WO2024136835A1 - System and method for plant-level coordination of inertial power response of grid-forming inverter-based resources - Google Patents

Abstract

A method of coordinating an inertial power response of a plurality of inverter-based resources in a power plant connected to an electrical grid includes receiving, via a plant-level controller of the power plant, at least one of a desired plant inertia or desired plant inertial power capability. The method also includes continuously, via the plant-level controller, determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources. Further, the method includes coordinating, via the plant-level controller, the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

Description

SYSTEM AND METHOD FOR PLANT-LEVEL COORDINATION OF INERTIAL POWER RESPONSE OF GRID-FORMING INVERTER-BASED RESOURCES

FIELD

[0001] The present disclosure relates generally to inverter-based resources, such as wind turbine power systems and, more particularly, to systems and methods for plant-level coordination of inertial power response of grid-forming inverter-based resources.

BACKGROUND

[0002] Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modem wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. For example, rotor blades typically have the cross-sectional profile of an airfoil such that, during operation, air flows over the blade producing a pressure difference between the sides. Consequently, a lift force, which is directed from a pressure side towards a suction side, acts on the blade. The lift force generates torque on the main rotor shaft, which is typically geared to a generator for producing electricity.

[0003] Wind turbines can be distinguished in two types: fixed speed and variable speed turbines. Conventionally, variable speed wind turbines are controlled as current sources connected to a power grid. In other words, the variable speed wind turbines rely on a grid frequency detected by a phase locked loop (PLL) as a reference and inject a specified amount of current into the grid. The conventional current source control of the wind turbines is based on the assumptions that the grid voltage waveforms are fundamental voltage waveforms with fixed frequency and magnitude and that the penetration of wind power into the grid is low enough so as to not cause disturbances to the grid voltage magnitude and frequency. Thus, the wind turbines simply inject the specified current into the grid based on the fundamental voltage waveforms. However, with the rapid growth of the wind power, wind power penetration into some grids has increased to the point where wind turbine generators have a significant impact on the grid voltage and frequency. When wind turbines are located in a weak grid, wind turbine power fluctuations may lead to an increase in magnitude and frequency variations in the grid voltage. These fluctuations may adversely affect the performance and stability of the PLL and wind turbine current control.

[0004] Many existing renewable generation converters, such as double-fed wind turbine generators, operate in a “grid-following” mode. Grid-following type devices utilize fast current-regulation loops to control active and reactive power exchanged with the grid. More specifically, FIG. 1 illustrates the basic elements of the main circuit and converter control structure for a grid-following double-fed wind turbine generator. As shown, the active power reference to the converter is developed by the energy source regulator, e.g., the turbine control portion of a wind turbine. This is conveyed as a torque reference which represents the lesser of the maximum attainable power from the energy source at that instant, or a curtailment command from a higher-level grid controller. The converter control then determines a current reference for the active component of current to achieve the desired torque. Accordingly, the double-fed wind turbine generator includes functions that manage the voltage and reactive power in a manner that results in a command for the reactive component of current. Wide-bandwidth current regulators then develop commands for voltage to be applied by the converters to the system, such that the actual currents closely track the commands.

[0005] Alternatively, grid-forming type converters provide a voltage-source characteristic, where the angle and magnitude of the voltage are controlled to achieve the regulation functions needed by the grid. With this structure, current will flow according to the demands of the grid while the converter contributes to establishing a voltage and frequency for the grid. This characteristic is comparable to conventional generators based on a turbine driving a synchronous machine. Thus, a grid-forming source must include the following basic functions: (1) support grid voltage and frequency for any current flow within the rating of the equipment, both real and reactive; (2) prevent operation beyond equipment voltage or current capability by allowing grid voltage or frequency to change rather than disconnecting equipment (disconnection is allowed only when voltage or frequency are outside of bounds established by the grid entity); (3) remain stable for any grid configuration or load characteristic, including serving an isolated load or connected with other grid-forming sources, and switching between such configurations; (4) share total load of the grid among other grid-forming sources connected to the grid; (5) ride through grid disturbances, both major and minor, and (6) meet requirements (1 )-(5) without requiring fast communication with other control systems existing in the grid, or externally-created logic signals related to grid configuration changes.

[0006] The basic control structure to achieve the above grid-forming objectives was developed and field-proven for battery systems in the early 1990’s (see e.g., United States Patent No.: 5,798,633 entitled “Battery Energy Storage Power Conditioning System”). Applications to full-converter wind generators and solar generators are disclosed in United States Patent No.: 7,804,184 entitled “System and Method for Control of a Grid Connected Power Generating System,” and United States Patent No.: 9,270,194 entitled “Controller for controlling a power converter.” Applications to grid-forming control for a doubly-fed wind turbine generator are disclosed in PCT/US2020/013787 entitled “System and Method for Providing Grid- Forming Control for a Doubly-Feb Wind Turbine Generator.”

[0007] As an example, FIG. 2 illustrates a schematic diagram of one embodiment of a main circuit of a grid-forming system. As shown, the main circuit includes a power-electronic converter with connections on DC and AC sides. This converter receives gating commands from a controller that creates an AC voltage phasor Vcnv at an angle of Thvcnv. The DC side is supplied with a device capable of generating or absorbing power for even a short duration. Such devices may include, for example, batteries, solar panels, rotating machines with a rectifier, or capacitors. In addition, as shown, the circuit includes an inductive impedance Xcnv connecting the converter to its point of interconnection, shown as the voltage Vt and angle ThVt in FIG. 2. The electrical system behind the point of interconnect is shown as a Thevenin equivalent with impedance Zthev and voltage Vthev at angle ThVthev. This equivalent can be used to represent any circuit, including grid-connected and islanded circuits with loads. In practical situations, the impedance Zthev will be primarily inductive.

