Modeling and control of gas cycle power plant operation by varying split loads of multiple gas turbines

Abstract

The invention is titled Modeling and Control of Gas Cycle Power Plant Operation by Altering Split Load of Multiple Gas Turbines. Embodiments of the present disclosure provide a method for operating a combined cycle power plant (CCPP) (12). The method can include generating a power plant model (68) for operating the CCPP (12), determining whether at least two gas turbines (30A, 30B) in the power plant model (68) generate an electrical power output, and modeling fuel consumption of the CCPP (12) for a baseline split ratio (226) between the at least two gas turbines (30A, 30B). The method can also include determining whether an altered split ratio (226) satisfies a quality threshold of the CCPP (12), and adjusting the CCPP (12) to use the altered split ratio (226) in response to the altered split ratio (226) satisfying the quality threshold.

Description

Background Technology

[0001] This disclosure relates generally to the modeling and control of power plants. More specifically, embodiments of this disclosure provide an operational method for modeling and controlling a power plant by modeling and analyzing variant shunt loads of multiple gas turbines within the power plant.

[0002] Power plants typically include various turbines and / or systems for generating electricity output. Two conventional power systems for generating electricity include gas turbine systems and combined cycle power plants, which typically include gas turbine systems. A conventional combined cycle power plant employs one or more gas turbine systems operatively coupled to one or more steam turbine systems. The gas turbine system includes a compressor coupled to the gas turbine. The gas turbine is typically coupled to and drives external components, such as generators, to generate loads or electricity output. The steam turbine system includes a high-pressure (HP) turbine section operatively coupled to an intermediate-pressure (IP) turbine section, which in turn is coupled to a low-pressure (LP) turbine. Similar to the gas turbine systems, the HP, IP, and LP turbines drive external components (e.g., generators). In a typical combined cycle power plant, exhaust gases from the gas turbines are fed to a heat recovery steam generator (HRSG), which generates steam to supply the various turbines of the steam turbine system and reheats the steam to improve the efficiency of the system and / or the power plant. Downstream of the HRSG, the exhaust gases are released into the atmosphere through a chimney.

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

[0004] A first aspect of this disclosure provides a method for operating a combined cycle power plant (CCPP), the method comprising: generating a power plant model for operating the CCPP under certain environmental and load conditions; determining whether at least two gas turbines in the CCPP's power plant model generate electrical output under the environmental and load conditions; modeling the CCPP's fuel consumption for a baseline split ratio between the at least two gas turbines using the CCPP's power plant model under the environmental and load conditions; creating a variant split ratio between the at least two gas turbines; determining, using the power plant model, whether the variant split ratio meets a quality threshold for the CCPP, the quality threshold including at least a minimum reduction in fuel consumption; recalculating the variant split ratio in response to the variant split ratio not meeting the quality threshold; and adjusting the CCPP to use the variant split ratio in response to the variant split ratio meeting the quality threshold.

[0005] A second aspect of this disclosure provides a program product stored on a computer-readable storage medium for operating a combined cycle power plant (CCPP), the computer-readable storage medium including program code that causes a computer system to perform actions including: generating a power plant model for operating the CCPP under certain environmental and load conditions; determining whether at least two gas turbines in the CCPP's power plant model generate electrical output under the environmental and load conditions; modeling the CCPP's fuel consumption for a baseline split ratio between the at least two gas turbines using the CCPP's power plant model under the environmental and load conditions; creating a variant split ratio between the at least two gas turbines; determining, using the power plant model, whether the variant split ratio meets a quality threshold for the CCPP, the quality threshold including at least a minimum reduction in fuel consumption; recalculating the variant split ratio in response to the variant split ratio not meeting the quality threshold; and adjusting the CCPP to use the variant split ratio in response to the variant split ratio meeting the quality threshold.

[0006] A third aspect of this disclosure provides a system comprising: a combined cycle power plant (CCPP) having a gas turbine and a heat recovery steam generator (HRSG); and a system controller communicating with the gas turbine and HRSG of the CCPP, the system controller being operable to perform the following operations: operating the CCPP under certain environmental and load conditions; generating a power plant model for the CCPP operating under the environmental and load conditions; modeling fuel consumption using a baseline split ratio and the power plant model of the CCPP under the environmental and load conditions; creating a variant split ratio for the CCPP; determining, using the power plant model, whether the variant split ratio meets a quality threshold for the CCPP, the quality threshold including at least a minimum reduction in fuel consumption; modifying the variant split ratio in response to the variant split ratio not meeting the quality threshold; and adjusting the CCPP to use the variant split ratio in response to the variant split ratio meeting the quality threshold.

[0007] Exemplary aspects of this disclosure are designed to address the problems described herein and / or other problems not discussed herein. Attached Figure Description

[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 in conjunction with the accompanying drawings depicting various embodiments thereof, wherein:

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

[0010] Figure 2 This is a schematic diagram of a system and a CCPP having multiple gas turbines according to various embodiments of this disclosure.

[0011] Figure 3 An exemplary computer environment operable to control a CCPP having multiple gas turbines is shown according to an embodiment of the present disclosure.

[0012] Figure 4 An exemplary flowchart of a method for operating a CCPP according to an embodiment of this disclosure is provided.

[0013] Figure 5 An exemplary curve of the power output of a CCPP to a load in a CCPP according to an embodiment of this disclosure is provided.

[0014] Figure 6 An exemplary curve of inlet heat release (IBH) variation versus load in a CCPP according to an embodiment of this disclosure is provided.

[0015] Figure 7An exemplary curve of the percentage change in heat rate versus the load of a variant split ratio in a CCPP according to embodiments of the present disclosure is provided.

[0016] Figure 8 Illustrative curves of inlet heat release (IBH) variation versus load in a CCPP under various environmental conditions are provided according to embodiments of this disclosure.

[0017] Figure 9 Illustrative curves of total heat consumption rates for multiple environmental conditions in a CCPP according to an embodiment of this disclosure are provided.

[0018] Figure 10 Illustrative curves of CCPP efficiency under various environmental conditions according to embodiments of this disclosure are provided.

[0019] It should be noted that the accompanying drawings of this disclosure are not drawn to scale. The drawings are intended to depict only typical aspects of this disclosure and therefore should not be considered as limiting the scope of this disclosure. In the drawings, similar numbers denote similar elements between the figures. Detailed Implementation

[0020] First, in order to clearly describe the present technology, it will be necessary to select certain terms when referring to and describing related machine parts within the various systems, components, and other embodiments of this 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 this application and the scope of the appended claims. Those skilled in the art will understand that several different or overlapping terms may generally be used to refer to a particular part. An object that can be described herein as a single part may include multiple parts and is referred to in another context as being composed of multiple parts. Alternatively, an object that can be described herein as comprising multiple parts may elsewhere be referred to as a single part.

