Wind farm power reduction control method and device, controller and storage medium

Abstract

This disclosure provides a power reduction control method, device, controller, and storage medium for wind farms. The power reduction control method for wind farms includes: determining the total power reduction amount that needs to be adjusted for the entire wind farm; determining the single-unit power reduction amount that needs to be adjusted for each wind turbine based on the total power reduction amount, the power reduction amount of each wind turbine in the wind farm, and the distance of each wind turbine with braking resistor power reduction capability from the grid connection point; and controlling each wind turbine to perform power reduction adjustment according to the single-unit power reduction amount that needs to be adjusted for each wind turbine; wherein, the power reduction amount of wind turbines with braking resistor power reduction capability is the sum of the power reduction amount of braking resistor and the power reduction amount of non-braking resistor power reduction method, and the power reduction amount of wind turbines without braking resistor power reduction capability is the power reduction amount of non-braking resistor power reduction method.

Description

Technical Field

[0001] This disclosure generally relates to the field of wind power technology, and more specifically, to a method, apparatus, controller, and storage medium for power reduction control in wind farms. Background Technology

[0002] Figure 1 This illustrates an example of a wind farm responding to grid frequency regulation of active power. For example... Figure 1 As shown, Fn represents the grid rated frequency, P0 represents the total power value, and Pn represents the total rated power value. When the frequency of the grid connection point is within [Fd-~Fd+] (i.e., the dead zone of primary frequency regulation), the wind turbine generators (hereinafter referred to as wind turbines) in the wind farm receive active power commands from the wind farm's Energy Management System (EMS). When the frequency of the grid connection point is within [F3~Fd-] or [Fd+~F1], the wind turbines can be controlled to regulate active power using primary frequency regulation. For example, when the frequency of the grid connection point is within [Fd+~F1], the active power frequency regulation amplitude of the entire field can be 10%Pn, and the response time can be 3s. When the frequency of the grid connection point is within [F1~F2], the grid is in a severely over-frequency state, and the wind farm needs to adopt a rapid power reduction control strategy. For example, the active power frequency regulation amplitude of the entire field can be 50%Pn, and the adjustment time can be 3s. When the frequency of the grid connection point is greater than F2, the active power remains unchanged. Further changes in frequency require a further reduction in power.

[0003] When there is a severe overfrequency problem requiring rapid power reduction, if the braking resistor of the wind turbine needs to be activated to reduce power after calculation and evaluation, then the amount of power reduction required for each wind turbine needs to be allocated. However, the existing allocation method does not take into account the actual application of the wind turbine braking resistor. Summary of the Invention

[0004] Exemplary embodiments of this disclosure provide a method, apparatus, controller, and storage medium for controlling power reduction in wind farms, which can effectively solve the aforementioned problems existing in the prior art.

[0005] According to a first aspect of the present disclosure, a power reduction control method for a wind farm is provided, comprising: determining the total power reduction amount that needs to be adjusted for the entire wind farm; determining the single-unit power reduction amount that needs to be adjusted for each wind turbine based on the total power reduction amount, the power reduction amount of each wind turbine in the wind farm, and the distance of each wind turbine with braking resistor power reduction capability from the grid connection point; and controlling each wind turbine to perform power reduction adjustment according to the single-unit power reduction amount that needs to be adjusted for each wind turbine; wherein, the power reduction amount of the wind turbine with braking resistor power reduction capability is the sum of the power reduction amount of braking resistor and the power reduction amount of non-braking resistor power reduction method, and the power reduction amount of the wind turbine without braking resistor power reduction capability is the power reduction amount of non-braking resistor power reduction method.

[0006] Optionally, the step of determining the amount of power reduction per unit required for each wind turbine includes: taking the sum of the power reduction capabilities of all wind turbines with braking resistor power reduction capabilities as the total rapid power reduction capability; in response to the total power reduction being less than or equal to the total rapid power reduction capability, determining the amount of power reduction per unit required for each wind turbine with braking resistor power reduction capability based on the total power reduction, the power reduction capability of each wind turbine with braking resistor power reduction capability, and the power reduction allocation coefficient; wherein, the closer the wind turbine with braking resistor power reduction capability is to the grid connection point, the smaller the power reduction allocation coefficient.

[0007] Optionally, the step of determining the amount of single-unit power reduction that needs to be adjusted for each wind turbine further includes: in response to the overall power reduction being greater than the overall rapid power reduction amount, determining the amount of single-unit power reduction that needs to be adjusted for each wind turbine with braking resistor power reduction capability based on the overall power reduction, the power reduction amount of each wind turbine with braking resistor power reduction capability, and the power reduction allocation coefficient; after allocating the amount of single-unit power reduction to all wind turbines with braking resistor power reduction capability, determining the amount of single-unit power reduction that needs to be adjusted for each wind turbine without braking resistor power reduction capability based on the remaining unallocated overall power reduction and the power reduction amount of each wind turbine without braking resistor power reduction capability.

[0008] Optionally, the step of determining the single-unit power reduction amount for each fan with braking resistor power reduction capability includes: arranging all fans with braking resistor power reduction capability according to the power reduction amount; selecting one fan from the arranged fans in sequence each time, allocating the single-unit power reduction amount to the selected fan according to the principle that if the power reduction amount is greater than or equal to the average power reduction amount, the average power reduction amount is allocated, and if it is less than the average power reduction amount, the single-unit power reduction amount is used up; based on the power lower limit value of the selected fan, limiting the product of the single-unit power reduction amount allocated to the selected fan and the power reduction allocation coefficient of the selected fan, and using the limited value as the single-unit power reduction amount that needs to be adjusted for the selected fan.

[0009] Optionally, the method further includes: calculating the shortest duration required for the current power reduction adjustment of each wind turbine with braking resistor power reduction capability, wherein the shortest duration is the ratio of the power reduction of a single unit to the target adjustment rate of the non-braking resistor power reduction method; determining the maximum value among the shortest durations required for the current power reduction adjustment of all wind turbines with braking resistor power reduction capability; and controlling each wind turbine to end the current power reduction adjustment in response to the current power reduction adjustment duration exceeding the sum of the maximum value and the time margin.

[0010] Optionally, it also includes: after controlling each fan to end the current power reduction adjustment, controlling each fan to perform a frequency adjustment.

[0011] Optionally, it further includes: after controlling each fan to end the current power reduction adjustment, in response to the need to reactivate the braking resistor, determining whether the difference between the current time and the end time of the current power reduction adjustment exceeds the cooling time of the braking resistor; in response to the difference exceeding the cooling time of the braking resistor, allowing the braking resistor to be reactivated; in response to the difference being less than or equal to the cooling time of the braking resistor, restricting the reactivation of the braking resistor.

