Black start of a wind power plant

Abstract

A method of performing black start in a wind power plant (100) comprising a main black start enabled wind turbine (T1), at least one auxiliary black start enabled wind turbine (T2, T3) and a wind power plant grid (120, 122) interconnecting at least a part of the wind turbines (110, 114) in the wind power plant (100), the method comprising (a) starting the main black start enabled wind turbine (T1) in a black start mode to supply voltage to the wind power plant grid (120, 122), (b) monitoring an electrical parameter value in the wind power plant grid (120, 122) at the at least one auxiliary black start enabled wind turbine (T2, T3), and (c) starting the at least one auxiliary black start enabled wind turbine (T2, T3) in a black start mode to supply voltage to the wind power plant grid (120, 122) when the monitored electrical parameter value fulfils a predetermined condition. A corresponding wind power plant (100) is also described.

Description

Technical Field

[0001] This invention relates to the field of wind power plants, and more specifically to a method for performing black start in a wind power plant. Furthermore, this invention relates to a wind power plant with black start capability. Background Technology

[0002] To date, wind farms have neither been required nor have been capable of participating in black starts and system recovery. As wind farms become increasingly important in electricity production, their black start capabilities could become beneficial in assisting with public grid black starts and in starting wind farms without external power.

[0003] When starting a wind farm without connection to an external power system, a diesel generator is typically introduced and connected to the individual wind turbine or substation. This is both cumbersome and expensive, especially when operating offshore equipment.

[0004] Another obstacle is that larger wind farms will require multiple wind turbines to help power the wind farm network. It is undesirable to keep the wind farm voltage outside its nominal range for extended periods, as the electrical components within the wind farm are not designed for such operation. This means that the participating wind turbines must start in a coordinated manner so that they can collectively power the wind farm network. However, when the wind farm experiences a power outage, if the communication network between the wind turbines is daisy-chained, it cannot be assumed that communication between the wind turbines is operational unless all the wind turbines in the daisy chain have operational IT equipment (e.g., switches) powered via a power source such as a UPS. That is, it cannot be assumed that black starts can be coordinated from a central SCADA system. Even where communication is available, it is advantageous to have a setup that does not rely on communication for time-critical information.

[0005] Therefore, it may be necessary to black-start wind power plants in a simple, coordinated, safe and reliable manner. Summary of the Invention

[0006] This need can be met by the subject matter of the independent claims. Advantageous embodiments of the invention are set forth in the dependent claims.

[0007] According to a first aspect of the invention, a method for performing a black start in a wind power plant is provided, the wind power plant including a primary black start wind turbine, at least one auxiliary black start wind turbine, and a wind power plant grid interconnecting at least a portion of the wind turbines in the wind power plant. The method includes (a) starting the primary black start wind turbine in a black start mode to supply voltage to the wind power plant grid, (b) monitoring electrical parameter values ​​in the wind power plant grid at the at least one auxiliary black start wind turbine, and (c) starting the at least one auxiliary black start wind turbine in a black start mode to supply voltage to the wind power plant grid when the monitored electrical parameter values ​​meet predetermined conditions.

[0008] This aspect of the invention is based on the idea that a primary black-start wind turbine begins operation in black-start mode, while at least one secondary black-start wind turbine monitors electrical parameters in the wind power plant grid. When the monitored electrical parameters meet predetermined conditions, the secondary black-start wind turbine also begins operation in black-start mode. In other words, once the monitored electrical parameters meet the predetermined conditions, the at least one secondary black-start wind turbine, in conjunction with the primary black-start wind turbine, supplies voltage to the wind power plant grid. Therefore, centralized control of the secondary black-start wind turbines is unnecessary. By carefully selecting the predetermined conditions, it can be ensured that the secondary black-start wind turbines work in conjunction with the primary black-start wind turbine in a way that optimizes the overall black-start process, particularly enabling smooth and rapid power-on of the wind power plant grid with minimal risk of damage to the electrical components of the wind turbines and the grid.