[0008] Still referring to FIG. 2, the closed-loop portion of the main control receives feedback signals from the voltage and current at the point of interconnection. Additional inputs are received from higher-level controls (not shown). While FIG. 2 illustrates a single converter as an example, any grouping of equipment that can create an electrical equivalent of a controlled voltage Vcnv behind an impedance Xcnv can have the control schemes disclosed applied to achieve the same performance benefits. [0009] Referring now to FIG. 3, a control diagram for providing grid-forming control according to conventional construction is illustrated. As shown, a converter controller 1 receives references (e.g., Vref and Pref) and limits (e.g., VcmdLimits and PcmdLimits) from higher-level controls 2. These high-level limits are on physical quantities of voltage, current, and power. The main regulators include a fast voltage regulator 3 and a slow power regulator 4. These regulators 3, 4 have final limits applied to the converter control commands for voltage magnitude (e.g., VcnvCmd) and angle (e.g., 0p_ang and 0PLL) to implement constraints on reactive- and real- components of current, respectively. Further, such limits are based upon a predetermined fixed value as a default, with closed-loop control to reduce the limits should current exceed limits.

[0010] To be effective, grid-forming (GFM) inverter-based resources (IB Rs) must be able to maintain an internal voltage phasor that does not move quickly when there are changes in grid conditions, e.g., sudden addition/removal of loads, opening or closing of grid connections that lead to phase jumps and/or rapid change of frequency. In other words, the power from the grid-forming resource must be able to change suddenly to stabilize the grid, with a subsequent slow reset to power being commanded from a higher-level control function. In addition, the grid-forming resource must be able to rapidly enforce power limits that exist due to constraints on the power-handling portions of the device, e.g., DC voltages/currents in a battery, solar array, and/or wind generating system. Such a response is needed for severe disturbances on the grid, e.g., faults where power limits will be dynamically adjusted to coordinate with grid conditions for secure recovery from the fault. Further, the grid-forming resource should be able to rapidly follow changes in commands from higher-level controls, e.g., for damping mechanical vibrations in a wind turbine.

[0011] As IBRs continue to displace synchronous generators, it has become more important for IBRs to provide some of the grid support services i.e., frequency and voltage support currently provided by synchronous generators. However, an adverse effect of the increased adoption of IBRs is the erosion of the high system inertia naturally provided by synchronous machines. GFM inverters have the capability of fast injection or absorption of energy during frequency disturbances to mimic the natural inertial energy injection demonstrated by synchronous machines.

[0012] Thus, the present disclosure is directed to a control strategy where GFMs IBRs having the capability of mimicking the inertial power response of synchronous machines are allowed to respond rapidly in an autonomous fashion to grid frequency disturbances.

BRIEF DESCRIPTION

[0013] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0014] In an aspect, the present disclosure is directed to a method of coordinating an inertial power response of a plurality of inverter-based resources in a power plant connected to an electrical grid. The method includes receiving, via a plant-level controller of the power plant, at least one of a desired plant inertia or desired plant inertial power capability. The method also includes continuously, via the plant-level controller, determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources. Further, the method includes coordinating, via the plant-level controller, the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

[0015] In another aspect, the present disclosure is directed to a system for coordinating an inertial power response of a plurality of grid-forming inverter-based resources in a power plant connected to an electrical grid. The system includes a plurality of local controllers and a plant-level controller communicatively coupled to the plurality of local controllers. The plant-level controller includes at least one processor configured to perform a plurality of operations, including but not limited to receiving at least one of a desired plant inertia or desired plant inertial power capability, continuously determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources, and coordinating the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

[0016] In still another aspect, the present disclosure is directed to a method for controlling a wind farm connected to an electrical grid, the wind farm having a plurality of wind turbines, with at least one of the plurality of wind turbines being a grid-forming wind turbine. The method includes receiving at least one of a desired transient power or energy availability for the wind farm. The method also includes receiving at least one of a transient power or energy availability feedback from each of the plurality of wind turbines. Further, the method includes receiving a steadystate power capability from each of the plurality of wind turbines. Further, the method includes determining an anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines. Moreover, the method includes determining at least one of a power limit for each of the plurality of wind turbines and a wind farm active power curtailment setpoint based on the steady-state power capability from each of the plurality of wind turbines and the anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines. In addition, the method includes controlling the wind farm based on the power limit to provide a desired transient power or energy to the electrical grid upon occurrence of a grid frequency or phase angle change.

[0017] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

[0019] FIG. 1 illustrates a one-line diagram of a double-fed wind turbine generator with structure of converter controls for grid-following application according to conventional construction;

[0020] FIG. 2 illustrates a schematic diagram of one embodiment of a main circuit of a grid-forming system according to conventional construction;

[0021] FIG. 3 illustrates a control diagram for providing grid-forming control according to conventional construction;

[0022] FIG. 4 illustrates a perspective view of one embodiment of a wind turbine according to the present disclosure;

[0023] FIG. 5 illustrates a simplified, internal view of one embodiment of a nacelle according to the present disclosure;

[0024] FIG. 6 illustrates a schematic view of one embodiment of a wind turbine electrical power system suitable for use with the wind turbine shown in FIG. 1;

[0025] FIG. 7 illustrates a schematic view of one embodiment of a wind farm having a plurality of wind turbines according to the present disclosure;

[0026] FIG. 8 illustrates a schematic view of another embodiment of a wind turbine electrical power system suitable for use with the wind turbine shown in FIG. i;

[0027] FIG. 9 illustrates a block diagram of one embodiment of a controller according to the present disclosure;

[0028] FIG. 10 illustrates a flow diagram of an embodiment of a method of coordinating an inertial power response of a plurality of grid-forming inverter-based resources in a power plant connected to an electrical grid according to the present disclosure;

[0029] FIGS. 11 and 12 illustrate a control diagram of an embodiment of a plantlevel controller for coordinating an inertial power response of a plurality of gridforming inverter-based resources in a power plant connected to an electrical grid according to the present disclosure; and

[0030] FIG. 13 illustrates a flow diagram of an embodiment of a method for controlling a wind farm connected to an electrical grid, the wind farm having a plurality of wind turbines according to the present disclosure.