[0012] Optionally, the steps of controlling each wind turbine to perform power reduction adjustment according to the required reduction in single-unit power of each wind turbine include: sending the target adjustment rate of non-braking resistor power reduction mode, the target adjustment rate of grid-side power output limitation, and the required reduction in single-unit power or target power value to each wind turbine with braking resistor power reduction capability, so as to control the wind turbine to perform power reduction adjustment; and sending the target adjustment rate of non-braking resistor power reduction mode, the required reduction in single-unit power or target power value to each wind turbine without braking resistor power reduction capability, so as to control the wind turbine to perform power reduction adjustment.

[0013] According to a second aspect of the present disclosure, a power reduction control device for a wind farm is provided, comprising: a determining unit configured to determine the total power reduction amount required for wind farm adjustment; an allocating unit configured to determine the single-unit power reduction amount required for adjustment of each wind turbine based on the total power reduction amount, the power reduction amount of each wind turbine in the wind farm, and the distance of each wind turbine with braking resistor power reduction capability from the grid connection point; and a controlling unit configured to control each wind turbine to perform power reduction adjustment according to the single-unit power reduction amount required for adjustment of each wind turbine; wherein the power reduction amount of the wind turbine with braking resistor power reduction capability is the sum of the power reduction amount with braking resistor and the power reduction amount without braking resistor, and the power reduction amount of the wind turbine without braking resistor power reduction capability is the power reduction amount without braking resistor.

[0014] According to a third aspect of the present disclosure, a computer-readable storage medium storing a computer program is provided, which, when executed by a processor, causes the processor to perform the power reduction control method for a wind farm as described above.

[0015] According to a fourth aspect of the present disclosure, a controller for a wind farm is provided, comprising: a processor; and a memory storing a computer program that, when executed by the processor, causes the processor to perform the wind farm power reduction control method as described above.

[0016] According to a fifth aspect of the present disclosure, a computer program product is provided, including a computer program that, when executed by a processor, implements the power reduction control method for a wind farm as described above.

[0017] According to exemplary embodiments of the present disclosure, the wind farm power reduction control method, apparatus, controller, storage medium, and program product consider the different dependencies of wind turbine braking resistance at different distances from the grid connection point during low voltage ride-through. In order to minimize the impact of severe over-frequency rapid power reduction and low voltage ride-through (LVRT) response, it proposes to allocate the single-unit power reduction amount based on the distance of each wind turbine with braking resistance power reduction capability from the grid connection point, thereby improving the reliability of grid demand functions by differentially adjusting the wind turbine braking resistance under severe over-frequency rapid power reduction conditions.

[0018] In the following description, some aspects and / or advantages of the general concept of this disclosure will be set forth, and other aspects and / or advantages will become apparent from the following description or from practice of the general concept of this disclosure. Attached Figure Description

[0019] These and / or other aspects and advantages of this application will become clearer and more readily understood from the following detailed description of embodiments of this application taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This illustrates an example of an existing wind farm responding to grid frequency regulation power.

[0021] Figure 2 An example of collector line voltage is shown according to an exemplary embodiment of the present disclosure;

[0022] Figure 3 An example of power jump when the braking resistor function is deactivated according to an exemplary embodiment of the present disclosure is shown;

[0023] Figure 4 A flowchart illustrating a power reduction control method for a wind farm according to an exemplary embodiment of the present disclosure is shown.

[0024] Figure 5A flowchart illustrating a method for determining the amount of single-unit power reduction required for each wind turbine to have braking resistor power reduction capability, according to an exemplary embodiment of the present disclosure;

[0025] Figure 6 A flowchart illustrating a method for determining the amount of single-unit power reduction that needs to be adjusted for each wind turbine that does not have braking resistor power reduction capability, according to an exemplary embodiment of the present disclosure;

[0026] Figure 7 A flowchart illustrating a power reduction control method for a wind farm according to another exemplary embodiment of the present disclosure is shown.

[0027] Figure 8 A structural block diagram of a power reduction control device for a wind farm according to an exemplary embodiment of the present disclosure is shown. Detailed Implementation

[0028] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings, examples of which are illustrated in the drawings, wherein the same reference numerals always refer to the same parts. The embodiments will now be described with reference to the accompanying drawings in order to explain this disclosure.

[0029] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0030] It should be noted that the phrase "at least one of several items" in this disclosure refers to three parallel cases: "any one of the several items", "a combination of any number of the several items", and "all of the several items". For example, "including at least one of A and B" includes the following three parallel cases: (1) including A; (2) including B; (3) including A and B. As another example, "performing at least one of step one and step two" indicates the following three parallel cases: (1) performing step one; (2) performing step two; (3) performing both step one and step two.

[0031] Rapidly reducing the power output of a wind turbine (e.g., reducing Pn by 50% within 2 seconds) is a highly demanding operation, requiring rapid and accurate adjustments to the turbine's operating status. The following are the resources and methods that may be used to achieve rapid power reduction:

[0032] Pitch control is one of the most commonly used power regulation methods in wind turbines. By rapidly adjusting the blade pitch angle, the blade's efficiency in capturing wind energy can be changed, thereby achieving a rapid reduction in power. Under rapid power reduction conditions, the pitch control system needs to respond quickly and accurately adjust the pitch angle to the predetermined position.

[0033] Braking resistor: When a wind turbine needs to rapidly reduce its power, excess electrical energy can be consumed by engaging a braking resistor, thereby achieving the purpose of reducing power. This method is suitable for situations where a large amount of electrical energy needs to be consumed in a short period of time. For example, direct-drive wind turbines can use a Chopper device for braking, and doubly-fed wind turbines can use a Crowbar circuit for braking.

[0034] Generator control: By adjusting the generator's excitation current or speed, the generator's output power can be changed. In scenarios involving rapid power reduction, the generator control system needs to quickly adjust parameters to ensure accurate power reduction.

[0035] Yaw control: While yaw control is primarily used to maintain the wind turbine's perpendicular relationship to the wind direction to maximize wind energy capture efficiency, it can also be used in certain situations to assist in rapidly reducing power output. That is, by adjusting the turbine's yaw angle, the energy captured from the wind can be reduced, thereby lowering the turbine's output power. In scenarios requiring rapid power reduction, this method may have relatively limited effectiveness and needs to be used in conjunction with other control methods.

