Method, control device and controller for reducing active power of wind farm

Abstract

Provided are a method, control device and controller for reducing the active power of a wind farm, the method comprising: obtaining the amount of active power reduction that the wind farm needs to reduce; determining the amount of active power reduction that can be reduced for each wind turbine generator set according to the controllable state of wind turbine power of each wind turbine generator set in the wind farm; determining the amount of active power reduction for each wind turbine generator set based on the amount of active power reduction that the wind farm needs to reduce and the amount of active power reduction that can be reduced for each wind turbine generator set, and using the determined amount of active power reduction for each wind turbine generator set to reduce the active power of the wind farm. The method for reducing the active power of a wind farm according to an embodiment of the present invention reduces the active power quickly and has little impact on the load of the wind turbine generator set.

Description

Technical Field

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

[0002] As the penetration rate of new energy-powered generators continues to increase, the safety and stability of wind turbines have attracted widespread attention in power grids in high-penetration areas.

[0003] In the actual operation of the power grid, when the power consumption does not match the power supply, it may cause the power grid frequency to change slightly with a short change period. This frequency disturbance is mainly adjusted directly and automatically by the wind turbine's own regulation system to complete the grid load compensation and correct the grid frequency fluctuation. This process is the primary frequency regulation of the wind turbine.

[0004] In addition, the braking resistor is used to quickly reduce the active power. The braking resistor power reduction and the pitch power reduction need to be coordinated and controlled on the same unit, and also between different units.

[0005] It is particularly important to quickly reduce the active power of wind farms to effectively meet the regulation needs. Summary of the invention

[0006] An exemplary embodiment of the present invention is to provide a method for reducing the active power of a wind farm, a control device and a controller, which can reduce the active power of the wind farm to effectively meet the regulation demand.

[0007] According to one aspect of the present invention, a method for reducing the active power of a wind farm is provided, the method comprising: obtaining an amount of active power reduction that the wind farm needs to reduce; determining an amount of active power reduction that can be achieved for each wind turbine generator set according to a controllable state of wind turbine power of each wind turbine generator set in the wind farm; and determining an amount of active power reduction for each wind turbine generator set based on the amount of active power reduction that the wind farm needs to reduce and the amount of active power reduction that can be achieved for each wind turbine generator set.

[0008] According to an embodiment of the present invention, the controllable power state of the wind turbine may include a first state reflecting that the wind turbine generator set only has pitch control capability, a second state reflecting that the wind turbine generator set has both pitch control capability and braking resistor control capability, and a third state reflecting that the wind turbine generator set does not have power reduction capability.

[0009] According to an embodiment of the present invention, the step of determining the amount of active power reduction of each wind turbine generator set may include: in response to the controllable power state of the wind turbine generator set being the first state, determining the amount of active power reduction of the wind turbine generator set as the amount of active power reduction by pitch change of the wind turbine generator set, and the amount of active power reduction by pitch change is the first power amount calculated by subtracting the actual power from the power lower limit, and determining a first number and a first total amount of power reduction for all wind turbine generator sets whose wind turbine power controllable state is the first state; in response to the controllable power state of the wind turbine generator set being the second state, determining the amount of active power reduction of the wind turbine generator set as the sum of the amount of active power reduction by the braking resistor of the wind turbine generator set and the amount of active power reduction by pitch change, and the sum is the second power amount calculated by subtracting the actual power from the power lower limit, and determining a second number and a second total amount of power reduction for all wind turbine generator sets whose wind turbine power controllable state is the second state; in response to the controllable power state of the wind turbine generator set being the third state, determining the amount of active power reduction of the wind turbine generator set to be zero.

[0010] According to an embodiment of the present invention, the step of determining the active power reduction of each wind turbine generator set may include: determining a control mode for reducing the active power of the wind farm based on the grid connection point frequency detected by the grid connection point, the control mode being a fast power reduction mode or a normal pitch power reduction mode.

[0011] According to an embodiment of the present invention, the step of determining the active power reduction amount of each wind turbine generator set may further include: determining the wind turbine generator sets involved in reducing the active power of the wind farm, and determining the active power reduction amount of the wind turbine generator sets involved in reducing the active power of the wind farm.

[0012] According to an embodiment of the present invention, the step of determining the amount of active power reduction of wind turbines participating in reducing the active power of a wind farm may include at least one of the following steps: separately sorting the amount of active power reduction of all wind turbines in a first state and determining the amount of active power reduction of all wind turbines in the first state according to the principle that the average power is allocated if it is greater than the average power and the power is used up if it is less than the average power; separately sorting the amount of active power reduction of all wind turbines in a second state and determining the amount of active power reduction of all wind turbines in the second state according to the principle that the average power is allocated if it is greater than the average power and the power is used up if it is less than the average power; mixedly sorting the amount of active power reduction of all wind turbines in the first state and all wind turbines in the second state and determining the amount of active power reduction of all wind turbines in the first state and all wind turbines in the second state according to the principle that the average power is allocated if it is greater than the average power and the power is used up if it is less than the average power.

[0013] According to an embodiment of the present invention, when the control mode is a fast power reduction mode and the amount of active power reduction that the wind farm needs to reduce is less than the second total reducible power amount, all wind turbine generator sets in the second state can participate in reducing the active power of the wind farm, and the available active power reduction amount of the wind turbine generator sets with smaller second power amounts can be preferentially used up, wherein a first predetermined reduction rate signal is sent to each wind turbine generator set in the second state; when the control mode is a fast power reduction mode and the amount of active power reduction that the wind farm needs to reduce is greater than the second total reducible power amount, all wind turbine generator sets in the second state and the first state can participate in reducing the active power of the wind farm, and after the active power reduction amount of all wind turbine generator sets in the second state is exhausted, the first predetermined reduction rate signal is sent to each wind turbine generator set in the second state. After the power reduction amount, the pitch-changing active power reduction amount of the wind turbine generator set with a smaller first power amount is preferentially used, wherein a first predetermined reduction rate signal is sent to each wind turbine generator set in the second state, and a second predetermined reduction rate signal is sent to each wind turbine generator set in the first state; when the control mode is the ordinary pitch-changing power reduction mode, all wind turbine generator sets in the first state and all wind turbine generator sets in the second state can participate in reducing the active power of the wind farm, and the active power reduction amount of the wind turbine generator set with a smaller active power reduction amount is preferentially used, wherein a second predetermined reduction rate signal is sent to all wind turbine generator sets in the first state and all wind turbine generator sets in the second state.

