Power reduction control method and device for wind power plant, controller and storage medium

Abstract

The invention provides a power reduction control method and device for a wind power plant, a controller and a storage medium. The power reduction control method for the wind power plant comprises the following steps: determining a whole-plant power reduction amount needing wind power plant adjustment; according to the full-field power reduction amount, the reducible power amount of each fan of the wind power plant and the distance between each fan with the brake resistor power reduction capability and a grid-connected point, single-machine power reduction amount needing to be adjusted by each fan is determined; according to the single-machine power reduction amount needing to be adjusted by each fan, each fan is controlled to carry out power reduction adjustment; wherein the reducible power amount of the fan with the braking resistor power reduction capability is the sum of the reducible power amount of the braking resistor and the reducible power amount of a non-braking resistor power reduction mode, and the reducible power amount of the fan without the braking resistor power reduction capability is the reducible power amount of the non-braking resistor power reduction mode.

Description

Technical Field

[0001] The present disclosure generally relates to the field of wind power technology, and more specifically, to a power reduction control method, device, controller and storage medium for a wind farm. Background Art

[0002] Figure 1 An example of wind farm regulating active power in response to grid frequency is shown. Figure 1 As shown, Fn represents the rated frequency of the power grid, P0 represents the full-field power value, and Pn represents the full-field rated power value. When the frequency of the grid connection point is in [Fd-~Fd+] (i.e., the dead zone range of the primary frequency modulation), the wind turbines in the wind farm (hereinafter referred to as wind turbines) receive the active power instructions of the energy management system (EMS) of the wind farm. When the frequency of the grid connection point is in [F3~Fd-] or [Fd+~F1], the wind turbines can be controlled to use primary frequency modulation to adjust the active power. For example, when the frequency of the grid connection point is in [Fd+~F1], the full-field active frequency modulation amplitude can be 10% Pn, and the response time can be 3s. When the frequency of the grid connection point is in [F1~F2], the power grid is in a serious overfrequency state, and the wind farm needs to adopt a fast power reduction control strategy. For example, the full-field active frequency modulation amplitude can be 50% Pn, and the adjustment time can be 3s. When the frequency of the grid-connected point is greater than F2, the active power remains unchanged at the current state, and further changes in frequency require further reduction of power.

[0003] When severe overfrequency requires rapid power reduction, if after calculation and evaluation it is necessary to enable the fan's braking resistor to reduce power, each fan needs to be allocated the amount of power reduction that needs to be adjusted. However, the existing allocation method does not take into account the actual application of the fan's braking resistor. Summary of the invention

[0004] An exemplary embodiment of the present disclosure provides a method, device, controller and storage medium for controlling power reduction of a wind farm, which can effectively solve the above-mentioned problems existing in the prior art.

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

[0006] Optionally, the step of determining the amount of power reduction that needs to be adjusted for each wind turbine includes: taking the sum of the power reduction amounts of all wind turbines with braking resistor power reduction capability as the amount of power that can be quickly reduced for the entire site; in response to the entire site power reduction amount being less than or equal to the entire site quickly reduced power amount, determining the amount of power reduction that needs to be adjusted for each wind turbine with braking resistor power reduction capability based on the entire site power reduction amount, the power reduction amount of each wind turbine with braking resistor power reduction capability, and the power reduction distribution coefficient; wherein, the closer the distance between the wind turbine with braking resistor power reduction capability and the grid connection point is, the smaller the power reduction distribution coefficient is.

[0007] Optionally, the step of determining the amount of single-machine power reduction that needs to be adjusted for each wind turbine also includes: in response to the total power reduction being greater than the total rapidly reducible power, determining the amount of single-machine power reduction that needs to be adjusted for each wind turbine with a braking resistor power reduction capability based on the total power reduction, the reducible power of each wind turbine with a braking resistor power reduction capability, and the power reduction distribution coefficient; after allocating the single-machine power reduction to all wind turbines with a braking resistor power reduction capability, determining the amount of single-machine power reduction that needs to be adjusted for each wind turbine without a braking resistor power reduction capability based on the remaining unallocated total power reduction and the reducible power of each wind turbine without a braking resistor power reduction capability.

[0008] Optionally, the step of determining the single-machine power reduction amount for each fan with braking resistor power reduction capability that needs to be adjusted includes: arranging all fans with braking resistor power reduction capability according to the power reduction amount that can be reduced; selecting one fan from the arranged fans in order each time, and allocating 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 used up; based on the lower power limit value of the selected fan, limiting the product of the single-machine power reduction amount allocated to the selected fan and the power reduction distribution coefficient of the selected fan, and using the limited value as the single-machine power reduction amount that needs to be adjusted by the selected fan.

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

[0010] Optionally, the method further includes: after controlling each fan to end the current power reduction adjustment, controlling each fan to perform frequency modulation once.

[0011] Optionally, it also includes: after controlling each fan to end the current power reduction adjustment, in response to the need to re-enable 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 re-enabled; in response to the difference being less than or equal to the cooling time of the braking resistor, restricting the re-enabling of the braking resistor.

[0012] Optionally, according to the single-machine power reduction amount that each wind turbine needs to adjust, the step of controlling each wind turbine to perform power reduction adjustment includes: sending the target adjustment rate of the non-braking resistor power reduction mode, the target adjustment rate of the grid-side power output limitation, the single-machine power reduction amount or the target power value that needs to be adjusted by the wind turbine to each wind turbine with the ability to reduce power by a braking resistor, so as to control the wind turbine to perform power reduction adjustment; sending the target adjustment rate of the non-braking resistor power reduction mode, the single-machine power reduction amount or the target power value that needs to be adjusted by the wind turbine to each wind turbine without the ability to reduce power by a braking resistor, so as to control the wind turbine to perform power reduction adjustment.

