Operation of power plants under transient loads during transmission line switching events.

Abstract

An embodiment of the present disclosure provides a method for controlling a power plant (100). The method includes detecting a transient load of the power plant (100) and monitoring a system reactance during operation at the transient load. The system reactance is compared to a switching threshold indicative of a switching event in a set of power transmission lines (160). If the switching threshold is exceeded, the gas turbine operates at the transient load using a first control setting including a transient fuel management profile, a transient split bias profile, and a dynamic inlet parameter of the gas turbine. If the switching threshold is not exceeded but one electrical characteristic of a plurality of electrical characteristics exceeds a stability threshold, the gas turbine operates at the transient load using a second control setting including the dynamic inlet parameter of the gas turbine and not including the transient fuel management profile and the transient split bias profile.

Description

[Background technology]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to the operation of power plants. More specifically, embodiments of the present disclosure provide a methodology for operating a power plant under transient loads during power line switching events.

[0002] Power plants typically include various turbomachinery and / or systems used to generate power. Such power plants may include a prime mover (e.g., a rotatable shaft, or an element similar to the shaft) for coupling a power source to a generator. For example, a power plant may include a gas turbine assembly having a compressor coupled to a gas turbine. The gas turbine may be coupled to and drive a generator mounted on the same shaft. The generator generates power.

[0003] Generators can be electrically coupled to the grid (i.e., the electrical infrastructure for delivering power to customers) through various transmission lines. A technical challenge associated with operating power plants is dealing with transient load demands, i.e., periods of significant fluctuations in customer demand that require the power plant to change from one output level to a significantly higher or lower output level. Conventional control systems for operating power plants can distinguish between non-transient and transient load settings by analyzing the electrical characteristics of the grid based on their impact on internal parameters of the power plant. However, this method is not sophisticated enough to distinguish between actual fluctuations in customer demand and fluctuations that may result from unforeseen events (e.g., natural disasters, grid maintenance operations, etc.). Summary of the Invention

[0004] An aspect of the present disclosure provides a method of controlling a power plant having a generator mechanically coupled to a gas turbine via a shaft, the generator being electrically coupled to a grid through a set of transmission lines, the method comprising: Detecting a transient load of the power plant based on a plurality of electrical characteristics of the grid and a plurality of electrical characteristics of the power plant, wherein the plurality of electrical characteristics of the grid include a system reactance of the grid; monitoring a system reactance of the grid through the generator during operation of the power plant under the transient load; determining whether a system reactance of the grid exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines; operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile.

[0005] Another aspect of the present disclosure provides a program product stored on a computer-readable storage medium for controlling a power plant having a generator mechanically coupled to a gas turbine via a shaft and electrically coupled to a grid through a set of transmission lines, the computer-readable storage medium comprising: Detecting a transient load of the power plant based on a plurality of electrical characteristics of the grid and a plurality of electrical characteristics of the power plant, wherein the plurality of electrical characteristics of the grid include a system reactance of the grid; monitoring a system reactance of the grid through the generator during operation of the power plant under the transient load; determining whether a system reactance of the grid exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines; operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. The program code includes program code for performing operations including:

[0006] A further aspect of the present disclosure provides a system including a power plant having a generator mechanically coupled to a gas turbine via a shaft and electrically coupled to a grid through a set of transmission lines, and a system controller in communication with the gas turbine of the power plant, the system controller comprising: Detecting a transient load of the power plant based on a plurality of electrical characteristics of the grid and a plurality of electrical characteristics of the power plant, wherein the plurality of electrical characteristics of the grid include a system reactance of the grid; monitoring a system reactance of the grid through the generator during operation of the power plant under the transient load; determining whether a system reactance of the grid exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines; operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. is feasible,

[0007] The exemplary aspects of the present disclosure are designed to solve the problems described herein and / or other problems not discussed herein. [Brief explanation of the drawings]

[0008] The above and other features of the present disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure, taken in conjunction with the accompanying drawings illustrating various embodiments of the disclosure. [Figure 1]FIG. 1 is a comparative plot of power transfer (megawatts (MW)) versus phase shift (degrees (deg)) illustrating the impact of switching events on a power plant while operating under transient loads. [Figure 2] 1 is a schematic diagram of a power plant, a grid, a gas turbine control system, and an excitation system according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of an exciter controller, a power plant, a grid, and various subcomponents according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is an exemplary flow diagram of a method for operating a power plant under transient loading during a transmission line switching event, according to an embodiment of the present disclosure. [Figure 5] FIG. 10 illustrates an example set of plots showing power and frequency during available transmission line losses in a method according to the present disclosure. [Figure 6] FIG. 10 illustrates an example set of plots showing power and frequency during the addition of available transmission lines in a method consistent with the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] It should be noted that the drawings of the present disclosure are not to scale. The drawings are intended to depict only typical aspects of the disclosure and therefore should not be considered limiting of the scope of the disclosure. In the drawings, like numbers represent like elements between the drawings.

[0010] First, to clearly explain the state of the art, it becomes necessary to select terminology when referring to and describing the various systems, components, and related machine components of other embodiments of the present disclosure. Wherever possible, common industry terminology is used and employed in a manner consistent with the accepted meaning of that industry terminology. Unless otherwise specified, the above 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 often, a particular component may be referred to using several different or overlapping terms. What is described herein as a single component may, in another context, consist of multiple components and may be referred to as consisting of multiple components. Alternatively, what is described herein as including multiple components may be referred to elsewhere as a single component.

[0011] Additionally, as explained below, certain descriptive terms may be used regularly herein: the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another, and are not intended to denote the location or importance of the individual components.

[0012] The terminology used in the specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural unless the context clearly dictates otherwise. It will be further understood that the terms "comprise" and / or "comprising," when used herein, refer to 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 the subsequently described event or circumstance may or may not occur, and that the description includes instances in which the event occurs and instances in which the event does not occur.

[0013] When an element or layer is referred to as being "disposed on," "engaged," "connected," or "coupled" to another element or layer, it can be directly engaged, connected, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly disposed on," "directly coupled," "directly connected," or "directly coupled" to another element or layer, intervening elements and layers may not be present. Other words used to describe relationships between elements should be construed in a similar manner (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.). As used herein, the term "and / or" includes any combination of one or more of the associated listed items, and all combinations of one or more of the associated listed items.

[0014] Embodiments of the present disclosure provide methods, program products, and systems for controlling a power plant. The power plant may include, for example, a generator mechanically coupled to a gas turbine via a shaft, and the generator is electrically coupled to a grid through a set of transmission lines. The methods of the present disclosure may be implemented to detect whether a transient load at the power plant is caused by a fluctuation in demand by customers on the grid or by a "switching event." As used herein, the term "switching event" refers to any event in the grid that changes the number of available transmission lines that can be used to transmit power from the generator to the grid infrastructure. Thus, a switching event is one of the events that causes the power plant to operate at a transient load.