[0021] In addition, several descriptive terms may be used regularly in this document, 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 location or importance of a single component.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that, when used in the specification, the terms “comprising” and / or “including” specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. “Optional” or “optionally” means that an event or condition subsequently described may or may not occur, and the description includes instances where the event occurs and instances where the event does not occur.

[0023] When an element or layer is referred to as “on,” “joined to,” “connected to,” or “linked to” another element or layer, it may be directly on, joined to, connected to, or linked to another element or layer, or an intermediary element or layer may be present. In contrast, when an element is referred to as “directly on another element or layer,” “directly joined to another element or layer,” “directly connected to another element or layer,” or “directly linked to another element or layer,” an intermediary element or layer may not be present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0024] Implementations of this disclosure provide methods, program products, and systems for controlling various properties of a combined cycle power plant (CCPP) by actively redistributing the power output from multiple gas turbines. Implementations of this disclosure may include, for example, generating a power plant model based on the CCPP for operation under specific environmental and load conditions. The generation of such a model may include validating the model's accuracy based on current and / or historical operating data of the CCPP. The method may include determining whether at least two gas turbines in the CCPP's power plant model will generate power output under those environmental and load conditions. The method may also include using the model to model the CCPP's fuel consumption when operating under those environmental and load conditions, and creating a variant split ratio to modify the relative power generated by two or more gas turbines. The method may include determining whether the variant split ratio meets one or more quality thresholds of the CCPP, and adjusting the CCPP to use the variant split ratio if these requirements are met. Adjustments to the CCPP may affect other CCPP variables, such as inlet heat release (IBH) flow, heat rate, expected remaining life of one or more gas turbines, and / or other variables affecting the CCPP's power output and operating characteristics.

[0025] Figure 1 A schematic diagram of system 10 according to various embodiments of the present disclosure is shown. As shown, 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, as illustrated, may include a high-pressure (HP) section 24, an intermediate-pressure (IP) section 20, and a low-pressure (LP) section 22, as known in the art. The HP section 24, IP section 20, and LP section 22 of the ST system 18 may be coupled and / or positioned on a shaft 26 and / or may be configured to rotate shafts to generate mechanical work and / or drive other components of the ST system 18. Figure 1 As shown, the shaft 26 of the ST system 18 can be coupled to and / or drive an external component, and more specifically, the external component is a generator 28 configured to generate electricity and / or produce loads.

[0026] CCPP 12 may also include at least one gas turbine (GT) system 30. While CCPP 12 may include two, five, ten, one hundred, or more GT systems 30, Figure 1 Only one GT system is shown here for illustrative purposes only. GT system 30 may include compressor 32. As an inlet fluid flow 34 (e.g., air) flows through compressor 32, compressor 32 compresses the inlet fluid flow. Compressor 32 may include a multi-stage stator vanes (not shown) and rotary vanes (not shown) positioned within compressor 32. The stator vanes and rotary vanes positioned within compressor 32 may be configured to facilitate the movement and / or delivery of fluid 34 through compressor 32. Compressor 32 may include a set of inlet guide vanes (IGV) 36. IGV 36 is a type of vane specifically configured to guide the inlet working fluid flow onto the rotary vanes of compressor 32. IGV 36 can be adjusted between several positions to influence the flow rate, angle of incidence, and / or other characteristics of the fluid entering compressor 32. IGV 36 can therefore influence the temperature of compressor 32, electrical output from GT system 30, and / or other characteristics. Compressor 32 delivers a compressed fluid flow 38 (e.g., compressed air) to burner 40. Combustor 40 mixes compressed fluid stream 38 with pressurized fuel stream 42 supplied by fuel source 44 and ignites the mixture to produce combustion gas stream 46. Combustion gas stream 46 is then delivered to turbine component 48, which typically includes multi-stage stator vanes (not shown) and turbine blades (not shown), similar to compressor 32. Combustion gas stream 46 drives turbine component 48 to generate mechanical work. The mechanical work generated in turbine component 48 drives compressor 32 via shaft 50 and can be used to drive generator 52 (e.g., an external component) configured to generate electricity and / or produce load.

[0027] Although CCPP 12 is Figure 1 The diagram illustrates a dual-shaft configuration including two separate generators 28 and 52; however, it should be understood that in other non-limiting examples, the ST system 18 and GT system 30 may share a single shaft, and consequently, a single generator. Furthermore, while CCPP 12 is shown as including only a single ST system 18 and a single GT system 30, it should be understood that CCPP 12 may include multiple ST systems 18 and / or GT systems 30, which may be configured to generate operating loads and / or electrical outputs.

[0028] CCPP 12 may also include a heat recovery steam generator (HRSG) 54 fluidly connected to ST system 18 (e.g., 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, HRSG 54 may be fluidly connected and / or coupled to ST system 18 via supply conduit 58 to supply steam to various parts of ST system 18 via supply conduit 58. Additionally, in Figure 1 In a non-limiting example, HRSG 54 may be fluidly connected to and / or coupled to GT system 30 via exhaust gas passage 59, which is coupled to and / or in fluid communication with turbine component 48. Exhaust gas passage 59 may supply waste fluid 60 (e.g., gas) from GT system 30 to HRSG 54 for generating and / or heating steam for ST system 18. Chimney 61 of HRSG 54 may discharge or release (excess or used) gas (e.g., waste fluid 60) and / or fluid from HRSG 54 to the atmosphere and / or from CCPP 12.

[0029] CCPP 12 may also include a condenser 62. The condenser 62 may be in fluid communication with and / or fluidly coupled to various components of CCPP 12. In a non-limiting example, the condenser 62 may be fluidly connected to and / or coupled to the LP section 22 of the ST system 18 via a steam discharge line 64. The condenser 62 may be configured to condense discharge flows and / or bypass flows from the ST system 18 and / or HRSG 54 (e.g., a line connecting HP 24 to the condenser 62) and to supply condensed fluid (e.g., condensate) to the HRSG 54, as is known in the art.