[0013] According to a second aspect of an embodiment of the present disclosure, a power reduction control device for a wind farm is provided, comprising: a determination unit, configured to determine a power reduction amount for the entire wind farm that needs to be adjusted; an allocation unit, configured to determine a single-machine power reduction amount that needs to be adjusted for each wind turbine according to the power reduction amount for the entire wind farm, a power reduction amount of each wind turbine in the wind farm, and a distance from a grid connection point to each wind turbine with a braking resistor power reduction capability; a control unit, configured to control each wind turbine to perform power reduction adjustment according to the power reduction amount of each wind turbine that needs to be adjusted; wherein the power reduction amount of a wind turbine with a braking resistor power reduction capability is: the sum of the power reduction amount of the braking resistor and the power reduction amount in a non-braking resistor power reduction mode, and the power reduction amount of a wind turbine without a braking resistor power reduction capability is: the power reduction amount in a non-braking resistor power reduction mode.

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

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

[0016] According to a fifth aspect of an embodiment of the present disclosure, there is provided a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the power reduction control method for a wind farm as described above is implemented.

[0017] According to the wind farm power reduction control method, device, controller, storage medium and program product of the exemplary embodiment of the present invention, taking into account the different dependence on the braking resistance of wind turbines at different distances from the grid connection point during low voltage ride-through, in order to minimize the response impact of severe overfrequency rapid power reduction and low voltage ride-through LVRT, it is proposed to allocate the power reduction amount of a single machine based on the distance from the grid connection point of each wind turbine with a braking resistance power reduction capability, thereby improving the reliability of the grid demand function by differentially regulating the braking resistance of the wind turbine in the case of severe overfrequency rapid power reduction.

[0018] In the following description, some aspects and / or advantages of the general inventive concept will be set forth, and some other aspects and / or advantages will be known through the following description or the implementation of the general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] These and / or other aspects and advantages of the present application will become clearer and easier to understand from the following detailed description of the embodiments of the present application in conjunction with the accompanying drawings, in which:

[0020] Figure 1 An example showing an existing wind farm regulating power in response to grid frequency;

[0021] Figure 2 shows an example of a collector voltage according to an exemplary embodiment of the present disclosure;

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

[0023] Figure 4 A flow chart showing a power reduction control method of a wind farm according to an exemplary embodiment of the present disclosure;

[0024] Figure 5A flow chart showing a method for determining a single-machine power reduction amount to be adjusted by each wind turbine having a braking resistor power reduction capability according to an exemplary embodiment of the present disclosure;

[0025] Figure 6 A flow chart showing a method for determining a single-machine power reduction amount that requires adjustment of each wind turbine that does not have a braking resistor power reduction capability according to an exemplary embodiment of the present disclosure;

[0026] Figure 7 A flow chart showing a power reduction control method of a wind farm according to another exemplary embodiment of the present disclosure;

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

[0028] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like parts throughout. The embodiments will be described below with reference to the drawings in order to explain the present disclosure.

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

[0030] It should be noted that the phrase "at least one of the items" in the present disclosure includes three types of parallel situations: "any one of the items", "a combination of any number of the items", and "all of the items". For example, "including at least one of A and B" includes the following three types of parallel situations: (1) including A; (2) including B; (3) including A and B. Another example is "executing at least one of step 1 and step 2" which means the following three types of parallel situations: (1) executing step 1; (2) executing step 2; (3) executing step 1 and step 2.

[0031] Rapid power reduction of a wind turbine (for example, reducing Pn by 50% within 2 seconds) is an extremely demanding operation that requires rapid and accurate adjustment of the wind turbine's operating state. The following are possible resources and methods for achieving rapid power reduction:

[0032] Pitch control: It is one of the most commonly used power regulation methods in wind turbines. By quickly adjusting the pitch angle of the blades, the efficiency of the blades in capturing wind energy can be changed, thereby achieving rapid power reduction. In the case of rapid power reduction, the pitch control system needs to respond quickly and accurately adjust the pitch angle to the predetermined position.

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

[0034] Generator control: The output power of the generator can be changed by adjusting the excitation current or speed of the generator. In the case of rapid power reduction, the generator control system needs to quickly adjust parameters to ensure accurate power reduction.

[0035] Yaw control: Although yaw control is mainly used to keep the wind turbine perpendicular to the wind direction to maximize wind energy capture efficiency, in some cases, yaw control can also be used to assist in achieving rapid power reduction. That is, by adjusting the yaw angle of the wind turbine, the energy captured by the wind can be reduced, thereby reducing the wind turbine output power. In the case of rapid power reduction, the effect of this method may be relatively limited and needs to be used in combination with other control methods.

[0036] The following will introduce inertia control. Inertia is an important parameter of the power system, which reflects the system's ability to resist rapid frequency changes. The inertia control of the wind turbine aims to adjust the operating state of the wind turbine so that it can provide inertial support for system frequency changes like a traditional synchronous generator. In the inertia control of the wind turbine, adjusting the excitation current and speed of the generator is a possible control method, but it is not the only method. In addition to adjusting the excitation current and speed, the inertia control of the wind turbine may also involve the use of energy storage systems, pitch angle control, and overspeed-load reduction operation strategies. The energy storage system can provide or absorb energy in a short period of time, thereby helping the wind turbine to respond quickly to changes in system frequency. In summary, the inertia control of the wind turbine is not limited to controlling the excitation current or speed of the generator. It is a comprehensive control strategy that may involve the combined use of multiple control methods and technologies to achieve a fast and effective response of the wind turbine to changes in system frequency.

