Method for controlling a wind power plant, computer program product, and wind power plant

Abstract

A method for controlling a wind power plant (1) comprising one or more generator devices (14) and a grid forming component (5) electrically connected to output terminals (17) of the one or more generator devices (14), the wind power plant (1) comprising a power grid and / or being electrically connected to a power grid (4), and the method comprising: a) determining (S4) a frequency deviation (ΔF) of a current frequency (F C ) of the respective power grid (4) from a nominal frequency (F N ), c) controlling (S7) a power flow in the wind power plant (1) and the grid forming component (5) based on the determined frequency deviation (ΔF) and a droop characteristic (27, 28) of the grid forming component (5) related to a current power output (PG C ) of the one or more generator devices (14). Thus, the frequency regulation of the grid can be improved.

Description

Technical Field

[0001] This invention relates to a method for controlling a wind power station, a computer program product, and a wind power station. Background Technology

[0002] During wind turbine operation, the mechanical components of the wind turbine are subjected to vibrations. For example, tower vibrations may occur. Furthermore, during wind turbine operation, the wind turbine's drivetrain, including the gearbox and / or one or more bearings and other mechanical components, may be energized to vibrate. These mechanical vibrations can lead to wear or even damage to the corresponding components.

[0003] In WO 2021 / 028198 A1, active damping control is proposed to stabilize tower or drivetrain oscillations and thus reduce loads on wind turbine components. The proposed active damping control may include measuring tower acceleration, nacelle acceleration, and / or the rotational speed of one or more components of the drivetrain. Furthermore, based on such measurements, a damping control signal (e.g., a sine curve offset) is generated and added to a power or torque reference supplied to the generator system to control the generator system. Therefore, the damping control in WO 2021 / 028198 A1 causes damping-related power output variations at the output terminals of the generator system.

[0004] US 2014 / 0316592 A1 describes a power plant controller that controls a power generation system having one or more electric generators and energy storage systems, and wherein it provides a utility grid or transmission system operator with the ability to select the droop response provided by the power generation system. Thus, the operator can request a specific generator droop response to provide appropriate frequency and grid control services. The power plant controller operates in real time to determine one or more power characteristics of the power generation system. Summary of the Invention

[0005] One object of the present invention is to provide an improved method for controlling a wind power station, and an improved wind power station.

[0006] This is especially true when wind farms are islanded or used in microgrids. In this context, a microgrid refers to any grid in which the power is small enough to be affected by oscillations from a single generator, such as a single wind turbine.

[0007] It also relates to the control of mechanical oscillations in one or more mechanical structures of one or more wind turbine units.

[0008] Therefore, a method for controlling a wind power station is provided. The wind power station includes one or more generator units and a grid forming component electrically connected to the output terminals of the one or more generator units. Furthermore, the wind power station includes and / or is electrically connected to a power grid. The method includes: a) Determine the frequency deviation between the current frequency and the nominal frequency of the corresponding power grid. c) Control the power flow in the wind power plant and grid forming components based on the determined frequency deviation and the droop characteristics of the grid forming components.

[0009] According to one embodiment, the grid forming component includes an energy storage device.

[0010] Energy storage devices include, for example, battery energy storage devices (BESS), supercapacitors, or other suitable energy storage devices.

[0011] Therefore, the present invention can relate to control based on droop characteristics, which at least include or are based on the droop characteristics of the energy storage device. Control based on droop characteristics can even be control based on the droop characteristics of the energy storage device.

[0012] In one embodiment, energy storage is associated with a single wind turbine station or shared by sub-selections of the wind turbine station. In another embodiment, energy storage is associated with the entire wind farm and therefore all wind turbines, for example, with the power fed into the utility grid.

[0013] In this context, controlling the power flow of a wind power plant and grid forming components is considered as controlling the power flow generated by generator equipment and possibly stored in a grid that electrically connects at least one generator equipment to the grid forming components. For a wind power plant comprising multiple generator equipment, the grid may also include all electrical connections between the generator equipment, in addition to the electrical connections from the generator equipment to the grid forming components.

[0014] In isolated scenarios, this method can be particularly relevant, for example, to systems with multiple generating units (such as wind farms comprising multiple wind turbines). This refers to situations where multiple generating units are permanently or temporarily electrically isolated from the main electrical grid or utility grid, but continue to generate power.

[0015] Some designs, often referred to as microgrids, achieve intentional islanding. In the event of a power outage, the microgrid controller disconnects the local circuitry from the grid via a dedicated switch and forces one or more distributed generators to power the entire local load.

[0016] In this context, a microgrid typically refers to any grid whose power is small enough to be affected by oscillations from a single generator, such as a single wind turbine. For example, during islanding or for a production plant, such as one used for hydrogen production, there might be a finite number of wind turbines connected to a finite number of loads.

