may continue to operate using the variant control profile map. In another example, the method may return to process P3 of modeling the fuel consumption of the CCPP 12 using the power plant model 68 and repeat process P4 and decisions D1, D2 using the new variant control profile to iteratively improve the CCPP as the CCPP 12 continues to operate. In some cases, embodiments of the method may be repeated after any significant change in the load conditions and / or ambient conditions of the CCPP 12.

[0053] Adjusting the CCPP 12 to use a variant control profile in process P6 may include one or more additional operations to provide a variant control profile, and / or further modify the CCPP 12. According to one example, the adjustment may include increasing or decreasing the fluid flow through the attemperator 74 to obtain a desired temperature increase or decrease within the CCPP 12. In another example, the adjustment may include adjusting the pitch angle of the IGV 36, thereby changing the inlet temperature and / or the temperature of other fluidly connected components within the GT system 30. In yet another example, the adjustment may include adjusting the amount of compressor exhaust fluid directed through the IBH line 76, thereby also modifying both the inlet temperature and the outlet temperature of the compressor 32. In yet another example, the modification may include adjusting the steam output from the HRSG 54 to further modify one or more temperatures within the ST system 18 and / or the GT system 30.

[0054] See also Figures 3 to 5 , embodiments of the present disclosure may be operable to modify the temperature-load curve of the CCPP 12 during operation, and thus may provide greater operational control of the CCPP 12 than conventional control systems. As described herein, the temperature-load characteristic map (indicated by curve C1) of the CCPP 12 may be approximately linear in the case where the inlet (alternatively, "fire") follows only a single control characteristic map. When operating according to its initial control characteristic map, the conventional temperature-load characteristic map C1 may increase from its initial value to its maximum value approximately linearly and / or at a certain decreasing rate. However, applying the variant control characteristic map to the CCPP 12 in accordance with the method according to the present disclosure may significantly change the rate at which the inlet temperature changes with respect to the load of the CCPP 12. In one example, the modified temperature characteristic map C2 may provide a reduced fire temperature, which in turn will result in a reduced exhaust temperature within a corresponding range of power output (e.g., up to about 87% of maximum load), but may provide an increased fire temperature, and therefore increased exhaust temperature, at a higher power output (e.g., above about 87% of maximum load). Therefore, it should be emphasized that the variant control profiles discussed in embodiments of the present disclosure may not simply reflect temperature increases or decreases within various portions of the CCPP 12, but may include both higher and lower temperatures within specific components, depending on the amount of load output.

[0055] See also Figure 3 , Figure 4 and Figure 6 Adjusting the CCPP 12 to use a variant control profile may also affect the outlet temperature (T 排气, measured in degrees Fahrenheit (℉). Thus, embodiments of the present disclosure may also modify the temperature-load curve of the CCPP 12 at the outlet of the GT system 30 during operation, and thus may affect several dependent properties of the CCPP 12 by using a variant control profile. The temperature-power profile of the CCPP 12 (indicated by curve C1) may follow a segmentally defined curve, where the exhaust temperature remains constant at lower loads and decreases linearly at higher loads. In contrast, the modified temperature-power profile of the CCPP 12 (indicated by curve C2) may decrease more rapidly at lower loads and increase linearly at higher loads, for example to provide greater responsiveness and / or sensitivity to potential operational changes.

[0056] See now Figure 3 , Figure 4 , Figure 7 and Figure 8 , adjusting the CCPP 12 to use a variant control characteristic map may also affect technical properties of the CCPP 12 other than temperature. For example, modifying the CCPP 12 to use a variant control characteristic map may also affect the IGV angle ( Figure 7 θ IGV ) and / or thermostat fluid flow ( Figure 8 The "Q Att ”). In terms of IGV angle, the variant control profile may change the IGV position to an angle of incidence that is greater than the conventional angle of incidence at lower loads and / or may change the IGV to an angle of incidence that is less than the conventional angle of incidence at higher loads. In terms of thermostat fluid flow, operating the CCPP 12 with the variant control profile may significantly reduce it at lower loads and slightly increase it at higher loads due to the above-mentioned changes in firing temperature and / or exhaust temperature.

[0057] Simply see Figure 3 , Figure 4 and Fig. 9 , embodiments of the present disclosure may also significantly affect other relevant characteristics of CCPP 12. Specifically, Fig. 9 The heat rate (Δ HR ). As shown, at loads of, for example, about 68% or 99% of the maximum CCPP 12 load, the heat rate (Δ HR ) can be as great as about 0.5%.

[0058] Advantages of the present disclosure allow for the agile deployment and use of the CCPP 12 in a grid with a variety of energy sources and / or in a non-base load operating setting. In an embodiment of the present disclosure, the CCPP 12 can easily fill demand gaps and / or maintain efficient performance despite rapid changes between different power outputs. Therefore, the embodiments of the present disclosure allow the CCPP 12 to internally compensate for fluctuations in energy demand, unavailability of other power sources, etc. Improvements to the CCPP 12 can reduce fuel consumption during operation and extend the life of various systems and their components. Operating the CCPP 12 in a mode that can reduce the temperature of various segments can provide significant life extension and lower maintenance requirements. In addition, the embodiments of the present disclosure can be implemented without significantly changing the CCPP 12 hardware by modifying existing control logic, circuits, etc. to accommodate the operating methods described herein.