[0014] According to another aspect of the present invention, there is provided a control device for reducing the active power of a wind farm, and the control device may include: a reduction amount acquisition unit, configured to acquire the active power reduction amount that needs to be adjusted by the wind farm; a reducible amount determination unit, configured to determine the reducible amount of active power of each wind turbine generator set according to the controllable state of wind turbine power of each wind turbine generator set in the wind farm; and a reduction amount determination unit, configured to determine the active power reduction amount of each wind turbine generator set based on the active power reduction amount that needs to be reduced by the wind farm and the reducible amount of active power of each wind turbine generator set.

[0015] According to an embodiment of the present invention, the controllable power state of the wind turbine may include a first state reflecting that the wind turbine generator set only has the pitch control capability, a second state reflecting that the wind turbine generator set has both the pitch control capability and the braking resistor control capability, and a third state reflecting that the wind turbine generator set does not have the power reduction capability. The reduction amount determination unit may be further configured to: in response to the controllable power state of the wind turbine generator set being the first state, determine that the active power reduction amount of the wind turbine generator set is the pitch reduction active power amount of the wind turbine generator set, and the pitch reduction active power amount is the first power amount calculated by subtracting the actual measured power from the power lower limit, and determine the wind turbine power. A first quantity and a first total reducible power amount of all wind generator sets whose controllable state is a first state; in response to the controllable state of the wind turbine power of the wind generator set being a second state, determining the reducible active power amount of the wind generator set as the sum of the reducible active power amount of the braking resistor and the reducible active power amount of the pitch of the wind generator set, and the sum is a second power amount calculated by subtracting the measured power from the power lower limit, and determining the second quantity and a second total reducible power amount of all wind generator sets whose controllable state of the wind turbine power is a second state; in response to the controllable state of the wind turbine power of the wind generator set being a third state, determining the reducible active power amount of the wind generator set to be zero.

[0016] According to an embodiment of the present invention, the reduction determination unit may be further configured to determine whether the control mode for reducing the active power of the wind farm is a fast power reduction mode or a normal pitch power reduction mode based on the grid connection point frequency detected by the grid connection point.

[0017] According to an embodiment of the present invention, the reducible amount determination unit can be further configured to: separately sort the reducible amounts of active power of all wind turbines in the first state and determine the reducible amounts of active power of all wind turbines in the first state according to the principle of allocating average power if it is greater than the average power and using up the power if it is less than the average power; separately sort the reducible amounts of active power of all wind turbines in the second state and determine the reducible amounts of active power of all wind turbines in the second state according to the principle of allocating average power if it is greater than the average power and using up the power if it is less than the average power; mixedly sort the reducible amounts of active power of all wind turbines in the first state and all wind turbines in the second state and determine the reducible amounts of active power of all wind turbines in the first state and all wind turbines in the second state according to the principle of allocating average power if it is greater than the average power and using up the power if it is less than the average power.

[0018] According to an embodiment of the present invention, the reduction amount determination unit may be further configured as follows: when the control mode is a fast power reduction mode and the amount of active power reduction that the wind farm needs to reduce is less than the second total reducible power amount, all wind turbine generator sets in the second state are enabled to participate in reducing the active power of the wind farm, and the available active power reduction amount of the wind turbine generator sets with smaller second power amounts is preferentially used up, wherein a first predetermined reduction rate signal is sent to each wind turbine generator set in the second state; when the control mode is a fast power reduction mode and the amount of active power reduction that the wind farm needs to reduce is greater than the second total reducible power amount, all wind turbine generator sets in the second state and the first state are enabled to participate in reducing the active power of the wind farm, and after all wind turbine generator sets in the second state are used up, the available active power reduction amount of the wind turbine generator sets is preferentially used up. After the active power reduction amount of the generator set, the active power reduction amount of the wind generator set with a smaller first power amount is preferentially used by the pitch-changing active power reduction amount, wherein a first predetermined reduction rate signal is sent to each wind generator set in the second state, and a second predetermined reduction rate signal is sent to each wind generator set in the first state; when the control mode is the ordinary pitch-changing power reduction mode, all wind generator sets in the first state and all wind generator sets in the second state are made to participate in reducing the active power of the wind farm, and the active power reduction amount of the wind generator set with a smaller active power reduction amount is preferentially used up, wherein a second predetermined reduction rate signal is sent to all wind generator sets in the first state and all wind generator sets in the second state.

[0019] According to another aspect of the present invention, a controller of a wind farm is provided. The controller may include: a processor; and a memory storing a computer program. When the computer program is executed by the processor, the above method of reducing the active power of the wind farm is implemented.

[0020] The method, control device and controller for reducing the active power of a wind farm according to an exemplary embodiment of the present invention can be suitable for reducing the active power of a wind farm in various scenarios, and can effectively meet the requirements of fast regulation speed and small impact on the load of wind turbines.

[0021] In addition, according to the method, control device and controller for reducing the active power of a wind farm according to an exemplary embodiment of the present invention, a small number of wind turbines are controlled and dispatched in the process of reducing the active power of the wind farm, which can effectively control and reduce the number of times the braking resistor is used, and has the function of protecting high and low penetration.

[0022] Additional aspects and / or advantages of the present general inventive concept will be set forth in part in the following description and in part will be obvious from the description, or may be learned through practice of the present general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects and features of the exemplary embodiments of the present invention will become more apparent through the following description in conjunction with the accompanying drawings which exemplarily illustrate the embodiments, in which:

[0024] Figure 1 A flow chart showing a method for reducing active power of a wind farm according to an exemplary embodiment of the present invention;

[0025] Figure 2 A schematic block diagram showing the determination of the amount of reduction of active power of each wind turbine generator set based on the controllable power state of the wind turbine according to an exemplary embodiment of the present invention;

[0026] Figure 3 A graph showing a droop control method based on a detection frequency of a grid connection point during a primary frequency modulation process according to an exemplary embodiment of the present invention;

[0027] Figure 4 A block diagram showing a control device for reducing active power of a wind farm according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0028] Reference will now be made in detail to embodiments of the present invention, examples of which are shown 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 invention.

