Temperature-based gas turbine control and method

Abstract

A method (100) for operating a gas turbine (10) at a desired gas turbine (10) output value is disclosed. The method (100) includes setting a desired gas turbine (10) output value based on a schedule (250) of reference gas turbine (10) shaft speed versus ambient temperature and exhaust (22) temperature, comparing a value of a gas turbine (10) shaft speed to a value of the reference gas turbine (10) shaft speed to determine whether a difference between the gas turbine (10) shaft speed and the reference gas turbine (10) shaft speed is within a predetermined range or outside the predetermined range, and initiating a change in the gas turbine (10) shaft speed to cause the gas turbine (10) to operate at substantially the desired gas turbine (10) output value in response to the difference being outside the predetermined range.

Description

Background Technology

[0001] The subject matter disclosed herein relates generally to turbomachinery systems, such as gas turbine engines (hereinafter referred to as "gas turbines"). Specifically, this subject matter relates to methods and systems for controlling gas turbine systems.

[0002] In a turbine system, ignition temperature is the temperature generated within the turbine's combustion system, such as flame temperature. An ignition control algorithm determines how to derive the desired ignition temperature and then provides the turbine's actual ignition temperature by controlling, for example, the combustion output generated by the gas turbine system. The ignition control algorithm can determine the desired ignition temperature based on turbine parameters such as exhaust temperature, compressor pressure ratio, and compressor inlet temperature.

[0003] Conventional ignition control algorithms incorporate static assumptions about the gas turbine operating environment and component performance. Current ignition control algorithms also consider interdependent gas turbine operating conditions and constraints. The accuracy of ignition temperature control, and the performance level associated with these ignition control algorithms, can degrade with gas turbine aging, and due to these interdependent assumptions and conditions, the algorithm may require seasonal adjustments. Conventional algorithms typically do not account for variations in environmental operating conditions, such as seasonal variations in ambient air temperature and humidity. Instead, they often assume that environmental conditions (e.g., humidity, compressor inlet pressure loss, and turbine back pressure) remain within certain constraints, or that variations in these conditions do not affect the target exhaust turbine temperature.

[0004] Some ignition control algorithms, such as model-based control (MBC) algorithms, can incorporate changes in the gas turbine operating environment and / or component performance over time. MBC ignition control algorithms treat various operating states and constraints of the gas turbine as individual states, resulting in more accurate ignition temperature control and improved performance levels. However, implementing MBC ignition control algorithms may require a complete and thorough overhaul of the gas turbine controller's software and / or hardware by qualified technicians, which can be slow and expensive. Summary of the Invention

[0005] A first aspect of this disclosure provides a method for operating a gas turbine at a desired gas turbine output value. The method includes: setting a desired gas turbine output value based on a schedule of reference gas turbine shaft speed relative to ambient temperature and exhaust temperature; comparing a value of the gas turbine shaft speed with a value of the reference gas turbine shaft speed to determine whether a difference between the gas turbine shaft speed and the reference gas turbine shaft speed is within or outside a predetermined range; and in response to the difference being outside the predetermined range, initiating a change in the gas turbine shaft speed such that the gas turbine operates approximately at the desired gas turbine output value.

[0006] A second aspect of this disclosure provides an apparatus for operating a gas turbine at a desired gas turbine output value. The apparatus includes a control system comprising at least one temperature matching algorithm disposed on a computer processor. The computer processor is operable to store computer-executable instructions operable to: set a desired gas turbine output value based on a schedule of reference gas turbine shaft speeds relative to ambient temperature and exhaust temperature; compare the value of the gas turbine shaft speed with the value of the reference gas turbine shaft speed to determine whether the difference between the gas turbine shaft speed and the reference gas turbine shaft speed is within or outside a predetermined range; and, in response to the difference being outside the predetermined range, initiate a change in the gas turbine shaft speed such that the gas turbine operates approximately at the desired gas turbine output value.