DETAILED DESCRIPTION

[0031] Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. [0032] Grid-forming inverter-based resources (GFM IBRs) have control functions that emulate the physical aspects of synchronous machines, including an inertial power regulator. Accordingly, the present disclosure is directed to a control strategy where GFM IBRs, e.g., in a power plant such as a wind farm, with the capability mimicking the inertial power response of synchronous machines are allowed to respond rapidly in an autonomous fashion to grid frequency disturbances. Further, in an embodiment, the inertial power response of the GFM IBRs during the transient event i.e., under-frequency and over-frequency, can be constrained within limits set by a plant-level controller to meet the required inertial power and energy at a point of interconnection of the plant. With the proposed control scheme, each GFM IBR in a power plant can independently detect a transient event and respond rapidly, e.g., without waiting for a cue from the plant-level controller, up to its allocated inertial power limit. Accordingly, in an embodiment, an overall inertial power response profile of the plant during the entire frequency disturbance event to satisfy one or more grid code requirements and/or a power market at the point of interconnection (POI) is coordinated by the plant-level controller. During this period, each of the GFM IBRs acts independently in response to the grid frequency while constraining its response to the continuous power limits dictated by the plant-level controller. It should be understood that the inverter-based resources described herein may include, but are not limited to, a wind turbine power system, a solar power system, an energy storage power system, or combinations thereof.

[0033] Referring now to the drawings, FIG. 4 illustrates a perspective view of one embodiment of a wind turbine 10 according to the present disclosure. As shown, the wind turbine 10 generally includes a tower 12 extending from a support surface 14, a nacelle 16 mounted on the tower 12, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outwardly from the hub 20. For example, in the illustrated embodiment, the rotor 18 includes three rotor blades 22. However, in an alternative embodiment, the rotor 18 may include more or less than three rotor blades 22. Each rotor blade 22 may be spaced about the hub 20 to facilitate rotating the rotor 18 to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy. For instance, the hub 20 may be rotatably coupled to an electric generator 24 (FIG. 5) positioned within the nacelle 16 to permit electrical energy to be produced.

[0034] The wind turbine 10 may also include a wind turbine controller 26 centralized within the nacelle 16. However, in other embodiments, the controller 26 may be located within any other component of the wind turbine 10 or at a location outside the wind turbine 10. Further, the controller 26 may be communicatively coupled to any number of the components of the wind turbine 10 in order to control the operation of such components and/or implement a corrective or control action. As such, the controller 26 may include a computer or other suitable processing unit. Thus, in several embodiments, the controller 26 may include suitable computer- readable instructions that, when implemented, configure the controller 26 to perform various different functions, such as receiving, transmitting and/or executing wind turbine control signals. Accordingly, the controller 26 may generally be configured to control the various operating modes (e.g., start-up or shut-down sequences), de-rating or up-rating the wind turbine, and/or individual components of the wind turbine 10.

[0035] Referring now to FIG. 5, a simplified, internal view of one embodiment of the nacelle 16 of the wind turbine 10 shown in FIG. 4 is illustrated. As shown, a generator 24 may be disposed within the nacelle 16 and supported atop a bedplate 46. In general, the generator 24 may be coupled to the rotor 18 for producing electrical power from the rotational energy generated by the rotor 18. For example, as shown in the illustrated embodiment, the rotor 18 may include a rotor shaft 34 coupled to the hub 20 for rotation therewith. The rotor shaft 34 may, in turn, be rotatably coupled to a generator shaft 36 of the generator 24 through a gearbox 38. As is generally understood, the rotor shaft 34 may provide a low speed, high torque input to the gearbox 38 in response to rotation of the rotor blades 22 and the hub 20. The gearbox 38 may then be configured to convert the low speed, high torque input to a high speed, low torque output to drive the generator shaft 36 and, thus, the generator 24. [0036] The wind turbine 10 may also one or more pitch drive mechanisms 32 communicatively coupled to the wind turbine controller 26, with each pitch adjustment mechanism(s) 32 being configured to rotate a pitch bearing 40 and thus the individual rotor blade(s) 22 about its respective pitch axis 28. In addition, as shown, the wind turbine 10 may include one or more yaw drive mechanisms 42 configured to change the angle of the nacelle 16 relative to the wind (e.g., by engaging a yaw bearing 44 of the wind turbine 10 that is arranged between the nacelle 16 and the tower 12 of the wind turbine 10).

[0037] In addition, the wind turbine 10 may also include one or more sensors 66, 68 for monitoring various wind conditions of the wind turbine 10. For example, the incoming wind direction 52, wind speed, or any other suitable wind condition near of the wind turbine 10 may be measured, such as through use of a suitable weather sensor 66. Suitable weather sensors may include, for example, Light Detection and Ranging (“LIDAR”) devices, Sonic Detection and Ranging (“SOD AR”) devices, anemometers, wind vanes, barometers, radar devices (such as Doppler radar devices) or any other sensing device which can provide wind directional information now known or later developed in the art. Still further sensors 68 may be utilized to measure additional operating parameters of the wind turbine 10, such as voltage, current, vibration, etc. as described herein.

[0038] Referring now to FIG. 6, a schematic diagram of one embodiment of a wind turbine power system 100 is illustrated in accordance with aspects of the present disclosure. Although the present disclosure will generally be described herein with reference to the wind turbine 10 shown in FIG. 4, those of ordinary skill in the art, using the disclosures provided herein, should understand that aspects of the present disclosure may also be applicable in other power generation systems, and, as mentioned above, that the invention is not limited to wind turbine systems.

[0039] In the embodiment of FIG. 6 and as mentioned, the rotor 18 of the wind turbine 10 (FIG. 4) may, optionally, be coupled to the gearbox 38, which is, in turn, coupled to a generator 102, which may be a doubly fed induction generator (DFIG). As shown, the DFIG 102 may be connected to a stator bus 104. Further, as shown, a power converter 106 may be connected to the DFIG 102 via a rotor bus 108, and to the stator bus 104 via a line side bus 110. As such, the stator bus 104 may provide an output multiphase power (e.g., three-phase power) from a stator of the DFIG 102, and the rotor bus 108 may provide an output multiphase power (e.g., three-phase power) from a rotor of the DFIG 102. The power converter 106 may also include a rotor side converter (RSC) 112 and a line side converter (LSC) 114. The DFIG 102 is coupled via the rotor bus 108 to the rotor side converter 112. Additionally, the RSC 112 is coupled to the LSC 114 via a DC link 116 across which is a DC link capacitor 118. The LSC 114 is, in turn, coupled to the line side bus 110.