[0029] Figure 1 A flow chart showing a method of reducing active power of a wind farm according to an exemplary embodiment of the present invention is shown.

[0030] The method of reducing active power of a wind farm according to an exemplary embodiment of the present invention may include steps S110 , S120 , and S130 .

[0031] Reference Figure 1 In step S110, the active power reduction amount that the wind farm needs to reduce is obtained.

[0032] The acquired active power reduction amount that the wind farm needs to reduce may be the active power reduction amount that the wind farm needs to reduce when it is in one of the following situations: the wind farm participates in primary frequency regulation (primary frequency regulation refers to the automatic control process in which the control system of the unit in the power grid automatically controls the increase or decrease of the active power of the unit once the frequency of the power grid deviates from the rated value, limits the change of the power grid frequency, and maintains a stable power grid frequency), the wind farm participates in secondary frequency regulation, and the wind farm and / or the power grid to which it is connected fails. It should be understood that it may also be the active power reduction amount that the wind farm needs to reduce in other situations where the wind farm needs to reduce its active power.

[0033] In other words, the method of reducing the active power of a wind farm according to an exemplary embodiment of the present invention can be applied to a variety of scenarios for reducing active power, such as primary frequency regulation, secondary frequency regulation, failure of the wind farm and / or the power grid to which it is connected (e.g., short circuit, circuit breaker failure, etc.), and other scenarios.

[0034] For example, after it is determined that the wind farm participates in a primary frequency regulation, the amount of active power reduction that the wind farm needs to reduce for this primary frequency regulation can be determined.

[0035] As an example, when the frequency of the grid connection point is not within the frequency dead zone, and the active power of the wind farm is not less than a predetermined percentage (e.g., 20%) of the rated power of the wind farm, and the active power reduction is greater than a predetermined percentage (e.g., 10%) of the rated output of the wind farm, it is determined that the wind farm participates in the primary frequency regulation. It should be understood that other appropriate methods can also be used to determine whether the wind farm participates in the primary frequency regulation.

[0036] As an example, the active power reduction amount DeltP (power demand) can be calculated by formula (1).

[0037]

[0038] Among them, f d Indicates the threshold value of fast frequency response action; f indicates the frequency of the grid connection point, P n Indicates the rated power of the wind farm; δ% indicates the regulation rate; P0 indicates the current active power of the wind farm, f N Indicates the rated frequency of the power grid. It should be understood that for over-frequency and under-frequency conditions, the parameters in the formula can be set independently and adjusted online. For example, the reference parameters are as follows: f d It can be set to 50±0.1Hz, and the modulation error rate δ% can be set to 2%~3%.

[0039] The above method for calculating the active power reduction is only an example, and the present invention is not limited thereto. When in different working conditions, the active power reduction can be determined in different ways.

[0040] In step S120, the amount by which the active power of each wind turbine generator set can be reduced is determined according to the controllable state of the wind turbine power of each wind turbine generator set in the wind farm.

[0041] The wind turbine power controllable state may be fed back from each wind turbine generator set, and the wind turbine power controllable state may reflect the power reduction capability and / or power reduction mode of each wind turbine generator set.

[0042] As an example, the wind turbine power controllable state may include a first state reflecting that the wind turbine generator set only has pitch control capability, a second state reflecting that the wind turbine generator set has both pitch control capability and braking resistor control capability, and a third state reflecting that the wind turbine generator set does not have power reduction capability.

[0043] In wind turbines, braking resistors are mainly used during low voltage ride-through to convert the active power on the machine side into heat energy, thereby quickly consuming the active power on the machine side to help the wind turbines achieve low voltage ride-through.

[0044] The variable pitch control capability refers to the ability to reduce the active power of a wind turbine generator set by controlling the variable pitch power reduction, and the braking resistor control capability refers to the ability to reduce the active power of a wind turbine generator set by using a braking resistor.

[0045] Specifically, when feedback data including an integer value 1 is received from a wind turbine generator set, it indicates that the wind turbine generator set only has variable pitch control capability and is in a first state; when feedback data including an integer value 2 is received from a wind turbine generator set, it indicates that the wind turbine generator set has variable pitch control capability and brake resistor control capability and is in a second state; when feedback data including other integer values ​​(for example, 0) other than integer values ​​1 and 2 is received from a wind turbine generator set, it indicates that the wind turbine generator set does not have power reduction capability and is in a third state. The specific integer value reflecting the controllable state of wind turbine power is not limited to the above values, and the controllable state of wind turbine power can also be determined by binary numbers, etc.

[0046] In step S130, the active power reduction amount of each wind turbine generator set is determined based on the active power reduction amount that the wind farm needs to reduce and the available active power reduction amount of each wind turbine generator set.

[0047] In addition, the method for reducing the active power of a wind farm according to an exemplary embodiment of the present invention may further include reducing the active power of the wind farm using the determined active power reduction amount of each wind turbine generator set. This step may be directly executed by the field control device to be described below, or may be executed by the power instruction received by the main controller of each wind turbine generator set, etc., to control the relevant execution components.

[0048] It should be noted that the execution order of the above steps is not limited to the order of S110 - S120 - S130 , but can be changed as needed.

[0049] Figure 2 A schematic block diagram showing determination of the amount of reduction in active power of each wind turbine generator set based on a controllable power state of the wind turbine according to an exemplary embodiment of the present invention.

[0050] like Figure 2As shown, the step of determining the amount of active power reduction of each wind turbine generator set may include determining the amount of active power reduction of each wind turbine generator set based on the controllable state of wind turbine power of each wind turbine generator set. According to an embodiment of the present invention, only the total amount of active power reduction of each wind turbine generator set is considered, without distinguishing the specific values ​​of the amount of active power reduction of each wind turbine generator set by pitch control and the amount of active power reduction of the braking resistor.