[0007] A third aspect of this disclosure provides a non-transitory computer-readable medium comprising computer-executable instructions for operating a gas turbine, the instructions including instructions for: setting a desired gas turbine output value based on a schedule of reference gas turbine shaft speed relative to ambient temperature and exhaust temperature; comparing the value of the gas turbine shaft speed with the value of the reference gas turbine shaft speed to determine whether the difference between the gas turbine shaft speed and the reference gas turbine shaft speed is within or outside a predetermined range; and in response to the difference being outside the predetermined range, initiating a change in the gas turbine shaft speed such that the gas turbine operates approximately at the desired gas turbine output value.

[0008] The exemplary aspects of this disclosure are designed to address the problems described herein and / or other problems not discussed herein. Attached Figure Description

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

[0010] Figure 1 This is an exemplary schematic diagram of a system for determining a target exhaust temperature of a gas turbine according to an embodiment of the present disclosure;

[0011] Figure 2 This is a schematic diagram illustrating the data stream used to determine the turbine shaft speed difference (NPT) according to an embodiment of the present disclosure; and

[0012] Figure 3 This is a flowchart of a method according to an embodiment of this disclosure.

[0013] 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

[0014] First, in order to clearly describe the present technology, it will be necessary to select certain terms when referring to and describing the relevant machine components within gas turbines and gas turbine control systems. 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 component. An object that can be described herein as a single part may include multiple components and is referred to in another context as being composed of multiple components. Alternatively, an object that can be described herein as comprising multiple components may elsewhere be referred to as a single part.

[0015] In addition, several descriptive terms may be used periodically throughout this document, and it should prove helpful to define these terms at the beginning of this section. Unless otherwise stated, these terms and their definitions are as follows. As used herein, “downstream” and “upstream” are terms indicating the direction of fluid flow, such as through the working fluid of a turbine engine, or, for example, through the airflow of a combustor or through the coolant of one of the turbine's component systems. The term “downstream” corresponds to the direction of fluid flow, and the term “upstream” refers to the direction opposite to the flow. Without any other particularity, the terms “front” and “rear” refer to directions, where “front” refers to the front end of the engine or the compressor end, and “rear” refers to the rear end of the engine or the turbine end.

[0016] It is often necessary to describe parts positioned at different radial locations relative to the central axis. The term "radial" refers to movement or position perpendicular to the axis. For example, if a first part is closer to the axis than a second part, this document will describe the first part as "radially inward" or "inner" of the second part. On the other hand, if the first part resides further away from the axis than the second part, this document may describe the first part as "radially outward" or "outer" of the second part. The term "axial" refers to movement or position parallel to the axis. Finally, the term "circumferential" refers to movement or position about the axis. It should be understood that such terms can be applied relative to the central axis of the turbine.

[0017] 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.

[0018] 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 the 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.

[0019] 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.

[0020] Figure 1 A gas turbine assembly 13 is depicted, comprising a compressor 11, a burner 12, a gas turbine 10 drivenly coupled to the compressor 12, and a control system 18 (hereinafter referred to as "control"). An inlet 20 of the compressor 12 supplies ambient air and possibly injected water to the compressor 12. The inlet 20 may have pipes, filters, screens, and sound-absorbing devices, each of which contributes to a pressure loss of the ambient air flowing into the inlet guide vanes 21 of the compressor 12 through the inlet 20. Figure 1 The gas turbine 10 can be an aero-derivative gas turbine (gas turbine) in which embodiments of the present disclosure can be used. Examples of such aero-derivative gas turbine engines include the LMS100, LM2500, LM6000, LM1800e, LM1600, and TM2500 series of aero-derivative gas turbines manufactured by General Electric Company of Schenectady, NY. Those skilled in the art will understand that the present embodiments are not limited to this type of gas turbine. The present embodiments can be used in gas turbine engines, such as engines for power generation and aircraft, steam turbine engines, and other types of rotary engines.

[0021] The exhaust port 22 of the gas turbine 10 directs combustion gases from the outlet of the gas turbine 10 through a duct equipped with, for example, emission controls and sound-absorbing devices. The exhaust port 22 applies back pressure to the gas turbine 10. The amount of back pressure can vary over time due to the addition of components to the exhaust port 22 and due to dust and dirt clogging the exhaust passage. The gas turbine 10 can drive a shaft 50 connected to a generator 24, which produces electricity (megawatt (MW) output) or "gas turbine output".