[0036] The following section introduces inertia control. Inertia is a crucial parameter of a power system, reflecting its ability to resist rapid frequency changes. Wind turbine inertia control aims to adjust the turbine's operating state so that it can provide inertial support to system frequency changes, similar to a traditional synchronous generator. Adjusting the generator's excitation current and speed are possible control methods in wind turbine inertia control, but not the only ones. Besides adjusting excitation current and speed, wind turbine inertia control may also involve the use of energy storage systems, pitch angle control, and overspeed-unloading strategies. Energy storage systems can provide or absorb energy in a short time, thus helping the wind turbine respond quickly to changes in system frequency. In summary, wind turbine inertia control is not limited to controlling the generator's excitation current or speed; it is a comprehensive control strategy that may involve the combined use of multiple control methods and technologies to achieve a rapid and effective response of the wind turbine to system frequency changes.

[0037] Chopper devices are typically designed for use in wind turbine converters to handle low-voltage ride-through faults. When the grid voltage drops, the voltage at the connection point decreases, hindering the wind turbine's energy delivery. In this situation, the chopper device discharges energy through a leakage resistor connected in series with the IGBT power module, protecting the wind turbine converter and enabling low-voltage ride-through. The chopper device operates instantaneously; it immediately engages leakage once the DC bus voltage exceeds a set value, resulting in very rapid energy discharge.

[0038] The primary application of crowbar circuits in wind turbines is to protect them from abnormal conditions such as sudden drops in grid voltage. Their working principle involves short-circuiting the generator rotor side, causing the rotor current to bypass through the crowbar resistor, thus preventing overcurrent damage to the turbine. Crowbar circuits were not initially designed for precise power reduction control, but rather as a protective device. In the event of abnormal grid voltage, the crowbar circuit can quickly activate, bypassing the rotor current and protecting the turbine from damage. Using crowbar circuits for power control may not achieve the precise 50% power reduction requirement because its primary purpose is protection, not precise control. Crowbar circuits are typically triggered based on grid voltage, rather than directly controlling the turbine's power output. Crowbar circuits typically have a very fast response time, acting within milliseconds, which is advantageous for short-term (e.g., within 2 seconds) power reduction. However, the accuracy and stability of the power reduction may be limited.

[0039] The relationship between wind turbine terminal voltage and power flow mainly involves the following two aspects:

[0040] Relationship between wind power output and turbine terminal voltage: When wind farm output increases, the active power output of wind turbines increases, which usually leads to an increase in turbine terminal voltage. This is because the injection of wind power reduces the active power absorbed by the regional power grid from the main grid, thereby reducing reactive power losses and voltage drop on the lines. However, when wind farm output further increases to a certain threshold, turbine terminal voltage may begin to decrease. This is because under high output conditions, the regional power grid where the wind farm is located supplies power to the main grid. As the external active power increases, the reactive power losses on the lines and the reactive power demand of asynchronous generators also increase accordingly, which may lead to insufficient reactive power in the regional power grid, thus causing a drop in voltage level.

[0041] Grid Structure and Power Flow Impact: The complex topology within a wind farm and the power flow between turbines can lead to differences in terminal voltage. This is especially true when operating with a constant power factor. Figure 2Since active power is transmitted from the end of the collector line (i.e., the tail end) to the beginning of the collector line (i.e., the head end), the node voltage may increase sequentially from the head end to the tail end. Under favorable wind conditions at the wind farm, the wind turbines output more active power, which may raise the voltage at the turbine end of the line, leading to a larger voltage difference between the wind turbines.

[0042] Because the temperature and power of the braking resistor have a non-linear relationship, it is impossible to accurately calculate how much energy the braking resistor will release, how much temperature rise it will cause, or how much remaining capacity can be used. Insufficient braking resistors can easily lead to excessive bus voltage and current. Furthermore, wind turbine braking resistors are required for low-voltage ride-through (LVRT). If the wind turbine braking resistor is used to rapidly reduce power during severe over-frequency conditions, and these two scenarios occur consecutively, subsequent triggered functions may not respond correctly. In addition, frequent use of the braking resistor can lead to unstable wind turbine operation, increasing maintenance costs and downtime. Therefore, the principle for using braking resistors during severe over-frequency rapid power reduction is: avoid using them unless absolutely necessary.

[0043] This disclosure takes into account, on the one hand, that: Figure 2 As shown, the voltage at the turbine terminals of each turbine collector line gradually increases from the beginning to the end of the line. When the grid voltage is low and LVRT (Low Voltage Ride-Through) occurs, the voltage at the beginning of the line will be lower than the voltage at the end. This means that the beginning of the line is more dependent on the low voltage ride-through braking resistor than the end. In other words, the demand for low voltage ride-through is not the same for all turbines; it exhibits a non-uniform and asymmetrical state, with turbines near the grid connection point having a higher demand than those far from the grid connection point. Therefore, this disclosure proposes that: in cases of severe overfrequency rapid power reduction, if the turbine braking resistor must be activated after calculation and evaluation, the activation amount of the turbine braking resistor should be allocated differentially.

[0044] This disclosure also takes into account that: since the working principle of the braking resistor is to trigger the braking resistor to quickly discharge energy when the DC bus voltage of the converter is too high, when the target value on the grid side of the converter is lower than the combined control power of the pitch, motor, etc., simply put, for example, when the power output of the primary frequency control is greater than the target power on the grid side, that is, when there is a power difference, the function of the braking resistor is deactivated, and the power jump will occur to varying degrees depending on the size of the power difference, such as... Figure 3As shown. This can cause unnecessary power fluctuations in the power grid and may also lead to excessively high bus voltage, generating excessive current and damaging the converter. To avoid this, this disclosure proposes that the braking resistor be deactivated when the converter-side power and the grid-side target power are balanced, and the braking resistor no longer needs to discharge energy (e.g., the power of primary frequency control is equal to the grid-side target power). This balance condition limits the deactivation time of the braking resistor; that is, once the braking resistor is engaged, it will not deactivate until the above balance condition is met, provided the temperature is satisfied.

[0045] The following will combine Figures 4 to 8 Exemplary embodiments of this disclosure will be described in detail.

[0046] Figure 4 A flowchart illustrating a power reduction control method for a wind farm according to an exemplary embodiment of the present disclosure is shown.

[0047] As an example, the power reduction control method for a wind farm according to an exemplary embodiment of this disclosure can be executed by a wind farm-level controller. The wind farm may include multiple wind turbines connected to the power grid in an appropriate manner.