[0051] Specifically, the step of determining the amount of active power reduction of each wind turbine generator set may include: in response to the controllable power state of the wind turbine generator set being the first state, determining the amount of active power reduction of the wind turbine generator set as the variable pitch active power reduction amount of the wind turbine generator set (that is, the total active power reduction amount of the wind turbine generator set is the total variable pitch active power reduction amount), and the variable pitch active power reduction amount is a first power amount pd1 calculated by subtracting the measured power from the power lower limit (for example, the frequency modulation power lower limit), and determining a first number n1 of all wind turbine generator sets whose wind turbine power controllable state is the first state and a first total reducible power amount p1 (p1=pd1×n1).

[0052] The lower power limit of the wind turbine generator set can be understood as if the power is lower than the lower limit, the wind turbine generator set will shut down. For example, the lower power limit of the wind turbine generator set can be 10% of the rated power value of the wind turbine generator set. The measured power of the wind turbine generator set can be understood as the current actual power of the wind turbine generator set.

[0053] The step of determining the amount of active power reduction of each wind turbine generator set may also include: in response to the wind turbine power controllable state of the wind turbine generator set being the second state, determining the amount of active power reduction of the wind turbine generator set as the sum of the active power reduction of the braking resistor of the wind turbine generator set and the active power reduction of the pitch controllable state, and the sum is a second power amount pd2 calculated by subtracting the measured power from the power lower limit, and determining a second number n2 of all wind turbine generator sets whose wind turbine power controllable state is the second state and a second total reducible power amount p2 (p2=pd2×n2).

[0054] Similarly, the step of determining the amount of active power reduction of each wind generator set may also include: in response to the wind turbine power controllable state of the wind generator set being the third state, determining the amount of active power reduction of the wind generator set to be zero. In addition, the reduced power pt of all wind generator sets may also be determined.

[0055] As an example, a control mode for reducing the active power of the wind farm may also be predetermined, and the control modes are a fast power reduction mode and a normal pitch control power reduction mode.

[0056] For example, the control mode may be determined to be a fast power reduction mode or a normal pitch control power reduction mode based on the grid connection point frequency detected by the grid connection point.

[0057] Figure 3 A graph showing a droop control method based on a detection frequency of a grid connection point during a primary frequency modulation process according to an exemplary embodiment of the present invention.

[0058] Specific as Figure 3 As shown in FIG. 1 , when the detection frequency of the grid-connected point satisfies Fd-≤f≤Fd+, the wind turbine generator set receives the active power instruction and does not participate in the system frequency regulation.

[0059] When the detection frequency of the grid-connected point satisfies F3<f<Fd- or Fd+<f<F1, the wind farm can adopt the ordinary variable pitch power reduction mode.

[0060] When the detection frequency of the grid connection point satisfies F1≤f≤F2, the power grid is in a serious overfrequency state, and the wind farm can adopt a rapid power reduction mode.

[0061] When the detection frequency of the grid-connected point is f>F2 or f<F3, the active power remains unchanged at the current state, and further changes in frequency will trigger the shutdown of the wind turbine generator set.

[0062] The above steps of detecting the frequency of the grid connection point and determining the power reduction mode are preferred steps for the wind turbine generator set to participate in the primary frequency modulation. In other working conditions, the above steps can be omitted. The specific power allocation method according to the embodiment of the present invention will be described in detail below.

[0063] If the amount of active power reduction that can be achieved for each wind turbine generator set is greater than or equal to the average value (p / (n1+n2)) of the amount of active power reduction that needs to be reduced by the wind farm, then the average value can be allocated to each wind turbine generator set, or the wind turbine generator sets with smaller amounts of active power reduction can be used up first. If there is a situation where the amount of active power reduction that can be achieved is less than the average value of the amount of active power reduction that needs to be reduced by the wind farm, then the amount of active power reduction that can be achieved for the wind turbine generator sets with smaller amounts of active power reduction can be used up first.

[0064] As an example, power may be allocated based on a specific power reduction mode and the magnitude of the active power reduction.

[0065] Optionally, when the control mode is a fast power reduction mode and the amount of active power reduction required to be reduced by the wind farm is less than the second total reducible power amount p2, all wind turbines in the second state can participate in reducing the active power of the wind farm, and the active power reduction amount of wind turbines with a smaller second power amount pd2 is preferentially used up. Therefore, the method for reducing the active power of a wind farm according to an embodiment of the present invention does not need to consider the specific proportion and specific value of the amount of active power that can be reduced by the pitch and the amount of active power that can be reduced by the brake resistor in the wind turbines in the second state, the power allocation is more simplified, and the number of required interfaces is greatly reduced.

[0066] In addition, in the above case, a first predetermined reduction rate signal is sent to each wind turbine in the second state (for example, when the wind turbine receives the first predetermined reduction rate signal, it instructs the wind turbine to reduce power at a rate of 20% Pn / s).

[0067] When the control mode is the fast power reduction mode and the amount of active power reduction required to be reduced by the wind farm is greater than the second total power reduction amount p2, all wind turbines in the second state and the first state can participate in reducing the active power of the wind farm, and after exhausting the active power reduction amounts of all wind turbines in the second state, the variable pitch active power reduction amounts of wind turbines with smaller first power amount pd1 are preferentially used. In addition, in this case, a first predetermined reduction rate signal can be sent to each wind turbine in the second state, and a second predetermined reduction rate signal can be sent to each wind turbine in the first state (for example, instructing the wind turbine to reduce power at a rate of 50kW / s).

[0068] When the control mode is the normal variable pitch power reduction mode, all wind turbines in the first state and all wind turbines in the second state can participate in reducing the active power of the wind farm, and the active power reduction of wind turbines with smaller active power reduction can be used up first. In addition, in this case, a second predetermined reduction rate signal is sent to all wind turbines in the first state and all wind turbines in the second state. The method of preferentially using a specific wind turbine will be described in detail below.

[0069] The step of determining the active power reduction amount of each wind turbine generator set may further include: determining the wind turbine generator sets participating in reducing the active power of the wind farm, and determining the active power reduction amount of the wind turbine generator sets participating in reducing the active power of the wind farm.

[0070] The step of determining the active power reduction amounts of the wind turbine generator systems participating in reducing the active power of the wind farm may include the step of sorting the available active power reduction amounts of the wind turbine generator systems.