[0022] The operation of the gas turbine can be monitored by a number of sensors 26 that detect various conditions of the turbine, generator, and environment. At least one sensor 26 is located at or within the exhaust port 22 of the gas turbine 10 to sense the temperature of the exhaust gas from the burner 12 and the gas turbine 10. In one aspect embodied in this disclosure, more than one sensor 26 may be provided; for example, and by no means limited to embodiments, two, three, four, five, six, seven, eight, or more sensors 26 may be located at or within the exhaust port 22. A general principle of gas turbine operation is that the exhaust temperature of the gas turbine is reactive and generally proportional to the power generated by the gas turbine.

[0023] In addition, the temperature sensors can monitor the ambient temperature around the gas turbine, the compressor discharge temperature, the turbine exhaust temperature, and other temperature measurements of the gas flow through the gas turbine. As illustrated in this disclosure, any number of temperature sensors can be placed at or within the aforementioned locations.

[0024] Additionally, at least one sensor 26 is positioned on, at, or therein the shaft / rotor 50 (hereinafter referred to as the "shaft" for ease of description) to determine the turbine shaft speed (NPT). In one aspect of the implementation, the turbine shaft speed (NPT) will be evaluated to determine the turbine shaft speed difference required to increase or decrease the shaft speed to achieve the desired output of the gas turbine 10, as described below.

[0025] Sensor 26 may also include flow sensors, speed sensors, flame detector sensors, valve position sensors, guide vane angle sensors, etc., for sensing various parameters related to the operation of gas turbine 10. As used herein, “parameter” and similar terms refer to items that can be used to define the operating conditions of the turbine, such as temperature, pressure, and flow rate at a defined location in the turbine that can be used to represent a given turbine operating condition.

[0026] Control system 18 may include Mark from General Electric Company in Schenectady, NY. TM Or SPEEDTRONIC TMGas turbine control system. MARK and SPEEDTRONIC are trademarks of General Electric Company, Schenectady, NY. Control system 18 may include a computer or computer system containing memory. The computer system may include a processor that executes programs to control the operation of the gas turbine using data input from sensor 26 or other sources and instructions from a human operator via, for example, a human-machine interface (HMI). The programs executed by control system 18 may include scheduling algorithms for regulating the fuel flow to combustor 14. Combustion gases flow out of exhaust port 22, where the exhaust temperature may be determined by temperature sensor 26 in or on exhaust port 22. Commands generated by control system 18 cause actuators on the gas turbine, such as valves adjusting the flow rate and type of fuel between the fuel supply source and the combustor, inlet guide vanes 21 on the compressor, and other control settings on the gas turbine 10.

[0027] The control system 18 regulates the gas turbine in part based on a temperature matching algorithm 25 stored in the controller's computer memory. The temperature matching algorithm 25 enables the control system 18 to maintain the gas turbine 10 within certain predefined operating conditions and limits, and to maintain the burner ignition temperature within predefined temperature limits.

[0028] The control system 18 receives measurements of the exhaust temperature of the gas turbine 10, as well as other variables of the operation of the gas turbine 10, as data or inputs. In some embodiments, the control system 18 receives data or inputs from sensor 26 or other sources. The control system 18 of the combustion system may rely on the turbine exhaust temperature to determine the operating conditions of the gas turbine 10 (e.g., turbine exhaust temperature) to manage the electric or gas turbine output (MW).

[0029] Ambient temperature is a factor to consider when determining operating conditions in control system 18, because increased ambient temperature reduces the density of the air at the gas turbine inlet, thereby reducing the mass flow rate through the gas turbine and thus reducing the power output (which is proportional to the mass flow rate). Changes in ambient temperature affect the full-load power and thermal rate of the gas turbine, but also affect its partial-load performance and optimal power turbine speed. At constant speed, where the volumetric flow rate remains approximately constant, the mass flow rate will increase with decreasing temperature and decrease with increasing temperature. Changes in ambient temperature affect the full-load power and thermal rate of the gas turbine, but also affect its partial-load performance and optimal power turbine speed.