[0015] A method according to the present disclosure detects transient loads on a power plant based on electrical characteristics of the grid and electrical characteristics of the power plant. Such characteristics and related operations for detecting transient loads on a power plant via a generator are described in further detail in U.S. Pat. No. 10,205,414, which is incorporated by reference. A method according to the present disclosure may include monitoring system reactance (i.e., electrical resistance to the flow of current due to inductive and / or capacitive components) during operation of the power plant under transient loads. Embodiments of the present disclosure may compare the monitored reactance to one or more switching thresholds to evaluate whether a switching event has occurred. If the calculated system reactance exceeds the switching thresholds (i.e., indicating a switching event), the present disclosure may include operating the gas turbine with a first control setting having a transient fuel management profile, a transient split bias profile, and a dynamic intake parameter to compensate for the switching event. The transient fuel management profile, transient split bias profile, and dynamic intake parameter of the first control setting may compensate for the sudden loss or restoration of the power line during the switching event. If the calculated reactance does not exceed the switching threshold (i.e., no switching event has occurred) but at least one monitored electrical characteristic exceeds a stability threshold, the present disclosure may include operating the gas turbine with a second control setting having only dynamic intake parameters and no transient fuel management profile or transient split bias profile. Thus, the second control setting compensates for instabilities that may occur during transient operation but does not further compensate for power line fluctuations.

[0016] Referring initially to FIG. 1 , a plot of an alternating current (AC) generator's power transfer for the grid (i.e., the amount of power transferred from the generator to the grid in megawatts (MW)) is shown. The plot shows power transfer versus load angle / torque angle / power (e.g., the angular difference between the generator and the grid in degrees (deg or °)), with two curves representing two states (i.e., operation with one transmission line in use and operation with two transmission lines in use). In a simple example, a switching event may involve a grid operator simply using an electrical switch to allow or prohibit current flow through selected transmission lines. In other examples, a switching event may include the sudden and unexpected unavailability of one or more transmission lines, for example, as a result of a natural disaster, and the sudden restoration of one or more transmission lines when maintenance work is performed on the grid. Regardless of the underlying cause, a switching event does not reflect a change in actual power demand on the grid, but may temporarily significantly increase or decrease the amount of power required for a power plant to continue reliable operation.

[0017] The plot in Figure 1 illustrates an example of a switching event in which one of two transmission lines becomes unavailable. Initially, the generator can operate at the output and phase shift indicated by point "OP2" on the power transfer profile. However, when a switching event occurs and one of multiple transmission lines becomes unavailable, the amount of power transferred to the grid immediately decreases, for example, proportional to the change in reactance from its initial value in the example of Figure 1. Even if the power plant operator responds by increasing the output from the generator, the loss of one transmission line affects the overall phase shift between the generator and the grid. This is shown in the plot at point "OP1" on the power transfer profile for the single transmission line case. Here, the amount of power transferred is equivalent to point "OP2," but the phase shift is approximately 20 degrees different. Therefore, the number of available transmission lines significantly affects the electrical behavior of a power plant. Meanwhile, instructing a power plant to overcompensate for electrical changes due to switching operations can adversely affect fuel combustion efficiency and / or the lifespan of power-generating components within the power plant. Embodiments of the present disclosure provide features to distinguish between switching events and other transient events to better manage gas turbine operation during these events.

[0018] FIG. 2 illustrates a schematic diagram of a power plant 100 according to various embodiments of the present disclosure. As illustrated, the power plant 100 may take the form of a power plant having at least one turbomachinery assembly 120 (e.g., a gas turbine system, a combined cycle power generation assembly, and / or other type of turbomachinery). While the turbomachinery assembly 120 is illustratively described herein as a gas turbine assembly, other types of turbomachinery assemblies may be used with embodiments of the present disclosure. The power plant 100 itself may include two, five, ten, one hundred, or more turbomachinery assemblies 120, with only one turbomachinery assembly 120 shown in detail in FIG. 2 by way of example only. The other turbomachinery assemblies 120 are illustrated schematically in FIG. 2 by boxes shown together. The turbomachinery assembly 120 may include a compressor 122. The compressor 122 compresses a fluid (e.g., air) entering through an inlet 124 as the fluid flows through the compressor 122. The compressor 122 may include multiple stages of stators (not shown) and rotors (not shown) disposed within the compressor 122. The stators and rotors disposed within the compressor 122 may be configured to facilitate fluid movement through and / or through the compressor 122. The compressor 122 may include a set of inlet guide vanes (IGVs) 126. The IGVs 126 are a type of adjustable compressor inlet vanes specifically configured to direct the flow of the incoming working fluid toward the rotors of the compressor 122. The IGVs 126 may be adjustable between several positions to affect the flow rate, angle of incidence, and / or other characteristics of the fluid entering the compressor 122. Thus, the IGVs 126 may affect the temperature of the compressor 122, the power output from the turbomachine assembly 120, and / or other characteristics.

[0019] The compressor 122 supplies a flow of compressed fluid (e.g., compressed air) to a combustor 138. The combustor 138 mixes the compressed fluid flow with a flow of pressurized fuel provided by a fuel supply 140 and ignites the mixture to create a flow of combustion gases. The flow of combustion gases is then supplied to a turbine component 142. Like the compressor 122, the turbine component 142 typically includes multiple stages of fixed blades (not shown) and turbine blades (not shown). The flow of combustion gases drives the turbine component 142 to generate mechanical work. The mechanical work generated by the turbine component 142 drives the compressor 122 via a shaft 150, which can be used to drive a generator 152 (e.g., an external component) configured to generate electrical power. A set of electrical transmission lines 160 (i.e., any desired number of electrical transmission lines) electrically couples the generator 152 to a grid 162. Each of the transmission lines 160 may be coupled to one or more of the various turbomachinery assemblies 120 in the power plant 100. The transmission lines 162 represent any electrical infrastructure for transmitting energy from the power plant 100 to customers (e.g., substations, distribution lines, etc.).

[0020] As shown in FIG. 2 , the power plant 100 may include an excitation system (hereinafter simply “exciter”) 170 for supplying direct current (DC) voltage and current to a field winding (not shown) of a shaft 150 in a generator 152. The exciter 170 generates a magnetic field large enough to cause the shaft 150, in the form of a generator rotor, to generate the generator's rated terminal voltage. The exciter 170 thus begins converting mechanical power into electrical power, which is supplied to a grid 162 via a transmission line 160. The exciter 170 may control the amplitude and phase characteristics of the voltage output by the generator 152. The exciter 170 may thus synchronize the voltage output by the generator 152 with the voltage of the grid 162 after the shaft 150 begins rotating at its target speed.