[0071] For example, the step of determining the active power reduction amount of the wind turbine generator systems participating in reducing the active power of the wind farm may include at least one of the following steps:

[0072] In the first step, the available active power reduction amounts of all wind generator sets in the first state are individually sorted and the available active power reduction amounts of all wind generator sets in the first state are determined according to the principle that the average power is allocated if the power is greater than the average power and the power is used up if the power is less than the average power.

[0073] In the second step, the available active power reduction amounts of all wind generator sets in the second state are separately sorted and the available active power reduction amounts of all wind generator sets in the second state are determined according to the principle that the average power is allocated if it is greater than the average power and the active power is used up if it is less than the average power.

[0074] The third step is to sort the available active power reduction amounts of all wind turbine generator sets in the first state and all wind turbine generator sets in the second state in a mixed manner and determine the available active power reduction amounts of all wind turbine generator sets in the first state and all wind turbine generator sets in the second state according to the principle that the average power is allocated if it is greater than the average power and the active power is used up if it is less than the average power. The first to third steps are not performed in any particular order.

[0075] The available active power reduction amounts of the wind turbine generator sets are sorted so as to give priority to using the available active power reduction amounts of the wind turbine generator sets with available active power reduction amounts.

[0076] Table 1

[0077] Wind turbine number 3# 4# 5# 2# 1# Reducible reserve power (kW) 0 350 700 705 850

[0078] The following is a detailed description of a case where a wind farm includes five wind turbines. The order of the amount of reduction of active power of the five wind turbines is shown in Table 1 above.

[0079] Assume that the wind farm needs to reduce the active power reduction amount P (ie, the frequency regulation demand is 800). The power can be calculated and allocated by averaging multiple active power reduction amounts.

[0080] The calculation of the average value of the first active power reduction and the distribution of active power can be performed. For example, the average value of the active power reduction of the wind turbines in the wind farm is first calculated (i.e., 800÷5=160). The only wind turbine #3 has a value smaller than 160, so the wind turbine #3 releases all the available active power reduction, and the active power distribution instruction is DeltP3=0 (i.e., the reduction determination unit 430 to be described below distributes the instruction to the wind turbines).

[0081] The calculation of the average value of the second active power reduction and the distribution of active power can be continued. For example, the remaining frequency regulation demand is 800-0=800, and the remaining valid wind turbines are 4. The average value of the active power reduction of the remaining wind turbines is calculated to be 800÷4=200. There is no wind turbine with an active power reduction less than 200. Therefore, the remaining four wind turbines release an active power reduction of 200. The active power reduction instructions are DeltP4=-200, DeltP5=-200, DeltP2=-200, and DeltP1=-200.

[0082] Finally, through the above method, the required active power reduction of the wind farm is met.

[0083] Furthermore, it is assumed that the frequency regulation demand (the amount of active power reduction P that the wind farm needs to reduce) is 3000. The average value of multiple active power reductions and the distribution of active power may also be calculated.

[0084] First calculation: calculate the average value 3000÷5=600. Only 3# and 4# wind turbines have a value smaller than 600. Therefore, 3# and 4# wind turbines release all the available active power reduction. The instructions for active power reduction are DeltP3=0 and DeltP4=350.

[0085] Second calculation: the remaining frequency regulation demand is 3000-0-350=2650, the remaining effective wind turbines are 3, and the calculated average value is 2650÷3=883. Only wind turbines 5# and 2# have a value smaller than 883, so these two wind turbines release all the available active power reduction. The active power reduction instructions are DeltP5=-700 and DeltP2=-705.

[0086] The third calculation: the remaining frequency regulation demand is 2650-700-705=1245, the remaining effective wind turbine generator set is 1#, and it is not enough to meet the frequency regulation demand, so this wind turbine generator set releases all the active power reduction, and the active power reduction instruction is DeltP1=-850.

[0087] According to an exemplary embodiment of the present invention, the order may also be sorted in ascending order. The above power allocation that preferentially uses the active power reduction amount of wind turbine generator sets with smaller active power reduction amount is only an example, and the exemplary embodiments of the present invention are not limited thereto.

[0088] The present invention fully considers the advantages and disadvantages of various ways of reducing the active power of a wind turbine generator set, and proposes a method for adjusting the active power of a wind farm quickly and flexibly without affecting the load safety of the set.

[0089] In addition, the present invention cooperates with the field control equipment and the wind turbine end equipment to realize a method for rapidly reducing the active power of the wind farm in a short time, which does not affect the load safety of the wind turbine generator set, and can realize rapid and flexible control of the wind farm power, or assist in handling wind farm / regional power grid faults (such as short circuit, circuit breaker failure, etc.). This will be described in detail below.

[0090] Figure 4 A block diagram showing a control device for reducing active power of a wind farm according to an exemplary embodiment of the present invention is shown.

[0091] The control device 400 for reducing active power of a wind farm according to an exemplary embodiment of the present invention includes a reduction amount acquisition unit 410 , a possible reduction amount determination unit 420 , and a reduction amount determination unit 430 .

[0092] The reduction acquisition unit 410, the reduction determination unit 420 and the reduction determination unit 430 may be field control devices, and the field control devices may cooperate with multiple wind turbine generator sets in the wind farm to jointly reduce the active power. For example, power control instructions may be sent to multiple wind turbine generator sets in the wind farm to reduce the active power of the wind farm.

[0093] The reduction acquisition unit 410 can be used to obtain the active power reduction amount P that the wind farm needs to reduce. As an example, the reduction acquisition unit 410 can also be used to determine when to trigger the entire system to start working. In other words, the reduction acquisition unit 410 can detect the signal of the grid frequency regulation demand (active power reduction), and the reduction acquisition unit 410 can determine the overall target of the active power reduction of the wind farm.

[0094] The reduction amount determination unit 420 may determine the reduction amount of active power of each wind turbine generator set according to the controllable state of wind turbine power of each wind turbine generator set in the wind farm.

[0095] Specifically, the reducible amount determination unit 420 can determine the reducible amount of active power of the wind turbine generator set as the pitch-reducible active power of the wind turbine generator set (that is, the total active power reducible amount of the wind turbine generator set is the total pitch-reducible active power) in response to the wind turbine power controllable state of the wind turbine generator set being the first state, and the pitch-reducible active power is the first power amount pd1 calculated by subtracting the measured power from the power lower limit (for example, the frequency regulation power lower limit), and determine the first number n1 of all wind turbine generator sets whose wind turbine power controllable state is the first state and the first total reducible power amount p1 (p1=pd1×n1).