[0030] For most gas turbines, the relationship between gas turbine output and gas turbine exhaust temperature is typically nonlinear. Furthermore, even using the same gas turbine, the relationship between output and exhaust temperature may differ between locations. This lack of consistency and linearity in the relationship between output and gas turbine exhaust temperature can be attributed to several factors, including but not limited to ambient temperature, fuel composition, ambient humidity, altitude, inlet cooling, fuel heating, and others.

[0031] Figure 2 A data stream for determining the turbine shaft speed difference (NPT) according to an embodiment of the present disclosure is shown, thereby modifying the operation of the gas turbine 10 with respect to the turbine exhaust temperature and the enhanced / optimized yield. Figure 3 This is a flowchart illustrating the process as depicted in this disclosure. (See reference) Figure 2 He Ru Figure 3 The method 100 shown, as embodied in this disclosure, controls the exhaust temperature of the gas turbine 10. Control method 100 can be achieved by adjusting the fuel demand and the flow rate to the gas turbine 10, as described below. Control system 18 modifies the fuel demand and flow rate using the shaft speed (NPT) corresponding to the shaft 50 coupled to a load (such as, but not limited to, a generator, mechanical drive, or other machinery), and thus modifies the gas turbine output.

[0032] refer to Figure 2 This illustrates data or inputs from the control system 18 according to the process, as embodied in this disclosure. Data is provided to the temperature matching algorithm 25 of the temperature matching module of the control system 18. The data includes, but is not limited to:

[0033] Temperature matching is enabled via the HMI. This input is provided by an HMI connected to the control system 18 for operator selection / enabling of this function.

[0034] Temperature matching is enabled via the HMI. This input is provided by an HMI connected to the control system 18 for the operator to select / disable this function.

[0035] The exhaust temperature setpoint is determined by the operator based on the desired setting.

[0036] A shaft speed reference (NPT) corresponds to the shaft speed (such as the gas turbine shaft connected to a generator or other load). This speed is used by the control system 18 and its algorithms and software to control the fuel flow.

[0037] ΔTamb is used to calculate the change in ambient temperature from the output of the gas turbine system.

[0038] Δexhaust temperature is the exhaust temperature setpoint minus the sensed exhaust temperature.

[0039] Speed ​​Reg (NPT) is a gas turbine fuel flow regulator value based on the sensed shaft speed (NPT) connected to the generator or other load.

[0040] The speed Reg (NPT) is the value used by the temperature matching algorithm 25 in the control system 18 to confirm the activation of the speed reference at the control system 18.

[0041] The exhaust temperature setpoint MAX is the maximum exhaust temperature allowed on the engine software, set by the operator of the gas turbine 10.

[0042] The exhaust temperature setpoint SEL is the average value of the temperature sensor located at the exhaust port 22. The exhaust temperature setpoint SEL is the output from the control system 18 and is re-inputted into the temperature matching algorithm 25.

[0043] Output in MW min is the minimum permissible output (in megawatts) for a power plant. For a given gas turbine, this is typically a constant (e.g., 1.5 MW).

[0044] The output MW max is the minimum permissible output (in megawatts) of the power plant. This limit is calculated by the control system 18.

[0045] NPTREQ is the shaft speed used to achieve the exhaust temperature setpoint.

[0046] NPTREF is the shaft speed reference set in the temperature matching algorithm 25 of the control system 18 of the gas turbine 10. NPTREF = NPTREQ – NPT.

[0047] The exhaust temperature (feedback) is the same as the exhaust temperature setpoint SEL, but it is the input value of temperature matching algorithm 25.

[0048] In some respects, as embodied in this disclosure, an exhaust temperature sensor obtains an exhaust temperature sensor value. This value is then compared to an exhaust temperature setpoint, which is the desired exhaust temperature of the gas turbine 10 for providing enhanced and desired gas turbine output, at which the gas turbine 10 operates with its highest desired and required efficiency. Fuel demand and flow rate are based on shaft speed (NPT) and are proportional to exhaust temperature. Controlling the gas turbine temperature, and naturally the resulting exhaust temperature, limits the exhaust temperature by reducing the fuel flow, as the airflow decreases with shaft speed. Conversely, increasing the shaft speed increases the fuel flow and gas turbine output, thus increasing both the gas turbine temperature and the resulting exhaust temperature.