[0021] The exciter controller 172 may be included within or in electrical communication with the exciter 170 to control various electrical characteristics of the exciter 170 during operation. Such characteristics may include target amplitude and / or phase characteristics of the AC current generated by the generator 152. The exciter controller 172 may control the time and magnitude of the voltage applied by the exciter 170, thereby affecting the electrical operation of the turbomachinery assemblies 120. The system 100 may also include a gas turbine (“GT”) controller 180 configured to directly control the operation of the turbomachinery assembly 120. Accordingly, the GT controller 180 may be structurally integrated into the turbomachinery assembly 120 or may be embodied as a separate controller in communication with the turbomachinery assembly 120. One or both of the exciter controller 172 and the GT controller 180 may be in operative communication with the turbomachinery assembly 120 by any suitable electronic and / or mechanical communication components or techniques. The controllers 172, 180 and the various components thereof described herein may each function as part of another power plant control system (e.g., a computing device) (not shown) that may control and / or regulate the operation and / or functions of the power plant 100, or may be a single standalone system that functions separately from another power plant control system.

[0022] Methods according to the present disclosure may be implemented, for example, by monitoring electrical characteristics of the grid 162 and the exciter 170 and controlling operation of the turbomachinery assembly 120 based on the monitored electrical characteristics. The exciter controller 172 may include and / or be in electrical and / or mechanical communication with the GT controller 180. The GT controller 180 may be connected to the turbomachinery assembly 120 through various sensors, valves, solenoids, actuators, converters, etc. (not shown) located in the power plant 100. Thus, the exciter controller 172 may directly measure one or more electrical characteristics of the turbomachinery assembly 120 to monitor corresponding characteristics of the grid 162. According to one embodiment, the exciter controller 172 may include one or more voltmeters, ammeters, or other electronic test equipment for monitoring amplitude, frequency, phase, and / or other electrical characteristics of the generator 152 as it operates. The exciter controller 172 may additionally or alternatively include position sensors, rotation sensors, etc. to derive electrical characteristics from the rotation and / or other related mechanical quantities of the shaft 150. The exciter controller 172 may apply algorithms, formulas, etc. to derive electrical characteristics (e.g., power transfer, impedance, reactance, etc.) of the grid 162 from the operation of the generator 152 and / or other components of the turbomachinery assembly 120.

[0023] 2 and 3, a schematic diagram of the exciter controller 172 and its subcomponents is shown as part of the power plant 100. In FIG. 3, only one turbomachinery assembly 120 is shown in detail, with the other turbomachinery assemblies 120 being represented in simplified form for clarity. As shown, the exciter controller 172 may include a computing device 200. The computing device 200 may include a memory 202 on which a control system 204 operates. The control system 204 may be a software system integrated as part of the exciter 170 or in operative communication with the exciter 170. The control system 204 may be implemented by two subprograms, for example, an exciter control program 212 and a GT control program 214. The exciter control program 212 can monitor and / or control various operations of the exciter 170, and the GT control program 214 can communicate with the GT controller 180 to provide instructions to the GT controller 180 and / or modify the operation of other control programs of the GT controller 180. The exciter controller 172 and the GT controller 180 can be operationally independent of one another and / or implemented using different computing devices 200, although it will be appreciated that the exciter controller 172 and the GT controller 180 can alternatively be implemented using a single device and / or a single piece of hardware. The exciter controller 172 shown in FIG. 3 represents one type of configuration for interacting with and / or controlling the power plant 100. As described herein, the exciter controller 172 can control the magnitude, time range, and / or other characteristics of the voltage that the exciter 170 applies to the generator 152. An exciter control program 212 may monitor and / or interact with the exciter 170 within the exciter controller 172, while a GT control program 214 may interact with, and in some cases override, the actions taken by the GT controller 180 to control the turbomachinery assembly 120 during operation.

[0024] According to one example, the exciter controller 172 may monitor electrical characteristics of the generator 152, the grid 162, and / or the exciter 170 to detect transient loads on the turbomachinery assembly 120 and evaluate whether a switching event has occurred in the transmission line. The GT control program 214 may interact with the exciter control program 212 to cause the GT controller 180 to operate the turbomachinery assembly 120 at a first control setting or a second control setting based on whether a switching event is detected. Embodiments of the present disclosure may be configured or operated in part by a technician, a computing device 200, and / or a combination of a technician and a computing device 200. It is understood that some of the various components shown in FIG. 3 may be implemented independently, implemented in combination, and / or stored in memory for one or more separate computing devices included in the computing device 200. Furthermore, it is understood that some of the components and / or functions may not be implemented, and additional schema and / or functionality may be included as part of the control system 204.

[0025] The computing device 200 may include a processor unit (PU) 228, an input / output (I / O) interface 230, a memory 202, and a bus 234. Additionally, the computing device 200 is shown communicating with an external I / O device 236 and a storage system 238. The control system 204 may implement an exciter control program 212. The exciter control program 212 may operate using various modules 242 (e.g., calculators, determiners, comparators, etc.) for performing various functions and / or various logical steps. The control system 204 may further provide the GT control program 214 with its own set of modules 244 (e.g., calculators, determiners, comparators, etc.) for performing each function and / or step of the GT control program 214. The various modules 242, 244 may process, analyze, and manipulate data to perform their respective functions using algorithm-based calculations, look-up tables, and similar tools stored in the memory 202. Generally, the PU 228 may execute computer program code to execute software (e.g., control system 204), which may be stored in memory 202 and / or storage system 238. While executing the computer program code, the PU 228 may read data from and / or write data to memory 202, storage system 238, and / or I / O interface 236. The bus 234 may be utilized as a communications link between each of the components within computing device 200. The I / O devices 230 may include any device that allows a user to interact with computing device 200 or any device that allows computing device 200 to communicate with the equipment described herein and / or other computing devices. The I / O devices 230 (including, but not limited to, a keyboard, a display, a pointing device, etc.) may be coupled to the exciter controller 172 directly or through an intervening I / O controller (not shown).