[0048] As an exemplary embodiment, the application scenario of the wind farm power reduction control method according to the exemplary embodiment of this disclosure can be: determining that the grid connection point frequency is severely over-frequency, and determining that the wind turbine braking resistor must be activated for rapid power reduction, that is, after resource analysis and target instruction demand analysis, determining that the braking resistor must be invoked to meet grid function. Further, as an example, the application scenario of the wind farm power reduction control method according to the exemplary embodiment of this disclosure can be: determining that the grid connection point frequency is severely over-frequency, and determining that in the first stage, the wind turbine is controlled to reduce power using a non-braking resistor power reduction method, and then in the second stage, the wind turbine is controlled to simultaneously use both a non-braking resistor power reduction method and a braking resistor to reduce power. For example, the application scenario of the wind farm power reduction control method according to the exemplary embodiment of this disclosure can be: determining that the grid connection point frequency is severely over-frequency, and determining that in the first stage, power is reduced according to primary frequency regulation, and then in the second stage, power is reduced simultaneously using primary frequency regulation and a braking resistor; or, determining that the grid connection point frequency is severely over-frequency, and determining that in the first stage, power is reduced according to inertia response, and then in the second stage, power is reduced simultaneously using primary frequency regulation and a braking resistor.

[0049] Reference Figure 4 In step S100, the total power reduction amount DeltP_damand that needs to be regulated by the wind farm is determined.

[0050] As an exemplary embodiment, step S100 may include: determining the total power reduction amount DeltP_damand that the wind farm needs to regulate in the second stage of severe overfrequency rapid power reduction (i.e., the stage in which power is reduced by both non-braking resistor power reduction and braking resistor). As an example, step S100 may further include: in response to the completion of the first stage of severe overfrequency rapid power reduction, determining the amount of power reduction regulated in the first stage based on the difference between the real-time value of the total power at the beginning of the first stage and the real-time value of the total power at the end of the first stage; and then using the difference between the total power reduction amount (e.g., 50% Pn) that the wind farm needs to regulate in both the first and second stages and the amount of power reduction regulated in the first stage as the total power reduction amount DeltP_damand that the wind farm needs to regulate in the second stage. For example, for a severe overfrequency rapid regulation requirement to reduce Pn by 50% within 2 seconds, if the entire field reduces Pn by 20% in the first stage, then the total power reduction required for wind farm regulation in the second stage is determined to be 30% Pn, i.e., DeltP_damand = 30% Pn.

[0051] In step S200, the amount of power reduction per unit that needs to be adjusted for each wind turbine is determined based on the total power reduction, the power reduction capacity of each wind turbine in the wind farm, and the distance of each wind turbine with braking resistor power reduction capability from the grid connection point.

[0052] The power reduction capacity of a fan with braking resistor power reduction capability is the sum of the power reduction capacity of braking resistor and the power reduction capacity of non-braking resistor power reduction method. The power reduction capacity of a fan without braking resistor power reduction capability is the power reduction capacity of non-braking resistor power reduction method.

[0053] As an example, if it is determined that the power reduction of the fan is achieved by simultaneously using primary frequency regulation and braking resistor in the second stage of control, the power reduction amount of the fan with braking resistor power reduction capability is: the sum of the power reduction amount of braking resistor and the power reduction amount of primary frequency regulation, and the power reduction amount of the fan without braking resistor power reduction capability is: the power reduction amount of primary frequency regulation.

[0054] As another example, if it is determined that the fan is controlled in the second stage by using both inertial response and braking resistor to reduce power, then the power reduction amount of the fan with braking resistor power reduction capability is: the sum of the power reduction amount of braking resistor and the power reduction amount of inertial response, and the power reduction amount of the fan without braking resistor power reduction capability is: the power reduction amount of inertial response.

[0055] As an exemplary embodiment, under the same conditions, the closer the wind turbine with braking resistor power reduction capability is to the grid connection point, the lower the amount of power reduction required for single-unit wind turbine adjustment.

[0056] As an exemplary embodiment, step S200 may include step S201 and step S202.

[0057] In step S201, the sum of the power reduction capabilities of all wind turbines with braking resistor power reduction capability is taken as the total rapid power reduction capability of the entire field.

[0058] In step S202, in response to the overall power reduction being less than or equal to the overall rapidly scalable power reduction, based on the overall power reduction, the scalable power of each wind turbine with braking resistor power reduction capability, and the power reduction allocation coefficient, the required single-unit power reduction for each wind turbine with braking resistor power reduction capability is determined. Specifically, the closer a wind turbine with braking resistor power reduction capability is to the grid connection point, the smaller its power reduction allocation coefficient. Conversely, the smaller the power reduction allocation coefficient, the lower the required single-unit power reduction for that turbine. For example, as the distance between the wind turbine and the grid connection point increases, the power reduction allocation coefficient σ% can be gradually increased in a certain step.

[0059] Specifically, if the total power reduction of the wind farm needs to be less than or equal to the total fast-reducible power G_FastUsefulDeltPowerMinus, and the power calculation command and trigger control mode at the grid connection point are in fast power reduction mode, then it is only necessary to allocate wind turbines with braking resistor power reduction capabilities to reduce active power.

[0060] As an exemplary embodiment, in addition to steps S201 and S202, step S200 may also include steps S203 and S204.

[0061] In step S203, in response to the fact that the total power reduction is greater than the total rapidly achievable power reduction, the power reduction amount of each wind turbine with braking resistor power reduction capability is determined based on the total power reduction, the power reduction capability of each wind turbine with braking resistor power reduction capability, and the power reduction allocation coefficient.

[0062] The following will combine Figure 5 This is an example of the balanced allocation method in steps S202 and S203, which involves "determining the single-unit power reduction amount that needs to be adjusted for each wind turbine with braking resistor power reduction capability based on the total power reduction amount, the power reduction amount of each wind turbine with braking resistor power reduction capability, and the power reduction allocation coefficient."

[0063] In step S204, after allocating the single-unit power reduction amount to all wind turbines with braking resistor power reduction capability, the single-unit power reduction amount that needs to be adjusted for each wind turbine without braking resistor power reduction capability is determined based on the remaining unallocated total power reduction amount and the power reduction amount of each wind turbine without braking resistor power reduction capability.

[0064] The following will combine Figure 6 This is an example of the balanced allocation method in step S204, which involves "determining the single-unit power reduction amount that needs to be adjusted for each wind turbine that does not have the ability to reduce power by braking resistors, based on the remaining unallocated total power reduction amount and the power reduction amount that each wind turbine does not have the ability to reduce power by braking resistors".

[0065] Specifically, if the total power reduction required for wind farm regulation, DeltP_demand, is greater than the total fast-reducible power, G_FastUsefulDeltPowerMinus, and the power command and trigger control mode at the grid connection point are in fast power reduction mode, wind turbines with braking resistor power reduction capability will be used first to reduce active power through a combination of braking resistor and non-braking resistor power reduction. When the reserve capacity of all wind turbines with braking resistor power reduction capability is insufficient, the remaining power commands that do not meet the grid connection point requirements will be allocated to wind turbines with only non-braking resistor power reduction capability to reduce active power.