[0049] Temperature matching algorithm 25 references schedule table 250 (considering ambient temperature) for shaft speed (NPT) and exhaust temperature. Schedule table 250 includes alignment comparisons between shaft speed and exhaust temperature, as the gas turbine shaft speed is directly related to the load and the gas turbine exhaust temperature. For a given gas turbine, a schedule relating the gas turbine exhaust temperature to the gas turbine shaft speed is available, and this schedule can be accessed by temperature matching algorithm 250 by referring to schedule table 250.

[0050] Furthermore, in some aspects of the implementation, the output of generator 24 is proportional to the operation of gas turbine 10. However, since generator 24 is connected to gas turbine 10 via shaft 50, the output of generator 24 is also proportional to the fuel demand of gas turbine 10 to provide enhanced and desired gas turbine output.

[0051] Therefore, the exhaust temperature of the gas turbine 10 and the output of the generator are both connected to the shaft 50 and are thus proportional to the shaft speed (NPT). The exhaust temperature of the gas turbine 10 and the output of the generator are also proportional to the fuel demand for the desired output of the gas turbine assembly 13. Therefore, the shaft speed (NPT) is directly related to the fuel demand. Thus, the shaft speed (NPT) is a variable that can be used to adjust the operation of the gas turbine 10 to adjust the fuel demand, which will be calculated by the control system 18 to provide enhanced and desired gas turbine output.

[0052] See Figure 2 and Figure 3 During operation method 100 (described in further detail below), the gas turbine operator can actuate the control system 18 by initiating the temperature matching algorithm 25 in the control system 18. Initiation of S101 involves the gas turbine operator setting the temperature matching algorithm "on" or "off" via a human-machine interface (HMI). Initiating the temperature matching algorithm 25 in the control system 18 enables the analysis of data (e.g., sensor readings) from the exhaust port 22 of the gas turbine 10 to enhance the operation of the gas turbine 10. Furthermore, regardless of whether the HMI is activated for method 100, the sensor 26 can monitor the gas turbine 10 and its relevant performance characteristics during operation at S102. Therefore, once the gas turbine operator initiates temperature matching at the HMI, sensor readings can be analyzed in real time.

[0053] At S105, the gas turbine operator can set various "fixed" values ​​for temperature matching and methods. These fixed values ​​include, but are not limited to, the expected gas turbine output value based on a schedule of reference gas turbine shaft speed relative to ambient temperature, the exhaust temperature setpoint, the shaft speed (NPT) reference, the maximum output (MW), and the minimum output (MW).

[0054] At S110, the control system 18 receives data on ambient temperature, sensed exhaust temperature, and sensed shaft speed (NPT) from, for example, sensor 26 or other sources. At S115, the sensed exhaust temperature can be compared with a desired exhaust temperature setpoint for operating the gas turbine 10 via temperature matching algorithm 25. More specifically, at S115, temperature matching algorithm 25 can determine whether the difference between the gas turbine shaft speed and a reference gas turbine shaft speed is within or outside a predetermined range.

[0055] At S116, a comparison is made to determine whether the difference between the gas turbine shaft speed and the reference gas turbine shaft speed is within or outside a predetermined range, i.e., whether it is greater than the predetermined range (described below). This difference can be due to the sensed exhaust temperature being higher than or lower than the desired exhaust temperature setpoint. The control system 18 initiates an action at S120 and modifies the shaft speed (NPT). Of course, if temperature matching has not yet been initiated at S101, method 100 is not implemented; however, as mentioned above, if the turbine operator later determines that temperature matching needs to be initiated, sensing can continue at S102. The predetermined range can be characterized as the error or deviation between the sensed exhaust temperature and the desired exhaust temperature setpoint.

[0056] Furthermore, if the comparison indication at S116 is not a difference outside the predetermined range (described below), the control system 18 determines that the gas turbine 10 is operating under conditions where the desired output can be achieved. Therefore, the control system 18 does not initiate any action, and the operation of the gas turbine 10 continues at S117. At S130, monitoring continues, and exhaust temperature continues to be monitored via method 100.