[0026] Memory 202 may also include various types of data 250 related to various components of power plant 100 (e.g., turbomachinery assembly 120 and / or one or more subcomponents of assembly 120, transmission line 160, grid 162, etc.). Control system 204 and one or more component programs of control system 204 (e.g., exciter control program 212 and / or GT control program 214) may store and interact with data 250 subdivided into various fields. For example, generator data field 252 may store data related to electrical characteristics of generator 152 (e.g., voltage amplitude, generated frequency, phase shift, internal reactance, etc.). Data 250 may also include grid data field 254 for listing data for monitored electrical characteristics of grid 162 (e.g., voltage amplitude, load frequency, load phase shift, external reactance, measured reactance, etc.). One or more switching thresholds for the system reactance of the generator 152 (i.e., its internal resistance to current flow caused by inductive and / or capacitive coupling) may be stored in a threshold field 256. The switching threshold may define a reactance (e.g., a monitored reactance of approximately 2000 megohms (MΩ)) that indicates a switching event. The threshold field 256 may include multiple switching threshold reactances for comparison in processing, for example, to distinguish between various types of switching events and other types of transient loads on the turbomachinery assembly 120. The data 250 may also include, for example, a control setting field 258 for recording different operating parameters for operating the power plant 100 under non-transient loads, under transient loads caused by switching events, and / or under transient loads not caused by switching events. The control setting field 258 may be separated into individual control settings (e.g., a first control setting, a second control setting, a non-transient control setting, etc.), each of which may correspond to operation of the turbomachinery assembly 120 under specific circumstances.Each control setting in the control settings field 258 may include one or more of a fuel management profile (e.g., controlling the firing rate, firing temperature, fuel injection rate, etc. of the turbomachinery assembly 120), a split bias profile (e.g., controlling the ratio of air to fuel supplied to the combustor 138 of the turbomachinery assembly 120 of the power plant 100), intake parameters (e.g., controlling the amount of air passing through the inlet 124, IGV location 126, etc.), and / or other parameters. The various parameters included within the control settings in the control settings field 258 may be adjusted using the GT controller 180 and / or other portions of the turbomachinery assembly 120.

[0027] Computing device 200 may include any general-purpose computing product (e.g., a personal computer, a server, a handheld device, etc.) for executing computer program code installed by a user. However, it is understood that computing device 200 is merely representative of various possible equivalent computing devices and / or technicians that may perform the various process steps of the present disclosure. Furthermore, computing device 200 may be part of a larger system architecture operable to model and / or control various aspects and elements of exciter 170, GT controller 180, and / or other components of turbomachinery assembly 120 or power plant 100.

[0028] In this regard, in other embodiments, computing device 200 may include any special-purpose computing product including hardware and / or computer program code for performing particular functions, any computing product including a combination of special-purpose and general-purpose hardware / software, etc. In either case, the program code and hardware, respectively, may be created using standard programming and engineering techniques. In one embodiment, computing device 200 may include a program product stored on a computer-readable storage device that, when executed, is operable to automatically control other elements of power plant 100. Computing device 200 may also take the form of a remote monitoring system that is part of a central monitoring system responsible for monitoring, for example, several power plants, turbomachinery assemblies 120, grid 162, etc. In this case, computing device 200 may represent a portion or subcomponent of the central monitoring system.

[0029] 3 and 4 , embodiments of the present disclosure provide methods for controlling a power plant, such as a power plant 100 that includes one or more turbomachinery assemblies 120. The power plant 100 may include a GT system 120 that transmits electrical power to a grid 162 through a transmission line 160, as described herein. According to certain examples, FIG. 4 illustrates a flow diagram for controlling the operation of the power plant 100 in the illustrated exemplary configuration, although control of the power plant 100 in other configurations may also use the exemplary process flow embodiment shown in FIG. 4 . Embodiments of the methodology described herein may be implemented using, for example, the exciter controller 172 and / or various modules and / or subcomponents of a computing device 200. Methods according to the present disclosure may also utilize other components, such as a GT controller 180, communicatively coupled to the computing device 200 to operate the turbomachinery assembly 120 using the various control settings described herein. The power plant 100 is operable to distinguish between multiple types of transient loads on the GT system 120, and in particular, to determine whether a transient load is caused by a switching event on one of the multiple transmission lines 160. The exemplary flow diagram of Figure 4 shows several processes organized in an example flow. However, it is understood that one or more processes can be performed simultaneously and / or sequentially and / or in any alternative order while maintaining various technical features exemplary described herein.

[0030] An example of the present disclosure can be implemented while the power plant 100 is generating power in response to a non-transient load on the grid 162 (operation P1). In this case, the method can include initially operating the power plant 100 to generate a non-transient load (e.g., a base load, a minimum load, a maximum load, and / or any other output that does not vary significantly over time). In this case, the exciter controller 172 and / or the GT controller 180 use a non-transient control setting to cause the turbomachinery assembly 120 to generate power at a substantially fixed magnitude and at a frequency and phase shift selected to match the operating characteristics of the grid 162. In other examples, the non-transient control setting can include varying the magnitude of the generated power (i.e., deviations from a target output, frequency, and / or phase shift by up to about 15 percent) based on a demand schedule and / or operational variations (operational variations that do not require significant changes in the output from the power plant 100).

[0031] Process P2 of the present disclosure may include monitoring electrical characteristics of the power plant 100 (e.g., including the GT system 12) and the grid 162 during operation. As used herein, the term "electrical characteristic" may refer to any conceivable characteristic and / or group of characteristics indicative of electrical operation, performance, etc., based on current data, historical operating data, models, etc., of the power plant 100 and / or the grid 162. During operation, the generator 152 may synchronize with the grid 162 and transmit power to the grid 162 through the transmission line 160. As the power transfer occurs, the exciter controller 172 may be configured to monitor various electrical characteristics of the grid 162. For example, the exciter controller 172 may monitor the grid 162 for transient events, such as an increase or decrease in grid frequency, an increase or decrease in the active or reactive power of the generator 152, etc. Transient events may include changes in electrical characteristics, such as voltage, current, active power, reactive power, power factor (i.e., the ratio of active power to apparent power in a circuit), etc.

[0032] To monitor the electrical characteristics of the power plant 100 in process P2, the exciter controller 172 may monitor, measure, calculate, etc., any conceivable electrical characteristic associated with the generator 152, the grid 162, or both. The electrical characteristics may include an increase or decrease in grid frequency, an increase or decrease in the active or reactive power of the generator 152, an output voltage by the generator 152 and / or the grid 162, an output current by the generator 152 and / or the grid 162, an output power by the generator 152 and / or the grid 162, a power factor of the generator 152 and / or the grid 162, etc. These and other electrical characteristics may be monitored using sensors (not shown), such as voltage sensors, current sensors, etc., coupled to and / or integrated with various components of the power plant 100. Additionally or alternatively, the exciter controller 172 may simulate these and other electrical characteristics of the power plant 100 based on data received from the sensors. In some cases, monitoring for "transients" may also include the exciter control program 212 monitoring whether any of the various electrical characteristics pose a risk of instability to the turbomachinery assembly 120 (e.g., frequency, voltage, etc., significantly greater than or less than predetermined limits). Regardless of the action taken in process P2, the electrical characteristics of the power plant 100 may be stored, for example, in generator data field 252, and the electrical characteristics of the grid 162 may be stored, for example, in grid data field 254.