[0030] like Figure 1As shown, system 10 may include at least one computing device 66 configured to generate (i.e., create and verify) a power plant model and / or directly control the operation of CCPP 12. The computing device 66 may be connected to and communicate with 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 connectivity components or technical hardwired and / or wireless connections. The computing device 66 and its various components discussed herein may be a single, independent system operating separately from another power plant control system (e.g., a computing device) (not shown), which may control and / or adjust the operation and / or functionality of CCPP 12 and its various components (e.g., ST system 18, GT system 30, etc.). Alternatively, the computing device 66 and its components may be integrally formed within, communicate with and / or form part of a larger power plant control system (e.g., a computing device) (not shown), which can control and / or adjust the operation and / or function of the CCPP 12 and its various components (e.g., ST system 18, one or more GT systems 30, etc.).

[0031] In various implementations, computing device 66 may generate (i.e., create and / or verify) a power plant model 68 of CCPP 12. Power plant model 68 may model or otherwise simulate many aspects of the operation of CCPP 12, including performance, economic variables, environmental data, and / or other properties of CCPP 12. In some cases, power plant model 68 may be referred to as a “digital twin” or “digital model,” and such terms should be understood in various implementations as referring to a specific form of power plant model 68. 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 CCPP 12. As described herein, computing device 66 may generate and / or modify power plant model 68. Computing device 66 may rely on analyses and / or outputs from power plant model 68, as described below, to control CCPP 12 and / or its various components to influence the operation of CCPP 12. For example, and as described herein, power plant model 68 can simulate various operating characteristics and / or settings of CCPP 12 (including the power output and / or other parameters of ST system 18, GT system 30, HRSG 54, etc.) and components included therein, in order to control the operation of system 10 and / or affect its various properties.

[0032] In some cases, the computing device 66 may include an operation control program (“Operation Control Program”) 72 for interacting with and / or controlling various aspects of the system 12. The Operation Control Program 72 may take the form of any currently known or later-developed control system suitable for managing the operation of a power plant, such as a proportional-integral-derivative (PID) controller for managing transient operation of CCPP 12. Alternatively, the Operation Control Program 72 may include a PID subsystem configured to operate selectively during various power generation modes of CCPP 12. A PID controller or subsystem is a system constructed to continuously calculate error values ​​as the difference between a desired target value and one or more predetermined variables. With respect to a PID controller, the Operation Control Program 72 may operate by detecting the variance between one or more variables and a corresponding target (e.g., a corresponding target in the power plant model 68) and applying corrective adjustments, i.e., instructions for changing one or more characteristics of CCPP 12 such as relative load output, component temperature, valve position, and / or other adjustable operating parameters. According to one example, the correction adjustments performed by the operation control program 72 can modify instructions executed by the computing device 66, such as adjusting the power output from the selected GT system 30 (e.g., switching between 50% of the total power output and a higher or lower value). Additional operations performed by the computing device 66 may include, for example, a correction instruction to adjust a valve controlling the fuel flow to a 90% capacity position to a 70% capacity position to reduce the ignition temperature and / or combustion rate of the GT system 30. The operation control program 72 can therefore amplify or mitigate correction actions from other algorithms and / or controller outputs of the CCPP 12, and / or modify the CCPP 12 to use settings in the power plant model 68. Regardless of implementation, the correction adjustments performed by the operation control program 72 can be calculated based on proportional, integral, and derivative terms, using variables within the power plant model 68, variables measured by the sensor 70, and / or other information within the computing device 66 and / or other devices communicating with it, from variables and targets.

[0033] like Figure 1 As shown, the computing device 66 may include the sensor 70 and many other additional and / or intermediate components located throughout the system 10, such as valves, solenoids, actuators, converters, etc. (not shown), and / or may be in electrical communication and / or mechanical connection with these components. Figure 1As shown in the non-limiting examples and as described herein, at least one sensor 70 of computing device 66 and / or at least one sensor connected to computing device 66 may be located within one or more sub-components of ST system 18, GT system 30, HRSG 54 and / or system 10, as described elsewhere herein. The sensor 70 communicating with computing device 66 of system 10 may be any suitable sensor or device configured to detect and / or determine data, information and / or operational characteristics related to CCPP 12 during operation. For example, and as described herein, the sensor 70 located within HRSG 54 of 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 working fluid temperature within portions and / or components of HRSG 54 (including ST system 18 and / or GT system 30), the temperature of components of HRSG 54 of CCPP 12, and / or steam flow rate measurements of steam flowing through HRSG 54. In a non-limiting example, sensor 70 may be configured as, but is not limited to, a thermometer, a thermistor, a thermocouple, and / or any other mechanical / electrical temperature sensor.

[0034] Although three sets of sensors 70 are shown, it should be understood that system 10 may include more sensors 70 (e.g., such as...). Figure 2 and Figure 3 As shown, these sensors can be configured to provide computing device 66 (and specifically operating control program 72) with information or data related to the temperature or pressure of the fluid and components included in HRSG 54, and / or fluid flow measurement results. Figure 1 The number of sensors 70 shown is merely illustrative and non-limiting. Therefore, system 10 may include more than Figure 1 Or, as shown in other accompanying figures, more or fewer sensors 70.

[0035] See Figure 2 The system 10 is shown. Figure 1 The diagram below is an expanded illustration to further illustrate various embodiments of this disclosure. System 10 may include, for example, an ST system 18 and a GT system 30 mounted together on shaft 26. Figure 2In the arrangement, multiple GT systems 30 are individually shown and identified, for example, a first GT system 30A, a second GT system 30B, and a third GT system 30C. Embodiments of this disclosure provide operating methods, related procedures, products, and systems for operating the CCPP 12 under various load levels (i.e., "load conditions") and various environmental conditions. In some cases, the CCPP 12 can operate under continuous load and within predetermined generation boundaries defined based on the CCPP 12's design specifications, providing a constant power output to meet all or part of customer demand. In other cases, the CCPP 12 can operate under non-continuous load levels for at least a threshold time period under conditions different from the CCPP 12's operating specifications. Varying load conditions can be selected to meet varying customer requirements for the CCPP 12.

[0036] As power grids diversify to include more power sources, operating CCPP 12 or other systems under fixed load conditions becomes less common. However, conventional implementations of CCPP 12 may not be designed to operate for extended periods in such settings. In cases where CCPP 12 comprises multiple GT systems 30 (e.g., systems 30A, 30B, 30C as shown in the figures), conventional methods for controlling CCPP 12 would distribute the generation load evenly across all GT systems 30 within CCPP 12, and / or distribute a higher generation load across selected GT systems 30, regardless of variations in load conditions and / or environmental conditions. Embodiments of this disclosure provide a method for actively modeling and controlling the load shunt ratio (hereinafter referred to as the "shunt ratio") among multiple GT systems 30 in CCPP 12 to maintain desired parameter and / or efficiency levels when operating under conditions different from those predicted in design specifications or otherwise envisioned. Throughout the specification, “split ratio” may refer to the percentage of load allocated to the different GT systems 30 in CCPP 12, and may also include, in addition to or alternatively, the split ratio between GT systems 30 and other parameters such as the inlet guide vane (IGV) angle or the variation of inlet exhaust heat (IBH) flow.