[0057] In response to the difference between the sensed exhaust temperature and the desired exhaust temperature setpoint exceeding a predetermined range, the gas turbine shaft speed (NPT) is changed at S120 so that the gas turbine operates approximately at the desired gas turbine output value, which is acceptable for the temperature gradient in the temperature matching process. The magnitude of the ramp is equal to the difference between the sensed exhaust temperature and the desired exhaust temperature setpoint, such that when the difference between the sensed exhaust temperature and the desired exhaust temperature setpoint is negative, the rate of change of fuel demand (step S125) decreases or becomes negative. When the difference between the sensed exhaust temperature and the desired exhaust temperature setpoint is positive, the fuel demand and the corresponding rate of change of fuel flow (S125) increase or become positive.

[0058] After initiating a change in the gas turbine shaft speed (at S120) and modifying the fuel flow (S125) in response to the difference being outside a predetermined range, the gas turbine 10 can operate approximately at the desired gas turbine output value. Additionally, at S130, sensor 26 continues to monitor and sense the exhaust temperature of the gas turbine 10. At S110, this sensed exhaust temperature of the gas turbine 10 can be fed back to method 100 as input. Therefore, method 100 receives the real-time sensed data or input and continues operating until, at S115, the temperature matching algorithm determines that the sensed shaft speed (NPT) is outside a predetermined range. At this point, method 100 modifies the shaft speed (NPT) at S120, and method 100 continues as discussed above.

[0059] As embodied in this disclosure, the rate of change of fuel flow is adjustable to accommodate any temperature gradient or characteristics required by downstream thermomechanical equipment and processes. According to certain aspects of this disclosure, such downstream thermomechanical equipment and processes include, but are not limited to, heat recovery systems, generators, mechanical loads, or other thermomechanical equipment and processes now known or developed below.

[0060] As illustrated in this disclosure, the rate of change of fuel flow (step S125) can also be adjusted or throttled during the change of the rate of change of fuel flow itself. For example, the rate of change of fuel flow can be reduced when the measured exhaust temperature is close to the desired exhaust temperature setpoint. This rate change of fuel flow slows down the change in the maximum value of fuel flow to prevent the sensed temperature from exceeding or decreasing past the desired exhaust temperature setpoint.

[0061] Provided the process of method 100 as embodied in this disclosure remains within the boundaries, the fuel flow to the gas turbine 10 can be controlled by the control system 18 by changing the shaft speed (NPT). Depending on various aspects of the implementation, these boundaries include:

[0062] a) The temperature sensed at the stage closest to the combustor and gas turbine 10 does not exceed the maximum exhaust temperature limit. The maximum exhaust temperature limit is determined and set by the operator in the control system 18.

[0063] b) The output of gas turbine 10 exceeds the established minimum limit. The minimum output limit is determined by the operator and set in control system 18.

[0064] c) The output of gas turbine 10 is below the established maximum limit. The maximum output limit is determined and set by the operator in control system 18.

[0065] Once the measured exhaust temperature relative to the desired exhaust temperature setpoint is within a predetermined range or reaches any process limit, the temperature matching algorithm 25 in the control system 18 stops compensating for the fuel flow rate. Thereafter, as embodied in this disclosure, the process transitions to steady-state operation.

[0066] As illustrated in this disclosure, data or inputs are provided to the control system 18, and the temperature matching algorithm 25 dynamically and automatically performs real-time analysis based on field conditions. This real-time analysis, along with static algorithms and programming via general relationships, allows the gas turbine 10 to operate at a "field" or real-time level, thereby providing the gas turbine owner with the desired gas turbine output.

[0067] As embodied in this disclosure, the control system 18 may be provided in computer form and includes a temperature matching algorithm 25 that takes into account at least a turbine shaft / rotor speed reference (NPT), ambient temperature, and sensed exhaust temperature to control gas turbine output, thereby enhancing performance. The control system 18 and temperature matching algorithm 25 use these factors to determine, based on an exhaust temperature target, the differential shaft speed (NPT) required to modify and operate the gas turbine 10 and its associated components (including, but not limited to, the combustor 14) to enhance or optimize output (increase or decrease).