[0040] The RSC 112 and the LSC 114 may be configured for normal operating mode in a three-phase, pulse width modulation (PWM) arrangement using one or more switching devices, such as insulated gate bipolar transistor (IGBT) switching elements. In addition, the power converter 106 may be coupled to a converter controller 120 in order to control the operation of the rotor side converter 112 and/or the line side converter 114 as described herein. It should be noted that the converter controller 120 may be configured as an interface between the power converter 106 and the turbine controller 26 and may include any number of control devices.

[0041] In typical configurations, various line contactors and circuit breakers including, for example, a grid breaker 122 may also be included for isolating the various components as necessary for normal operation of the DFIG 102 during connection to and disconnection from a load, such as the electrical grid 124. For example, a system circuit breaker 126 may couple a system bus 128 to a transformer 130, which may be coupled to the electrical grid 124 via the grid breaker 122. In alternative embodiments, fuses may replace some or all of the circuit breakers. [0042] In operation, alternating current power generated at the DFIG 102 by rotating the rotor 18 is provided to the electrical grid 124 via dual paths defined by the stator bus 104 and the rotor bus 108. On the rotor bus side 108, sinusoidal multiphase (e.g., three-phase) alternating current (AC) power is provided to the power converter 106. The rotor side converter 112 converts the AC power provided from the rotor bus 108 into direct current (DC) power and provides the DC power to the DC link 116. As is generally understood, switching elements (e.g., IGBTs) used in the bridge circuits of the rotor side converter 112 may be modulated to convert the AC power provided from the rotor bus 108 into DC power suitable for the DC link 116.

[0043] In addition, the line side converter 114 converts the DC power on the DC link 116 into AC output power suitable for the electrical grid 124. In particular, switching elements (e.g., IGBTs) used in bridge circuits of the line side converter 114 can be modulated to convert the DC power on the DC link 116 into AC power on the line side bus 110. The AC power from the power converter 106 can be combined with the power from the stator of DFIG 102 to provide multi-phase power (e.g., three- phase power) having a frequency maintained substantially at the frequency of the electrical grid 124 (e.g., 50 Hz or 60 Hz).

[0044] Additionally, various circuit breakers and switches, such as grid breaker 122, system breaker 126, stator sync switch 132, converter breaker 134, and line contactor 136 may be included in the wind turbine power system 100 to connect or disconnect corresponding buses, for example, when current flow is excessive and may damage components of the wind turbine power system 100 or for other operational considerations. Additional protection components may also be included in the wind turbine power system 100.

[0045] Moreover, the power converter 106 may receive control signals from, for instance, the turbine controller 26 via the converter controller 120. The control signals may be based, among other things, on sensed states or operating characteristics of the wind turbine power system 100. Typically, the control signals provide for control of the operation of the power converter 106. For example, feedback in the form of a sensed speed of the DFIG 102 may be used to control the conversion of the output power from the rotor bus 108 to maintain a proper and balanced multi-phase (e.g., three-phase) power supply. Other feedback from other sensors may also be used by the controller(s) 120, 26 to control the power converter 106, including, for example, stator and rotor bus voltages and current feedbacks. Using the various forms of feedback information, switching control signals (e.g., gate timing commands for IGBTs), stator synchronizing control signals, and circuit breaker signals may be generated.

[0046] The power converter 106 also compensates or adjusts the frequency of the three-phase power from the rotor for changes, for example, in the wind speed at the hub 20 and the rotor blades 22. Therefore, mechanical and electrical rotor frequencies are decoupled and the electrical stator and rotor frequency matching is facilitated substantially independently of the mechanical rotor speed.

[0047] Under some states, the bi-directional characteristics of the power converter 106, and specifically, the bi-directional characteristics of the LSC 114 and RSC 112, facilitate feeding back at least some of the generated electrical power into generator rotor. More specifically, electrical power may be transmitted from the stator bus 104 to the line side bus 110 and subsequently through the line contactor 136 and into the power converter 106, specifically the LSC 114 which acts as a rectifier and rectifies the sinusoidal, three-phase AC power to DC power. The DC power is transmitted into the DC link 116. The capacitor 118 facilitates mitigating DC link voltage amplitude variations by facilitating mitigation of a DC ripple sometimes associated with three- phase AC rectification.

[0048] The DC power is subsequently transmitted to the RSC 112 that converts the DC electrical power to a three-phase, sinusoidal AC electrical power by adjusting voltages, currents, and frequencies. This conversion is monitored and controlled via the converter controller 120. The converted AC power is transmitted from the RSC 112 via the rotor bus 108 to the generator rotor. In this manner, generator reactive power control is facilitated by controlling rotor current and voltage.

[0049] Referring now to FIG. 7, the wind turbine power system 100 described herein may be part of a wind farm 150. As shown, the wind farm 150 may include a plurality of wind turbines 152, including the wind turbine 10 described above, and an overall farm-level controller 156. For example, as shown in the illustrated embodiment, the wind farm 150 includes twelve wind turbines, including wind turbine 10. However, in other embodiments, the wind farm 150 may include any other number of wind turbines, such as less than twelve wind turbines or greater than twelve wind turbines. In one embodiment, the turbine controllers of the plurality of wind turbines 152 are communicatively coupled to the farm-level controller 156, e.g., through a wired connection, such as by connecting the turbine controller 26 through suitable communicative links 154 (e.g., a suitable cable). Alternatively, the turbine controllers may be communicatively coupled to the farm-level controller 156 through a wireless connection, such as by using any suitable wireless communications protocol known in the art. In further embodiments, the farm-level controller 156 is configured to send and receive control signals to and from the various wind turbines 152, such as for example, distributing real and/or reactive power demands across the wind turbines 152 of the wind farm 150.

[0050] Referring now to FIG. 8, a schematic diagram of another embodiment of a wind turbine power system 170 is illustrated in accordance with aspects of the present disclosure. In contrast to FIG. 6, however, the wind turbine power system 170 of FIG. 7 is a full-conversion system. In particular, as shown, the wind turbine power system 100 includes a generator 172, a generator side converter 174, and a grid side converter 176. The wind turbine power system 170 further includes a grid side controller 178, a generator side controller 180, and a power grid 182. Further, as shown, the power grid 182 typically includes traditional synchronous generators 184 and electrical loads 186. A direct current (DC) link 188 connects the generator side converter 174 and the grid side converter 176. As such, the generator side converter 174 converts alternating current (AC) power generated by the generator 172 into DC power. The grid side converter 176 then converts the DC power to AC power at a frequency compatible with the power grid 182. Thus, in an embodiment, the combination of the grid side controller 178 and the grid side converter 176 functions as a current source for the power grid 182. In other words, the grid side controller 178 controls the phase and amplitude of the output current of grid side converter 176.