[0033] Proceeding to decision D1, the method of the present disclosure may include detecting the presence of a transient load (i.e., output power that varies significantly over time) on the grid 162 and the power plant 100. Operation of the power plant 100 under a transient load may be sufficiently evident from the system reactance of the transmission network 162 measured by the exciter controller 172. Decision D1 may include, for example, using module 242 of the exciter control program 212 to identify the transient event based on the output power of the generator 152, the system reactance of the grid 162, and / or by reference to other electrical characteristics monitored in process P2. As used herein, the term "system reactance" refers to the resistance to current flow due to inductive and / or capacitive elements within the power plant 100 and grid 162 and / or the resistance to current flow due to inductive and / or capacitive elements between the power plant 100 and grid 162. According to one embodiment, the exciter control program 212 may determine that a transient load exists if the generator 152 increases its output to either increase or decrease the load, if the reactance detected on the grid 162 through the exciter 170 increases significantly, and if these events occur within a predetermined time of each other (e.g., the high load and reactance are detected within milliseconds of each other). According to another embodiment, detecting a transient load may include identifying an increase or decrease in the load fluctuation of the generator 152 due to, for example, an increase or decrease in the number of available transmission lines in the set of transmission lines 160. The term "load fluctuation" refers to a change in the amount of power transferred from the power plant 100 to the grid 162 at a given time and operating conditions. Load fluctuation refers to a variation in power transfer from the power plant 100 to the grid 162 over time. An increase in the load angle may indicate an increase in the number of transmission lines, and a decrease in the load angle may indicate a decrease in the number of transmission lines.

[0034] With brief reference to FIGS. 4-6, the monitoring of electrical characteristics in process P2 can be configured to identify an increase in the number of available transmission lines 160 (FIG. 5) or a decrease in the number of available transmission lines 160 (FIG. 6). For example, the generator 152 may initially generate a stable output, e.g., approximately 450 MW, as shown in the plot of FIG. 5. The sudden loss of one or more transmission lines 160 can cause a sudden increase in the torque of the generator 152 and thus a large fluctuation in output power over a short period of time (e.g., a fluctuation between approximately 300 MW and 600 MW in as little as 50 ms). The loss of a transmission line 160 can also cause a fluctuation in the frequency of the generator 152, e.g., a sudden loss or gain of approximately 2% or more of the signal frequency over the same time period. The sudden addition of a new transmission line 160 (e.g., due to repairs) can cause a similar, though less severe, disturbance in the output power and frequency of the generator 152. For example, when one or more transmission lines 160 are restored to service, the power output fluctuates between approximately 550 MW and approximately 350 MW over a period of approximately 200 ms, gradually returning to approximately 450 MW, as shown in the accompanying plot of FIG. 6. Over the same time period, the frequency fluctuates between approximately 1% above and approximately 1% below its initial value. These distinct characteristics may be considered to indicate that a switching event has occurred. If the exciter control program 212 does not detect a transient event (i.e., "No" at decision D1), the method may return to operations P1 and P2 to operate the power plant 100 and monitor the electrical characteristics of the generator 152 and the grid 162. If the exciter control program 212 detects a transient event (i.e., "Yes" at decision D1), the method may proceed to determine whether a switching operation caused a transient event.

[0035] 3 and 4 , process P3 may include monitoring the system reactance of the power plant 100 throughout operation of the power plant 100 under transient loads. This element may strongly resist power transfer during operation under transient loads, thus affecting the overall power transferred from the power plant 100 to the grid 162. Monitoring the system reactance in process P3 may include, for example, sampling the electrical impedance of the generator 152 of the power plant 100 by the exciter controller 172. The electrical impedance may be sampled at predetermined intervals or continuously as the turbomachinery assembly 120 and the generator 152 continue to operate. By measuring the impedance and comparing it to defined, known parameters of the power plant 100 and / or the grid 162, the exciter control program 212 can determine the maximum / minimum power transfer capability of the power plant 100 in a particular instance. During execution of process P3, the power plant 100 may continue to operate using its non-transient control settings (e.g., the non-transient control settings described in process P1). Other processing according to the present disclosure may include evaluating whether the monitored reactance is within an expected range for a change in load on the power plant 100 or whether the reactance exceeds one or more switching thresholds, thus indicating the occurrence of a switching event (e.g., whether one or more of the transmission lines 160 have been taken out of service or restored to service).

[0036] The method of the present disclosure may include additional or alternative processes for distinguishing between different magnitudes of system reactance during transient operation. In particular, module 242 of exciter control program 212 may perform other operations to characterize the system reactance of the power plant 100 during transient operation. Some embodiments of the present disclosure may include process P3.1 to calculate switching thresholds for operation under transient loads (e.g., expressed as a maximum system reactance, a percentage of a baseline value for system response, etc.). In process P3.1, module 242 of exciter control program 212 may calculate one or more threshold magnitudes of system reactance that indicate a switching event on the transmission line 160 or a significant electrical fault in the transmission system. The calculated switching thresholds may be based at least in part on monitored electrical characteristics of the power plant 100 and the grid 162 and may be stored in threshold field 256 after calculation. After the switching thresholds are calculated in process P3.1, the method may return to process P3, which monitors the system reactance of the power plant 100.

[0037] The disclosed method may include decision D2, determining (e.g., via module 242 of exciter control program 212) whether the grid system reactance monitored in action P3 exceeds a switching threshold. A monitored reactance value exceeding the switching threshold may be considered an indication that a switching event has occurred on transmission line 160 (e.g., one or more transmission lines have been newly enabled or disabled). The switching threshold used for comparison may be one or more predetermined switching thresholds provided in threshold field 256 and / or may include at least one threshold reactance calculated in action P3.1, if applicable. As an example, an operator of power plant 100 may characterize a range of system reactance values ​​as being higher or lower than expected values ​​for operating power plant 100 under transient loads. While performing actions P2, P3, and P3.1 and decisions D1 and D2, power plant 100 may continue to operate in a non-transient control setting, as described herein with respect to action P1. As previously mentioned, the switching threshold may represent a maximum system reactance (e.g., approximately 0.25 for a generator-based unit). If the system reactance monitored in action P3 exceeds the switching threshold (i.e., "yes" to decision D2), another action may include operating the turbomachinery assembly 120 at a first control setting. The first control setting of the gas turbine controller may include various operating settings of the gas turbine that compensate for the effects of switching events on the power line 160. Various characteristics of the first control setting are described in further detail elsewhere herein.