[0068] The temperature matching algorithm 25 in control system 18 includes calculations that can be performed in real time, dynamically, and automatically. Therefore, the operator of control system 18 does not need to reprogram the temperature matching algorithm periodically. As used herein, real-time refers to a substantially short period of time following a change in data or inputs that affects the outcome (e.g., numerical calculation). In an exemplary embodiment, the calculations are updated periodically in real time, determined by the scan time and clock speed of control system 18.

[0069] One aspect of the implementation is that the control system 18 of an existing power plant (such as, but not limited to, a combined cycle power plant) may be located within a combined cycle power plant (CCPP). Additionally, certain aspects of the provided implementation may provide a control system 18 as embodied in this disclosure, used to control auxiliary power units, industrial gas turbines, industrial gas turbines for power generation, industrial gas turbines for mechanical drive, micro turbines, or any other turbine now known or developed below.

[0070] As those skilled in the art will understand, this disclosure may be embodied as a system, method, or computer program product. Accordingly, this disclosure may take the form of a completely hardware implementation, a completely software implementation (including firmware, resident software, microcode, etc.), or a combination of software and hardware implementations that are generally referred to herein as a “circuit,” “module,” or “system.” Furthermore, this disclosure may take the form of a computer program product embodied in any tangible medium containing computer-usable program code.

[0071] Any combination of one or more computer-usable or computer-readable media may be used. Computer-usable or computer-readable media can be, for example, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, devices, or propagation media. More specific examples of computer-readable media (not an exhaustive list) will include: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable optical disc read-only memory (CD-ROM), optical storage devices, transmission media (such as those supporting the Internet or intranets), or magnetic storage devices. It should be noted that computer-usable or computer-readable media can be a suitable medium on which a program is printed, because a program can be captured electronically via, for example, optically scanned paper or other media, then compiled, interpreted, or otherwise processed as appropriate, and then stored in computer memory. In the context of this document, computer-usable or computer-readable media can be any medium on which a program can be contained, stored, communicated, propagated, or transmitted for use by or in conjunction with an instruction execution system, apparatus, or device. Computer-usable media may include propagated data signals embodying computer-usable program code, either in baseband or as part of a carrier wave. The computer-usable program code may be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cable, RF, etc.

[0072] Computer program code used to perform the operations of this disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages ​​(such as Java, Smallalk, C++, etc.) and conventional procedural programming languages ​​(such as the "C" programming language or similar programming languages). The program code may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer, and partially on a remote computer or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network (including a local area network (LAN) or a wide area network (WAN)), or the connection may be to an external computer (e.g., via the Internet using an Internet service provider).

[0073] These computer program instructions may also be stored in a computer-readable medium that instructs a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of writing including instruction means that perform the functions / actions specified in one or more blocks of a flowchart and / or block diagram.

[0074] Computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide a process for implementing the function / action specified in one or more boxes of a flowchart and / or block diagram.

[0075] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible specific implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each box in a flowchart or block diagram may represent a module, segment, or portion of code, including one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions described in the boxes may not occur in the order shown in the figures. For example, two boxes shown consecutively may actually be executed substantially simultaneously, or the boxes may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each box in the block diagrams and / or flowcharts, and combinations of boxes in the block diagrams and / or flowcharts, may be implemented by a system based on dedicated hardware or a combination of dedicated hardware and computer instructions that performs the specified function or action.

[0076] The foregoing figures illustrate some associated processes according to several embodiments of the present disclosure. In this regard, each figure or block within the flowcharts of the figures represents a process associated with an embodiment of the method. It should also be noted that in some alternative embodiments, the actions mentioned in the figures or blocks may not occur in the order shown in the figures, or, for example, may actually be performed substantially simultaneously or in reverse order, depending on the actions involved. Moreover, those skilled in the art will recognize that additional blocks may be added to describe the process.

[0077] As used throughout the specification and claims, approximate language can be used to modify any quantitative representation that may be varied without causing a change in its underlying function. As used herein, “about” means + / - 10% of the value, or if the value is within a certain range. 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 can correspond to the precision of the instrument used to measure the value.