[0009] It should be noted that black start can be applied to a subset of wind power plant equipment, such as a single or multiple radial systems, the entire wind power plant network, or it can cover both the wind power plant network and a portion of the external transmission system.

[0010] In this context, the term "black-start enabled wind turbine" can specifically refer to a wind turbine capable of operating (at least for a specific period of time) without external power (e.g., in the event of a public grid failure or when the wind turbine (potentially part of a wind farm with multiple turbines) is disconnected from the public grid). Black-start enabled wind turbines can particularly have their own auxiliary generator (such as a diesel generator, solar panels, or any other type of generator) and / or energy storage devices (such as batteries or capacitor banks, uninterruptible power supplies, UPS, etc.) capable of providing sufficient power to operate the wind turbine independently for some time.

[0011] In this context, the term "black start mode" can specifically refer to the operating mode in which a wind turbine operates to supply power to the wind farm's grid without external power.

[0012] In this context, the term "wind farm grid" can specifically refer to the electrical network that interconnects multiple or all wind turbines in a wind farm. In some cases, a wind farm may include multiple grids that are interconnected in sequence and thus form various segments of the network structure within the wind farm. In this context, a "wind farm grid" interconnects at least the main and auxiliary wind turbines that enable black start.

[0013] According to an embodiment of the present invention, the electrical parameter value is the voltage level in the wind power plant grid, and a predetermined condition is met when the voltage level is higher than a predetermined voltage threshold.

[0014] In other words, the grid voltage of the wind farm is monitored by at least one auxiliary black-start wind turbine and compared with a predetermined voltage threshold to determine when the voltage threshold is exceeded. Thus, when the grid voltage rises above the predetermined voltage threshold, particularly because the primary black-start wind turbine (and possibly other second black-start wind turbines) supplies power to the wind farm grid, the at least one auxiliary black-start wind turbine begins to operate in black-start mode to also supply power to the wind farm grid.

[0015] According to another embodiment of the present invention, the electrical parameter value is the voltage frequency in the wind power plant grid, and the predetermined condition is satisfied when the voltage frequency is higher or lower than a predetermined frequency threshold.

[0016] In other words, the wind farm grid frequency is monitored by the at least one auxiliary black-start wind turbine and compared with a predetermined frequency threshold to determine when the actual wind farm grid frequency is above or below the threshold. Thus, when the wind farm grid frequency rises or falls to a level above or below the predetermined frequency threshold, particularly because the primary black-start wind turbine (and possibly other second black-start wind turbines) supplies power to the wind farm grid, the at least one auxiliary black-start wind turbine begins operating in black-start mode to also supply power to the wind farm grid.

[0017] According to another embodiment of the invention, the electrical parameter value is a code modulated onto the mains voltage, and wherein a predetermined condition is satisfied when the code corresponds to a predetermined code.

[0018] In other words, the at least one wind turbine that assists in enabling black start monitors whether a code corresponding to a predetermined code (particularly a predetermined code unique to the at least one wind turbine that assists in enabling black start) is modulated onto the grid voltage. If this is the case, the at least one wind turbine that assists in enabling black start begins to operate in black start mode so as to also supply power to the wind farm grid.

[0019] According to another embodiment of the present invention, the code is modulated onto the grid voltage when the wind turbine that is enabled for black start has been operating in black start mode for a predetermined period of time and / or when the voltage level in the wind power plant grid reaches a predetermined voltage level and / or when the frequency of the wind power plant grid is higher or lower than a predetermined frequency value and / or when the wind turbine that is enabled for black start has used a predetermined amount of its capacity (e.g., current, reactive power and / or active power).

[0020] In other words, the code is modulated into the grid voltage when a predetermined time period has elapsed since the wind turbine that initiated black start operation began operating in black start mode, and / or when the grid voltage of the wind power plant reaches a predetermined voltage level, and / or when the wind power plant frequency rises above a predetermined frequency value or falls below a predetermined frequency value, and / or when the wind turbine that initiated black start operation has used its predetermined amount of capacity (e.g., current, reactive power, and / or active power).