[0037] The embodiments of this disclosure also take into account the differences in operation of CCPP 12 under different "ambient conditions," i.e., differences in the temperature, pressure, and / or other properties of the settings for operating CCPP 12. For example, CCPP 12 can operate in a region where the temperature is between approximately 15 degrees Celsius (°C) and 25°C. Embodiments of this disclosure can distinguish different ambient conditions based on a predetermined temperature range above or below another ambient condition (e.g., a predetermined temperature range of approximately 5°C). Therefore, "ambient conditions" refer to the characteristics of external variables (temperature, pressure, etc.) within a particular embodiment rather than within user control. In the various sub-components of CCPP 12, higher temperatures can affect variables such as inlet temperature, exhaust temperature, fluid flow rate, and heat rate. Similar changes in the above and / or other variables of CCPP 12 can be caused by higher or lower operating pressures. In any case, changes caused by the ambient conditions of CCPP 12 may be independent of the load conditions of CCPP 12.

[0038] According to the implementation scheme, system 10 may include CCPP 12 operating under varying load and / or environmental conditions. As the power output of CCPP 12 varies under different operating conditions, CCPP 12 may generate its maximum output, reduced output, etc. In such cases, the operating schedule of CCPP 12 may disproportionately generate more power from some systems 18, 30 within CCPP 12 than from other systems. This situation may be associated with undesirable consequences, such as reduced efficiency of one or more GT systems 30 of CCPP 12 as operation continues.

[0039] To improve operation under varying environmental and / or load conditions, the computing device 66 and / or operation control system 72 coupled to systems 18, 30 can rely on the power plant model 68 to adjust the split ratio of the GT system 30, thereby changing the power generation load on each GT system 30 as the CCPP 12 operates. Where applicable, variant split ratios can be implemented, for example, by changing the amount of fuel supplied to the GT system 30, adjusting the operating settings of one or more GT systems 30 in the CCPP 12, and / or other operations described herein for increasing and decreasing the electrical power generated by the target GT system 30. The generation and validation of the power plant model 68 can then be based on monitoring and modeling of the ignition rate, exhaust temperature, and / or heat loss rate within the turbine component 48 (based on load and environmental conditions), and also on modeling other parameters of the GT system 30 (based on modeled variables). In various implementations, the operation control system 72 may modify additional operating parameters, such as the position of IGV 36, the fluid flow rate through the inlet heat release (IBH) line 76, and / or other operating parameters, to further improve the efficiency of CCPP 12 and / or to align CCPP 12 with the operation of the power plant model 68.

[0040] See you together Figure 2 and Figure 3 An exemplary environment 150 for operating system 10 and its subcomponents is shown, in which CCPP 12 is simplified. Figure 3 In the illustrations, for clarity, only the first GT system 30A is shown in detail, while the second GT system 30B and the third GT system 30C are represented in simplified form. 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 another example, the power plant model 68 and / or the operation control program 72 may be implemented independently of each other and / or using different computing devices 66. The computing device 66 may be a separate component as shown, or it may be included as part of the power plant model 68, as previously described. Figure 3 The environment 150 shown represents one type of configuration for controlling CCPP 12. As described herein, the power plant model 68 of the computing device 66 can simulate the operation of CCPP 12 under a set of environmental and load conditions. The operation control program 72 may include components for modifying the operation of CCPP 12, for example by providing and implementing a variant shunt ratio created using the power plant model 68. Embodiments of this disclosure can be constructed or operated in part by a person skilled in the art, the computing device 66, and / or a combination of a person skilled in the art and the computing device 66. It should be understood that Figure 3 Some of the various components shown may be implemented, combined, and / or stored in memory independently for one or more separate computing devices included in computing device 66. Furthermore, it should be understood that some components and / or functions may not be implemented, or alternative schemes and / or functions may be included as part of CCPP system 154.

[0041] 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. Furthermore, the computing device 66 is shown communicating with external I / O devices 166 and a storage system 168. The CCPP system 154 may provide a power plant model 68, which can then be operated using various modules 202 (e.g., calculators, determiners, comparators, etc.) to implement various functions and / or logical steps. Alternatively, the CCPP system 154 may provide its own set of modules 212 (e.g., calculators, determiners, comparators, etc.) for the operation control program 72 to implement 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 to process, analyze, and manipulate data to perform their respective functions. Generally, PU 158 can execute computer program code to run software, such as a CCPP system 154 that can be stored in memory 152 and / or storage system 168. When executing the computer program code, PU 158 can read and / or write data to or from memory 152, storage system 168, and / or I / O interface 160. Bus 164 can provide a communication link between each component in computing device 66. I / O device 166 can include any means that enable a user to interact with computing device 66 or any means that enable computing device 66 to communicate with the equipment and / or other computing devices described herein. I / O device 166 (including, but not limited to, keyboard, display, pointing device, etc.) can be coupled directly or via an intermediate I / O controller (not shown) to controller 160.

[0042] The memory 152 may also include various forms of data 220 relating to CCPP 12 (or more specifically, systems 18, 30 of CCPP 12). As described elsewhere herein, the power plant model 68 may simulate the operation of CCPP 12 under specific environmental and / or load conditions, while the operation control program 72 may adjust the exhaust temperature, ignition temperature, relative load, and / or other operating parameters of CCPP 12 to achieve one or more variant shunt ratios output from the power plant model 68. To implement the method according to this disclosure, CCPP system 154 may store and interact with the data 220 subdivided into various fields. For example, the environmental conditions field 222 may store data relating to the environmental conditions of the CCPP under various temperatures, pressures, and / or other environmental variables unrelated to the CCPP 12 specifications. The data 220 may also include a load conditions field 224 for cataloging specification data that will operate at various output levels, including fixed and non-fixed outputs. A subset of shunt ratios of CCPP 12 may be stored in shunt ratio field 226, which may include one or more distributions of the operating load of GT system 30. Each shunt ratio recorded in shunt ratio field 226 may optionally be represented as a load-related schedule of the shunt loads of CCPP 12 under different load conditions and / or environmental conditions. In some cases, the value of each parameter stored in shunt ratio field 226 may be based on calibration data and / or simulated values ​​derived from power plant model 68 for one or more parameters during non-base load operation. Therefore, it should be understood that data 220 may include several measured and / or calculated variables that can be applied to and / or stored in shunt ratio field 226 to control the relative power output of a set of GT systems 30. Data 220 may also include, for example, a quality threshold field 228 for cataloging quality thresholds such as minimum improvement to CCPP 12 performance (e.g., reduced heat rate, increased power plant efficiency, reduced fuel consumption, increased power plant capacity, etc.) and compliance with emission limits (e.g., NO). X This includes compliance with operational stability limits (e.g., compressor operability limits, combustion stability limits, gas turbine ignition temperature, gas turbine exhaust temperature, turbine shaft torque limits for systems 18 and 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. As noted herein, the quality threshold field 228 may define one or more parameters that CCPP 12 must meet in order to switch from one split ratio to another.