[0066] In step S300, each fan is controlled to reduce its power according to the required reduction in the single-unit power of each fan.

[0067] As an exemplary embodiment, a target regulation rate for non-braking resistor power reduction (e.g., the target regulation rate for primary frequency regulation or the target regulation rate for inertial response), a target regulation rate for grid-side power output limitation, and a single-unit power reduction amount or target power value (calculated based on the single-unit power reduction amount required for the wind turbine) can be sent to each wind turbine with braking resistor power reduction capability to control the wind turbine to perform power reduction regulation; and a target regulation rate for non-braking resistor power reduction, a single-unit power reduction amount or target power value required for the wind turbine can be sent to each wind turbine without braking resistor power reduction capability to control the wind turbine to perform power reduction regulation.

[0068] As an example, the target adjustment rate for primary frequency modulation can be 50 kW / s, and the target adjustment rate for inertial response can be 15% Pn. 单机 / s~20%Pn 单机 / s.

[0069] As an exemplary embodiment, the target regulation rate for limiting power output of each wind turbine with braking resistor power reduction capability in the second stage can be determined based on the regulation time requirement (e.g., for a severe overfrequency rapid regulation requirement of reducing Pn by 50% within 2 seconds, the regulation time is 2 seconds), the regulation time of the first stage, the single-unit power reduction of each wind turbine with braking resistor power reduction capability, and the regulation coefficient.

[0070] As an exemplary embodiment, the adjustment time of the first stage (i.e., the time spent in the first stage) can be rounded to obtain a first time value, and the difference between the adjustment time parameter and the first time value can be used as a second time value t2; then, for each wind turbine with braking resistor power reduction capability, the target adjustment rate of the grid-side limited power output of the wind turbine in the second stage can be calculated. Among them, Deltp break[i] This indicates the amount of power reduction required for the single unit of the fan in the second phase. This represents the control coefficient.

[0071] Because the braking resistor cannot precisely control the power, a control coefficient needs to be added. Adjustments can be made to the control coefficient based on actual conditions and specific needs. Configure the settings. For example, if the power regulation speed is slow and the actual power response is small, increase the regulation coefficient. Conversely, reduce the control coefficient.

[0072] According to exemplary embodiments of this disclosure, an asymmetric rapid power reduction regulation concept is proposed. Employing the principle of asymmetry, the power regulation amount that needs to be borne by the braking resistor in the second stage is asymmetrically allocated to the wind turbines. Wind turbines closer to the grid connection point bear less of the regulation target demand, while wind turbines farther from the grid connection point bear more of the regulation target demand. This increases the consumption of braking resistors in the farther wind turbines and reduces the consumption of braking resistors in the closer wind turbines during rapid power reduction response.

[0073] In the above embodiments, the power reduction control of pitch, generator, yaw and other functions is uniformly incorporated into the primary frequency regulation and inertial response. This disclosure does not specifically reflect the detailed control strategy of the primary frequency regulation or inertial response inside the wind turbine. It only takes the comprehensive and balanced regulation of the three resources of primary frequency regulation, inertial response and braking resistor as the core idea. It is necessary to meet the requirements of the power grid in terms of speed and accuracy, and also to consider the safety and reliability of the wind turbine. Therefore, the available resources will be balanced to minimize the strong dependence on any one resource and to minimize the consumption of braking resistor.

[0074] Figure 5 A flowchart illustrating a method for determining the amount of single-unit power reduction required for each wind turbine to have braking resistor power reduction capability, according to an exemplary embodiment of the present disclosure.

[0075] Reference Figure 5 In step S501, all fans with braking resistor power reduction capability are arranged according to the amount of power reduction they can reduce.

[0076] As an example, all fans with braking resistor power reduction capability can be sorted in ascending order according to the amount of power reduction they can reduce, or they can be sorted in descending order according to the amount of power reduction they can reduce.

[0077] In step S502, one fan is selected from the arranged fans in sequence each time, and the single-unit power reduction is allocated according to the principle that if the power reduction amount is greater than the average power reduction amount, the average power reduction amount is allocated, and if it is less than or equal to the average power reduction amount, the power reduction amount is used up.

[0078] When step S502 is executed for the first time, the average power reduction is the ratio of the total power reduction DeltP_demand to the total number of wind turbines with braking resistor power reduction capability. As an example, the average power reduction can be updated after each wind turbine is allocated.

[0079] If the power reduction of the selected fan is greater than or equal to the average power reduction, the average power reduction will be allocated to the selected fan; if the power reduction of the selected fan is less than the average power reduction, the power reduction amount will be allocated to the selected fan.

[0080] In step S503, based on the power lower limit of the selected fan, the product of the single-unit power reduction allocated to the selected fan and the power reduction allocation coefficient of the selected fan is limited, and the limited value is used as the single-unit power reduction amount that needs to be adjusted for the selected fan.

[0081] As an exemplary embodiment, the product of the single-unit power reduction allocated to the selected wind turbine and its power reduction allocation coefficient σ% is calculated. If the difference between the current power value of the selected wind turbine and the product is lower than its power lower limit, the single-unit power reduction of the selected wind turbine is limited so that the difference is not lower than its power lower limit.

[0082] After allocating power to each wind turbine, the power command just allocated is subtracted from DeltP_damand to obtain the remaining unallocated total power reduction. The total number of wind turbines with braking resistor power reduction capability is then reduced by 1. The ratio of these two values ​​is recalculated to obtain the updated average power reduction, and then the next round of calculation begins (i.e., the process returns to step S502). This continues until the DeltP_damand requirement is met.

[0083] Figure 6 A flowchart illustrating a method for determining the amount of single-unit power reduction required for each wind turbine that does not have braking resistor power reduction capability, according to an exemplary embodiment of the present disclosure.

[0084] Reference Figure 6 In step S601, all fans that do not have the power reduction capability of braking resistors are arranged according to the amount of power reduction they can reduce.

[0085] As an example, all fans that do not have the power reduction capability of braking resistors can be sorted in ascending order according to the amount of power reduction they can reduce, or they can be sorted in descending order according to the amount of power reduction they can reduce.

[0086] In step S602, one fan is selected from the arranged fans in sequence each time, and the single-unit power reduction is allocated according to the principle that if the power reduction amount is greater than the average power reduction amount, the average power reduction amount is allocated, and if it is less than or equal to the average power reduction amount, the power reduction amount is used up.