[0051] Referring now to FIG. 9, a block diagram of one embodiment of suitable components that may be included within the controller (such as any one of the converter controller 120, the turbine controller 26, and/or the farm-level controller 156 described herein) in accordance with example aspects of the present disclosure is illustrated. As shown, the controller may include one or more processor(s) 158, computer, or other suitable processing unit and associated memory device(s) 160 that may include suitable computer-readable instructions that, when implemented, configure the controller to perform various different functions, such as receiving, transmitting and/or executing wind turbine control signals (e.g., performing the methods, steps, calculations, and the like disclosed herein).

[0052] As used herein, the term “processor” refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. Additionally, the memory device(s) 160 may generally include memory element(s) including, but not limited to, computer readable medium (e.g., random access memory (RAM)), computer readable non-volatile medium (e.g., a flash memory), a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD) and/or other suitable memory elements.

[0053] Such memory device(s) 160 may generally be configured to store suitable computer-readable instructions that, when implemented by the processor(s) 158, configure the controller to perform various functions as described herein.

Additionally, the controller may also include a communications interface 162 to facilitate communications between the controller and the various components of the wind turbine 10. An interface can include one or more circuits, terminals, pins, contacts, conductors, or other components for sending and receiving control signals. Moreover, the controller may include a sensor interface 164 (e.g., one or more analog- to-digital converters) to permit signals transmitted from the sensors 66, 68 to be converted into signals that can be understood and processed by the processor(s) 158. [0054] Referring now to FIG. 10, a flow diagram of one embodiment of a method 200 of coordinating an inertial power response of a plurality of inverter-based resources (that may include grid-forming and/or grid-following capability) in a power plant connected to an electrical grid according to the present disclosure is provided. In general, the method 200 is described herein with reference to the wind turbine power system 100 of FIGS. 4-9 and the control diagrams 300, 400 of FIGS. 11-12. However, it should be appreciated that the disclosed method 200 may be implemented with any other suitable power generation systems having any other suitable configurations. In addition, although FIG. 10 depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. One skilled in the art, using the disclosures provided herein, will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

[0055] As shown at (202), the method 200 includes receiving, via a plant-level controller of the power plant, at least one of a desired plant inertia or desired plant inertial power capability. As shown at (204), the method 200 includes continuously, via the plant-level controller, determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources. As shown at (206), the method 200 includes coordinating, via the plant-level controller, the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

[0056] The inertia (or virtual inertia) of a power plant is a common term used in the art, and reflects the physical inertia of a conventional synchronous generator or a controller setting in a GFM IBR that may be intended to emulate physical characteristics of a synchronous machine. An inertial response of these systems is characterized by a change in internal speed or frequency that is proportional to the integral of a power imbalance. This change in internal speed or frequency causes a change in angle, leading to a change active power. In GFL systems, a pseudo-inertial response may be provided according to a predetermined relationship between a frequency feedback and a temporary change in power setpoint of the inverter-based resource (e.g., these may be also called fast-frequency response (FFR) control functions, see e.g., FIG. 12). This GFL inertial response may be subject to frequency deadbands and/or time delays. Inertial power capability refers to the amount of power change of an IBR from an initial condition for which the inertial response can be maintained before stopping the inertial response or constraining the inertial response in some other way. The inertial response may need to be constrained to respect various equipment limits (e.g., current limits or mechanical limits of a wind turbine) or to avoid tripping the resource. Typically, the inertial response occurs when the grid frequency suddenly changes, either due to a loss of load within the grid or tripping of a generator within the grid.

[0057] Furthermore, the method 200 of FIG. 10 can be better understood with reference to FIGS. 11-12. More specifically, as shown in FIGS. 11 and 12, control diagrams 300, 400 of an embodiment of a plant-level controller 302 (FIG. 11) configured to coordinate an inertial power response of a plurality of inverter-based resources (FIG. 12) in a power plant connected to an electrical grid is provided. Thus, as shown, the plant-level controller 302 may include, for example, a plant inertial response coordinator module 304, an inertial power limit distribution module 306, an inertial power capacity aggregator module 308, a plant power regulator 310, and an active power distribution module 312.

[0058] Accordingly, in an embodiment, based on the expected plant inertial response reference 314 (e.g., APinerRef) from the grid operator, the plant inertial response coordinator module 304 of the plant-level controller 302 is configured to compute a capacity adjustment signal 334 (e.g., APinerCapAdj). In an embodiment, for example, the capacity adjustment signal 334 (e.g., APinerCapAdj) can be computed as a non-zero value when there is a deficit between the potential plant inertial capacity and the expected plant inertial response 314 (e.g., APinerRef). In this particular embodiment, as shown, the plant power regulator 310 is configured to receive an input 336 based on a difference between a power reference 332 (e.g., PRef) from a grid operator and a capacity adjustment signal 334 from the plant inertial response coordinator module 304 (e.g., APinerCapAdj). In such embodiments, for example, the capacity adjustment signal 334 allows the power reference 332 to be adjusted based on the capacity of the inverter-based resources in the power plant to generate an inertial power response. For example, it may be beneficial to curtail the steady-state power output of the power plant during high output to operate the inverter-based resources further away from their own equipment limits, thereby increasing the inertial power capability higher. [0059] Accordingly, in an embodiment, the plant power regulator 310 of the plant-level controller 302 regulates the power plant to the adjusted active power reference 336. The regulated active power from the plant power regulator 310 to achieve the desired inertial capacity adjustment signal 334 is distributed by the active power distribution module 312 to each of the plurality of grid forming and gridfollowing inverter-based resources in the plant. The active power command to each of the inverter-based resources, gets passed on to the turbine controls 406, 408 of the GFM controls 402 and the GFL controls 404. The capacity adjustment signal 334 is continuously distributed to all the inverter-based resources in the power plant via the power command signal 330 (e.g., Pcmd(i)). In certain embodiments, for example, the desired capacity adjustment signal 334 is configured to be distributed to each of the GFM inverter-based resources and/or the GFL inverter-based resources based on, for example, one or more steady state power distribution signals 338 received therefrom. In such embodiments, for example, the steady state power distribution signals 338 may relate to individual possible/potential power generation capacities, online status, etc. of the inverter-based resources. Moreover, as shown, the active power distribution module 312 may also receive an inertial capability -based distribution bias signal 340 (e.g., InerTurbAdjBias(i)) generated from the plant inertial response coordinator module 304 (e.g., InerTurbAdjBias(i)) that can be used along with the steady state power distribution signals 338 to distribute the required adjustment to each of the plurality of GFM inverter-based resources accordingly, i.e., prior to the occurrence of a frequency disturbance event. The inertial capability-based distribution bias signal 340 (e.g., InerTurbAdjBias(i)) allows the selection of the inverter-based resources within the power plant that can potentially be manipulated by the plant-level controller 302 to achieve the desired inertial capacity deficit reflected in the capacity adjustment signal 334 (e.g., APinerCapAdj).