[0037] Chopper devices are usually designed for use in wind power converters to deal with grid low voltage ride-through faults. When the grid voltage drops, the grid voltage at the grid connection point decreases, resulting in obstruction of wind turbine energy delivery. At this time, the Chopper device discharges energy through the IGBT power module in series with the energy discharge resistor to protect the wind power converter and achieve low voltage ride-through function. The action of the Chopper device is instantaneous. Once the DC bus voltage exceeds the set value, it will immediately start to discharge energy, so its energy discharge speed is very fast.

[0038] The application of Crowbar circuit in wind turbine is mainly to protect the wind turbine from abnormal conditions such as grid voltage sag. Its working principle is to bypass the rotor current through the Crowbar resistor by short-circuiting the rotor side of the generator, thereby avoiding damage to the wind turbine caused by overcurrent. The original design of the Crowbar circuit is not for precise control of power reduction, but as a protection device. When the grid voltage is abnormal, the Crowbar circuit can act quickly to bypass the rotor current and protect the wind turbine from damage. It may be difficult to achieve the requirement of accurately reducing 50% power using the Crowbar circuit for power control because its main purpose is protection rather than precise control. The Crowbar circuit is usually triggered based on the grid voltage rather than directly used to control the wind turbine power output. The response time of the Crowbar circuit is usually very fast and can act within milliseconds, which is beneficial for achieving power reduction in a short time (for example, within 2 seconds). However, the accuracy and stability of power reduction may be limited.

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

[0040] Relationship between wind power output and terminal voltage: When the output of a wind farm increases, the active power output of the wind turbine increases, which usually leads to an increase in 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 the reactive power loss and voltage drop on the line. However, when the output of the wind farm further increases to a certain threshold, the terminal voltage may begin to drop. 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 loss of the line and the reactive power demand of the asynchronous generator also increase accordingly, which may lead to insufficient reactive power in the regional power grid, resulting in a drop in voltage levels.

[0041] Grid structure and power flow impact: The topological relationship within the wind farm is complex, and the power flow relationship between wind turbines will lead to differences in terminal voltage. Especially when using constant power factor operation, refer to Figure 2Since the active power is transmitted from the end of the collector line (i.e., the end of the line) to the beginning of the collector line (i.e., the beginning of the line), the node voltage may increase from the beginning of the line to the end of the line. When the wind conditions in the wind farm are good, the wind turbine has a large active power output, and the wind turbine terminal voltage at the end of the line may be raised, resulting in an increase in the voltage difference between wind turbines.

[0042] Since the temperature and power of the brake resistor are nonlinear, it is impossible to accurately calculate how much energy the brake resistor releases and how much temperature rise it will cause, and it is also impossible to calculate and evaluate how much margin is available for use later. Insufficient brake resistance can easily lead to the risk of excessive bus voltage and excessive current; and the wind machine brake resistor is required for low voltage ride-through LVRT. If the wind machine brake resistor is used to quickly reduce power in the case of severe overfrequency, then if the scenes of severe overfrequency rapid power reduction and low voltage ride-through appear continuously, the functions triggered later will not respond normally; in addition, frequent use of brake resistors can easily lead to unstable operation of the fan, which will increase maintenance costs and downtime. Therefore, the principle of using brake resistors for severe overfrequency rapid power reduction can be: do not enable unless necessary.

[0043] On the one hand, the present disclosure takes into account: Figure 2 As shown, since the voltage at the fan end of each fan collector line gradually increases from the beginning to the end of the line, when the grid voltage is low and the LVRT condition occurs, the voltage at the beginning of the line will be lower than the voltage at the end of the line, that is to say, the dependence of the beginning of the line on the low voltage through-brake resistor is stronger than that of the end of the line. That is, not all fans have the same demand for low-voltage through-brake, and actually present a non-uniform symmetrical state, with more demand for fans near the grid connection point than for fans far from the grid connection point. Therefore, the present disclosure proposes: in the case of severe overfrequency and rapid power reduction, if the fan brake resistor must be enabled after calculation and evaluation, the enabled amount of the fan brake resistor needs to be differentially allocated.

[0044] On the other hand, the present disclosure takes into account that: since the working principle of the brake resistor is to trigger the brake resistor to quickly discharge energy when the DC bus voltage of the converter is too high. When the grid-side target value of the converter is lower than the comprehensive control power of the variable pitch, motor, etc., it is simply expressed as, for example, when the power emitted by the primary frequency modulation control is greater than the grid-side target power, that is, when there is a power difference, the function of the brake resistor is exited, and different degrees of power jump will occur according to the size of the power difference, such as Figure 3As shown. This will cause unnecessary power fluctuations to the power grid, and may also cause the bus voltage to be too high, generate excessive current, and damage the converter. In order to avoid this situation, the present disclosure proposes: when the power on the machine side of the converter is balanced with the target power on the grid side and the brake resistor no longer needs to discharge energy (for example, the power of the primary frequency modulation control is equal to the target power on the grid side), the brake resistor is controlled to exit. This balance condition limits the exit time of the brake resistor, that is, once the brake resistor enters, it can only exit when the temperature is met until the above balance condition is reached.