[0038] If the monitored system reactance does not exceed the switching threshold (i.e., "No" at decision D2), further processing may include decision D3 determining whether one or more of the monitored electrical characteristics exceed a stability threshold for the power plant 100. As described elsewhere herein, process P2 may include monitoring electrical characteristics of the power plant 100 and the grid 162 to detect, for example, the presence of a transient load on the power plant 100. Decision D3 may further include determining whether one or more of the monitored electrical characteristics exceed a stability threshold for the power plant 100. As used herein, the term "stability threshold" refers to a maximum value, minimum value, or range of an electrical parameter for stable operation of the power plant 100 (i.e., operation without significant power outages, electrical or mechanical damage to components, etc.). According to one embodiment, the stability thresholds used for comparison in decision D2 may include a frequency deviation (e.g., up to about ±5% of the rated nominal frequency), a voltage amplitude deviation (e.g., about ±5% to 80%), and a maximum load angle drift (e.g., up to about greater than 90°) between the output of the power plant 100 and the load on the grid 162. If the electrical characteristics do not exceed the stability thresholds (i.e., “No” at decision D3), the method may end (“Done”) without making any changes to the operation of the power plant 100, or alternatively, may return to process P1, which continues operation of the power plant 100 with non-transient control settings. If one or more electrical characteristics exceed the stability thresholds (i.e., “Yes” at decision D3), the method may proceed to process P5, which operates the turbomachinery assembly 120 at a second control setting. The second control setting implemented in process P5 may differ from the first control setting in process P4, for example, at least because potential operational instability is primarily responsible and no further corrections are made to compensate for switching events in the power line 160.

[0039] Referring first to process P4, embodiments of the present disclosure may include operating the turbomachinery assembly 120 at a first control setting in response to detecting that a system reactance on the grid 162 has exceeded a switching threshold. The system reactance value exceeding the switching threshold may indicate that a switching event has occurred on the transmission line 160, causing the power plant 100 to operate in a transient state. In this case, embodiments of the present disclosure may include modifying the operation of the power plant 100 to compensate for the electrical effects of the switching event (e.g., changes in load change, power transfer, phase shift, etc.). In process P4, the GT control program 214 may operate the turbomachinery assembly 120 using the first control setting. The first control setting may differ from the non-transient control setting by at least causing the turbomachinery assembly 120 to use a transient fuel management profile, a transient split bias profile, and dynamic intake parameters. In some cases, methods according to the present disclosure may include an additional process P4.1, for example, creating the first control setting based on monitored electrical characteristics and / or grid reactance. The term "generate," when used in the context of control settings for the power plant 100, may refer to calculating, modeling, simulating, and / or other predicting how the turbomachinery assembly 120 will operate during a transient event, and calculating various operating parameters and / or target values ​​for the turbomachinery assembly 120 that may be adjusted by the exciter controller 172 and / or the GT controller 180. However, the derived various parameters of the first control setting and / or the second control setting may be stored in the control setting field 258 of the data 250, for example.

[0040] The “transient fuel management” profile represents specified parameters for fuel combustion and usage in the turbomachinery assembly 120. By way of example, the transient fuel management profile may control one or more of the firing temperature, firing rate, fuel injection rate, and / or other variables affecting the movement of fuel from the fuel supply 140 to the combustor 138 and / or the behavior of the combustor 138 during operation. The transient fuel management profile for a first control setting may, for example, increase the firing temperature or fuel injection rate to a higher / lower value to compensate for an increase / decrease in load on the power plant 100 from the grid 162, and may be different from a non-transient control setting. By way of example, operating the turbomachinery assembly 120 at the first control setting may include increasing the firing temperature from approximately 1200 degrees Celsius (°C) to approximately 1400°C, increasing the fuel injection rate (liters / second) by approximately 20% of the initial value of the fuel injection rate, and / or making similar adjustments to fuel usage in the turbomachinery assembly 120.

[0041] The first control setting may also include a transient split bias profile that causes other operating parameters of the turbomachinery assembly 120 to differ from their values ​​in the non-transient control setting. The transient split bias profile of the first control setting may, for example, affect the ratio of air to fuel ("split ratio") for different burners in the combustion chamber when air and fuel are introduced into the combustor 138 from the compressor 122 and fuel supply 140, respectively. While the split ratio may be fixed at a set value or within a limited range during non-transient operation, the transient split bias profile may cause the turbomachinery assembly 120 to use a different split ratio and / or a different range of split ratios depending on the current demand by the grid 162 of the turbomachinery assembly 120 and / or the rate at which the transient load increases or decreases during transient operation. The split ratio used by the GT control program 214 as part of the first control setting may include a different or expanded range compared to the corresponding split ratio in the non-transient operating setting. According to one embodiment, the non-transient control setting of the GT system 100 may be biased to have a split ratio of approximately 170:1, and the first control setting may be biased to have a split ratio of approximately 150:1.

[0042] In addition to the on-the-fly adjustments described above, the first control setting may also affect the “dynamic inlet parameters” of the turbomachinery assembly 120. As used herein, the term “dynamic inlet parameters” may refer to any parameters of the operation of the compressor 122 and / or inlet 124 that are independent of the fuel management or split bias of the turbomachinery assembly 120. Such parameters may include, for example, the temperature or pressure of the inlet 124, the position and / or orientation of the IGV 126, and / or other operating parameters of the compressor 122. Such parameters are referred to as “dynamic” in the context of the first control setting because they do not remain at fixed values ​​to adequately compensate for transient loads of the power plant 100 and switching events of the transmission line 160. According to one embodiment, the first control setting may cause the IGV 126 to adjust between two or more angular positions (e.g., offset between 5 and 10 degrees from an initial fully open position) over a predetermined time period, and may regulate the temperature or pressure of the inlet 124 (e.g., using one or more heat exchangers, liquid control valves, etc.) between two or more predetermined values ​​(e.g., between about 22°C and about 26°C) over a predetermined time period.

[0043] Regardless of the particular parameters selected for adjusting the first control setting, process P4 may include causing the GT controller 180 to adjust one or more components of the turbomachinery assembly 120 to use the first control setting during a transient load. In process P4, the first control setting may continue to be used until the exciter controller 172 detects an end of the transient event and / or a decrease in the system reactance of the grid 162. Such a determination, and subsequent actions, are performed in decision D4, as described elsewhere herein.

[0044] If the system reactance does not exceed the switching threshold but one or more electrical characteristics exceed the stability threshold (i.e., “No” at decision D2 and “Yes” at decision D3), the method may include operation P5 of operating the turbomachinery assembly 120 at a second control setting. In operation P5, the controller 172 may cause the GT controller 180 to change various operating settings of the turbomachinery assembly 120 differently than the first operating setting. Specifically, the second operating setting may include the dynamic intake parameters used for the first control profile, but does not include the transient fuel management profile and the split bias profile. The absence of the transient fuel management profile and the split bias profile in the second control setting may reflect the previous determination in decision D2 that the switching threshold was not exceeded and therefore no switching event occurred at the transmission line 160. Thus, the second control setting may be set to accommodate a situation in which one or more electrical characteristics exceed the stability threshold, but does not compensate for a switching event at the transmission line 160.