[0021] The code can preferably be modulated onto the grid voltage by a wind turbine that is enabled by a black start.

[0022] According to another embodiment of the invention, the at least one wind turbine with assisted black start includes a plurality of wind turbines with assisted black start, and the predetermined condition is individual for each wind turbine with assisted black start.

[0023] In other words, a wind farm includes multiple wind turbines that assist in black start, and each of these multiple black start-enabled wind turbines monitors electrical parameter values ​​in the wind farm's grid and determines whether predetermined conditions for the turbine are met individually. Thus, when the corresponding individual conditions are met, each wind turbine assisting in black start begins to supply power to the wind farm's grid individually to aid in black start.

[0024] According to another embodiment of the invention, the predetermined conditions are different for each wind turbine that is assisted in enabling black start.

[0025] By applying different predetermined conditions to each wind turbine that assists in black-starting, these turbines will begin to assist in black-starting one after another. This can be advantageous because the voltage in the wind farm grid can increase in a stepped manner as the number of active wind turbines assisting in black-starting increases steadily, thereby counteracting the increased reactive load on the wind farm grid.

[0026] According to another embodiment of the invention, the predetermined conditions are the same for each wind turbine that is assisted in enabling black start.

[0027] In this scenario, all auxiliary black-start wind turbines will essentially work in conjunction with the primary black-start wind turbines. This could be beneficial in terms of rapidly increasing grid voltage at wind farms and simplifying the configuration of black-start wind turbines.

[0028] According to another embodiment of the present invention, the predetermined condition is a first predetermined condition for a first group of wind turbines assisted in black start, and wherein the predetermined condition is a second predetermined condition for a second group of wind turbines assisted in black start.

[0029] By adding auxiliary black-start wind turbines in groups, a rapid and stable increase in grid voltage for wind power plants can be achieved.

[0030] According to another embodiment of the invention, the main-enabled black-start wind turbine is started in response to receiving a black-start initiation signal at the main-enabled black-start wind turbine.

[0031] The black start initiation signal can be transmitted by the wind farm controller via the normal wind farm communication network (if this is operational prior to the black start) or via a separate communication network or connection (such as a dedicated wired or wireless communication channel). Specifically, for onshore wind farms, the black start can also be initiated via local control of the first black-start wind turbine, for example by an operator pressing a corresponding button inside or near the main black-start wind turbine. However, the black start initiation signal can optionally be transmitted from another unit (such as the public grid controller).

[0032] According to another embodiment of the present invention, the method further includes: operating the at least one auxiliary black-start wind turbine in a black-start standby mode before starting the pre-selected black-start enabled wind turbine in black-start mode.

[0033] In other words, the at least one auxiliary black-start wind turbine operates in a black-start standby mode, which allows it to enter black-start mode when it detects that the monitored electrical parameter values ​​meet the predetermined conditions. In black-start standby mode, the blades of the at least one auxiliary black-start wind turbine rotate, the converter is energized, the circuit breaker is closed, and the control system is powered on and operational.

[0034] By operating the at least one auxiliary black-start enabled wind turbine in black-start standby mode, it is ensured that it can switch to black-start mode with minimal delay when the monitored electrical parameter values ​​are determined to meet the predetermined conditions.

[0035] According to another embodiment of the present invention, when a black start initiation signal is received at the at least one wind turbine with auxiliary black start enabled, operation of the at least one wind turbine with auxiliary black start enabled in black start standby mode is initiated.

[0036] In other words, just like the primary black-start wind turbine, the at least one secondary black-start wind turbine receives the black-start initiation signal discussed above and uses this signal as a trigger to enter black-start standby mode. The primary black-start wind turbine can also be started in black-start standby mode before entering black-start operation mode. As discussed above in conjunction with the primary black-start wind turbine, the black-start initiation signal can also correspond to local control of the at least one secondary black-start wind turbine, for example, by an operator pressing a corresponding button inside or near the at least one secondary black-start wind turbine.