[0087] When step S602 is executed for the first time, the average power reduction is the ratio of the remaining unallocated total power reduction to the total number of wind turbines without braking resistor power reduction capability. As an example, the average power reduction is updated after each wind turbine is allocated.

[0088] If the power reduction of the selected fan is greater than or equal to the average power reduction, the average power reduction will be allocated to the selected fan; if the power reduction of the selected fan is less than the average power reduction, the power reduction amount will be allocated to the selected fan.

[0089] In step S603, based on the power lower limit of the selected fan, the reduction amount of the single-unit power allocated to the selected fan is limited, and the limited value is used as the reduction amount of the single-unit power of the selected fan to be adjusted.

[0090] As an exemplary embodiment, if the difference between the current power value of the selected wind turbine and the single-unit power reduction amount allocated to the selected wind turbine is lower than its power lower limit, then the single-unit power reduction amount of the selected wind turbine is limited so that the difference is not lower than its power lower limit.

[0091] After each fan is assigned, the total number of fans without braking resistor power reduction capability is reduced by 1, the remaining unassigned total power reduction is reduced by the newly assigned power command, the average power reduction is recalculated, and then the next round of calculation begins (i.e., return to step S602). This continues until the DeltP_damand requirement is met or no fans are available for assignment.

[0092] Figure 7 A flowchart illustrating a power reduction control method for a wind farm according to another exemplary embodiment of the present disclosure is shown.

[0093] The braking resistor reduces power very quickly. However, if the power is released before the power reduction method of the non-braking resistor and the braking resistor are balanced, it will cause a rapid power surge. In order to reduce the impact on power, this disclosure proposes to increase the calculation of the balance time between the non-braking resistor power reduction method and the braking resistor. Only after the balance is achieved can the braking resistor be released.

[0094] Due to the uncertainty of the power grid environment, in cases of severe overfrequency, after the wind farm's power rapidly decreases, if the grid connection point frequency remains in the severely overfrequency range, the farm-level controller will wait and assess the situation according to grid requirements. If the grid connection point frequency still does not recover after a certain period (e.g., 10 seconds), the power will continue to decrease to the wind farm's lower power limit (e.g., 8% Pn). During this 10-second pause, if the braking resistor remains engaged, wind speed fluctuations will cause continuous consumption of the braking resistor.

[0095] Therefore, this disclosure proposes that when the power control power of the non-braking resistor power reduction mode is balanced with the grid-side target value, the wind turbine's operating state should be switched off from the braking resistor power reduction mode as soon as possible. Once the braking resistor is activated, a balance judgment between the braking resistor and non-braking resistor power reduction modes should be added, and once balanced, the braking resistor mode should be switched off immediately in advance.

[0096] Reference Figure 7 In addition to steps S100-S300, the power reduction control method for a wind farm according to another exemplary embodiment of the present disclosure may also include steps S400-S600.

[0097] In step S400, the shortest time required for the current power reduction adjustment of each wind turbine with braking resistor power reduction capability is calculated.

[0098] The shortest duration is the reduction in single-unit power ΔP i The ratio of the target regulation rate to that of non-braking resistor power reduction methods (e.g., primary frequency modulation or inertial response).

[0099] As an example, the shortest duration T required for the current power reduction adjustment of each wind turbine with braking resistor power reduction capability can be calculated using the following formula. i :

[0100] T i =△P i / Rate_Pitch i

[0101] Among them, Rate_Pitch i This represents the target regulation rate of primary frequency regulation (i.e., the target regulation rate of pitch).

[0102] In step S500, the maximum value among the shortest durations required for current power reduction adjustment of all wind turbines with braking resistor power reduction capability is determined.

[0103] Considering that the control commands assigned to each wind turbine are differentiated, the latest execution time is used as the cut-off condition. Therefore, the minimum execution time T for all wind turbines can be determined. i After performing the calculations uniformly, extract the maximum value T. max :

[0104] T max =max(T) i )

[0105] In step S600, in response to the current power reduction adjustment duration exceeding the maximum value T max The sum of the time margin and the current power reduction adjustment of each wind turbine is controlled to end.

[0106] As an example, the specific value of the time margin can be set according to the actual situation and specific needs. For example, the specific value of the time margin can be set to 0.5s.

[0107] Setting a time margin delay avoids active power surges during the transient regulation of the converter's DC bus voltage Udc. Therefore, the condition for controlling the braking resistor to disengage is:

[0108] T>T max +0.5

[0109] If the frequency is severely over-frequency, and after resource analysis and calculation, it is determined that the braking resistor must be activated, then the time T at which the braking resistor is first activated is recorded. start And set the cut-out flag Flag_FastP = 1:

[0110] T = T now -T start

[0111] When T>T max When the value is +0.5, set the cut-out flag Flag_FastP = 0.

[0112] According to an exemplary embodiment of this disclosure, the cut-out conditions (i.e., cut-out timing) for braking resistor regulation are defined.

[0113] Furthermore, as an exemplary embodiment, the power reduction control method for a wind farm according to another exemplary embodiment of this disclosure may further include: after controlling each wind turbine to end the current power reduction adjustment, controlling each wind turbine to perform a frequency adjustment.

[0114] When Flag_FastP = 0, indicating power balance, the braking resistor can be switched off. At this point, the braking resistor mode should be switched off immediately, and the primary frequency regulation mode (e.g., fast primary frequency regulation mode) should be entered. If the frequency subsequently recovers, since some countries / regions typically use slow primary frequency regulation mode, the mode can be switched from fast primary frequency regulation mode to slow primary frequency regulation mode during the recovery phase. If the frequency does not subsequently recover, the power regulation should be adjusted downwards to the lower limit of the wind farm's power according to the fast primary frequency regulation mode. The power regulation rate of the fast primary frequency regulation mode is higher than that of the slow primary frequency regulation mode.

[0115] Furthermore, as an exemplary embodiment, the power reduction control method for a wind farm according to another exemplary embodiment of this disclosure may further include: after controlling each wind turbine to end the current power reduction adjustment, in response to the need to reactivate the braking resistor, determining whether the difference between the current time and the end time of the current power reduction adjustment exceeds the cooling time of the braking resistor; in response to the difference exceeding the cooling time of the braking resistor, allowing the braking resistor to be reactivated; and in response to the difference being less than or equal to the cooling time of the braking resistor, restricting the reactivation of the braking resistor.

[0116] When the cut-out flag Flag_FastP is set to 0, the start time T after the cut-out is recorded. end When compared with the start time T end The braking resistor may be reactivated only if necessary after an interval greater than the cooling time of the braking resistor (e.g., 30 minutes); otherwise, it shall not be activated.