[0043] The computing device 66 may include any general-purpose computing artifact (e.g., personal computer, server, handheld device, etc.) installed by the user for executing computer program code. However, it should be understood that the computing device 66 represents only various possible equivalent computing devices and / or skilled workers capable of performing the various process steps of this 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 CCPP 12.

[0044] In this regard, in other embodiments, computing device 66 may include any dedicated computing article having hardware and / or computer program code for performing a particular function, or any computing article including a combination of dedicated and general-purpose hardware / software. In each case, the program code and hardware may be created using standard programming and engineering techniques, respectively. In one embodiment, computing device 66 may include a program product stored on a computer-readable storage device that is operable to automatically control the elements of CCPP 12 (e.g., system 18, system 30, HRSG 54, etc.) when executed.

[0045] See Figures 2 to 4 The embodiments of this disclosure provide, for example, a method for operating CCPP 12 using a power plant model 68 and an operation control program 72. According to a specific example, Figure 4 A flowchart is provided for controlling the operation of CCPP12 in the exemplary configuration shown, but using... Figure 4 The exemplary processing flow shown can also control CCPP 12 in other configurations. Implementations of the methods described herein can be implemented, for example, using a power plant model 68 of computing device 66 and an operation control system 72, and / or various modules and / or sub-components of computing device 66, power plant model 68, or operation control system 72. The methods according to this disclosure can also rely on other components, such as sensors 70 communicatively coupled to computing device 66 and / or power plant model 68, to measure and / or otherwise determine various parameters to be used as the basis for the processes described herein. Environment 150 is operable to model and adjust various operating parameters of CCPP 12, for example, by modifying the shunt ratio among multiple GT systems 30 within CCPP 12. In another embodiment, power plant model 68 can be operated to modify other instructions and / or actions taken via computing device 66 and / or power plant model 68, for example, by creating one or more variant shunt ratios that modify the relative generation load on the target GT system 30 within CCPP 12. Figure 4 The exemplary flowcharts shown herein have several processes organized in an exemplary process, but it should be understood that one or more processes may be implemented simultaneously and / or sequentially and / or executed in any alternative order, while retaining the various technical features described in the examples herein.

[0046] To initiate the method according to this disclosure, process P1 may include causing CCPP 12 to operate under specific load and environmental conditions. Load conditions may refer to the electrical output from CCPP 12 during operation and may include fixed or variable loads to accommodate changing conditions. For example, load conditions for CCPP 12 may include peak load operation, base load operation, reduced load operation, variable load operation, and / or extended transient operation. Environmental conditions for operating CCPP 12 may refer to external temperature, pressure, and / or other external variables affecting the operation of CCPP 12. Environmental conditions for CCPP 12 may include, for example, specification temperature operation, elevated temperature operation, decreased temperature operation, transient temperature operation, etc. Various load conditions, environmental conditions, and / or combinations thereof may cause CCPP 12 to exhibit operating parameters (e.g., temperature, pressure, and flow rate) significantly different from its specification level. The operation of CCPP 12 can be simulated according to other processes disclosed herein, and in some cases, the operation of CCPP 12 can be modified by changing the relative power generation load on the multiple GT systems 30 within CCPP 12 to prevent inefficient operation, exceeding the expected use of cooling fluid and / or components, and / or avoiding the negative consequences of operation outside the specified range.

[0047] During the operation of CCPP 12, embodiments of this disclosure may include generating a power plant model 68 of CCPP 12. As used herein, the term "generation" may include one or more processes for: simulating the operation of CCPP 12 under specific load and environmental conditions; modifying an existing power plant model 68 to "operational" conditions; correcting an existing power plant model 68 to "operational" conditions; tuning an existing power plant model 68 to "operational" conditions; calibrating an existing power plant model 68 to "operational" conditions; and, in addition to or alternatively, verifying the accuracy of the power plant model 68 based on parallel operation data of CCPP 12 and / or other forms of data suitable for verifying the accuracy of the power plant model 68. In cases where verification is based on comparing the power plant model 68 to the operation of CCPP 12, process P2 may include indicating whether the power plant model 68 is effective based on whether one or more modeling parameters of CCPP 12 are similar to (i.e., equal to or within predetermined error limits) actual CCPP 12 parameters. Alternatively or in addition, such verification may include modifying the power plant model 68 to account for differences between the model parameters and the actual CCPP 12 parameters, and subsequently verifying the accuracy of the power plant model 68 after such adjustments have occurred. The terms “generating” and / or “modifying” for the power plant model 68 also encompass actions such as “correcting, calibrating, tuning, or updating” the power plant model, as CCPP power plant performance changes over time, for example, due to degradation, variation, upgrades, etc. In such cases, terms such as “operationally tuned power plant model” may refer to further refining the existing model to obtain the desired diversion ratio. Process P2 may therefore include, for example, determining whether the power plant model 68 is acceptablely accurate based on meeting or exceeding a predetermined accuracy metric (e.g., the percentage of modeling parameters conforming to CCPP 12, optionally within a predetermined time interval). Once verified, the power plant model 68 may represent a baseline set of operating parameters for CCPP 12.

[0048] During its operation, a specific implementation of CCPP 12 having multiple GT systems 30 may or may not generate electricity from more than one GT system 30 at a time. For example, CCPP 12 having three GT systems 30A, 30B, 30C may output electricity from only one GT system 30 during a particular time span, but may output electricity from multiple GT systems 30 during another time span. The embodiments of this disclosure modify the load distribution on the GT systems 30 only when multiple GT systems 30 are generating electricity simultaneously. In decision D1, module 202 of power plant model 68 can determine whether multiple GT systems 30 are generating electricity as CCPP 12 continues to operate under a set of environmental and load conditions. In the case that only one GT system 30 is generating electricity (i.e., "No" at decision D1), the method may return to process P1 to continue operating CCPP 12 under the existing load and environmental conditions until one or both of the conditions change. When multiple GT systems 30 generate power (i.e., "yes" at decision D1), the method can continue by evaluating whether the change in the shunt ratio among the GT systems 30 of CCPP 12 will improve the performance of CCPP 12.