[0017] Without frequency control, the balance between load and generation in islanded circuits or microgrids may be disrupted, leading to abnormal frequencies and voltages.

[0018] Furthermore, in this scenario, each generator (or wind turbine) provides a large portion of the total generated power, and therefore, a turbine's large oscillations are not balanced as they would in a main electrical grid or utility grid, where it would provide a negligible portion of the total power.

[0019] In one embodiment, the method includes controlling the power output of the grid forming component via the droop characteristics of the grid forming component to reduce frequency deviation.

[0020] Therefore, the power flow can be controlled to store or extract the required power at the frequency required to offset the frequency (or to prevent unwanted oscillation) and at the voltage / current level (amplitude), respectively.

[0021] Therefore, the method includes using grid forming components to smooth oscillations, thereby absorbing individual oscillations from generator equipment and feeding power into the system when needed.

[0022] In one embodiment, the method may further include control based on the sag characteristics of the power grid forming components, rather than on the sag characteristics of the generator equipment.

[0023] Therefore, in this embodiment, the droop characteristics of the power grid forming components replace the droop characteristics of the generator equipment, or, in the case of more than one generator equipment, replace the droop characteristics of individual generator equipment.

[0024] The frequency deviation is then corrected via grid forming components. This is particularly relevant in islanded and / or microgrid scenarios.

[0025] Therefore, in this embodiment, for example in islanded or microgrid mode, instead of operating individual generators based on their respective droop characteristics as is usually the case in normal mode, control is based on the droop characteristics of the grid forming elements, and thus only a shared droop characteristic.

[0026] Therefore, the present invention can provide the possibility of transforming into a method that operates according to any of the embodiments.

[0027] Therefore, the method according to this embodiment includes two modes. - Normal operating mode, in which at least some of the multiple generator units operate according to the respective generator unit droop characteristics, and / or use grid forming components to control the power supplied to the power grid, and - Island control mode: If the wind power station is in an island or microgrid state, the method according to the embodiment operates based on the droop characteristics of the grid forming components.

[0028] …

[0029] Therefore, during islanding situations, for example, for temporary islanding situations, the controller (e.g., wind farm controller, microgrid controller, dedicated wind turbine controller, etc.) can change from normal operating mode to islanding control mode, wherein it operates in any of the embodiments according to the invention.

[0030] The method may include the following step b) (between step a) and step c): based on the current power output (PG) of one or more generator devices C Determine the droop characteristics of the (S6) grid forming components to enable larger power output (PG) C ), which has a large gradient of drooping characteristics.

[0031] The presence of frequency events in the corresponding power grid can be detected by determining the frequency deviation between the current frequency and the nominal frequency of an islanded power grid formed by a wind power station or an external power grid connected to a wind power station.

[0032] Furthermore, by controlling the power output of the grid-forming components of a wind power plant based on a determined frequency deviation, the frequency of the corresponding power grid can be adjusted. For example, the power output of the grid-forming components can be controlled to supply additional power to the grid during low-frequency events and to extract power from the power grid during high-frequency events.

[0033] In addition to the frequency deviation of the power grid, the power output of the grid forming components is controlled based on specifically defined droop characteristics. Specifically, the droop characteristics are determined based on the current power output of one or more generator units (e.g., based on wind conditions at the wind harvesting location). Therefore, frequency regulation can be adjusted according to the power generated by the wind power station. For example, the speed at which the frequency of the power grid is adjusted by the grid forming components can be adjusted based on the power generated by the generator units of the wind power station.

[0034] By applying a droop characteristic with a large gradient (i.e., a steeper droop curve), the frequency events of the corresponding power grid can be adjusted more quickly when the power output of the generator is high.

[0035] Similarly, by applying a droop characteristic with a smaller gradient (i.e., a less steep droop curve), the frequency events of the corresponding power grid are regulated more slowly when the power output of the generator is low.

[0036] By determining (e.g., selecting) the droop characteristics of grid-forming components that allow for rapid regulation of the grid frequency, interference with other (electrical or mechanical) functions of the wind power plant can be minimized and / or avoided. Furthermore, interference with other (electrical or mechanical) functions of the wind power plant can have particularly negative effects during the high-power output phases of one or more generator units.

[0037] On the other hand, by determining (e.g., selecting) the droop characteristics of the grid forming components that allow for slow adjustment of the grid frequency, wear on the grid forming components can be reduced, and / or their lifespan increased.