[0117] According to exemplary embodiments of this disclosure, the reliability of grid demand functions is improved, and the response effects of severe over-frequency rapid power reduction and low voltage ride-through LVRT are minimized; the safety and stability of wind turbine operation are improved, avoiding the risk of excessive bus voltage and current due to insufficient braking resistors, and allowing wind turbines to respond as slowly as possible with an active power control strategy, thereby improving the safety factor and stability and extending wind turbine lifespan; the instability of wind turbine operation caused by frequent use of braking resistors is avoided, thereby reducing maintenance costs and downtime.

[0118] Figure 8 A structural block diagram of a power reduction control device for a wind farm according to an exemplary embodiment of the present disclosure is shown.

[0119] like Figure 8 As shown, the wind farm power reduction control device according to an exemplary embodiment of the present disclosure includes: a determination unit 100, an allocation unit 200, and a control unit 300.

[0120] Specifically, the determining unit 100 is configured to determine the total power reduction required for wind farm regulation.

[0121] The distribution unit 200 is configured to determine the amount of power reduction per unit that needs to be adjusted for each wind turbine based on the total power reduction, the power reduction capacity of each wind turbine in the wind farm, and the distance of each wind turbine with braking resistor power reduction capability from the grid connection point.

[0122] The control unit 300 is configured to control each fan to reduce its power according to the required reduction in individual fan power.

[0123] The power reduction capacity of a fan with braking resistor power reduction capability is the sum of the power reduction capacity of braking resistor and the power reduction capacity of non-braking resistor power reduction method. The power reduction capacity of a fan without braking resistor power reduction capability is the power reduction capacity of non-braking resistor power reduction method.

[0124] As an exemplary embodiment, the allocation unit 200 may be configured to: take the sum of the power reduction capabilities of all wind turbines with braking resistor power reduction capabilities as the total field rapid power reduction capability; in response to the total field power reduction being less than or equal to the total field rapid power reduction capability, determine the single-unit power reduction capability that needs to be adjusted for each wind turbine with braking resistor power reduction capability based on the total field power reduction capability, the power reduction capability of each wind turbine with braking resistor power reduction capability, and the power reduction allocation coefficient; wherein, the closer the wind turbine with braking resistor power reduction capability is to the grid connection point, the smaller the power reduction allocation coefficient.

[0125] As an exemplary embodiment, the allocation unit 200 may also be configured to: in response to the overall power reduction being greater than the overall rapid power reduction being greater than the overall ...

[0126] As an exemplary embodiment, the allocation unit 200 may be configured to: arrange all fans with braking resistor power reduction capability according to the power reduction amount; select one fan from the arranged fans in sequence each time, and allocate the average power reduction amount to the selected fan according to the principle that if the power reduction amount is greater than or equal to the average power reduction amount, the average power reduction amount is allocated, and if it is less than the average power reduction amount, the power reduction amount is exhausted; based on the power lower limit value of the selected fan, limit the product of the power reduction amount allocated to the selected fan and the power reduction allocation coefficient of the selected fan, and use the limited value as the power reduction amount of the selected fan that needs to be adjusted.

[0127] As an exemplary embodiment, the control unit 300 may also be configured to: calculate the shortest duration required for the current power reduction adjustment of each wind turbine with braking resistor power reduction capability, wherein the shortest duration is the ratio of the power reduction of a single unit to the target adjustment rate of the non-braking resistor power reduction mode; determine the maximum value among the shortest durations required for the current power reduction adjustment of all wind turbines with braking resistor power reduction capability; and control each wind turbine to end the current power reduction adjustment in response to the current power reduction adjustment duration exceeding the sum of the maximum value and the time margin.

[0128] As an exemplary embodiment, the control unit 300 may also be configured to: control each wind turbine to perform a frequency adjustment after controlling each wind turbine to end the current power reduction adjustment.

[0129] As an exemplary embodiment, the control unit 300 may also be configured to: after controlling each fan to end the current power reduction adjustment, in response to the need to reactivate the braking resistor, determine whether the difference between the current time and the end time of the current power reduction adjustment exceeds the cooling time of the braking resistor; in response to the difference exceeding the cooling time of the braking resistor, allow the braking resistor to be reactivated; in response to the difference being less than or equal to the cooling time of the braking resistor, restrict the reactivation of the braking resistor.

[0130] As an exemplary embodiment, the control unit 300 may be configured to: send a target adjustment rate for non-braking resistor power reduction mode, a target adjustment rate for grid-side power output limitation, and a single-unit power reduction amount or target power value that the wind turbine needs to adjust to each wind turbine with braking resistor power reduction capability, respectively, to control the wind turbine to perform power reduction adjustment; and send a target adjustment rate for non-braking resistor power reduction mode, and a single-unit power reduction amount or target power value that the wind turbine needs to adjust to each wind turbine without braking resistor power reduction capability, respectively, to control the wind turbine to perform power reduction adjustment.

[0131] It should be understood that the specific processing performed by the power reduction control device for a wind farm according to the exemplary embodiments of this disclosure has been referenced. Figures 2 to 7 A detailed description has been provided, and the relevant details will not be repeated here.

[0132] It should be understood that the various units in the wind farm power reduction control device according to the exemplary embodiments of this disclosure can be implemented as hardware components and / or software components. Those skilled in the art can implement the various units, for example, using field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs), based on the processes performed by the defined various units.

[0133] A controller for a wind farm according to an exemplary embodiment of the present disclosure includes a processor (not shown) and a memory (not shown), wherein the memory stores a computer program that, when executed by the processor, implements the power reduction control method for the wind farm as described in the exemplary embodiment above.

[0134] According to exemplary embodiments of the present disclosure, a computer-readable storage medium storing instructions may also be provided, wherein when the instructions are executed by at least one processor, they cause at least one processor to perform the power reduction control method for a wind farm as described in the exemplary embodiments above. Examples of computer-readable storage media herein include: read-only memory (ROM), random access programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, non-volatile memory, CD-ROM, CD-R, CD+R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, Blu-ray or optical disc storage, hard disk drive (HDD), solid-state drive (SSD), card storage (such as multimedia cards, secure digital (SD) cards, or ultra-fast digital (XD) cards), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, and any other device configured to store a computer program and any associated data, data files, and data structures in a non-transitory manner and to provide the computer program and any associated data, data files, and data structures to a processor or computer so that the processor or computer can execute the computer program. The computer program in the aforementioned computer-readable storage medium can run in an environment deployed in computer devices such as clients, hosts, agent devices, servers, etc. Furthermore, in one example, the computer program and any associated data, data files, and data structures are distributed across a networked computer system, such that the computer program and any associated data, data files, and data structures are stored, accessed, and executed in a distributed manner through one or more processors or computers.