[0037] According to a second aspect of the invention, a wind power plant is provided, comprising: (a) a primary black-start wind turbine, (b) at least one auxiliary black-start wind turbine, and (c) a wind power plant grid interconnecting at least a portion of the wind turbines in the wind power plant. The primary black-start wind turbine is configured to begin operation in a black-start mode to supply voltage to the wind power plant grid. The at least one auxiliary black-start wind turbine is configured to monitor electrical parameter values ​​in the wind power plant grid and begin operation in a black-start mode to supply voltage to the wind power plant grid when the monitored electrical parameter values ​​meet predetermined conditions.

[0038] This aspect of the invention is essentially based on the same idea as the first aspect described above. That is, the at least one auxiliary black-start wind turbine is configured to, in conjunction with the primary black-start wind turbine, supply voltage to the wind farm grid once the monitored electrical parameter values ​​meet predetermined conditions. Therefore, centralized control of the auxiliary black-start wind turbine is unnecessary. By carefully selecting the predetermined conditions, it can be ensured that the auxiliary black-start wind turbine works in conjunction with the primary black-start wind turbine in a manner that optimizes the overall black-start process, particularly enabling smooth and rapid power-on of the wind farm grid with minimal risk of damage to the electrical components of the wind turbines and the wind farm grid.

[0039] According to another embodiment of the invention, the wind power plant also includes at least one conventional wind turbine that does not enable black start.

[0040] Modern wind farms comprise dozens or even hundreds of individual wind turbines. In many cases, conventional wind turbines may account for 85% to 95% of the total number of wind turbines in a wind farm, while black-start wind turbines may account for 5% to 15%. In other words, a wind farm with 100 wind turbines may include approximately 90 conventional wind turbines and approximately 10 black-start wind turbines.

[0041] According to another embodiment of the invention, the wind turbine further includes a controller configured to transmit a black-start initiation signal to the primary black-start wind turbine and / or to the at least one auxiliary black-start wind turbine.

[0042] The black-start initiation signal enables the primary black-start wind turbine and / or the at least one auxiliary black-start wind turbine to enter a black-start standby mode. In this mode, the blades of the corresponding wind turbine rotate, the converter is energized, the circuit breaker closes, and the control system is powered on and operational. Furthermore, in response to receiving the black-start initiation signal, the primary black-start wind turbine can enter a black-start mode, possibly with a short delay allowing the at least one auxiliary black-start wind turbine to enter a black-start standby mode.

[0043] The black start initiation signal can be transmitted via the normal wind farm communication network (if this is operational before black start) or via a separate communication network or connection (such as a dedicated wired or wireless communication channel). Specifically, for onshore wind farms, the black start initiation signal can also be given via local control at the wind turbine that initiates black start, for example by an operator pressing a corresponding button inside or near the wind turbine that initiates black start.

[0044] Note that embodiments of the invention have been described with reference to different subjects. Specifically, some embodiments have been described with reference to method type claims, while others have been described with reference to device type claims. However, those skilled in the art will understand from the above and below description that, unless otherwise stated, any combination of features relating to different subjects, particularly combinations of features from method type claims and device type claims, is also part of this disclosure, in addition to any combination of features belonging to one type of subject matter.

[0045] The above and other aspects of the invention will be apparent from the examples of the embodiments described below, and will be explained with reference to these examples. The invention will now be described in more detail with reference to examples of embodiments. However, it is clearly indicated that the invention is not limited to the exemplary embodiments described. Attached Figure Description

[0046] Figure 1 The illustration shows a hybrid wind power plant that includes conventional wind turbines and wind turbines that enable black start.

[0047] Figure 2 A flowchart of a method for performing a black start in a wind power plant according to an embodiment is shown.

[0048] Figure 3 A timing diagram of control signals for operating a wind turbine in a wind power plant that enables black start during black start, according to an embodiment, is shown. Detailed Implementation

[0049] The illustrations in the accompanying drawings are schematic. It should be noted that in different drawings, similar or identical elements are provided with the same reference numerals or reference numerals that differ only in the first digit.