[0059] As used throughout the specification and claims, approximate language can be used to modify any quantitative representation that can be allowed to vary without causing a change in the basic function associated with it. Therefore, the values ​​modified by one or more terms (such as "about", "approximately" and "substantially") are not limited to the specified precise values. In at least some cases, approximate language can correspond to the precision of the instrument used to measure the value. Here and throughout the specification and claims, range limitations can 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 specific value of a range applies to both end values, and + / -10% of the value can be indicated unless otherwise dependent on the precision of the instrument for measuring the value.

[0060] 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 operating a combined cycle power plant (CCPP) (12), the method comprising: operating the combined cycle power plant (12) under certain ambient conditions (222) and certain load conditions (224); generating a power plant model (68) for the combined cycle power plant (12) operating under the ambient conditions (222) and the load conditions (224); modeling fuel (42) consumption using a baseline control characteristic map and the power plant model (68) of the combined cycle power plant (12) under the ambient conditions (222) and the load conditions (224); Creating a variant control characteristic map of the combined cycle power plant (12); determining, using the power plant model (68), whether the variant control characteristic map satisfies a quality threshold (228) of the combined cycle power plant (12), the quality threshold (228) comprising at least a fuel efficiency of the combined cycle power plant (12); modifying the variant control characteristic map in response to the variant control characteristic map not satisfying the quality threshold (228); and In response to the variant control characteristic map satisfying the quality threshold (228), the combined cycle power plant (12) is adjusted to use the variant control characteristic map, wherein the variant control characteristic map adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule of the combined cycle power plant (12).

2. The method of any preceding claim, wherein adjusting the combined cycle power plant (12) to use the variant control characteristic map reduces attemperator fluid flow within the combined cycle power plant (12).

3. The method of any preceding claim, wherein adjusting the combined cycle power plant (12) to use the variant control characteristic map includes adjusting an inlet guide vane (IGV) (36) pitch angle within the combined cycle power plant (12).

4. A method according to any preceding claim, wherein adjusting the combined cycle power plant (12) to use the variant control characteristic diagram reduces the inlet blow-off heat (IBH) flow of the waste fluid (60) from the exhaust section to the inlet section of the compressor (32) of the combined cycle power plant (12).

5. The method of any preceding claim, wherein adjusting the combined cycle power plant (12) to use the variant control characteristic map increases steam output from a heat recovery steam generator (HRSG) assembly (54) within the combined cycle power plant (12).

6. A method according to any preceding claim, wherein the quality threshold (228) also includes at least a minimum heat rate reduction, a minimum power plant efficiency increase, a minimum fuel consumption reduction, a fuel consumption limit, an emission limit or an operational stability limit of the combined cycle power plant (12).

7. The method according to any preceding claim, further comprising: modifying one of the load condition (224) or the environmental condition (222) of the combined cycle power plant (12); as well as The modeling, the creating, the determining, and one of modifying the variant control characteristic map or adjusting the combined cycle power plant (12) are repeated.

8. The method of any preceding claim, wherein creating the variant control profile comprises applying a predetermined temperature increase or temperature decrease to the baseline control profile based on the ambient conditions (222) and the load conditions (224).

9. The method of any preceding claim, wherein the adjusted turbine section inlet temperature schedule and the adjusted exhaust gas temperature schedule of the combined cycle power plant (12) are dependent on the load conditions (224).

10. A program product for operating a combined cycle power plant (CCPP) (12) stored on a computer readable storage medium, the computer readable storage medium comprising program code for causing a computer system to perform actions comprising: operating the combined cycle power plant (12) under certain ambient conditions (222) and certain load conditions (224); generating a power plant model (68) for the combined cycle power plant (12) operating under the ambient conditions (222) and the load conditions (224); modeling fuel consumption using a baseline control characteristic map and the power plant model (68) of the combined cycle power plant (12) under the ambient conditions (222) and the load conditions (224); Creating a variant control characteristic map of the combined cycle power plant (12); determining, using the power plant model (68), whether the variant control characteristic map satisfies a quality threshold (228) of the combined cycle power plant (12), the quality threshold (228) comprising at least a fuel efficiency of the combined cycle power plant (12); modifying the variant control characteristic map in response to the variant control characteristic map not satisfying the quality threshold (228); and In response to the variant control characteristic map satisfying the quality threshold (228), the combined cycle power plant (12) is adjusted to use the variant control characteristic map, wherein the variant control characteristic map adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule of the combined cycle power plant (12).

11. The program product of claim 10, wherein adjusting the combined cycle power plant (12) to use the variant control profile reduces attemperator fluid flow within the combined cycle power plant (12).

12. The program product of claim 10 or 11, wherein adjusting the combined cycle power plant (12) to use the variant control characteristic map includes adjusting an inlet guide vane (IGV) (36) pitch angle within the combined cycle power plant (12).

13. The program product of claim 10, wherein adjusting the combined cycle power plant (12) to use the variant control characteristic map reduces an inlet blow-off heat (IBH) flow of a waste fluid (60) from an exhaust section to an inlet section of a compressor (32) of the combined cycle power plant (12).

14. A program product according to any one of claims 10-13, wherein adjusting the combined cycle power plant (12) to use the variant control characteristic map increases steam output from a heat recovery steam generator (HRSG) (54) component within the combined cycle power plant (12).

15. A program product according to any one of claims 10-14, wherein the quality threshold (228) includes at least a minimum heat rate reduction, a minimum power plant efficiency increase, a minimum fuel consumption reduction, a fuel consumption limit, an emission limit or an operational stability limit of the combined cycle power plant (12).

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