[0049] Embodiments of this disclosure may include modeling the fuel consumption of CCPP 12 using a power plant model 68. Fuel consumption may be relative to a specific time interval during which CCPP 12 operates, and relative to the aforementioned environmental and / or load conditions of CCPP 12. The fuel consumption of CCPP 12 may be expressed, for example, the total amount of fuel expected to be consumed by the target GT system 30 within a specific time interval under modeled load and environmental conditions. Alternatively or additionally, fuel consumption modeled in process P3 may be expressed as an efficiency percentage, a percentage of fuel consumed relative to a desired level, a relative amount of fuel consumed by each GT system 30, or other load and / or environmental conditions. Therefore, fuel consumption modeled in process P3 may include any conceivable metric for modeling the amount of fuel consumed by CCPP 12.

[0050] Continuing with process P4, embodiments of this disclosure may include using power plant model 68 to create variant split ratios for CCPP 12. Variant split ratios may be created in process P4 through any conceivable modeling operation, based on various operating parameters included within and / or modeled by the power plant model 68. Variant split ratios may include alternating relative distributions of power generation across GT systems 30A, 30B, and 30C. Variant split ratios may also include a schedule of alternative split ratios, each dependent on the total load output from CCPP 12. Regardless of the representation, variant split ratios may affect operating parameters and / or ranges of operating parameters that differ from their current values ​​in power plant model 68. These and other parameters may be indirectly modified, for example, by modifying the load conditions at the time of CCPP 12 operation. Such parameters may include one or more of inlet temperature, outlet temperature, inlet guide vane (IGV) pitch angle, inlet heat release (IBH), combustion rate, etc. Based on the CCPP 12 operating schedule, variant shunt ratios may be biased to support specific GT systems 30 and / or allocation characteristic maps, such as those GT systems using newer GT systems 30 and / or whose operating specifications are more closely aligned with current environmental and / or load conditions. The relative generation load of each GT system 30 in the variant shunt ratio can be determined, for example, by randomly selecting the magnitude and / or direction of the bias, and / or by applying predetermined logic to variant shunt ratios that are more likely to improve CCPP 12 operation. Such logic may be based on power plant model 68, actual parameters of CCPP 12, and / or other variables or models related to CCPP 12.

[0051] The variant split ratios created in process P4 may include increases and / or decreases in the power output of each GT system 30 currently generating electricity in CCPP 12. In some cases, one or more quality thresholds of CCPP 12 can be improved by modifying the split ratios among the GT systems 30 in CCPP 12. In such cases, the variant split ratios may reduce exhaust temperature / energy, thereby directing less fluid through the thermostat 74 and improving the efficiency of CCPP 12 by reducing fuel consumption for stationary loads. In other cases, the variant split ratios may increase the temperature within the load path of CCPP 12. Specifically, the variant split ratios may propose higher or lower power outputs for each GT system 30 in CCPP 12. Such modifications may be desirable when one or more GT systems 30 are operating at above-specification loads. While several variant split ratios may exist at a given time to improve efficiency, fuel consumption, system health, etc., process P4 may require any variant split ratio to have a minimum expected improvement before applying the power plant model to the control of CCPP 12.

[0052] After creating the variant split ratio from power plant model 68 in process P4, the method according to this disclosure may include several decisions for determining whether to modify the operation of CCPP 12 based on the variant split ratio created in process P4. At decision D2, module 212 of operation control procedure 72 may assess whether applying the variant split ratio to CCPP 12 will continue to meet the quality thresholds of CCPP 12 (e.g., maximum values ​​of temperature, pressure, fuel consumption, etc.). According to one example, the quality threshold may be expressed as whether the fuel consumption of 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 another example, the quality threshold may include additional threshold improvements in the operation of CCPP 12, such as a reduction in the minimum heat rate of 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 the maximum permissible level of carbon dioxide and / or nitrogen oxide emission levels of CCPP 12. "Operational stability limit" may refer to the maximum amount by which the variant split ratio shortens the expected lifespan and / or exceeds the specification limits of CCPP 12 and / or its sub-components. As noted herein, the quality thresholds evaluated in decision D2 and stored in the quality threshold field 228 may include various metrics such as minimum improvement to CCPP 12 performance (e.g., reduced heat rate, increased power plant efficiency, reduced fuel consumption, increased power plant capacity, etc.) and compliance with emission limits (e.g., NO...). X (e.g., emissions, CO emissions, etc.), compliance with operational stability limits (e.g., compressor operability limits, combustion stability limits, gas turbine ignition temperature, gas turbine exhaust temperature, turbine shaft torque limits for systems 18 and 30, operational limits of HRSG 54, operational limits of ST system 18, condenser pressure limits, etc.) and / or other operational quality measures of CCPP 12.

[0053] If the variant split ratio does not meet the quality threshold (i.e., "No" at decision D2), the method may proceed to the process P5 of modifying the variant split ratio. Such modification may be a random change, 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 the results of experimental and / or calculated power plant models (e.g., a "digital twin"). If the quality threshold is met (i.e., "Yes" at decision D2), the method may continue with further operations for applying the variant split ratio to CCPP 12. In some cases, the method according to this disclosure may test only a predetermined number of variant split ratios (e.g., five, ten, fifty, or one hundred or more variant split ratios). In such examples, the method may terminate ("Complete") after decision D2 indicates that none of the tested variant split ratios meet the relevant quality threshold.

[0054] When the variant split ratio meets a quality threshold, the method according to this disclosure may include a process P6 in which the operating control system 72 adjusts CCPP 12 to use the variant split ratio. Process P6 may involve the operating control system 72 applying one or more modifications to the GT system 30 (e.g., temperature, such as ignition temperature, inlet temperature, exhaust temperature, etc.) to modify their outputs as defined in the variant split ratio. In some cases, the operating control system 72 may adjust and / or otherwise modify the changing parameters based on one or more characteristics of the specific CCPP 12 unit being controlled. In any case, the modified parameters (e.g., temperature) may be biased substantially in real time as CCPP 12 continues to operate. After adjusting CCPP 12 in process P6, the method may end (“complete”), and CCPP 12 may continue to operate using the variant split ratio. In another example, the method may return to process P1, which operates CCPP 12 under specific load and environmental conditions, and, where applicable, repeat all subsequent processes if the load or environmental conditions of CCPP 12 change from their previous state to a new state.