[0045] The following will be combined Figures 4 to 8 Exemplary embodiments of the present disclosure are described in detail.

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

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

[0048] As an exemplary embodiment, the application scenario of the power reduction control method of the wind farm according to the exemplary embodiment of the present disclosure may be: determining that the frequency of the grid connection point is seriously over-frequency, and determining that the wind machine braking resistor must be enabled for rapid power reduction, that is, after resource analysis and target instruction demand analysis, it is determined that the braking resistor must be called to meet the grid function. Further, as an example, the application scenario of the power reduction control method of the wind farm according to the exemplary embodiment of the present disclosure may be: determining that the frequency of the grid connection point is seriously over-frequency, and determining that in the first stage, the wind turbine is controlled to reduce power by a non-braking resistor power reduction method, and then in the second stage, the wind turbine is controlled to reduce power by a non-braking resistor power reduction method and a braking resistor. For example, the application scenario of the power reduction control method of the wind farm according to the exemplary embodiment of the present disclosure may be: determining that the frequency of the grid connection point is seriously over-frequency, and determining that in the first stage, the power is reduced according to the primary frequency modulation, and then in the second stage, the primary frequency modulation and the braking resistor are used to reduce power; or, determining that the frequency of the grid connection point is seriously over-frequency, and determining that in the first stage, the power is reduced according to the inertia response, and then in the second stage, the primary frequency modulation and the braking resistor are used to reduce power.

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

[0050] As an exemplary embodiment, step S100 may include: determining the total power reduction amount DeltP_damand that needs to be adjusted by the wind farm in the second stage of severe overfrequency rapid power reduction (i.e., the stage of simultaneously using non-braking resistor power reduction mode and braking resistor to reduce power). As an example, step S100 may further include: in response to the completion of the first stage of severe overfrequency rapid power reduction, according to the difference between the total power real-time value at the beginning of the first stage and the total power real-time value at the end of the first stage, determining the power reduction amount that has been adjusted in the first stage; and then using the difference between the total power reduction amount (e.g., 50% Pn) that needs to be adjusted by the wind farm in the first stage and the second stage and the power reduction amount that has been adjusted in the first stage as the total power reduction amount DeltP_damand that needs to be adjusted by the wind farm in the second stage. For example, for the severe overfrequency rapid regulation requirement of reducing Pn by 50% within 2s, if the whole field reduces Pn by 20% in the first stage, it is determined that the whole field power reduction required for wind farm regulation in the second stage is 30% Pn, that is, DeltP_damand=30%Pn.

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

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

[0053] As an example, if it is determined that in the second stage, the fan is controlled to use both primary frequency modulation and braking resistance to reduce power, then the power that can be reduced for the fan with the power reduction capability of braking resistance is: the sum of the power that can be reduced by braking resistance and the power that can be reduced by primary frequency modulation, and the power that can be reduced for the fan without the power reduction capability of braking resistance is: the power that can be reduced by primary frequency modulation.

[0054] As another example, if it is determined that in the second stage, the fan is controlled to use both inertia response and braking resistance to reduce power, then the amount of power that can be reduced for the fan with the power reduction capability of braking resistance is: the sum of the power reduction capability of braking resistance and the power reduction capability of inertia response, and the amount of power that can be reduced for the fan without the power reduction capability of braking resistance is: the power reduction capability of inertia response.

[0055] As an exemplary embodiment, under the condition that other conditions are the same, the closer the wind turbine with the power reduction capability of the braking resistor is to the grid connection point, the lower the power reduction amount of the single wind turbine that needs to be adjusted.

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

[0057] In step S201, the sum of the power reduction amounts of all wind turbines having the power reduction capability by means of braking resistors is taken as the total field-wide fast power reduction amount.

[0058] In step S202, in response to the fact that the total power reduction is less than or equal to the total power reduction that can be quickly reduced, the power reduction amount of each wind turbine with the power reduction capability of the braking resistor is determined based on the total power reduction, the power reduction amount of each wind turbine with the power reduction capability of the braking resistor, and the power reduction distribution coefficient. The closer the wind turbine with the power reduction capability of the braking resistor is to the grid connection point, the smaller the power reduction distribution coefficient is, and the smaller the power reduction distribution coefficient of the wind turbine is, the lower the power reduction amount of the single wind turbine that needs to be adjusted by the wind turbine. For example, as the distance between the wind turbine and the grid connection point increases, the power reduction distribution coefficient σ% of the wind turbine can be gradually increased according to a certain step size.

[0059] Specifically, if the total power reduction amount DeltP_demand required to be regulated by the wind farm is ≤ the total fast power reduction amount G_FastUsefulDeltPowerMinus, and the power command calculated by the grid connection point and the trigger control mode are in the fast power reduction mode, then it is only necessary to allocate wind turbines with braking resistor power reduction capability to reduce active power.

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

[0061] In step S203, in response to the fact that the total power reduction amount is greater than the total fast power reduction amount that can be reduced, based on the total power reduction amount, the power reduction amount that can be reduced of each wind turbine with braking resistor power reduction capability and the power reduction distribution coefficient, the single-machine power reduction amount that needs to be adjusted for each wind turbine with braking resistor power reduction capability is determined.

[0062] The following will be combined Figure 5 To describe an example of the balanced distribution method of "determining the single-machine 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 reducible power amount of each wind turbine with braking resistor power reduction capability and the power reduction distribution coefficient" in step S202 and step S203.