[0038] For example, rapid grid frequency regulation may be advantageous during high-power output phases of one or more generator units in a wind power plant. Specifically, during high-power output phases of one or more generator units (e.g., during strong winds), mechanical oscillations of the mechanical structures (e.g., towers, drivetrains) of the wind turbine unit at the wind power plant may be significant. Therefore, active oscillation damping for mechanical oscillations may be required during this phase, as described, for example, in WO2021 / 028198 A1. This active damping control stabilizes tower oscillations and / or drivetrain oscillations by adding a varying offset (e.g., a sinusoidal offset) to the power or torque reference supplied to one or more generator units. This causes damping-related power output variations at the output terminals of one or more generator units. Rapid frequency regulation is advantageous to minimize disturbances from mechanical oscillation damping and frequency regulation.

[0039] A wind power plant includes, for example, one or more wind turbine units. A wind turbine unit is equipment used to convert the kinetic energy of wind into electrical energy (electric power). A wind turbine unit includes, for example, a rotor, a nacelle, and a tower. The rotor has one or more blades, each connected to a hub. The nacelle includes generator equipment. The tower holds the nacelle at its top. The tower of the wind turbine can be connected to the base of the wind turbine, such as a concrete foundation in the seabed or a monopile, via transition pieces.

[0040] One or more blades can be rotatably connected to the hub, for example, via a pitch bearing, to adjust the pitch angle of the one or more blades.

[0041] The rotor hub is mechanically connected to a rotating shaft (e.g., a main shaft) supported by one or more bearings inside the nacelle. The main shaft may be directly coupled to a generator unit for generating electrical power. Alternatively, the wind turbine unit may include a gearbox for converting the rotation of the main shaft into the rotation of a secondary shaft, which is coupled to the generator unit.

[0042] Generator equipment includes electric generators, such as permanent magnet synchronous machines, for generating electrical power. Generator equipment also includes, for example, converters for converting a variable-frequency power stream supplied by the generator into a substantially fixed-frequency power stream at the output terminals of the generator equipment.

[0043] A wind power station can be an onshore wind power station, for example, equipped with onshore wind turbines. However, a wind power station can also be an offshore wind power station, equipped with offshore wind turbines. Offshore includes marine environments as well as lakes and other open waters.

[0044] Wind power plants can, for example, form islanded power grids and / or microgrids. Islanded power grids and / or microgrids can be off-grid systems not connected to an external power grid. Islanded power grids and / or microgrids can also be systems electrically connected (e.g., very weakly) to an external power grid. If a wind power plant forms an islanded power grid and / or microgrid, this method allows for frequency regulation of this islanded power grid and / or microgrid.

[0045] Alternatively, the wind farm is electrically connected to an external power grid (also known as the main grid or public grid), and this method allows for regulation of the frequency of this external power grid. An external power grid is, for example, an interconnected network that transmits electricity from producers to consumers. An example of an external power grid is the national power grid.

[0046] The frequency of a power grid (also known as the utility frequency) is the oscillation frequency of the alternating current (AC) in the power grid. Typically, current is transmitted from generators to end users through the grid at a synchronous frequency. In most parts of the world, including Europe, the nominal frequency of the power grid is 50 Hz. In the United States and parts of Asia, the nominal frequency is 60 Hz.

[0047] For power grids (islanded grids or large national grids) to operate at a near-constant frequency, it is important for the grid's generators to remain synchronized. When the amount of electricity consumed from the grid changes, the output of the generators must be controlled to follow the load. For example, if the load increases faster than a turbine generator can respond, the generator slows down, temporarily operating at a lower frequency. If the load changes drastically, other generators in the grid may become out of sync, and widespread blackouts may occur.

[0048] Adjusting the power generation of a wind turbine is a slow process. Advantageously, grid forming components can be used to reduce or increase the load on the corresponding grid. Therefore, by applying grid forming components, faster grid frequency regulation can be provided.

[0049] The nominal frequency of the power grid is, for example, 50 Hz or 60 Hz.

[0050] The droop characteristic, particularly the droop curve. The droop characteristic is, for example, a (e.g., linear) function of the grid frequency.

[0051] Grid forming components are, in particular, units capable of feeding electrical power into the power grid. Grid forming components are, for example, units capable of reducing or increasing the load on the power grid.

[0052] Grid-forming components may be arranged, for example, away from the wind turbine units of the power station. Alternatively, grid-forming components may also be arranged, for example, in the tower of one of the (e.g., multiple) wind turbine units of the power station.

[0053] If a wind power plant includes more than one wind turbine unit and / or more than one generator unit, then only a single grid forming component may be provided in the plant, which is electrically connected to the output terminals of all the generator units in the plant.

[0054] Step c) may include generating a control signal based on the determined frequency deviation and the determined droop characteristic, and performing control based on the determined control signal. Furthermore, step c) may include feedback control and / or closed-loop control of the grid forming components (e.g., discharging and charging the grid forming components).

[0055] In several embodiments, the method may include the step of determining and / or estimating the current power output of one or more generator units based on secondary parameters. Such secondary parameters may include wind speed at one or more wind turbine units and / or other environmental conditions that affect the power generation of the wind turbine units (e.g., icy rotor blades).