[0096] As mentioned above, the lower power limit of the wind turbine generator set can be understood as if the power is lower than the lower power limit, the wind turbine generator set will shut down. For example, the lower power limit of the wind turbine generator set can be 10% of the rated power value of the wind turbine generator set. The measured power of the wind turbine generator set can be understood as the current actual power of the wind turbine generator set.

[0097] The reducible amount determination unit 420 can determine the reducible amount of active power of the wind turbine generator set as the sum of the reducible active power of the braking resistor of the wind turbine generator set and the reducible active power of the pitch change in response to the controllable power state of the wind turbine generator set being the second state, and the sum is a second power amount pd2 calculated by subtracting the measured power from the lower power limit, and determine a second number n2 of all wind turbine generator sets whose wind turbine power controllable state is the second state and a second total reducible power amount p2 (p2=pd2×n2).

[0098] The reducible amount determining unit 420 may determine that the reducible amount of active power of the wind turbine generator set is zero in response to the wind turbine power controllable state of the wind turbine generator set being the third state.

[0099] The reduction determination unit 430 may determine the active power reduction of each wind turbine generator set based on the active power reduction amount P required to be reduced by the wind farm and the available active power reduction amount of each wind turbine generator set (eg, p1 and p2, etc.).

[0100] The reduction determination unit 430 may send corresponding power allocation instructions to each wind turbine generator set.

[0101] As described above, the wind turbine power controllable state may include a first state reflecting that the wind turbine generator set only has the variable pitch control capability, a second state reflecting that the wind turbine generator set has both the variable pitch control capability and the brake resistor control capability, and a third state reflecting that the wind turbine generator set does not have the power reduction capability. No further details will be given here.

[0102] The reduction amount determination unit 430 can determine a control mode for reducing the active power of the wind farm, and the control mode can include a fast power reduction mode and a normal pitch power reduction mode. The reduction amount determination unit 430 can send instructions related to the determined fast power reduction mode and the normal pitch power reduction mode to each wind turbine generator set.

[0103] Specifically, the reduction determination unit 430 may send a signal including different predetermined reduction rate instructions to the wind turbine generator set. For example, when the wind turbine generator set receives an instruction from the reduction determination unit 430 indicating that the power is reduced at a rate of 20% Pn / s, it indicates that the wind turbine generator set is operating in a fast power reduction mode). Furthermore, when the wind turbine generator set receives an instruction from the reduction determination unit 430 indicating that the power is reduced at a rate of 50 kW / s, it indicates that the wind turbine generator set is operating in a normal variable pitch power reduction mode).

[0104] As an example, the reduction determination unit 430 can determine whether the control mode for reducing the active power of the wind farm is a fast power reduction mode or a normal pitch power reduction mode based on the grid connection point frequency detected by the grid connection point. The frequency of the grid connection point can be detected by another grid frequency monitoring / control unit. The relationship between the magnitude of the grid connection point frequency and the adopted power reduction mode is as described above and will not be repeated here.

[0105] The reduction amount determination unit 430 may determine the wind turbine generator sets involved in reducing the active power of the wind farm, and determine the active power reduction amounts of the wind turbine generator sets involved in reducing the active power of the wind farm.

[0106] When the control mode is the rapid power reduction mode and the active power reduction amount that the wind farm needs to reduce is less than the second total reducible power amount, the reduction amount determination unit 430 can enable all wind turbines in the second state to participate in reducing the active power of the wind farm, and give priority to using up the active power reduction amount of the wind turbines with a smaller second power amount.

[0107] The reduction amount determination unit 430 may send a first predetermined reduction rate signal to each wind turbine generator set in the second state to instruct the wind turbine generator set to operate in the fast power reduction mode.

[0108] When the control mode is the rapid power reduction mode and the active power reduction amount that the wind farm needs to reduce is greater than the second total reducible power amount, the reduction amount determination unit 430 can enable all wind turbines in the second state and the first state to participate in reducing the active power of the wind farm, and after the active power reduction amount of all wind turbines in the second state is exhausted, the pitch-changing active power reduction amount of the wind turbines with a smaller first power amount is preferentially used.

[0109] The reduction amount determination unit 430 may send a first predetermined reduction rate signal to each wind turbine generator set in the second state, and send a second predetermined reduction rate signal to each wind turbine generator set in the first state.

[0110] When the control mode is the normal variable pitch power reduction mode, the reduction amount determination unit 430 can enable all wind turbines in the first state and all wind turbines in the second state to participate in reducing the active power of the wind farm, and give priority to using up the active power reduction of wind turbines with smaller active power reduction amounts, wherein a second predetermined reduction rate signal is sent to all wind turbines in the first state and all wind turbines in the second state.

[0111] The communication between field control equipment and wind turbines can be carried out using EtherCAT, profinet, OPC-UA and other communication methods, but the communication cycle should not be greater than 50ms to avoid adverse effects caused by system delays. It is recommended to use OPC-UA communication method.

[0112] In a wind turbine generator set, the components involved in power control may include the main controller, the pitch mechanism and the converter. The main controller receives the control command issued by the field control equipment, executes the coordinated control of the relevant units inside the wind turbine generator set, and the pitch mechanism and the converter execute the action command, and finally uses the output of the active power on the grid side of the converter as the output signal.

[0113] The reduction amount determination unit 420 sorts the active power reduction amounts of the wind turbine generator sets so that the reduction amount determination unit 430 preferentially uses the active power reduction amounts of the wind turbine generator sets with the active power reduction amounts.

[0114] As an example, the degradable amount determination unit 420 may separately sort the degradable amount of active power of all wind turbines in the first state and determine the degradable amount of active power of all wind turbines in the first state according to the principle of allocating average power if it is greater than average power and using up if it is less than average power. The degradable amount determination unit 420 separately sorts the degradable amount of active power of all wind turbines in the first state so as to give priority to using wind turbines with smaller active power when only the active power of all wind turbines in the first state is used, so that the wind turbines do not need to be included in the subsequent calculation of the degradable amount of active power.