[0045] In some approaches, process P5 may be preceded by an additional process P5.1 that creates a second control profile. Process P5.1 may include any combination of calculations, models, simulations, etc. suitable for providing a dynamic intake profile for use in the second control setting based on monitored electrical characteristics of the power plant 100 and the grid 162. In addition to not using a transient fuel management profile and a split bias profile, the exciter controller 172 and the GT controller 180 may cause the turbomachinery assembly 120 to implement the dynamic intake profile in substantially the same manner, or in a similar manner, as part of the first control setting. Thus, process P5 may include adjusting the IGV 126 between various positions, increasing or decreasing the temperature or pressure of the inlet 124 (e.g., using one or more heat exchangers, fluid control valves, etc.). Various parameters used to adjust the turbomachinery assembly 120 may be stored, for example, in a control setting field 258 of the data 250, as described elsewhere herein. Note that the dynamic intake profile used in process P5 should not include any parameters applicable to the transient fuel management profile and / or the transient split bias profile, and therefore should not affect the split ratio or combustion parameters of the turbomachinery assembly 120 by operating the turbomachinery assembly 120 at the second control setting.

[0046] If action P4 or action P5 is performed and the turbomachinery assembly 120 is operating at the first control setting or the second control setting, other actions may include continuing to evaluate whether the turbomachinery assembly 120 should continue operating at the first control setting or the second control setting. Decision D4 may include, for example, determining, by module 242 of the exciter control program 212, whether the power plant 100 has resumed operation at a previous non-transient load or has reached a new operating steady state. The new operating steady state represents a situation in which the power plant 100 has changed from operating at an initial load level to operating at a new load level (e.g., transitioning from base load to full load and vice versa, or transitioning from starting load to base and vice versa). The determination in decision D4 may be based, for example, on electrical characteristics of the power plant 100 and / or the grid 162 observable by the exciter control system 172, which evaluates the operation of the generator 152. If the non-transient load has not resumed or a new steady-state operation has not been reached (i.e., "No" at decision D4), the method returns to decision D2 to again determine whether the monitored reactance exceeds the switching threshold and proceeds to one or more of actions P1, P4, D3, and P5 as described herein. If the non-transient load has resumed or a new steady-state operation has been reached (i.e., "Yes" at decision D4), the exciter control program 172 and the GT controller 180 may stop applying the appropriate first or second control setting ("Done"), or the method may return to action P1 to resume operation of the turbomachinery assembly 120 at the non-transient control setting.

[0047] Technical effects of the embodiments described herein include adjusting the response of the power plant 100 to transient loads from the grid 162 caused by various causes. The power plant 100 can respond to a switching event on the transmission line 160 with one set of operational settings and continue to respond to other types of transient loads with a separate, second control setting that is not related to the variables affected by the switching event (e.g., fuel management and / or split ratio). As a result, the power plant 100 can compensate for various types of conditions without being taken offline and / or reprogrammed in response to abrupt opening or closing of the transmission line from the power plant 100 to the grid 162.

[0048] As used herein throughout this specification and claims, approximation language can be applied to modify any quantitative expression that can reasonably vary without resulting in a change in the basic function involved. Thus, values ​​modified by terms such as "approximately," "about," and "substantially" are not limited to the exact value specified. In at least some instances, approximation language can correspond to the precision of the instrument used to measure the value. Here, and throughout this specification and claims, range limitations are combinable and / or interchangeable, and unless the context or language dictates otherwise, such ranges are identified and include all subranges encompassed therein. The term "about," as applied to a particular value in a range, applies to both ends of the range and can indicate + / - 10% of the stated value, unless specifically dependent on the precision of the instrument used to measure the value.

[0049] The corresponding structure, material, acts, and equivalents of all means-plus-function or step-plus-function elements in the following claims are intended to encompass any structure, material, or acts for performing that function in combination with other specifically claimed claim elements. The description of the present disclosure has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The present embodiments were chosen and described in order to best explain the principles and practical application of the disclosure and to enable others skilled in the art to understand the disclosure in various embodiments with various modifications as suited to the particular uses envisioned.

[0050] 1. A method of controlling a power plant (100) having a generator (152) mechanically coupled to a gas turbine via a shaft (150), the generator (152) being electrically coupled to a grid (162) through a set of transmission lines (160), the method comprising: detecting a transient load of the power plant (100) based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100), wherein the plurality of electrical characteristics of the grid (162) includes a system reactance of the grid (162); monitoring a system reactance of the grid (162) through the generator (152) during operation of the power plant (100) under the transient load; determining whether a system reactance of the grid (162) exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines (160); operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant (100) exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. A method comprising: [Embodiment 2] The detecting of the transient load comprises: 2. The method of claim 1, further comprising detecting an increase in the load fluctuation of the generator (152) caused by an increase in available transmission lines (160) in the set of transmission lines (160), or a decrease in the load fluctuation of the generator (152) caused by a decrease in available transmission lines (160) in the set of transmission lines (160). [Embodiment 3] The method of embodiment 1, further comprising generating the first control setting and the second control setting based on the calculated difference between the system reactance and the switching threshold. [Embodiment 4] The method of embodiment 1, wherein the dynamic intake parameters of the gas turbine do not affect combustion parameters of a combustor (138) of the gas turbine. [Embodiment 5] The method of embodiment 1, wherein the dynamic intake parameters do not affect the split ratio between the air intake and fuel intake of the power plant (100). [Embodiment 6] The method of embodiment 1, wherein each of the first control setting and the second control setting is different from a non-transient control setting for operating the gas turbine at a non-transient load. [Embodiment 7] The method of embodiment 6, further comprising operating the gas turbine at the non-transient control setting while determining whether the system reactance exceeds the switching threshold. 8. A program product stored on a computer-readable storage medium for controlling a power plant (100) having a generator (152) mechanically coupled to a gas turbine via a shaft (150) and electrically coupled to a grid (162) through a set of power transmission lines (160), the program product being stored on a computer-readable storage medium and configured to include: detecting a transient load of the power plant (100) based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100), wherein the plurality of electrical characteristics of the grid (162) includes a system reactance of the grid (162); monitoring a system reactance of the grid (162) through the generator (152) during operation of the power plant (100) under the transient load; determining whether a system reactance of the grid (162) exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines (160); operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant (100) exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. A program product comprising program code for performing operations including: [Embodiment 9] Detecting the transient load includes: 9. The program product of claim 8, further comprising detecting an increase in the load fluctuation of the generator (152) caused by an increase in available transmission lines (160) in the set of transmission lines (160), or a decrease in the load fluctuation of the generator (152) caused by a decrease in available transmission lines (160) in the set of transmission lines (160). [Embodiment 10] The program product described in embodiment 8, further comprising generating the first control setting and the second control setting based on the calculated difference between the system reactance and the switching threshold. [Embodiment 11] The program product of embodiment 8, wherein the dynamic intake parameters of the gas turbine do not affect combustion parameters of a combustor (138) of the gas turbine. [Embodiment 12] The program product of embodiment 8, wherein the dynamic intake parameters do not affect the split ratio between the air intake volume and the fuel intake volume of the power plant (100). [Embodiment 13] A program product as described in embodiment 8, wherein each of the first control setting and the second control setting is different from a non-transient control setting for operating the gas turbine at a non-transient load. [Embodiment 14] The program product described in embodiment 13, further comprising operating the gas turbine at the non-transient control setting while determining whether the system reactance exceeds the switching threshold. [Embodiment 15] A power plant (100) having a generator (152) mechanically coupled to a gas turbine via a shaft (150) and electrically coupled to a grid (162) through a set of power transmission lines (160); a system controller (172) in communication with the gas turbine of the power plant (100); a system (120) including: detecting a transient load of the power plant (100) based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100), wherein the plurality of electrical characteristics of the grid (162) includes a system reactance of the grid (162); monitoring a system reactance of the grid (162) through the generator (152) during operation of the power plant (100) under the transient load; determining whether a system reactance of the grid (162) exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines (160); operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant (100) exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. is feasible,system. [Explanation of symbols]