[0056] Energy storage devices, for example, are discharged to regulate low-frequency events in the power grid and recharged to regulate high-frequency events in the power grid.

[0057] The storage capacity of an energy storage device depends on the size of the wind turbine, or, in the case of multiple wind turbines, on the number and size of the multiple wind turbines.

[0058] For example, the rated energy capacity is in the range of 0.5 MWh to 20 MWh, and the rated power is in the range of 0.5 MW to 50 MW.

[0059] According to another embodiment, the wind power station includes one or more wind turbine units, each wind turbine unit including one of a generator set. Furthermore, the method includes the step of receiving a value representing the current operating point of the one or more wind turbine units. Additionally, the current power output of the one or more generator sets is determined based on the received value.

[0060] The current operating point of one or more wind turbine units includes, for example, the wind speed at one or more wind turbine units.

[0061] According to another embodiment, the wind power station includes one or more wind turbine units, which include one or more mechanical structures. Additionally, the method can be used for active oscillation damping of mechanical oscillations in one or more mechanical structures of the one or more wind turbine units.

[0062] Therefore, large mechanical vibrations in the mechanical structures of one or more wind turbine units, such as the tower or drive system, can be avoided. This also prevents wear or even damage to such structures.

[0063] According to another embodiment, active oscillation damping includes: Receive oscillation data of mechanical oscillations from one or more mechanical structures of one or more wind turbine units. Damping control signals are generated based on oscillation data received from one or more wind turbine units, and Damping control is applied to one or more generator units of one or more wind turbine units based on damping control signals, thereby causing damping-related power output changes at the output terminals of one or more generator units.

[0064] For example, oscillation data can be received for each wind turbine unit. Furthermore, individual control signals can be generated for each wind turbine unit. Additionally, damping control can be implemented individually for the generator equipment of each wind turbine unit.

[0065] The droop characteristic can limit the dependence of the desired power output of the grid forming components on the frequency of the corresponding power grid.

[0066] In particular, the droop characteristic limits the dependence of the desired power output of the grid forming components on the frequency deviation of the corresponding power grid from the nominal frequency.

[0067] The droop characteristic can be determined by selecting one from a set of predetermined droop characteristics based on the current power output of one or more generator devices.

[0068] For example, different droop characteristics (e.g., different droop curves) can be predetermined for different power generation conditions (e.g., different wind conditions).

[0069] According to another embodiment, the method includes determining whether the percentage of the current power output of one or more generator devices, or at least one of them, is higher than a predetermined threshold. Furthermore, if it is determined that the percentage of the current power output of one or more generator devices is higher than the predetermined threshold, then step c) is performed (possibly after step b).

[0070] As can be seen, if the percentage of the current power output to the rated power output of a given or predefined number of generator units is higher than a predetermined threshold (such as exceeding 50%), then step b is performed.

[0071] Therefore, under conditions of high power generation (e.g., high wind conditions), it is possible to trigger a customized droop characteristic of the grid forming components based on the current power output of one or more generator units.

[0072] The predetermined thresholds are, for example, 40% or more, 50% or more, 60% or more, and / or 70% or more.

[0073] Furthermore, if it is determined that the percentage of the current power output of one or more generator devices, or at least one of them, relative to the rated power output is lower than a predetermined threshold, steps b) and c) are not performed. Instead, the power output of the grid forming component is controlled based on the frequency deviation determined in step a) and the default droop characteristics of the grid forming component.

[0074] The method may include: Receive current frequency data from the corresponding power grid, including frequency oscillations within a first frequency range, and A second frequency range is provided, which corresponds to the damping frequency range of mechanical oscillations of one or more mechanical structures of one or more wind turbine units in a wind power station.

[0075] Furthermore, if it is determined that the first frequency range at least partially overlaps with the second frequency range, then steps b) and c) are performed.

[0076] Therefore, if the frequency range of the power grid's frequency oscillations (the first frequency range) is determined to overlap at least partially with the frequency range (the second frequency range) required for damping control of mechanical oscillations in a damping mechanical structure, the droop characteristics of the power grid forming components can be adjusted. For example, the droop characteristics of the power grid forming components can be adjusted to regulate the frequency events of the power grid more quickly when the frequency ranges overlap.

[0077] The method may include, for example, determining the frequency range (first frequency range) of frequency oscillations in the received frequency data.

[0078] The method according to any of the embodiments can be used on wind power plants that form islanded power grids and / or microgrids.

[0079] According to another aspect, a computer program product is provided. This computer program product includes program code, when run on at least one computer, for performing the aforementioned methods for controlling a wind power plant.

[0080] Computer program products, such as computer program devices, can be embodied in memory cards, USB flash drives, CD-ROMs, DVDs, or files that can be downloaded from a server on a network. For example, this file can be provided by transmitting a file containing a computer program product from a wireless communication network.