[0135] According to exemplary embodiments of the present disclosure, a computer program product may also be provided, wherein the instructions in the computer program product are executable by at least one processor to perform the power reduction control method for a wind farm as described in the exemplary embodiments above.

[0136] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0137] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for controlling power reduction in a wind farm, characterized in that, include: Determine the total power reduction required for wind farm regulation; Based on the total power reduction of the wind farm, the power reduction capacity of each wind turbine in the wind farm, and the distance of each wind turbine with braking resistor power reduction capability from the grid connection point, determine the single-unit power reduction amount that each wind turbine needs to adjust. Control each fan to adjust its power reduction according to the required reduction in the power of each fan. Among them, the power reduction capacity of the fan with braking resistor power reduction capability is: the sum of the power reduction capacity of braking resistor and the power reduction capacity of non-braking resistor power reduction method; the power reduction capacity of the fan without braking resistor power reduction capability is: the power reduction capacity of non-braking resistor power reduction method. The steps for determining the required reduction in individual wind turbine power include: The sum of the power reduction capabilities of all wind turbines with braking resistors is taken as the total rapid power reduction capability of the entire field. In response to the fact that the total power reduction is less than or equal to the total rapidly scalable power reduction, based on the total power reduction, the scalable power of each wind turbine with braking resistor power reduction capability, and the power reduction distribution coefficient, the single-unit power reduction amount that needs to be adjusted for each wind turbine with braking resistor power reduction capability is determined. Among them, the closer the wind turbine with braking resistor power reduction capability is to the grid connection point, the smaller the power reduction distribution coefficient is.

2. The power reduction control method according to claim 1, characterized in that, The steps to determine the amount of power reduction required for each wind turbine also include: In response to the fact that the total power reduction is greater than the total rapid power reduction, based on the total power reduction, the power reduction capacity of each wind turbine with braking resistor power reduction capability, and the power reduction distribution coefficient, the single-unit power reduction amount that needs to be adjusted for each wind turbine with braking resistor power reduction capability is determined. After allocating the single-unit power reduction amount to all wind turbines with braking resistor power reduction capability, based on the remaining unallocated total power reduction amount and the power reduction amount of each wind turbine without braking resistor power reduction capability, determine the single-unit power reduction amount that needs to be adjusted for each wind turbine without braking resistor power reduction capability.

3. The power reduction control method according to claim 1, characterized in that, The steps for determining the individual power reduction amount for each wind turbine that requires braking resistor power reduction capability include: All fans with braking resistor power reduction capability are arranged according to the amount of power reduction they can reduce; Each time, a fan is selected from the arranged fans in sequence. The average power reduction amount is allocated to the selected fan if the power reduction amount is greater than or equal to the average power reduction amount, and if it is less than the average power reduction amount, the power reduction amount is used up. Based on the power lower limit of the selected fan, the product of the single-unit power reduction allocated to the selected fan and the power reduction allocation coefficient of the selected fan is limited, and the limited value is used as the single-unit power reduction amount that the selected fan needs to adjust.

4. The power reduction control method according to claim 1, characterized in that, Also includes: Calculate the shortest time required for the current power reduction adjustment of each wind turbine with braking resistor power reduction capability, wherein the shortest time is the ratio of the power reduction of a single unit to the target adjustment rate of the non-braking resistor power reduction method. Determine the maximum value among the shortest durations required for current power reduction regulation of all wind turbines with braking resistor power reduction capability; In response to the fact that the current power reduction adjustment duration has exceeded the sum of the maximum value and the time margin, control each wind turbine to end the current power reduction adjustment.

5. The power reduction control method according to claim 4, characterized in that, Also includes: After controlling each fan to end its current power reduction adjustment, control each fan to perform a frequency adjustment.

6. The power reduction control method according to claim 4, characterized in that, Also includes: After controlling each fan to end the current power reduction adjustment, in response to the need to reactivate the braking resistor, it is determined whether the difference between the current time and the end time of the current power reduction adjustment exceeds the cooling time of the braking resistor. In response to the difference exceeding the cooling time of the braking resistor, the braking resistor can be reactivated; In response to the cooling time when the difference is less than or equal to that of the braking resistor, the reactivation of the braking resistor is restricted.

7. The power reduction control method according to claim 1, characterized in that, The steps for controlling the power reduction adjustment of each wind turbine, based on the required reduction in individual turbine power, include: Send the target adjustment rate of non-braking resistor power reduction mode, the target adjustment rate of grid-side power output limitation, and the amount of single-unit power reduction or target power value that the wind turbine needs to adjust to each wind turbine with braking resistor power reduction capability, respectively, so as to control the wind turbine to perform power reduction adjustment. The target adjustment rate of the non-braking resistor power reduction method, the amount of single-unit power reduction required for the wind turbine, or the target power value are sent to each wind turbine that does not have the power reduction capability of the braking resistor, so as to control the wind turbine to perform power reduction adjustment.

8. A power reduction control device for a wind farm, characterized in that, include: The determination unit is configured to determine the total power reduction required for wind farm regulation. The distribution unit is configured to determine the amount of power reduction per unit that needs to be adjusted for each wind turbine based on the total power reduction, the power reduction capacity of each wind turbine in the wind farm, and the distance of each wind turbine with braking resistor power reduction capability from the grid connection point. The control unit is configured to control each fan to adjust its power reduction according to the required reduction in individual fan power. Among them, the power reduction capacity of the fan with braking resistor power reduction capability is: the sum of the power reduction capacity of braking resistor and the power reduction capacity of non-braking resistor power reduction method; the power reduction capacity of the fan without braking resistor power reduction capability is: the power reduction capacity of non-braking resistor power reduction method. The allocation unit is specifically configured as follows: The sum of the power reduction capabilities of all wind turbines with braking resistors is taken as the total rapid power reduction capability of the entire field. In response to the fact that the total power reduction is less than or equal to the total rapidly scalable power reduction, based on the total power reduction, the scalable power of each wind turbine with braking resistor power reduction capability, and the power reduction distribution coefficient, the single-unit power reduction amount that needs to be adjusted for each wind turbine with braking resistor power reduction capability is determined. Among them, the closer the wind turbine with braking resistor power reduction capability is to the grid connection point, the smaller the power reduction distribution coefficient is.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it causes the processor to perform the power reduction control method for wind farms as described in any one of claims 1 to 7.

10. A controller for a wind farm, characterized in that, include: processor; A memory storing a computer program that, when executed by a processor, causes the processor to perform the power reduction control method for a wind farm as described in any one of claims 1 to 7.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the power reduction control method for wind farms as described in any one of claims 1 to 7.

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