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

[0064] The following will be combined Figure 6 To describe an example of the balanced allocation method in step S204: "Determine the single-machine power reduction amount that needs to be adjusted for each wind turbine that does not have the power reduction capability of a braking resistor based on the remaining unallocated power reduction amount for the entire field and the power reduction amount of each wind turbine that does not have the power reduction capability of a braking resistor."

[0065] Specifically, if the total power reduction amount DeltP_demand that needs to be regulated by the wind farm is greater than the total fast power reduction amount G_FastUsefulDeltPowerMinus, and the power command calculated by the grid connection point and the trigger control mode are in the fast power reduction mode, the wind turbines with braking resistor power reduction capability will be preferentially used to reduce the active power by braking resistor + non-braking resistor power reduction method. When the backup capacity of all wind turbines with braking resistor power reduction capability is insufficient, the remaining power commands that do not meet the requirements of the grid connection point are allocated to the wind turbines with only non-braking resistor power reduction method to reduce the active power.

[0066] In step S300, each wind turbine is controlled to perform power reduction adjustment according to the power reduction amount of each wind turbine that needs to be adjusted.

[0067] As an exemplary embodiment, the target regulation rate of a non-braking resistor power reduction method (for example, the target regulation rate of primary frequency regulation or the target regulation rate of inertia response), the target regulation rate of grid-side power output limitation, the single-machine power reduction amount or target power value that needs to be adjusted by the wind turbine (calculated based on the single-machine power reduction amount that needs to be adjusted by the wind turbine) can be sent to each wind turbine with a braking resistor power reduction capability to control the wind turbine to perform power reduction regulation; and the target regulation rate of a non-braking resistor power reduction method, the single-machine power reduction amount or target power value that needs to be adjusted by the wind turbine can be sent to each wind turbine that does not have a braking resistor power reduction capability to control the wind turbine to perform power reduction regulation.

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

[0069] As an exemplary embodiment, the target regulation rate for limiting the power output of the grid side (i.e., the grid side of the converter) of each wind turbine with the power reduction capability of a braking resistor in the second stage can be determined based on the regulation time requirement (for example, for the severe overfrequency rapid regulation demand of reducing Pn by 50% within 2 seconds, the regulation time requirement is 2s), the regulation time of the first stage, the single-machine power reduction amount of each wind turbine with the power reduction capability of a braking resistor, and the control 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 the second time value t2; then, for each wind turbine with a braking resistor power reduction capability, the target adjustment rate of the grid-side power output restriction of the wind turbine in the second stage is calculated. Among them, Deltp break[i] Indicates the power reduction of the single unit that needs to be adjusted by the fan in the second stage. represents the control coefficient.

[0071] Because the brake resistor cannot accurately control the power, a regulation factor needs to be added Adjust the control coefficient according to the actual situation and specific needs. For example, if the power regulation speed is slow and the actual power response is small, increase the regulation coefficient. Otherwise, the control coefficient will be reduced.

[0072] According to the exemplary embodiment of the present disclosure, the idea of ​​asymmetric rapid power reduction regulation is proposed. The asymmetry principle is adopted to asymmetrically distribute the power regulation amount required by the brake resistor in the second stage to the wind turbines. The wind turbines close to the grid connection point bear less regulation target demand, and the wind turbines far from the grid connection point bear more regulation target demand. In the case of rapid power reduction response, the consumption of brake resistors is increased for the wind turbines in the far area, and the consumption of brake resistors in the near area is reduced.

[0073] In the above embodiment, the power reduction control of pitch control, generator, yaw and the like is uniformly incorporated into the primary frequency modulation and inertia response. The present disclosure does not specifically reflect the detailed control strategy of the primary frequency modulation or inertia response inside the wind turbine, but only takes the comprehensive balanced regulation of the three resources of primary frequency modulation, inertia response and braking resistor as the core idea. It is necessary to meet the requirements of the speed and accuracy of the power grid, and to consider the safety and reliability of the wind turbine. Therefore, the available resources will be balanced, the strong dependence on a certain resource will be minimized, and the consumption of the braking resistor will be minimized.

[0074] Figure 5 A flow chart showing a method for determining a single-machine power reduction amount that requires adjustment of each wind turbine having a braking resistor power reduction capability according to an exemplary embodiment of the present disclosure.

[0075] Reference Figure 5 In step S501, all fans with the power reduction capability of brake resistors are arranged according to the power reduction amount.

[0076] As an example, all fans with the ability to reduce power by a braking resistor may be arranged in ascending order according to the amount of power reduction that can be achieved, or all fans with the ability to reduce power by a braking resistor may be arranged in descending order according to the amount of power reduction that can be achieved.

[0077] In step S502, one wind turbine is selected from the arranged wind turbines in order each time, and the single-machine power reduction amount is allocated to the selected wind turbine 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 single-machine power reduction amount is used up.

[0078] When step S502 is performed for the first time, the average power reduction is the ratio of the total power reduction DeltP_demand to the total number of fans with the power reduction capability of the brake resistor. As an example, the average power reduction may be updated after each fan is allocated.

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

[0080] In step S503, based on the power lower limit of the selected fan, the product of the single-machine power reduction amount 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-machine power reduction amount that needs to be adjusted for the selected fan.

[0081] As an exemplary embodiment, the product of the single-machine power reduction amount 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-machine power reduction amount of the selected wind turbine is limited so that the difference is not lower than its power lower limit.