[0081] According to another aspect, a wind power station is provided. The wind power station includes a power grid and / or is configured to be electrically connected to the power grid. Furthermore, the wind power station includes: One or more generator devices, A grid forming component electrically connected to the output terminals of the one or more generator units, and One or more control units, the control units being configured to be used for Determine the frequency deviation between the current frequency and the nominal frequency of the corresponding power grid, and Power flow in wind farms and grid forming components is controlled based on frequency deviation and determined droop characteristics of grid forming components related to the current power output of one or more generator units.

[0082] This method can include in After determining the frequency deviation between the current frequency and the nominal frequency of the corresponding power grid, the following steps are taken: The droop characteristics of grid forming components are determined based on the current power output of one or more generator devices, so that for larger power outputs, droop characteristics with larger gradients are applied. The power output of the grid forming components is controlled based on the determined frequency deviation and the determined droop characteristics.

[0083] For example, a corresponding entity such as one or more control units can be implemented in hardware and / or software. If the entity is implemented in hardware, it can be embodied as a device, for example, as part of a computer or processor or a system such as a computer system. If the entity is implemented in software, it can be embodied as a computer program product, function, routine, program code, or executable object.

[0084] The embodiments and features described with reference to the method of the present invention, with necessary modifications in detail, are applicable to the wind power plants of the present invention, and vice versa.

[0085] Other possible embodiments or alternative solutions of the present invention include combinations of features not expressly mentioned herein that are described above or below with reference to the embodiments. Those skilled in the art can also add individual or isolated aspects and features to the most basic form of the invention. Attached Figure Description

[0086] Further embodiments, features, and advantages of the invention will become apparent from the accompanying drawings, the following description, and the dependent claims, wherein: Figure 1 A wind power plant according to one embodiment is shown; Figure 2 A wind power plant according to another embodiment is shown; Figure 3 Show Figure 1 or Figure 2 An enlarged partial view of a wind power plant, showing a wind turbine assembly and grid forming components according to an embodiment; Figure 4 The figure illustrates an embodiment. Figure 3 The current power output of the generator equipment of the wind turbine unit; Figure 5 The figure illustrates frequency regulation for a power grid and for active damping according to an embodiment. Figure 3 The frequency range of mechanical oscillations in the mechanical structure of a wind turbine device; Figure 6 A control according to an embodiment is shown. Figure 3 The sag characteristics of the power grid forming components; and Figure 7 The illustration shows a control according to an embodiment. Figure 1 or Figure 2 The flowchart shows the method for building a wind power station.

[0087] In the accompanying drawings, unless otherwise specified, similar reference numerals denote similar or functionally equivalent elements. Detailed Implementation

[0088] Figure 1 A wind turbine power station 1 is shown, having at least one wind turbine unit 2. For example... Figure 2 As shown, the wind turbine power station 1' may also include multiple electrically interconnected wind turbine units 2'.

[0089] Wind turbine power station 1, 1' ( Figure 1 , Figure 2The components 3 and 3' (common contact point, PCC) of the power station 1 and 1' are electrically connected to the power grid 4 and 4'.

[0090] The wind turbine power stations 1 and 1' include grid forming components 5 and 5' for frequency regulation of the power grid 4 and 4'. Specifically, the grid forming components 5 and 5' are used to regulate the frequency of the current grid at the specified frequency F. C Deviation (e.g., significant deviation) from the nominal frequency F of the power grid 4', 4' N Adjust the frequency F of grid 4 and 4' in the case of (for example, 50 Hz).

[0091] The grid forming components 5, 5' include, for example, energy storage devices 6, 6', which can be discharged during low-frequency events of the grid 4, 4' and can be recharged during high-frequency events of the grid 4, 4'.

[0092] Although in the following description, grid forming components 5, 5' are used to regulate the external grid 4, 4'; in other examples, wind power stations 1, 1' can also form an islanded grid, and grid forming components 5, 5' can be used to regulate the frequency of the islanded grid.

[0093] Figure 3 Detailed views of wind power stations 1 and 1' are shown. Specifically, in... Figure 3 The image shows a detailed view of one of the wind turbine units 2 and 2'.

[0094] like Figure 3 As shown, each wind turbine unit 2, 2' includes a rotor 7 having one or more blades 8 mechanically connected to a hub 9. The rotor hub 9 is mechanically connected to a rotating shaft 10 (e.g., a main shaft 10). The drivetrain 11 of the wind turbine unit 2, 2' may optionally include a gearbox 12 for converting the rotation of the main shaft 10 into the rotation of a secondary rotating shaft 13. The rotating shafts 10, 13 are supported by one or more bearings (not shown). Furthermore, the wind turbine unit 2, 2' includes a generator unit 14 having a generator 15 for generating electrical power. The generator unit 14 may optionally include a converter 16 for converting the variable-frequency power flow delivered by the generator 15 into a substantially fixed-frequency power flow at the output terminal 17 of the generator unit 14 (e.g., the output terminal 17 of the converter 16). Thus, the generated power PG is provided at the output terminal 17 of the generator unit 14, particularly at the output terminal 20 of the wind turbine unit 2, 2'.