[0050] Figure 1A wind power plant 100 is shown, comprising a mix of conventional wind turbines 114 and black-start enabled wind turbines 110. The wind turbines 110 and 114 are arranged in a row and interconnected by a cable 122 connected to a common feeder 120, which is connected to a public power grid 160 via a main circuit breaker switch 140 and a transformer 150. The common feeder 120 and cable 122 form the wind power plant's power grid. Each black-start enabled wind turbine 110 is connected to its own dedicated generator / storage unit 112, which is configured to supply auxiliary power to the black-start enabled wind turbine 110 when the wind power plant's power grids 120 and 122 are interrupted. The wind farm 100 also includes a wind farm controller 130, which is configured to receive internal inputs 132 from a sensor device 142 on the wind farm side of the main circuit breaker switch 140 and another sensor device 144 on the grid side of the main circuit breaker switch 140. Measurements on both sides of the wind farm circuit breaker are optional features, but enable the wind farm controller 130 to resynchronize the wind farm and connect it to the public grid 160 when this portion of the network is energized. The internal inputs 132 of the controller 130 may include measurements of voltage frequency and magnitude on both the wind farm side and the public grid side of the main circuit breaker switch 140. Additionally, the internal inputs 132 may include the state of the main circuit breaker switch 140. The controller 130 is also configured to receive external inputs 134, for example, from a public grid operator (not shown). The controller 130 is connected to a wind farm communication network 136, which (at least during normal operation) allows the controller 130 to communicate with each individual wind turbine 110, 114 in the wind farm 100.

[0051] The wind turbine 110 with black start enabled can operate in black start mode to generate and provide power to supply power to the wind farm grids 120 and 122 in the event of a power outage in which power cannot be obtained from the public grid 160.

[0052] Figure 2 An example of a wind power plant 100 (see embodiment) is shown. Figure 1 The flowchart of the black start method 200 is shown. Here, one of the wind turbines 110 that enable black start is pre-selected as the main wind turbine T1 that enables black start, and the remaining wind turbines 110 that enable black start are pre-selected as auxiliary wind turbines T2 and T3 that enable black start.

[0053] Method 200 begins at 210, initiating the primary black-start wind turbine T1 in black-start mode to supply voltage to the wind farm grid, thereby increasing the voltage in the wind farm grid. This can occur in response to receiving a black-start initiation signal at the primary black-start wind turbine T1 via an operable portion of communication network 136 or via a dedicated communication channel (not shown).

[0054] At 220, the at least one auxiliary-enabled black-start wind turbine ( Figure 1 The diagram illustrates two auxiliary black-start wind turbines (T2 and T3) monitoring electrical parameters in the wind power plant's grid, such as voltage levels, frequency, or codes modulated onto the voltage. Each of the auxiliary black-start wind turbines T2 and T3 can operate in black-start standby mode, where the rotor rotates and the converter is energized. The auxiliary black-start wind turbines T2 and T3 can begin operating in black-start standby mode in response to receiving the aforementioned black-start initiation signal.

[0055] At point 230, when the monitored electrical parameter values ​​meet predetermined conditions for each of the auxiliary black-start wind turbines T2 and T3, the at least one auxiliary black-start wind turbine T2 or T3 is started in black-start mode to supply voltage to the wind farm grid. For example, the predetermined conditions can be met when the voltage level in the wind farm grids 120 and 122 is higher than a predetermined voltage threshold, or when the voltage frequency in the wind farm grid is higher or lower than a predetermined frequency threshold, or when the code modulated onto the grid voltage is determined to correspond to a predetermined code. The predetermined conditions can be different or the same for each of the auxiliary black-start wind turbines T2 and T3. Alternatively, the predetermined conditions can be a first predetermined condition for a first group of auxiliary black-start wind turbines 110, and a second predetermined condition for a second group of auxiliary black-start wind turbines 110.