[0082] After each fan is allocated, the control is to subtract the power command just allocated from DeltP_damand to obtain the remaining unallocated total power reduction, the total number of fans with brake resistor power reduction capability minus 1, and then recalculate the ratio of the two to obtain the updated average power reduction, and then enter the next round of calculation (i.e., return to step S502), until the DeltP_damand requirement is met.

[0083] Figure 6 A flow chart showing a method for determining a single-machine power reduction amount for each wind turbine that does not have a braking resistor power reduction capability to adjust according to an exemplary embodiment of the present disclosure is shown.

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

[0085] As an example, all fans without the ability to reduce power by a braking resistor may be arranged in ascending order according to the amount of power reduction that can be achieved, or all fans without the ability to reduce power by a braking resistor may be arranged in descending order according to the amount of power reduction that can be achieved.

[0086] In step S602, one wind turbine is selected from the arranged wind turbines one by one in order each time, and the single-machine power reduction amount is allocated to the selected wind turbine 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 single-machine power reduction amount is used up.

[0087] When step S602 is performed for the first time, the average power reduction is the ratio of the remaining unallocated total power reduction to the total number of fans without the brake resistor power reduction capability. As an example, the average power reduction will be updated after each fan is allocated.

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

[0089] In step S603, based on the power lower limit value of the selected wind turbine, the single-machine power reduction amount allocated to the selected wind turbine is limited, and the limited value is used as the single-machine power reduction amount that needs to be adjusted for the selected wind turbine.

[0090] As an exemplary embodiment, if the difference between the current power value of the selected wind turbine and the single-machine power reduction amount allocated to the selected wind turbine is lower than its power lower limit, the single-machine 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 allocated, the total number of fans without brake resistor power reduction capability is reduced by 1, the remaining unallocated total power reduction amount is reduced by the power command just allocated, and the average power reduction amount is recalculated, and then the next round of calculation is entered (i.e., returning to step S602), until the DeltP_damand requirement is met or there is no fan to be allocated.

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

[0093] The power reduction rate of the braking resistor is very fast. However, before the power reduction mode of the non-braking resistor and the power between the braking resistor are balanced, if the suppression of the braking resistor is released, it will cause a rapid impact and fluctuation of the power. In order to reduce the impact on the power, the present disclosure proposes to increase the calculation of the non-braking resistor power reduction mode and the braking resistor balance time. The braking resistor can only be released after the balance is reached.

[0094] Due to the uncertainty of the power grid environment, in the case of severe overfrequency, after the wind farm power is rapidly reduced, if the frequency of the grid connection point is still in the severe overfrequency range, the field-level controller will wait for judgment according to the requirements of the power grid, and after a certain period of time (for example, 10s), if the frequency of the grid connection point still does not recover, it will continue to reduce the power to the lower limit of the wind farm power (for example, 8% Pn). During this 10s stay, if the brake resistor is always in the input state, the wind speed fluctuation will cause the continuous consumption of the brake resistor.

[0095] Therefore, the present disclosure proposes that: when the power controlled by the non-braking resistor power reduction mode is balanced with the grid-side target value, the operation state of the fan needs to be switched out of the braking resistor rapid power reduction as soon as possible. Once the braking resistor is enabled, the balance judgment of the braking resistor and non-braking resistor power reduction modes is added. Once the balance is reached, the braking resistor mode is immediately switched out in advance.

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

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

[0098] The shortest duration is the power reduction of a single machine △P i The ratio of the target regulation rate to the non-braking resistor power reduction method (for example, primary frequency modulation or inertia response).

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

[0100] T i =△P i / Rate_Pitch i

[0101] Among them, Rate_Pitch i Indicates the target adjustment rate of primary frequency modulation (ie, the target pitch adjustment rate).

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

[0103] Considering that the adjustment instructions assigned to each fan are processed differently, the latest execution time is used as the cut-out condition, so the minimum execution time T of all fans can be set. i After unified calculation, take out the maximum value T max :

[0104] T max =max(T i )

[0105] In step S600, in response to the current power reduction adjustment time length exceeding the maximum value T max The sum of the power reduction and the time margin is used to control each fan to end the current power reduction regulation.

[0106] As an example, the specific value of the time margin may be set according to actual conditions and specific requirements. For example, the specific value of the time margin may be set to 0.5 s.

[0107] The time margin delay is set to avoid active impact during the transient regulation of the DC bus voltage Udc of the converter. Therefore, the condition for controlling the exit of the braking resistor is:

[0108] T>T max +0.5

[0109] When the frequency is seriously over-frequency, and after resource analysis and calculation, it is determined that the brake resistor must be used, the time T when the brake resistor is started is recorded. start And set the cut-out flag Flag_FastP = 1:

[0110] T=T now -T start

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

[0112] According to an exemplary embodiment of the present disclosure, a cut-out condition (ie, a cut-out timing) of the brake resistance regulation is defined.

[0113] In addition, as an exemplary embodiment, a power reduction control method for a wind farm according to another exemplary embodiment of the present 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, that is, the power is balanced, the braking resistor can be switched out. At this time, the braking resistor mode is immediately switched out in advance and the primary frequency modulation mode (for example, the fast primary frequency modulation mode) is switched in. If the frequency is subsequently restored, since some countries / regions usually use the slow primary frequency modulation mode, the recovery phase can be switched from the fast primary frequency modulation mode to the slow primary frequency modulation mode. If the subsequent frequency is not restored, it is adjusted downward to the lower limit of the wind farm power according to the fast primary frequency modulation mode. The power regulation rate of the fast primary frequency modulation mode is higher than that of the slow primary frequency modulation mode.