[0095] like Figure 3As shown, the wind turbine units 2, 2' include a nacelle 18 that houses the components 10, 12-16 of the drivetrain 11. The nacelle 18 (e.g., rotatably) is mounted at the upper end of the tower 19.

[0096] Each wind turbine unit 2, 2' may also include an active oscillation damping system 21 for damping mechanical oscillations of the mechanical structures of the wind turbine unit 2, 2' (such as the tower 19, drivetrain 11, and / or components 10, 12-16 of the drivetrain 11). The active oscillation damping system 21 includes one or more sensors 22 (e.g., accelerometers) to obtain oscillation data A of the mechanical structures 10-16, 19 of the wind turbine unit 2, 2'. Furthermore, the active oscillation damping system 21 includes a damping control unit 23 for receiving and processing the oscillation data A. The damping control unit 23 is also configured to generate a damping control signal B based on the processed oscillation data A and send the damping control signal B to the generator unit 14, for example, to the converter 16 of the generator unit 14. Based on the damping control signal B, the generator unit 14 (e.g., the converter 16) is controlled to cause a change in power output PG at the output terminal 17. For more details on the active oscillation damping system 21 and its applications, please refer to document WO 2021 / 028198 A1.

[0097] Figure 3 The diagram also shows grid forming components 5 and 5' for frequency regulation of the power grids 4 and 4'. The grid forming components 5 and 5' are electrically connected to the output terminals 17 of one or more generator units 14 of one or more wind turbine units 2 and 2'. The grid forming components 5 and 5' include energy storage devices 6 and 6' and an energy storage control unit 24 for controlling the power output PB of the energy storage devices 6 and 6'.

[0098] Figure 3 The main control unit 25 of the wind power station 1, 1' is also shown.

[0099] Figure 3 Only the functional connections (e.g., electrical connections and / or data transmission connections) between the grid forming components 5, 5' and the main control unit 25 and the wind turbine units 2, 2' and the power grid 4, 4' are shown in the figure. Their physical locations are not visible in the figure.

[0100] The grid forming components 5, 5' and / or the main control unit 25 may be arranged, for example, in the tower 19 of one of the wind turbine units 2, 2'. Alternatively, the grid forming components 5, 5' and / or the main control unit 25 may also be arranged, for example, away from (e.g., multiple) the wind turbine units 2, 2'.

[0101] In the following text, see references Figures 4 to 7Several steps are described, all of which can be included in the method for controlling wind power plants 1, 1'.

[0102] In the first step S1 of the method, the current power output PG of one or more generator devices 14 is determined. C ( Figure 3 ).

[0103] If the wind power station 1' ( Figure 2 It has multiple wind turbine units 2' and therefore multiple generator units 14 ( Figure 3 In step S1, the current power output PG of each of the plurality of generator devices 14 can be determined (e.g., individually). C .

[0104] The current power output PG of one or more generator devices 14 C For example, it is determined by the main control unit 25 of power station 1, 1'. Alternatively, the current power output PG of one or more generator units 14 C It can be determined, for example, by the energy storage control unit 24 of the grid forming components 6, 6'.

[0105] For example, each wind turbine unit 2, 2' may include one or more wind sensors 26 ( Figure 3 The main control unit 25 and / or the energy storage control unit 24 can receive the obtained value of the current wind speed V and determine the current power output PG of one or more generator units 14 (e.g., each of the one or more generator units 14) based on the received value of the current wind speed V. C .

[0106] In the second step S2 of the method, the current power output PG of one or more generator devices 14 (e.g., at least one of one or more generator devices 14) is determined. C With rated power output PG R Is the percentage higher than a predetermined threshold Th, such as Figure 4 As illustrated in the diagram. The predetermined threshold Th is, for example, 50%. However, the predetermined threshold Th can also have other values ​​besides 50%.

[0107] In an optional third step S3 of the method, active oscillation damping can be applied to the mechanical structures 10-16, 19 of the wind turbine units 2, 2'. Step S3 can, for example, only determine the current power output PG of at least one of the one or more generator units 14 in step S2. CIt is only implemented when the power output PG is above a predetermined threshold Th. C The mechanical oscillations of the mechanical structures 10 – 16, 19 of the wind turbine units 2, 2' may be small enough that active oscillation damping is not required.