[0060] In addition, as shown in FIG. 11, the plant-level controller 302 is configured to continuously determine and send respective allocated inertial power limits 326, 328 to each of the plurality of grid-forming inverter-based resources upon receiving an indication of a frequency event occurring in the power plant. Thus, in an embodiment, the plant inertial response coordinator module 304 of the plant-level controller 302 is configured to receive an expected inertial response 314 (e.g., APinerRef), one or more limits 316, 318 from the inertial power capacity aggregator module 308 (e.g., APAggPosinerCap and APAggPosinerCap), and/or one or more signals 320 from local controllers 402 of each of the plurality of grid-forming (GFM) inverterbased resources (also referred to herein as GFM controls 402) or local controllers 404 of one or more grid-following (GFL) inverter-based resources (also referred to herein as GFL controls 404). In such embodiments, for example, the signal(s) 320 may include an online status or availability of the inverter-based resources in the power plant, an inertial power capability of the inverter-based resources in the power plant, an inertial energy content of the inverter-based resources in the power plant, and/or a possible power of the inverter-based resources in the power plant.

[0061] Using the various inputs, the plant inertial response coordinator module 304 of the plant-level controller 302 is configured to determine limits 322, 324 (e.g., APiner Max and APiner Min). Thus, as shown, the limits 322, 324 can be sent to the inertial power limit distribution module 306 of the plant-level controller 302 for determining the respective allocated inertial power limits 326, 328 (e.g., APiner Max© and APiner Min(i)) that can be distributed to the GFM controls 402 (FIG. 12), as well as the GFL controls 404. In an embodiment, for example, the respective allocated inertial power limits 326, 328 may include a maximum inertial power limit APiner Max© and a minimum inertial power limit APiner Min©.

[0062] Accordingly, the plant inertial response coordinator module 304 and the inertial power limit distribution module 306 of the plant-level controller 302 are configured to continuously determine and send the respective allocated inertial power limits 326, 328 (e.g., APiner Max© and APiner_Min©) to each of the plurality of gridforming inverter-based resources during the frequency event. In certain embodiments, for example, the plant inertial response coordinator module 304 and/or the inertial power limit distribution module 306 may continuously receive the signals(s) 338 from the GFM controls 402 and/or the GFL controls 404 and may thus continuously determine the respective allocated inertial power limits 326, 328 for the GFM controls 402 and/or the GFL controls 404 based on the signal(s) 338.

Furthermore, in certain embodiments, as an example, GFM inverter-based resources having high energy availability and low power production i.e., high generator speeds, may be prioritized with higher inertial power limits. [0063] Accordingly, in certain embodiments, the plant-level controller 302 is configured to coordinate the inertial power response of the power plant during the frequency event to satisfy one or more grid code requirements and/or the power market by allowing the GFM controls 402 to independently detect and respond rapidly to the frequency event up to the respective allocated inertial power limits. In another embodiment, if, at any time, there is a gap in the potential inertial power that can be generated or absorbed to satisfy the predefined inertial power reference specified by the grid code requirement(s) and/or the power market, the plant-level controller 302 can adjust operation in order to increase the inertial power capability of the plant by adjusting the plant reference power 332 (e.g., Pref).

[0064] Referring now particularly to FIG. 12, the distributed initial amounts of the inertial power response from to each of the plurality of grid-forming inverter-based resources (from FIG. 11) may initially serve as the respective allocated inertial power limits for the GFM inverter-based resources to constrain an amount of inertial power that can be injected to the electrical grid upon detection of the frequency event. Further, in an embodiment, the GFM controls 402 are configured to independently detect the frequency event by monitoring one or more grid feedbacks of the electrical grid. In such embodiments, for example, the grid feedback(s) may include phase angle, frequency, voltage, current, or combinations thereof. Thus, upon detection of the frequency event, the GFM controls 402 are configured to instantaneously inject a corresponding amount of the inertial power required in accordance with a frequency deviation and within the respective allocated inertial power limits 326, 328 that are continuously determined and updated as described herein. In such embodiments, for example, the GFM controls 402 can independently detect and respond rapidly to the frequency event up to the respective allocated inertial power limits 326, 328 without waiting for a signal from the plant-level controller 302.

[0065] The inverter-based resource may continuously supply its virtual inertia capability or inertial power capability back to the plant level control. These capabilities may be constrained due to the operating point, equipment limits, stored energy (either by batteries or stored kinetic energy in a wind turbine). For example, if the inverter-based resource is a wind turbine, its positive inertial power capability may be more constrained at low operating speeds due to relatively low stored energy in the rotating mass and operating at a point relatively close to an underspeed trip level.