[0078] Throughout this specification and claims, scope limitations may be combined and / or interchanged; unless the context or language otherwise indicates otherwise, these scopes are identified and include all subscopes contained herein. The term "about" applied to a specific value of a scope applies to both terminating values, and may indicate + / - 10% of said value unless otherwise dependent on the accuracy of the instrument used to measure the value.

[0079] 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 (100) for operating a gas turbine (10) at a desired gas turbine (10) output value, the method (100) comprising: The desired gas turbine (10) output value is set based on the schedule (250) of the reference gas turbine (10) shaft (50) speed relative to the ambient temperature and the exhaust port (22) temperature; The value of the gas turbine (10) shaft (50) speed is compared with the value of the reference gas turbine (10) shaft (50) speed to determine whether the difference between the gas turbine (10) shaft (50) speed and the reference gas turbine (10) shaft (50) speed is within a predetermined range or outside a predetermined range; as well as In response to the difference being outside the predetermined range, a change in the speed of the gas turbine (10) shaft (50) is initiated so that the gas turbine (10) operates approximately at the desired gas turbine (10) output value. The method (100) includes: Sensing the speed of the gas turbine (10) shaft (50); The ambient temperature at the gas turbine (10) is sensed; and The temperature of the exhaust port (22) of the gas turbine (10) is sensed.

2. The method (100) according to claim 1, wherein the change in the speed of the gas turbine (10) shaft (50) is one of increasing the speed of the gas turbine (10) shaft (50) or decreasing the speed of the gas turbine (10) shaft (50).

3. The method (100) according to claim 1, wherein the method (100) is performed in real time.

4. The method (100) according to claim 1, wherein the gas turbine (10) comprises an aero-derivative gas turbine (10).

5. The method (100) according to claim 1, wherein the determination in the control system (18) is whether the difference between the speed of the gas turbine (10) shaft (50) and the speed of the reference gas turbine (10) shaft (50) is within the predetermined range or outside the predetermined range.

6. An apparatus for operating a gas turbine (10) at a desired gas turbine (10) output value, the apparatus comprising: Control system (18), the control system including at least one temperature matching algorithm (25), the at least one temperature matching algorithm (25) being disposed on a computer processor; and The computer processor is operable to store computer-executable instructions operable to: The desired gas turbine (10) output value is set based on the schedule (250) of the reference gas turbine (10) shaft (50) speed relative to the ambient temperature and the exhaust port (22) temperature; The value of the speed of the gas turbine (10) shaft (50) is compared with the value of the speed of the reference gas turbine (10) shaft (50) to determine whether the difference between the speed of the gas turbine (10) shaft (50) and the speed of the reference gas turbine (10) shaft (50) is within a predetermined range or outside a predetermined range; as well as In response to the difference being outside the predetermined range, a change in the speed of the gas turbine (10) shaft (50) is initiated so that the gas turbine (10) operates approximately at the desired gas turbine (10) output value. The speed of the gas turbine (10) shaft (50), the ambient temperature at the gas turbine (10), and the temperature of the exhaust port (22) of the gas turbine (10) are obtained in the following manner: Sensing the speed of the gas turbine (10) shaft (50); The ambient temperature at the gas turbine (10) is sensed; and The temperature of the exhaust port (22) of the gas turbine (10) is sensed.

7. The apparatus according to claim 6, wherein the change in the speed of the gas turbine (10) shaft (50) increases the speed of the gas turbine (10) shaft (50).

8. The apparatus according to claim 6, wherein the change in the speed of the gas turbine (10) shaft (50) reduces the speed of the gas turbine (10) shaft (50).

9. The apparatus of claim 6, wherein the instruction is initiated automatically.

10. The apparatus of claim 6, wherein the gas turbine (10) comprises an aero-derivative gas turbine (10).

11. The apparatus of claim 6, wherein the control system (18) includes a temperature matching algorithm (25) to determine whether the difference between the speed of the gas turbine (10) shaft (50) and the speed of the reference gas turbine (10) shaft (50) is within the predetermined range or outside the predetermined range.

12. A non-transitory computer-readable medium storing computer-executable instructions for operating a gas turbine (10), the instructions including instructions causing a computer processor of the apparatus of claim 6 to perform the steps of the method of claim 1.

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