[0108] In one embodiment, when the current power output PG of a given or predefined number of generator devices 14 is determined in step S2... C When the value exceeds a predetermined threshold Th, step S3 is performed. For example, this could be a majority of the generator units 14, which is at least or more than 50%, exceeding the predetermined threshold Th.

[0109] In the fourth step S4 of this method, frequency events of power grids 4 and 4' are detected. Specifically, the current frequency F of power grids 4 and 4' is determined. C With the nominal frequency F of the power grid 4, 4' N The deviation ΔF between them Figure 6 ).

[0110] For example, in step S4, the current frequency F is received, for example, by the main control unit 25 or by the energy storage control unit 24. C Frequency data D of the power grid 4' and 4' included Figure 3 Furthermore, regarding the frequency data D received, analysis is performed on the frequency events. If a frequency event is detected, the frequency deviation ΔF of that event is determined.

[0111] In the optional fifth step S5 of the method, the frequency range R1 (first frequency range R1) of the frequency oscillations included in the frequency data D is determined, see [link to relevant documentation]. Figure 5 .

[0112] Furthermore, in step S5, a second frequency range R2 is provided (e.g., determined). The second frequency range R2 corresponds to the damping frequency range used in step S3 for damping the mechanical oscillations of the mechanical structures 10-16, 19 of the wind turbine devices 2, 2'.

[0113] In addition, in step S5, it is determined whether the first frequency range R1 at least partially overlaps with the second frequency range R2.

[0114] In the sixth step S6 of the method, based on the determined current power output PG of one or more generator devices 14 C Determine the droop characteristics of power grid forming components 5 and 5' 27 and 28 ( Figure 6 ).

[0115] In the seventh step S7 of the method, based on the determined frequency deviation ΔF and the current power output (PG) of one or more generator devices (14),C The droop characteristics (27, 28) of the relevant grid forming components (5) (such as the determined (e.g., selected) droop characteristics 27, 28) are used to control the power flow in the wind power station 1 and the grid forming components 5, 5', including the power output PB and / or power input of the grid forming components 5, 5'.

[0116] Figure 6 Two different (e.g., predetermined) droop characteristics 27 and 28 (first and second droop characteristics 27 and 28) are shown for the grid forming components 5 and 5'. The corresponding droop characteristics 27 and 28 define the desired power output PB of the grid forming components 5 and 5'. D (e.g., linear) dependence of the frequency F of the power grid 4, 4'. Figure 6 The gradients 29 and 30 of the two droop characteristics 27 and 28 shown are different from each other, with the second droop characteristic 28 having a larger gradient (i.e., steeper) than the first droop characteristic 27. Therefore, applying the second droop characteristic 28 to control the power output PB of the grid forming components 5 and 5' allows for faster frequency regulation of the grid 4 and 4'.

[0117] For example, if the current frequency F of power grid 4, 4' is... C The nominal frequency F is less than 4' of the power grid. N (In the event of a low-frequency event), the grid forming components 5 and 5' will provide positive power output PB. D To adjust the power grid frequency F.

[0118] By selecting a steeper droop characteristic 28 (second droop characteristic 28), the energy storage control unit 24 of the grid forming components 5, 5' will be based on the desired power output PB. D2 Control grid forming components 5 and 5', energy storage devices 6 and 6', such as Figure 6 As illustrated in the diagram. This will result in rapid regulation of grids 4, 4'. Therefore, the frequency regulation of grids 4, 4' can keep the interference with other functions of wind power stations 1, 1' (e.g., active oscillation damping in step S3) to a minimum.

[0119] Alternatively, by selecting a less steep droop characteristic 27 (first droop characteristic 27), the energy storage control unit 24 of the grid forming components 5, 5' will be based on less than PB. D2 The desired power output PB D1 The energy storage devices 6 and 6' control the grid forming components 5 and 5'. This results in slower regulation of the grid 4 and 4'. This slower response of the grid forming components 5 and 5' helps increase the lifespan of the grid forming components 5 and 5', and especially the energy storage devices 6 and 6'.

[0120] Steps S6 and S7 may be performed only if, in step S2, it is determined that the percentage of the current power output of at least one of the one or more generator devices 14 to the rated power output is higher than a predetermined threshold Th.

[0121] Alternatively or additionally, steps S6 and S7 may be performed only if, in step S5, it is determined that the first frequency range R1 and the second frequency range R2 at least partially overlap.

[0122] In one embodiment applied to any of the preceding embodiments, the wind power plant or wind power generation plant includes a plurality of generator units 14, such as a plurality of wind turbines 2, 2'.

[0123] Although the invention has been described with reference to preferred embodiments, it will be apparent to those skilled in the art that modifications are possible in all embodiments.