[0115] As an example, the degradable amount determination unit 420 may separately sort the degradable amount of active power of all wind turbines in the second state and determine the degradable amount of active power of all wind turbines in the second state according to the principle of allocating average power if it is greater than average power and using up if it is less than average power. The degradable amount determination unit 420 separately sorts the degradable amount of active power of all wind turbines in the second state so as to give priority to using wind turbines with smaller active power when only the active power of all wind turbines in the second state is used, so that the wind turbines do not need to be included in the subsequent calculation of the degradable amount of active power.

[0116] As an example, the degradable amount determination unit 420 may perform mixed sorting on the active power degradable amounts of all wind turbine generator sets in the first state and all wind turbine generator sets in the second state, and determine the active power degradable amounts of all wind turbine generator sets in the first state and all wind turbine generator sets in the second state according to the principle that the average power is allocated if it is greater than the average power and the active power is used up if it is less than the average power. The degradable amount determination unit 420 sorts all wind turbine generator sets in the second state and all wind turbine generator sets in the first state, so as to give priority to using the wind turbine generator set with smaller active power when using the active power of all wind turbine generator sets in the first state and the second state, so that the wind turbine generator set does not need to be included in the subsequent calculation of the active power degradable amount.

[0117] The specific method of preferentially using the available active power reduction amount is as described above and will not be repeated here.

[0118] It should be understood that the specific processing performed by the control device for reducing the active power of a wind farm according to the exemplary embodiment of the present invention has been described in detail, and the relevant details will not be repeated here.

[0119] It should be understood that each unit in the control device for reducing the active power of a wind farm according to an exemplary embodiment of the present invention can be implemented as a hardware component and / or a software component. Those skilled in the art can implement each unit, for example, using a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC) according to the processing performed by each defined unit.

[0120] An exemplary embodiment of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for regulating the active power of a wind farm as described in the above exemplary embodiment. The computer-readable storage medium is any data storage device that can store data read by a computer system. Examples of computer-readable storage media include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier wave (such as data transmission through the Internet via a wired or wireless transmission path).

[0121] According to an exemplary embodiment of the present invention, a controller of a wind farm comprises: 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 method of reducing the active power of the wind farm as described in the above exemplary embodiment is implemented.

[0122] The method for reducing active power and the control device according to the exemplary embodiments of the present invention can quickly reduce the active power of a wind farm.

[0123] The method and control device for reducing active power according to the exemplary embodiment of the present invention have minimal impact on the load of the wind turbine generator set.

[0124] The method and control device for reducing active power according to the exemplary embodiment of the present invention can be applied to the occasion of reducing active power, and the number of wind turbine generator sets controlled and dispatched each time is minimal.

[0125] The method and control device for reducing active power according to the exemplary embodiment of the present invention can effectively control and reduce the number of times the braking resistor is used, protect the high and low wear functions, organically and seamlessly connect the slow pitch control and the fast braking resistor control, and have better domestic and foreign compatibility.

[0126] Although certain exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that modifications may be made to these embodiments (for example, different technical features in different embodiments may be combined) without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for reducing the active power of a wind farm, characterized in that: The method comprises: Obtaining the active power reduction amount that the wind farm needs to reduce; Determine the amount by which the active power of each wind turbine generator set can be reduced according to the controllable state of the wind turbine power of each wind turbine generator set in the wind farm; Based on the amount of active power reduction that the wind farm needs to reduce and the amount of active power reduction that can be achieved for each wind turbine generator set, the amount of active power reduction for each wind turbine generator set is determined. The wind turbine power controllable state includes a first state reflecting that the wind turbine generator set only has a variable pitch control capability, a second state reflecting that the wind turbine generator set has both a variable pitch control capability and a brake resistor control capability, and a third state reflecting that the wind turbine generator set does not have a power reduction capability. The steps for determining the amount of active power reduction that can be achieved for each wind turbine generator set include: In response to the wind turbine power controllable state of the wind turbine generator set being the first state, determining that the active power reduction amount of the wind turbine generator set is the variable pitch active power reduction amount of the wind turbine generator set, and the variable pitch active power reduction amount is a first power amount calculated by subtracting the measured power from the power lower limit, and determining a first number of all wind turbine generator sets whose wind turbine power controllable state is the first state and a first total reducible power amount; In response to the wind turbine power controllable state of the wind turbine generator set being the second state, determining that the active power reduction amount of the wind turbine generator set is the sum of the brake resistor reduction active power amount of the wind turbine generator set and the pitch reduction active power amount, and the sum is a second power amount calculated by subtracting the measured power from the power lower limit, and determining a second number of all wind turbine generator sets whose wind turbine power controllable state is the second state and a second total reduction power amount; In response to the wind turbine power controllable state of the wind turbine generator set being the third state, it is determined that the amount by which the active power of the wind turbine generator set can be reduced is zero.

2. The method for reducing active power of a wind farm according to claim 1, characterized in that: The step of determining the active power reduction amount of each wind turbine generator set includes: determining a control mode for reducing the active power of the wind farm based on the grid connection point frequency detected by the grid connection point, wherein the control mode is a fast power reduction mode or a normal pitch power reduction mode.

3. The method for reducing active power of a wind farm according to claim 2, characterized in that: The step of determining the active power reduction amount of each wind turbine generator set also includes: determining the wind turbine generator sets participating in reducing the active power of the wind farm, and determining the active power reduction amount of the wind turbine generator sets participating in reducing the active power of the wind farm.

4. The method for reducing active power of a wind farm according to claim 3, characterized in that: The step of determining the active power reduction amount of the wind turbine generator sets participating in reducing the active power of the wind farm comprises at least one of the following steps: The available active power reduction amounts of all wind generator sets in the first state are individually sorted and the available active power reduction amounts of all wind generator sets in the first state are determined according to the principle that the average power is allocated if the power is greater than the average power and the power is used up if the power is less than the average power; The available active power reduction amounts of all wind generator sets in the second state are individually sorted and the available active power reduction amounts of all wind generator sets in the second state are determined according to the principle that the average power is allocated if the power is greater than the average power and the power is used up if the power is less than the average power; The available active power reduction amounts of all wind turbine generator sets in the first state and all wind turbine generator sets in the second state are mixed and sorted, and the available active power reduction amounts of all wind turbine generator sets in the first state and all wind turbine generator sets in the second state are determined according to the principle that average power is allocated if it is greater than average power and that power is used up if it is less than average power.