[0055] Adjusting CCPP 12 in process P6 to use a variant split ratio can affect one or more other operations due to the implementation of the variant split ratio. According to one example, the adjustment affects the fluid flow rate through thermostat 74 to achieve a desired temperature increase or decrease within CCPP 12. In another example, the adjustment can affect the pitch angle of IGV 36, thereby changing the inlet temperature and / or the temperature of other fluid connection components within GT system 30. In yet another example, the adjustment can affect the amount of compressor waste fluid directed through IBH line 76, thereby also modifying both the inlet and outlet temperatures of compressor 32. In yet another example, the modification can affect the steam output from HRSG 54 to further modify one or more temperatures within ST system 18 and / or GT system 30.

[0056] See Figures 3 to 5The embodiments of this disclosure can significantly modify the power load profiles of the CCPP 12 of multiple GT systems 30 during operation, and thus provide superior operational control of the CCPP 12 compared to conventional control systems. As described herein, the temperature-load characteristic plot (indicated by curve C1) of the CCPP 12 in a normal setting can uniformly distribute the load between the two GT systems 30 according to a baseline shunt ratio. This baseline shunt ratio may be inefficient if one of the two GT systems 30 is better suited to operate under moderate loads (e.g., between approximately 40% and 80% of the output capacity of the CCPP 12). In normal operation, the load on each GT system 30 can increase and decrease linearly with the load on the CCPP 12 via the first characteristic plot C1. Applying a variant shunt ratio to the CCPP 12 according to this disclosure can cause one of the two GT systems 30 to generate more power than the other system within the range of the CCPP 12 output. As shown in the figure, a GT system 30A may have a power load characteristic curve C2A, which has a higher power distribution than the power load characteristic curve C2B of another GT system 30B, located between approximately 40% and 80% of the load in CCPP 12. At the same variant shunt ratio, when below 40% and above 80% of the total load, the GT system 30A may have a lower power output distribution than the GT system 30B. In the illustrated example, this may be because the GT system 30B is better suited for operation at both very high and very low power outputs. Therefore, the method according to this disclosure provides robust control over the relative power output from the GT system 30 to accommodate a variety of environments.

[0057] Simply see Figure 3 , Figure 4 and Figure 7 Furthermore, the embodiments disclosed herein can also significantly affect other relevant characteristics of CCPP12. Specifically, Figure 8 The heat loss rate (Δ) of operating CCPP 12 with a variant split ratio compared to the conventional split ratio of CCPP 12 is shown. HR Improvement in heat dissipation rate (Δ) is shown in the figure. At approximately 40% or 68% of the maximum CCPP 12 load, for example, the heat dissipation rate (Δ) is improved. HR The percentage improvement can be as high as approximately 0.6%.

[0058] See Figure 3 , Figure 4 , Figure 6 and Figure 8 Adjusting CCPP 12 to use a variant split ratio can significantly reduce the amount of fluid split through the inlet exothermic (IBH) pathway of each GT system 30. Figure 6Characteristic maps of two gas turbine systems 30 (labeled C2A and C2B, respectively) for a GT system 30 of CCPP 12 with conventional and variant split ratios were compared. Figure 8 The percentage variation of IBH flow was compared for a set of different environmental conditions operating at different temperatures for CCPP 12. Figure 6 The diagram depicts the percentage reduction in IBH and load for the normal shunt ratio in curve C1 and the variant shunt ratio in curve C2. As shown, when the variant shunt ratio is implemented, the change in IBH begins at a lower total output of CCPP 12, and therefore provides a lower amount of IBH usage across the entire range of possible load outputs of CCPP 12. See now. Figure 8 IBH can vary significantly between different environmental conditions. In such cases, embodiments of this disclosure can compare each of the various IBH levels used for operation under different environmental conditions and achieve one of the possible variant shunt ratios based on the varying IBH levels and / or other parameters.

[0059] See now Figure 3 , Figure 4 , Figure 9 and Figure 10 Choosing one of many possible environmental conditions can affect other characteristics of CCPP 12 during operation. For example, Figure 9 The results show that operating CCPP 12 under different environmental conditions can significantly affect the total heat rate of CCPP 12. The range of possible environmental conditions can cause the total heat rate of CCPP 12 to vary by, for example, at least about five percent of the baseline heat rate of CCPP 12. Figure 10 Similarly, it is shown how implementing embodiments of this disclosure under different environmental conditions can significantly affect the overall fuel efficiency of CCPP 12. Depending on the base load conditions, environmental conditions, and variant split ratio applied to CCPP 12, the method according to this disclosure can increase the fuel efficiency of CCPP 12 by up to about 0.60% based on the total load generated by CCPP 12.

[0060] The advantages of this disclosure allow for the agile deployment and use of CCPP 12 in power grids with diverse energy sources and / or in non-basic load operating settings. In embodiments of this disclosure, CCPP 12 allows for more efficient use of GT systems 30 and their potential fuel consumption when switching between different power outputs and / or different operating conditions. Therefore, embodiments of this disclosure allow CCPP 12 to internally compensate for fluctuations in energy demand, unavailability of other power sources, etc., with minimal impact on the health of each GT system 30. Improvements to CCPP 12 reduce fuel consumption and increase efficiency during operation, thereby extending the lifespan of each GT system 30 and its components. Operating CCPP 12 in a mode that actively modifies the shunt ratio between each GT system 30 provides significant lifespan extension and lower maintenance requirements. Furthermore, embodiments of this disclosure can be implemented by modifying existing control logic, circuitry, etc., without significantly altering the CCPP 12 hardware to accommodate the operating methods described herein.

[0061] As used throughout the specification and claims, approximate language can be used to modify any quantitative expression that allows for variation without causing a change in its underlying function. Therefore, values ​​modified by one or more terms (such as “about,” “approximately,” and “substantially”) are not limited to specified exact values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. Range limitations may be combined and / or interchanged herein and throughout the specification and claims. Unless otherwise specified by context or language, these ranges are identified and include all subranges contained therein. The term “about” applied to a specific value within a range applies to both terminating values ​​and may indicate + / - 10% of said value unless otherwise dependent on the precision of the instrument used to measure the value.

[0062] All means or steps plus functional elements in the following claims are intended to include any structure, material, action, and equivalent for performing a function in conjunction with other claimed elements of a particular claim. This disclosure has been described for purposes of illustration and description, but it is not intended to be exhaustive or to limit the disclosure to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. Embodiments have been selected and described to best explain the principles and practical application of this disclosure and to enable others skilled in the art to understand various embodiments of this disclosure with various modifications suitable for the intended particular use.