Claims

1. A method for controlling a wind power station (1), the wind power station (1) comprising one or more generator units (14) and a grid forming component (5) electrically connected to the output terminals (17) of the one or more generator units (14), the wind power station (1) comprising a power grid and / or electrically connected to a power grid (4), and the method comprising: a) Determine the current frequency (F) of the corresponding power grid (4) (S4). C ) and nominal frequency (F N Frequency deviation (ΔF), c) Based on the determined frequency deviation (ΔF) and the current power output (PG) of the one or more generator devices (14) C The drooping characteristics (27, 28) of the grid forming component (5) are used to control (S7) the power flow in the wind power station (1) and the grid forming component (5), wherein the grid forming component (5) includes an energy storage device (6).

2. The method according to claim 1, wherein the method includes controlling the power output (PB) of the grid forming component (5) via the droop characteristics (27, 28) of the grid forming component (5) to reduce the frequency deviation (ΔF).

3. The method according to claim 1 or 2, wherein the control (S7) of the power flow in the wind power station (1) and the grid forming component (5) is based on the droop characteristics (27, 28) of the energy storage device (6), or the droop characteristics (27, 28) of the energy storage device (6).

4. A method for controlling a wind power station (1), wherein the method includes two modes, - Normal operating mode, wherein at least some of the multiple generator units (14) operate according to the respective generator unit droop characteristics, and / or use the grid forming component (5) to control the power supplied to the power grid, and - Island control mode, if the wind power station (1) is in an island or microgrid state, then the method according to claim 1, 2 or 3 is used, and the droop characteristics (27, 28) of the grid forming component (3) are used.

5. The method according to claim 4, wherein, When in the islanded control mode, the method includes replacing control based on the droop characteristics of the generator equipment (14) with control based on the droop characteristics (27, 28) of the grid forming component (5).

6. The method according to any one of the preceding claims, wherein The wind power station (1) includes one or more wind turbine units (2), each wind turbine unit (2) including one of the generator sets (14). The method includes receiving the value (V) of a signal representing the current operating point of the one or more wind turbine units (2), and The current power output (PG) of the one or more generator devices (14) is determined based on the received value (V). C ).

7. The method according to any one of the preceding claims, wherein The wind power station (1) includes one or more wind turbine units (2), which include one or more mechanical structures (10-16, 19), and The method is used for active oscillation damping (S3) of mechanical oscillations of one or more mechanical structures (10-16, 19) of the one or more wind turbine units (2).

8. The method according to claim 7, wherein the active oscillation damping (S3) comprises: The system receives oscillation data (A) of mechanical oscillations from one or more mechanical structures (10-16, 19) of the one or more wind turbine units (2). A damping control signal (B) is generated based on the received oscillation data (A) from the one or more wind turbine units (2), and Damping control is performed on one or more generator units (14) of the one or more wind turbine units (2) based on the damping control signal (B), thereby causing a damping-related power output change at the output terminal (17) of the one or more generator units (14).

9. The method according to any one of the preceding claims, comprising: Determine (S2) the current power output (PG) of the one or more generator devices (14) or at least one of the one or more generator devices (14). C ) and rated power output (PG) R Whether the percentage of the current power output (PG) of the one or more generator devices (14) is higher than a predetermined threshold (Th), wherein if the current power output (PG) of the one or more generator devices (14) is determined to be higher than a predetermined threshold (Th), then the current power output (PG) of the generator devices (14) is determined to be higher than a predetermined threshold (Th). C ) and rated power output (PG) R If the percentage of ) is higher than the predetermined threshold (Th), then steps b) and c) are performed.

10. The method of claim 9, wherein if the current power output (PG) of a given or predefined number of generator devices (14) is determined... C ) and rated power output (PG) R If the percentage of ) is higher than the predetermined threshold Th, then step b) is performed.

11. The method of claim 10, wherein the given number of generator devices (14) exceeds 50%.

12. The method according to any one of claims 1-11, wherein the method is used on a wind power plant forming an islanded power grid and / or microgrid.

13. A computer program product comprising program code, when run on at least one computer, for performing the method according to any one of claims 1-12.

14. A wind power station (1) comprising a power grid and / or configured to be electrically connected to a power grid (4), comprising: One or more generator units (14), A grid forming component (5) electrically connected to the output terminal (17) of the one or more generator devices (14), and One or more control units (24, 25), said control units (24, 25) being configured to be used for Determine the current frequency (F) of the corresponding power grid (4). C ) and nominal frequency (F N Frequency deviation (ΔF), as well as Based on the determined frequency deviation (ΔF) and the current power output (PG) of the one or more generator devices (14) C The droop characteristics (27, 28) of the grid forming component (5) are used to control the power flow in the wind power station (1) and the grid forming component (5), and the grid forming component (5) includes an energy storage device (6).

15. A wind power plant (1) operated by the method according to claim 14 and any one of claims 1-12.

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