5. The method for reducing active power of a wind farm according to claim 3, characterized in that: When the control mode is a fast power reduction mode and the amount of active power reduction required to be reduced by the wind farm is less than the second total power reduction amount, all wind turbine generator sets in the second state are enabled to participate in reducing the active power of the wind farm, and the active power reduction amount of the wind turbine generator sets with smaller second power amounts is preferentially used up, wherein a first predetermined reduction rate signal is sent to each wind turbine generator set in the second state; When the control mode is a fast power reduction mode and the amount of active power reduction required to be reduced by the wind farm is greater than the second total reducible power amount, all wind turbine generator sets in the second state and the first state are made to participate in reducing the active power of the wind farm, and after exhausting the amount of active power reduction of all wind turbine generator sets in the second state, the amount of active power reduction of the wind turbine generator sets with smaller first power amount is preferentially used, wherein a first predetermined reduction rate signal is sent to each wind turbine generator set in the second state, and a second predetermined reduction rate signal is sent to each wind turbine generator set in the first state; When the control mode is the normal variable pitch power reduction mode, all wind turbines in the first state and all wind turbines in the second state participate in reducing the active power of the wind farm, and the active power reduction of wind turbines with smaller active power reduction amounts is preferentially used up, wherein a second predetermined reduction rate signal is sent to all wind turbines in the first state and all wind turbines in the second state.

6. A control device for reducing the active power of a wind farm, characterized in that: The control device comprises: A reduction acquisition unit is configured to acquire an active power reduction that needs to be adjusted by the wind farm; A reduction amount determination unit is configured to determine the reduction amount of active power of each wind turbine generator set according to the controllable state of wind turbine power of each wind turbine generator set in the wind farm; a reduction amount determination unit configured to determine the active power reduction amount of each wind turbine generator set based on the active power reduction amount that the wind farm needs to reduce and the active power reduction amount of each wind turbine generator set, The wind turbine power controllable state includes a first state reflecting that the wind turbine generator set only has a pitch control capability, a second state reflecting that the wind turbine generator set has both a pitch control capability and a brake resistor control capability, and a third state reflecting that the wind turbine generator set does not have a power reduction capability. The reduction amount determination unit is further configured as follows: In response to the wind turbine power controllable state of the wind turbine generator set being the first state, determining that the active power reduction amount of the wind turbine generator set is the variable pitch active power reduction amount of the wind turbine generator set, and the variable pitch active power reduction amount is a first power amount calculated by subtracting the measured power from the power lower limit, and determining a first number of all wind turbine generator sets whose wind turbine power controllable state is the first state and a first total reducible power amount; In response to the wind turbine power controllable state of the wind turbine generator set being the second state, determining that the active power reduction amount of the wind turbine generator set is the sum of the brake resistor reduction active power amount of the wind turbine generator set and the pitch reduction active power amount, and the sum is a second power amount calculated by subtracting the measured power from the power lower limit, and determining a second number of all wind turbine generator sets whose wind turbine power controllable state is the second state and a second total reduction power amount; In response to the wind turbine power controllable state of the wind turbine generator set being the third state, it is determined that the amount by which the active power of the wind turbine generator set can be reduced is zero.

7. The control device for reducing the active power of a wind farm according to claim 6, characterized in that: The reduction amount determination unit is further configured to determine whether the control mode for reducing the active power of the wind farm is a fast power reduction mode or a normal pitch change power reduction mode based on the grid connection point frequency detected by the grid connection point.

8. The control device for reducing the active power of a wind farm according to claim 7, characterized in that: The reducible amount determination unit is further configured to: The available active power reduction amounts of all wind generator sets in the first state are individually sorted and the available active power reduction amounts of all wind generator sets in the first state are determined according to the principle that the average power is allocated if the power is greater than the average power and the power is used up if the power is less than the average power; The available active power reduction amounts of all wind generator sets in the second state are individually sorted and the available active power reduction amounts of all wind generator sets in the second state are determined according to the principle that the average power is allocated if the power is greater than the average power and the power is used up if the power is less than the average power; The available active power reduction amounts of all wind generator sets in the first state and all wind generator sets in the second state are mixed and sorted, and the available active power reduction amounts of all wind generator sets in the first state and all wind generator sets in the second state are determined according to the principle that average power is allocated if it is greater than average power and is used up if it is less than average power.

9. The control device for reducing active power of a wind farm according to claim 7, characterized in that: The reduction amount determination unit is further configured to: when the control mode is a fast power reduction mode and the active power reduction amount required to be reduced by the wind farm is less than the second total reducible power amount, enable all wind turbine generator sets in the second state to participate in reducing the active power of the wind farm, and preferentially use up the active power reduction amount of the wind turbine generator sets with smaller second power amounts, wherein a first predetermined reduction rate signal is sent to each wind turbine generator set in the second state; When the control mode is a fast power reduction mode and the amount of active power reduction required to be reduced by the wind farm is greater than the second total reducible power amount, all wind turbine generator sets in the second state and the first state are made to participate in reducing the active power of the wind farm, and after exhausting the amount of active power reduction of all wind turbine generator sets in the second state, the amount of active power reduction of the wind turbine generator sets with smaller first power amount is preferentially used, wherein a first predetermined reduction rate signal is sent to each wind turbine generator set in the second state, and a second predetermined reduction rate signal is sent to each wind turbine generator set in the first state; When the control mode is the normal variable pitch power reduction mode, all wind turbines in the first state and all wind turbines in the second state participate in reducing the active power of the wind farm, and the active power reduction of wind turbines with smaller active power reduction amounts is preferentially used up, wherein a second predetermined reduction rate signal is sent to all wind turbines in the first state and all wind turbines in the second state.

10. A controller for a wind farm, characterized in that: The controller comprises: processor; A memory storing a computer program, which, when executed by a processor, implements the method for reducing the active power of a wind farm according to any one of claims 1 to 5.

Images