[0066] Referring now to FIG. 13, a flow diagram of another embodiment of a method 500 for controlling a wind farm connected to an electrical grid according to the present disclosure is provided. In such embodiments, for example, the wind farm includes a plurality of wind turbines, with at least one of the plurality of wind turbines being a grid-forming wind turbine. In general, the method 500 is described herein with reference to the wind turbine power system 100 of FIGS. 4-9 and the control diagrams 300, 400 of FIGS. 11-12. However, it should be appreciated that the disclosed method 200 may be implemented with any other suitable power generation systems having any other suitable configurations. In addition, although FIG. 13 depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. One skilled in the art, using the disclosures provided herein, will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

[0067] As shown at (502), the method 500 includes receiving at least one of a desired transient power or energy availability for the wind farm. As shown at (504), the method 500 includes receiving at least one of a transient power or energy availability feedback from each of the plurality of wind turbines. As shown at (506), the method 500 includes receiving a steady-state power capability from each of the plurality of wind turbines. As shown at (508), the method 500 includes determining an anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines. As shown at (510), the method 500 includes determining at least one of a power limit for each of the plurality of wind turbines and a wind farm active power curtailment setpoint based on the steady-state power capability from each of the plurality of wind turbines and the anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines. As shown at (512), the method 500 includes controlling the wind farm based on the power limit to provide a desired transient power or energy to the electrical grid upon the occurrence of a grid frequency or phase angle change. [0068] Further aspects of the invention are provided by the subject matter of the following clauses:

[0069] A method of coordinating an inertial power response of a plurality of inverter-based resources in a power plant connected to an electrical grid, the method comprising: receiving, via a plant-level controller of the power plant, at least one of a desired plant inertia or desired plant inertial power capability; continuously, via the plant-level controller, determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources; and coordinating, via the plant-level controller, the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

[0070] The method of any preceding clause, further comprising distributing, via the plant-level controller, the inertial power limits to each of the plurality of gridforming inverter-based resources based on at least one of possible power of each of the plurality of grid-forming inverter-based resources or an online status or availability of one or more of the plurality of grid-forming inverter-based resources. [0071] The method of any preceding clause, wherein the inertial power limits constrain an amount of inertial power that can be injected to the electrical grid for a grid frequency event.

[0072] The method of any preceding clause, further comprising injecting, via the respective controllers of each of the plurality of inverter-based resources, a corresponding amount of the inertial power required based on a respective inertial power regulator response with the virtual inertia settings and within the inertial power limits.

[0073] The method of any preceding clause, wherein continuously determining and sending at least one of the inertial power limits, the virtual inertia settings, or the active power reference change to each of the plurality of inverter-based resources further comprises: continuously receiving one or more signals from each of the plurality of inverter-based resources; and continuously determining the inertial power limits, virtual inertia setting, or active power reference change for each of the plurality of inverter-based resources based on the one or more signals.

[0074] The method of any preceding clause, wherein the one or more signals from each of the plurality of inverter-based resources comprises at least one of an online status or availability of one or more of the plurality of inverter-based resources, an inertial power capability of one or more of the plurality of inverter-based resources, an inertial energy capability of one or more of the plurality of inverter-based resources, a maximum virtual inertia capability, or a possible power of one or more of the plurality of inverter-based resources.

[0075] The method of any preceding clause, further comprising distributing, via the plant-level controller, higher inertial power limits for grid-forming inverter-based resources with higher inertial power capability to make up for other inverter-based resources having a lower inertial power capability or being offline, thereby making a net plant inertial capability of the power plant meet the desired plant inertial power capability.

[0076] The method of any preceding clause, further comprising distributing, via the plant-level controller, a reduced active power reference for a portion of the inverter-based resources to meet the desired inertial power capability of the plant. [0077] The method of any preceding clause, further comprising notifying, via the plant-level controller, a grid operator if either the desired plant inertial power capability or the inertial power capability cannot be met by the power plant.

[0078] The method of any preceding clause, further comprising continuously determining and sending the inertial power limits to each of the plurality of inverterbased resources based on one or more grid code requirements of the electrical grid. [0079] The method of any preceding clause, wherein the inertial power limits comprise a maximum inertial power limit and a minimum inertial power limit.

[0080] The method of any preceding clause, wherein grid-forming inverter based resources of the plurality of inverter-based resources independently detect and respond rapidly to the grid frequency event up to the inertial power limits without waiting for a signal from the plant-level controller. [0081] The method of any preceding clause, wherein the inverter-based resource comprises at least one of a wind turbine power system, a solar power system, an energy storage power system, or combinations thereof.

[0082] A system for coordinating an inertial power response of a plurality of gridforming inverter-based resources in a power plant connected to an electrical grid, the system comprising: a plurality of local controllers; and a plant-level controller communicatively coupled to the plurality of local controllers, the plant-level controller comprising at least one processor, the at least one processor configured to perform a plurality of operations, the plurality of operations comprising: receiving at least one of a desired plant inertia or desired plant inertial power capability; continuously determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources; and coordinating the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

[0083] The system of any preceding clause, wherein the plurality of operations further comprise distributing the inertial power limits to each of the plurality of gridforming inverter-based resources based on at least one of possible power of each of the plurality of grid-forming inverter-based resources or an online status or availability of one or more of the plurality of grid-forming inverter-based resources. [0084] The system of any preceding clause, wherein the inertial power limits constrain an amount of inertial power that can be injected to the electrical grid for a grid frequency event.

[0085] The system of any preceding clause, wherein the plurality of operations further comprise injecting, via the respective controllers of each of the plurality of inverter-based resources, a corresponding amount of the inertial power required based on a respective inertial power regulator response with the virtual inertia settings and within the inertial power limits.

[0086] The system of any preceding clause, wherein continuously determining and sending at least one of the inertial power limits, the virtual inertia settings, or the active power reference change to each of the plurality of inverter-based resources further comprises: continuously receiving one or more signals from each of the plurality of inverter-based resources; and continuously determining the inertial power limits for each of the plurality of inverter-based resources based on the one or more signals.

[0087] The system of any preceding clause, wherein the one or more signals from each of the plurality of inverter-based resources comprises at least one of an online status or availability of one or more of the plurality of inverter-based resources, an inertial power capability of one or more of the plurality of inverter-based resources, an inertial energy content of one or more of the plurality of inverter-based resources, or a possible power of one or more of the plurality of inverter-based resources.

[0088] A method for controlling a wind farm connected to an electrical grid, the wind farm having a plurality of wind turbines, with at least one of the plurality of wind turbines being a grid-forming wind turbine, the method comprising: receiving at least one of a desired transient power or energy availability for the wind farm; receiving at least one of a transient power or energy availability feedback from each of the plurality of wind turbines; receiving a steady-state power capability from each of the plurality of wind turbines; determining an anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines; determining at least one of a power limit for each of the plurality of wind turbines and a wind farm active power curtailment setpoint based on the steady-state power capability from each of the plurality of wind turbines and the anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines; and controlling the wind farm based on the power limit to provide a desired transient power or energy to the electrical grid upon occurrence of a grid frequency or phase angle change.