[0051] 100 Power Plants 120 Turbomachinery Assembly 122 Compressor 124 Entrance 126 IGV 138 Combustor 140 Fuel Source 142 Turbine Components 150 shaft 152 Generator 160 Power Lines 162 grid 170 Exciter 172 Exciter Controller 200 Computing Devices 202 memory 204 Control System 212 Exciter Control Program 214 GT control program 228 PU 230 I / O interface 234 Bus 236 I / O devices 238 Memory System 242, 244 modules 252 Generator Data Field 254 Grid Data Fields 256 Threshold Field 258 Control Settings Field

Claims

1. A method of controlling a power plant (100) having a generator (152) mechanically coupled to a gas turbine via a shaft (150), the generator (152) being electrically coupled to a grid (162) through a set of transmission lines (160), the method comprising: detecting a transient load of the power plant (100) based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100), wherein the plurality of electrical characteristics of the grid (162) includes a system reactance of the grid (162); monitoring a system reactance of the grid (162) through the generator (152) during operation of the power plant (100) under the transient load; determining whether a system reactance of the grid (162) exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines (160); operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant (100) exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. A method comprising:

2. Detecting the transient load comprises:

2. The method of claim 1, comprising detecting an increase in a load change on the generator caused by an increase in available transmission lines in the set of transmission lines, or a decrease in a load change on the generator caused by a decrease in available transmission lines in the set of transmission lines.

3. creating a first control setting based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100) or a system reactance of the grid when the system reactance exceeds the switching threshold; and 10. The method of claim 1, further comprising: if the system reactance does not exceed the switching threshold and at least one electrical characteristic of the plurality of electrical characteristics of the power plant exceeds a stability threshold, generating a second control setting based on a plurality of electrical characteristics of the grid and a plurality of electrical characteristics of the power plant.

4. The method of claim 1 , wherein the dynamic intake parameters of the gas turbine do not affect combustion parameters of a combustor (138) of the gas turbine.

5. The method of claim 1, wherein the dynamic intake parameters do not affect the split ratio between the air intake and the fuel intake of the power plant (100).

6. The method of claim 1 , wherein each of the first control setting and the second control setting is different from a non-transient control setting for operating the gas turbine at a non-transient load.

7. The method of claim 6 , further comprising operating the gas turbine at the non-transient control setting while determining whether the system reactance exceeds the switching threshold.

8. 1. A program product stored on a computer-readable storage medium for controlling a power plant (100) having a generator (152) mechanically coupled to a gas turbine via a shaft (150) and electrically coupled to a grid (162) through a set of transmission lines (160), the computer-readable storage medium being configured to include: detecting a transient load of the power plant (100) based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100), wherein the plurality of electrical characteristics of the grid (162) includes a system reactance of the grid (162); monitoring a system reactance of the grid (162) through the generator (152) during operation of the power plant (100) under the transient load; determining whether a system reactance of the grid (162) exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines (160); operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant (100) exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. A program product comprising program code for performing operations including:

9. Detecting the transient load comprises:

9. The program product of claim 8, further comprising detecting an increase in a load change of the generator (152) caused by an increase in available transmission lines (160) in the set of transmission lines (160) or a decrease in a load change of the generator (152) caused by a decrease in available transmission lines (160) in the set of transmission lines (160).

10. When the system reactance exceeds the switching threshold, generating a first control setting based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100) or a system reactance of the grid; and 10. The program product of claim 8, further comprising: generating a second control setting based on a plurality of electrical characteristics of the grid and a plurality of electrical characteristics of the power plant when the system reactance does not exceed the switching threshold and at least one electrical characteristic of the power plant exceeds a stability threshold.

11. The program product of claim 8 , wherein the dynamic intake parameters of the gas turbine do not affect combustion parameters of a combustor (138) of the gas turbine.

12. 9. The program product of claim 8, wherein the dynamic intake parameters do not affect the split ratio between the air intake and the fuel intake of the power plant.

13. The program product of claim 8 , wherein each of the first control setting and the second control setting is different from a non-transient control setting for operating the gas turbine at a non-transient load.

14. The program product of claim 13 , further comprising operating the gas turbine at the non-transient control setting while determining whether the system reactance exceeds the switching threshold.

15. a power plant (100) having a generator (152) mechanically coupled to a gas turbine via a shaft (150) and electrically coupled to a grid (162) through a set of transmission lines (160); a system controller (172) in communication with the gas turbine of said power plant (100); a system (120) including: detecting a transient load of the power plant (100) based on a plurality of electrical characteristics of the grid (162) and a plurality of electrical characteristics of the power plant (100), wherein the plurality of electrical characteristics of the grid (162) includes a system reactance of the grid (162); monitoring a system reactance of the grid (162) through the generator (152) during operation of the power plant (100) under the transient load; determining whether a system reactance of the grid (162) exceeds a switching threshold, the switching threshold indicating a switching event in the set of transmission lines (160); operating the gas turbine at the transient load using a first control setting in response to the system reactance exceeding the switching threshold, the first control setting including a transient fuel management profile, a transient split bias profile, and dynamic intake parameters of the gas turbine; and and operating the gas turbine at the transient load using a second control setting in response to the system reactance not exceeding the switching threshold and one electrical characteristic of a plurality of electrical characteristics of the power plant (100) exceeding a stability threshold, the second control setting including the dynamic intake parameters of the gas turbine, and the second control setting not including the transient fuel management profile and the transient split bias profile. is feasible,system.

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