[0056] In short, the above process causes the primary black-start wind turbine T1 to begin supplying power to the wind farm grids 120 and 122, and causes the auxiliary black-start wind turbines T2 and T3 to join the primary black-start wind turbine T1 once their respective conditions are met (i.e., one after another, all substantially simultaneously, or in groups). The trigger for the auxiliary black-start wind turbines T2 and T3 to begin operating in black-start mode is a separate condition related to electrical parameter values ​​in the wind farm grid. Therefore, no active interaction from the power plant controller 130 or any other control unit is required for the auxiliary black-start wind turbines T2 and T3 to perform the wind farm black-start 100 together with the primary black-start wind turbine T1. Once the primary black-start wind turbine T1 has started in black-start mode, the other (auxiliary) black-start wind turbines T2 and T3 will immediately join the primary black-start wind turbine T1 when their monitoring displays meet the corresponding conditions.

[0057] Figure 3 A timing diagram of control signals for operating a wind turbine in a wind power plant to enable black start during black start, according to an embodiment, is shown. More specifically, Figure 3 A graph 310 is shown, illustrating the wind farm grid voltage V as a function of time, the control signal 321 for the primary black-start wind turbine T1, the control signal 322 for the first auxiliary black-start wind turbine T2, and the control signal 323 for the third auxiliary black-start wind turbine T3. In this embodiment, the wind farm grid voltage V is monitored and used to determine when the auxiliary black-start wind turbines T2 and T3 begin operating in black-start mode. At time t = t1, when the corresponding control signal 321 turns ON, the primary black-start wind turbine T1 begins operating in black-start mode. This causes the wind farm grid voltage V to increase along a first ramp segment 311. When the wind farm grid voltage V reaches a first threshold V at time t = t2... thres1 At that time, the first auxiliary wind turbine T2, which enables black start, determines that its predetermined conditions have been met and therefore switches to black start mode by switching its corresponding control signal 322 to ON. The wind power plant voltage continues to increase along the second ramp section 312. When the wind power plant grid voltage V reaches the second threshold V at time t = t3... thres2 At that time, the second auxiliary wind turbine T3, which enables black start, determines that its predetermined conditions have been met and therefore switches to black start mode by switching its corresponding control signal 323 to ON. Then, the wind power plant voltage V continues to increase along the third ramp segment 313. At time t = t4, the wind power plant grid voltage V reaches level V. minV min This is the lowest voltage at which the entire wind power plant can operate safely without the risk of damaging ordinary wind turbines. At time t = t5, the grid voltage V at the wind power plant reaches the target level V. target V target This is the expected voltage level in the wind farm's grid during normal operation. This level is maintained along section 314, and the wind farm 100 can now (re)connect to the public grid 160 and, if necessary, help restore the public grid voltage. Alternatively, the wind farm operates in islanded mode as a means of supplying power to islanded electrical loads, which can be wind turbines and substation auxiliary loads, and may also include dedicated customers such as electrolysis plants.

[0058] Energizing, i.e., from 0% to V min The complete voltage ramp must be completed quickly enough to avoid damaging electrical components; that is, t4-t1 ≤ T. Limit It is desirable to maintain a short period outside this window, for example, less than 30 to 60 seconds, to avoid the risk of prolonged operation at unverified voltage levels for electrical components, or possibly even shorter, for example, less than 5 seconds if electrical protection equipment cannot safely detect an electrical fault during a voltage ramp. This is possible with respect to the present invention, in which the auxiliary black-start wind turbines T2 and T3 automatically and jointly activate the primary black-start wind turbine based on one or more conditions related to electrical parameter values ​​monitored in the wind turbine power grids 120 and 122.

[0059] It should be noted that the term "comprising" does not exclude other elements or steps, and the use of the article "a" or "an" does not exclude multiple. Elements described in conjunction with different embodiments may also be combined. It should also be noted that the reference numerals in the claims should not be construed as limiting the scope of the claims.