[0115] In addition, as an exemplary embodiment, a power reduction control method for a wind farm according to another exemplary embodiment of the present disclosure may also include: after controlling each wind turbine to end the current power reduction adjustment, in response to the need to re-enable 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 re-enabled; in response to the difference being less than or equal to the cooling time of the braking resistor, limiting the re-enabling of the braking resistor.

[0116] When the cut-out flag Flag_FastP is set to 0, the start time after the cut-out is recorded T end , when the starting time T end The braking resistor can be enabled again only when necessary after an interval greater than the cooling time of the braking resistor (for example, 30 minutes), otherwise it will not be enabled.

[0117] According to the exemplary embodiments of the present disclosure, the reliability of the grid demand function is improved, and the response effects of severe overfrequency rapid power reduction and low voltage ride-through LVRT are reduced as much as possible; the safety and stability of the wind turbine operation are improved, and the risk of excessive bus voltage and excessive current due to insufficient braking resistance is avoided. The wind turbine responds as much as possible according to the active power control strategy of relatively slow speed as possible, thereby improving the safety factor and stability, and increasing the life of the wind turbine; the unstable operation of the wind turbine caused by frequent use of braking resistance is avoided, thereby reducing maintenance costs and downtime.

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

[0119] like Figure 8 As shown, the power reduction control device of a wind farm 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 determination unit 100 is configured to determine the amount of wind farm-wide power reduction that requires wind farm regulation.

[0121] The allocation unit 200 is configured to determine the single-machine 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 from the grid connection point to each wind turbine with braking resistor power reduction capability.

[0122] The control unit 300 is configured to control each wind turbine to perform power reduction adjustment according to the power reduction amount of each wind turbine that needs to be adjusted.

[0123] The power reduction amount of a fan with the power reduction capability of a braking resistor is: the sum of the power reduction amount of the braking resistor and the power reduction amount of the non-braking resistor power reduction method. The power reduction amount of a fan without the power reduction capability of a braking resistor is: the power reduction amount of the 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 amounts of all wind turbines with braking resistor power reduction capability as the total rapid power reduction amount for the entire field; in response to the total power reduction amount being less than or equal to the total rapid power reduction amount for the entire field, determine the single-machine 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 distribution coefficient; wherein, the closer the distance between the wind turbine with braking resistor power reduction capability and the grid connection point is, the smaller the power reduction distribution coefficient is.

[0125] As an exemplary embodiment, the allocation unit 200 can also be configured to: in response to the full-field power reduction amount being greater than the full-field quickly reducible power amount, determine the single-machine power reduction amount that needs to be adjusted for each wind turbine with a braking resistor power reduction capability based on the full-field power reduction amount, the reducible power amount of each wind turbine with a braking resistor power reduction capability, and the power reduction allocation coefficient; after allocating the single-machine power reduction amount to all wind turbines with a braking resistor power reduction capability, determine the single-machine power reduction amount that needs to be adjusted for each wind turbine without a braking resistor power reduction capability based on the remaining unallocated full-field power reduction amount and the reducible power amount of each wind turbine without a braking resistor power reduction capability.

[0126] As an exemplary embodiment, the allocation unit 200 can be configured to: arrange all fans with braking resistor power reduction capability according to the amount of power that can be reduced; select one fan from the arranged fans in order each time, and allocate a single-machine power reduction amount to the selected fan according to the principle that if the amount of power that can be reduced 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 used up; based on the lower power limit value of the selected fan, the product of the single-machine power reduction amount 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-machine power reduction amount that needs to be adjusted by the selected fan.

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

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

[0129] As an exemplary embodiment, the control unit 300 can also be configured to: after controlling each fan to end the current power reduction adjustment, in response to the need to re-enable 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 re-enabled; in response to the difference being less than or equal to the cooling time of the braking resistor, limit the re-enabling of the braking resistor.

[0130] As an exemplary embodiment, the control unit 300 can be configured to: send the target adjustment rate of the non-braking resistor power reduction method, the target adjustment rate of the grid-side power output limitation, the single-machine power reduction amount or the target power value that needs to be adjusted by the wind turbine to each wind turbine with the braking resistor power reduction capability, so as to control the wind turbine to perform power reduction adjustment; send the target adjustment rate of the non-braking resistor power reduction method, the single-machine power reduction amount or the target power value that needs to be adjusted by the wind turbine to each wind turbine without the braking resistor power reduction capability, so as 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 of the wind farm according to the exemplary embodiment of the present disclosure has been referred to. Figures 2 to 7 The details have been described in detail and will not be repeated here.

[0132] It should be understood that the various units in the power reduction control device for a wind farm according to the exemplary embodiment of the present disclosure may be implemented as hardware components and / or software components. Those skilled in the art may implement the various units, for example, using a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC) according to the processing performed by the various defined units.

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

[0134] According to an exemplary embodiment 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, the at least one processor is prompted to execute the power reduction control method for a wind farm as described in the above exemplary embodiment. Examples of computer-readable storage media here 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 disk storage, hard disk drive (HDD), solid state drive (SSD), card storage (such as, multimedia card, secure digital (SD) card or extreme digital (XD) card), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid state disk and any other device, any other device is configured to store computer programs and any associated data, data files and data structures in a non-transitory manner and provide the computer programs 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 above-mentioned computer-readable storage medium can be run in an environment deployed in a computer device such as a client, a host, an agent device, a server, etc. In addition, in one example, the computer program and any associated data, data files and data structures are distributed on a networked computer system, so that the computer program and any associated data, data files and data structures are stored, accessed and executed in a distributed manner by one or more processors or computers.