Claims

1. A method for operating a combined cycle power plant CCPP (12), the CCPP comprising a steam turbine system, a gas turbine system, and a heat recovery steam generator (HRSG), the method comprising: Generate a power plant model (68) for simulating the operation of the CCPP (12) under environmental conditions (222) and load conditions (224), wherein the power plant model simulates at least one operating feature and setting of the CCPP, the at least one operating feature and setting of the CCPP including the power output and parameters of the steam turbine system, the gas turbine system and the HRSG, and wherein, in the case of verification based on a comparison of the power plant model with the operation of the CCPP, the generation step includes indicating whether the power plant model is effective based on whether one or more modeling parameters of the CCPP are similar to actual CCPP parameters; Determine whether at least two gas turbines (30A, 30B) in the power plant model (68) of the CCPP (12) generate power output under the environmental conditions (222) and the load conditions (224); Using the CCPP (12) in the power plant model (68) under the environmental conditions (222) and the load conditions (224), the fuel consumption of the CCPP (12) is modeled for the baseline split ratio between the at least two gas turbines (30A, 30B); Create a variant split ratio (226) between the at least two gas turbines (30A, 30B); The power plant model (68) is used to determine whether the variant split ratio (226) meets the quality threshold of the CCPP (12), which includes at least the minimum reduction in fuel consumption. The variant split ratio (226) is recalculated in response to the quality threshold not being met. as well as The CCPP (12) is adjusted to use the variant split ratio (226) in response to the quality threshold being met.

2. The method of claim 1, wherein adjusting the CCPP (12) to use the variant split ratio (226) includes modifying the load conditions (224) to affect the pitch angle of the inlet guide vane (IGV) (36) within the CCPP (12).

3. The method of claim 1, wherein the CCPP (12) is adjusted to reduce the inlet heat release (IBH) flow of waste fluid (60) from the exhaust section of the compressor (32) of one of the at least two gas turbines (30A, 30B) of the CCPP (12) to the inlet section using the variant split ratio (226).

4. The method of claim 1, wherein creating the variant split ratio (226) comprises applying a predetermined bias to each of the at least two gas turbines (30A, 30B) based on the environmental conditions (222) and baseline load conditions (224).

5. The method of claim 4, wherein the predetermined bias is further based on the health status of one of the at least two gas turbines (30A, 30B).

6. The method of claim 1, wherein the variant split ratio (226) is created based on the fuel consumption of the CCPP (12) indicated by the power plant model (68).

7. The method according to claim 1, wherein the quality threshold further includes at least the minimum heat loss rate reduction, minimum power plant efficiency increase, minimum fuel consumption reduction, fuel consumption limit, emission limit or operational stability limit of the CCPP (12).

8. The method according to claim 1, further comprising: Detect new load conditions (224) or new environmental conditions (222) of the CCPP (12); Create a new variant of the load shedding for the new load condition (224) or the new environmental condition (222); Use the power plant model (68) to determine whether the new variant split ratio (226) meets the quality threshold of the CCPP (12); The new variant split ratio (226) is recalculated in response to the new variant split ratio (226) not meeting the quality threshold. as well as The CCPP (12) is adjusted to use the new variant split ratio (226) in response to the new variant split ratio (226) meeting the quality threshold.

9. The method of claim 1, wherein the variant shunt ratio (226) comprises a plurality of load-related shunt ratios of the CCPP (12).

10. A program product stored on a computer-readable storage medium for operating a combined cycle power plant CCPP (12), the CCPP including a steam turbine system, a gas turbine system, and a heat recovery steam generator (HRSG), the computer-readable storage medium including program code for causing a computer system to perform actions, the actions including: Generate a power plant model (68) for simulating the operation of the CCPP (12) under environmental conditions (222) and load conditions (224), wherein the power plant model simulates at least one operating feature and setting of the CCPP, the at least one operating feature and setting of the CCPP including the power output and parameters of the steam turbine system, the gas turbine system and the HRSG, and wherein, in the case of verification based on a comparison of the power plant model with the operation of the CCPP, the generation action includes indicating whether the power plant model is effective based on whether one or more modeling parameters of the CCPP are similar to actual CCPP parameters; Determine whether at least two gas turbines (30A, 30B) in the power plant model (68) of the CCPP (12) generate power output under the environmental conditions (222) and the load conditions (224); Using the CCPP (12) in the power plant model (68) under the environmental conditions (222) and the load conditions (224), the fuel consumption of the CCPP (12) is modeled for the baseline split ratio between the at least two gas turbines (30A, 30B); Create a variant split ratio (226) between the at least two gas turbines (30A, 30B); The power plant model (68) is used to determine whether the variant split ratio (226) meets the quality threshold of the CCPP (12), which includes at least the minimum reduction in fuel consumption. The variant split ratio (226) is recalculated in response to the quality threshold not being met. as well as The CCPP (12) is adjusted to use the variant split ratio (226) in response to the quality threshold being met.

11. The program product of claim 10, wherein adjusting the CCPP (12) to use the variant split ratio (226) includes modifying the load conditions (224) to affect the pitch angle of the inlet guide vane (IGV) (36) within the CCPP (12).

12. The program product of claim 10, wherein the CCPP (12) is adjusted to reduce the waste fluid (60) from the exhaust section of the gas turbine of one of the at least two gas turbines (30A, 30B) of the compressor (32) of the CCPP (12) to the inlet exothermic (IBH) section using the variant split ratio (226).

13. The procedure product of claim 10, wherein creating the variant split ratio (226) comprises applying a predetermined bias to each of the at least two gas turbines (30A, 30B) based on the environmental conditions (222) and the baseline load conditions (224).

14. The program product according to claim 10, wherein the quality threshold further includes at least the minimum heat rate reduction, minimum power plant efficiency increase, minimum fuel consumption reduction, fuel consumption limit, emission limit or operational stability limit of the CCPP (12).

15. The program product of claim 10, further comprising program code for the following operations: Detect new load conditions (224) or new environmental conditions (222) of the CCPP (12); Create a new variant of the load shedding for the new load condition (224) or the new environmental condition (222); Use the power plant model (68) to determine whether the new variant split ratio (226) meets the quality threshold of the CCPP (12); The new variant split ratio (226) is recalculated in response to the new variant split ratio (226) not meeting the quality threshold. as well as The CCPP (12) is adjusted to use the new variant split ratio (226) in response to the new variant split ratio (226) meeting the quality threshold.

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