Claims

1. A method for performing a black start in a wind power plant (100), the wind power plant (100) including a primary black start wind turbine (T1), at least one auxiliary black start wind turbine (T2, T3), and a wind power plant grid (120, 122) interconnecting at least a portion of the wind turbines (110, 114) in the wind power plant (100), the method comprising: The main black-start wind turbine (T1) is started in black-start mode to supply voltage to the wind power plant grid (120, 122). Electrical parameter values ​​in the wind power plant grid (120, 122) are monitored at at least one wind turbine (T2, T3) that has assisted black start activation. When the monitored electrical parameter values ​​meet predetermined conditions, the at least one auxiliary black-start wind turbine (T2, T3) is started in black-start mode to supply voltage to the wind power plant grid (120, 122). Once the electrical parameter values ​​monitored at the at least one auxiliary black-start wind turbine (T2, T3) meet predetermined conditions, the at least one auxiliary black-start wind turbine, together with the main black-start wind turbine, supplies voltage to the wind power plant grid.

2. The method according to claim 1, wherein, The electrical parameter value is the voltage level in the wind power plant's power grid, and the predetermined condition is met when the voltage level is higher than a predetermined voltage threshold.

3. The method according to claim 1, wherein, The electrical parameter value is the voltage frequency in the power grid of the wind power plant, and the predetermined condition is met when the voltage frequency is higher or lower than a predetermined frequency threshold.

4. The method according to claim 1, wherein, The electrical parameter value is a code modulated onto the mains voltage, and wherein the predetermined condition is satisfied when the code corresponds to a predetermined code.

5. The method of claim 4, wherein the code is modulated onto the grid voltage when the main activated black-start wind turbine has been operating in black-start mode for a predetermined period of time and / or when the voltage level in the wind power plant grid reaches a predetermined voltage level and / or when the frequency of the wind power plant grid is higher or lower than a predetermined frequency value and / or when the main activated black-start wind turbine has used a predetermined amount of its capacity.

6. The method according to claim 5, wherein the predetermined capacity includes current, reactive power and / or active power.

7. The method according to any one of claims 1 to 6, wherein the at least one wind turbine that assists in enabling black start comprises a plurality of wind turbines that assist in enabling black start, and wherein the predetermined condition is individual for each of the wind turbines that assist in enabling black start.

8. The method of claim 7, wherein the predetermined conditions are different for each of the wind turbines that are assisted in enabling black start.

9. The method of claim 7, wherein the predetermined condition is the same for each of the wind turbines that are assisted in enabling black start.

10. The method according to claim 7, wherein, The predetermined condition is a first predetermined condition for a first group of wind turbines that assist in black start, and the predetermined condition is a second predetermined condition for a second group of wind turbines that assist in black start.

11. The method according to any one of claims 1 to 6, wherein, The wind turbine that is enabled for black start is started in response to receiving a black start initiation signal at the wind turbine that is enabled for black start.

12. The method of claim 11, further comprising: Before starting the pre-selected wind turbine with black start enabled in black start mode, the at least one wind turbine with auxiliary black start enabled is operated in black start standby mode.

13. The method of claim 12, wherein when the black start initiation signal is received at the at least one auxiliary black start-enabled wind turbine, operation of the at least one auxiliary black start-enabled wind turbine in black start standby mode is initiated.

14. A wind power plant (100), comprising: The main start-up wind turbine (T1) is activated by black start. At least one wind turbine (T2, T3) that enables black start, and The wind power plant grid (120, 122) interconnects at least a portion of the wind turbines (110, 114) in the wind power plant (100). The primary black-start wind turbine (T1) is configured to start operation in black-start mode to supply voltage to the wind farm grid (120, 122), and The at least one wind turbine (T2, T3) that assists in enabling black start is configured to monitor electrical parameter values ​​in the wind power plant grid (120, 122) and start operating in black start mode to supply voltage to the wind power plant grid (120, 122) when the monitored electrical parameter values ​​meet predetermined conditions.

15. The wind power plant according to claim 14 further includes at least one conventional wind turbine (114) that does not enable black start.

16. The wind power plant according to claim 14 or 15 further includes a controller (130) configured to transmit a black start initiation signal to the primary black start-enabled wind turbine (T1) and / or to the at least one auxiliary black start-enabled wind turbine (T2, T3).

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