[0089] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

WHAT IS CLAIMED IS:

1. A method of coordinating an inertial power response of a plurality of inverter-based resources in a power plant connected to an electrical grid, the method comprising: receiving, via a plant-level controller of the power plant, at least one of a desired plant inertia or desired plant inertial power capability; continuously, via the plant-level controller, determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources; and coordinating, via the plant-level controller, the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

2. The method of claim 1, further comprising distributing, via the plantlevel controller, the inertial power limits to each of the plurality of grid-forming inverter-based resources based on at least one of possible power of each of the plurality of grid-forming inverter-based resources or an online status or availability of one or more of the plurality of grid-forming inverter-based resources.

3. The method of claim 2, wherein the inertial power limits constrain an amount of inertial power that can be injected to the electrical grid for a grid frequency event.

4. The method of claim 1, further comprising injecting, via the respective controllers of each of the plurality of inverter-based resources, a corresponding amount of the inertial power required based on a respective inertial power regulator response with the virtual inertia settings and within the inertial power limits.

5. The method of claim 1, wherein continuously determining and sending at least one of the inertial power limits, the virtual inertia settings, or the active power reference change to each of the plurality of inverter-based resources further comprises: continuously receiving one or more signals from each of the plurality of inverter-based resources; and continuously determining the inertial power limits, virtual inertia setting, or active power reference change for each of the plurality of inverter-based resources based on the one or more signals.

6. The method of claim 5, wherein the one or more signals from each of the plurality of inverter-based resources comprises at least one of an online status or availability of one or more of the plurality of inverter-based resources, an inertial power capability of one or more of the plurality of inverter-based resources, an inertial energy capability of one or more of the plurality of inverter-based resources, a maximum virtual inertia capability, or a possible power of one or more of the plurality of inverter-based resources.

7. The method of claim 5, further comprising distributing, via the plantlevel controller, higher inertial power limits for grid-forming inverter-based resources with higher inertial power capability to make up for other inverter-based resources having a lower inertial power capability or being offline, thereby making a net plant inertial capability of the power plant meet the desired plant inertial power capability.

8. The method of claim 5, further comprising distributing, via the plantlevel controller, a reduced active power reference for a portion of the inverter-based resources to meet the desired inertial power capability of the plant.

9. The method of claim 5, further comprising notifying, via the plantlevel controller, a grid operator if either the desired plant inertial power capability or the inertial power capability cannot be met by the power plant.

10. The method of claim 1, further comprising continuously determining and sending the inertial power limits to each of the plurality of inverter-based resources based on one or more grid code requirements of the electrical grid.

11. The method of claim 1 , wherein the inertial power limits comprise a maximum inertial power limit and a minimum inertial power limit.

12. The method of claim 1, wherein grid-forming inverter based resources of the plurality of inverter-based resources independently detect and respond rapidly to the grid frequency event up to the inertial power limits without waiting for a signal from the plant-level controller.

13. The method of claim 1, wherein the inverter-based resource comprises at least one of a wind turbine power system, a solar power system, an energy storage power system, or combinations thereof.

14. A system for coordinating an inertial power response of a plurality of grid-forming inverter-based resources in a power plant connected to an electrical grid, the system comprising: a plurality of local controllers; and a plant-level controller communicatively coupled to the plurality of local controllers, the plant-level controller comprising at least one processor, the at least one processor configured to perform a plurality of operations, the plurality of operations comprising: receiving at least one of a desired plant inertia or desired plant inertial power capability; continuously determining and sending at least one of inertial power limits, virtual inertia settings, or an active power reference change to each of the plurality of inverter-based resources; and coordinating the inertial power response of the power plant to satisfy at least one of the desired plant inertia or the desired plant inertial power capability by allowing respective controllers of each of the plurality of inverter-based resources to independently respond to a grid frequency event up to the inertial power limits.

15. The system of claim 14, wherein the plurality of operations further comprise distributing the inertial power limits to each of the plurality of grid-forming inverter-based resources based on at least one of possible power of each of the plurality of grid-forming inverter-based resources or an online status or availability of one or more of the plurality of grid-forming inverter-based resources.

16. The system of claim 15, wherein the inertial power limits constrain an amount of inertial power that can be injected to the electrical grid for a grid frequency event.

17. The system of claim 14, wherein the plurality of operations further comprise injecting, via the respective controllers of each of the plurality of inverterbased resources, a corresponding amount of the inertial power required based on a respective inertial power regulator response with the virtual inertia settings and within the inertial power limits.

18. The system of claim 14, wherein continuously determining and sending at least one of the inertial power limits, the virtual inertia settings, or the active power reference change to each of the plurality of inverter-based resources further comprises: continuously receiving one or more signals from each of the plurality of inverter-based resources; and continuously determining the inertial power limits for each of the plurality of inverter-based resources based on the one or more signals.

19. The system of claim 18, wherein the one or more signals from each of the plurality of inverter-based resources comprises at least one of an online status or availability of one or more of the plurality of inverter-based resources, an inertial power capability of one or more of the plurality of inverter-based resources, an inertial energy content of one or more of the plurality of inverter-based resources, or a possible power of one or more of the plurality of inverter-based resources.

20. A method for controlling a wind farm connected to an electrical grid, the wind farm having a plurality of wind turbines, with at least one of the plurality of wind turbines being a grid-forming wind turbine, the method comprising: receiving at least one of a desired transient power or energy availability for the wind farm; receiving at least one of a transient power or energy availability feedback from each of the plurality of wind turbines; receiving a steady-state power capability from each of the plurality of wind turbines; determining an anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines; determining at least one of a power limit for each of the plurality of wind turbines and a wind farm active power curtailment setpoint based on the steady-state power capability from each of the plurality of wind turbines and the anticipated portion of the desired transient power or energy availability for the wind farm to be satisfied by each of the plurality of wind turbines based on the transient power or energy availability feedback from each of the plurality of wind turbines; and controlling the wind farm based on the power limit to provide a desired transient power or energy to the electrical grid upon occurrence of a grid frequency or phase angle change.