[0135] According to an exemplary embodiment of the present disclosure, a computer program product may also be provided, and instructions in the computer program product may be executed by at least one processor to implement the power reduction control method for a wind farm as described in the above exemplary embodiment.

[0136] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the claims.

[0137] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A power reduction control method for a wind farm, characterized in that: include: Determine the amount of overall power reduction that requires wind farm regulation; Determine the power reduction amount of each wind turbine that needs to be adjusted according to the power reduction amount of the entire wind farm, the power reduction amount of each wind turbine in the wind farm, and the distance between each wind turbine with the power reduction capability of the braking resistor and the grid connection point; According to the power reduction amount of each fan that needs to be adjusted, each fan is controlled to reduce power; Among them, the power reduction amount of the fan with braking resistor power reduction capability is: the sum of the power reduction amount of the braking resistor and the power reduction amount of the non-braking resistor power reduction method; the power reduction amount of the fan without braking resistor power reduction capability is: the power reduction amount of the non-braking resistor power reduction method.

2. The power reduction control method according to claim 1, characterized in that: The steps to determine the power reduction required for each wind turbine include: The sum of the power reduction amounts of all fans with the power reduction capability of brake resistors is taken as the total power reduction amount of the entire site; In response to the whole-field power reduction amount being less than or equal to the whole-field fast reducible power amount, based on the whole-field power reduction amount, the reducible power amount of each wind turbine with a braking resistor power reduction capability and a power reduction distribution coefficient, determining a single-machine power reduction amount to be adjusted for each wind turbine with a braking resistor power reduction capability; 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.

3. The power reduction control method according to claim 2, characterized in that: The step of determining the power reduction amount of each wind turbine that needs to be adjusted also includes: In response to the whole-field power reduction being greater than the whole-field fast power reduction amount, based on the whole-field power reduction amount, the power reduction amount of each wind turbine with a braking resistor power reduction capability and a power reduction distribution coefficient, determining a single-machine power reduction amount to be adjusted for each wind turbine with a braking resistor power reduction capability; After allocating the single-machine power reduction amount to all fans with braking resistor power reduction capability, the single-machine power reduction amount that needs to be adjusted for each fan without braking resistor power reduction capability is determined based on the remaining unallocated total field power reduction amount and the power reduction amount that can be reduced for each fan without braking resistor power reduction capability.

4. The power reduction control method according to claim 2 or 3, characterized in that: The steps of determining the power reduction amount of each fan that needs to have the braking resistor power reduction capability include: Arrange all fans with brake resistor power reduction capability according to the amount of power reduction they can achieve; Each time, one fan is selected from the arranged fans in order, and the power reduction amount of a single fan is allocated 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 used up; Based on the lower power limit of the selected fan, the product of the single-machine power reduction amount 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-machine power reduction amount that needs to be adjusted by the selected fan.

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

6. The power reduction control method according to claim 5, characterized in that: Also includes: After controlling each fan to finish the current power reduction adjustment, each fan is controlled to perform a frequency adjustment.

7. The power reduction control method according to claim 5, characterized in that: Also includes: After controlling each fan to end the current power reduction adjustment, in response to the need to re-enable the brake 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 brake resistor; In response to the difference exceeding the cooling time of the braking resistor, allowing the braking resistor to be enabled again; In response to the difference being less than or equal to the cooling time of the braking resistor, reactivation of the braking resistor is restricted.

8. The power reduction control method according to claim 1, characterized in that: According to the power reduction amount of each fan that needs to be adjusted, the steps of controlling each fan to reduce power include: Send the target regulation rate of non-braking resistor power reduction mode, the target regulation rate of grid-side power output restriction, the single-machine power reduction amount or target power value that needs to be regulated by the wind turbine to each wind turbine with braking resistor power reduction capability, so as to control the wind turbine to perform power reduction regulation; The target adjustment rate of the non-braking resistor power reduction mode, the single-machine power reduction amount or the target power value that needs to be adjusted by the fan are sent to each fan that does not have the braking resistor power reduction capability, so as to control the fan to perform power reduction adjustment.

9. A power reduction control device for a wind farm, characterized in that: include: A determination unit configured to determine a field-wide power reduction amount that requires wind farm regulation; The allocation unit is configured to determine the single-machine power reduction amount that needs to be adjusted for each wind turbine according to the total power reduction amount, the power reduction amount of each wind turbine in the wind farm, and the distance between each wind turbine with a braking resistor power reduction capability and the grid connection point; The control unit is configured to control each fan to reduce power according to the power reduction amount of each fan that needs to be adjusted; Among them, the power reduction amount of the fan with braking resistor power reduction capability is: the sum of the power reduction amount of the braking resistor and the power reduction amount of the non-braking resistor power reduction method; the power reduction amount of the fan without braking resistor power reduction capability is: the power reduction amount of the non-braking resistor power reduction method.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the processor is prompted to execute the power reduction control method for a wind farm as claimed in any one of claims 1 to 8.

11. A controller for a wind farm, characterized in that: include: processor; A memory stores a computer program, which, when executed by a processor, prompts the processor to execute the power reduction control method for a wind farm as claimed in any one of claims 1 to 8.

12. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the power reduction control method for a wind farm as claimed in any one of claims 1 to 8 is implemented.

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