Power distribution method, device and electronic equipment for wind farm super-speed pitch-changing coordinated load reduction

Abstract

This invention relates to the field of wind farm frequency regulation power control technology, and provides a power allocation method, device, and electronic equipment for wind farm overspeed pitch control and coordinated load reduction. The power allocation method includes: acquiring the structural parameters, wind speed information, pitch angle information, pitch control frequency regulation response time limits, and wind farm operation load reduction rate requirements of the wind turbines within the wind farm; constructing a linear programming problem based on the acquired data, using the pitch angle change of the wind turbines within the wind farm as an optimization variable; determining the pitch angle change of the wind turbines within the wind farm based on the optimization results of the linear programming problem; and outputting a power reference value for the wind turbines within the wind farm based on the determined pitch angle change. This method achieves more refined power allocation, and the computation time required for the linear programming problem is relatively short, which is beneficial for its online application in wind farms.

Description

Technical Field

[0001] This invention relates to the field of wind farm frequency regulation power control technology, and in particular to a power distribution method, device and electronic equipment for wind farm overspeed pitch coordinated load reduction. Background Technology

[0002] With the increasing proportion of wind power installed capacity, wind power participation in power system frequency regulation has become an inevitable trend, and load shedding control is an important technical approach. Wind turbine load shedding control is mainly divided into overspeed control and pitch angle control. Since pitch angle control causes wear on the turbine, overspeed control is generally preferred for load shedding. However, due to the upper limit of the turbine rotor speed, the capacity for overspeed load shedding is limited. When overspeed load shedding in a wind farm cannot meet the wind farm's load shedding rate requirements, further pitch shedding is needed on top of overspeed shedding, i.e., coordinated overspeed and pitch shedding. Existing methods set the same load shedding power for all turbines in the wind farm to be pitch-controlled, with each turbine's pitch angle determined by its actual operating power. However, this method does not fully consider the differences between different turbines in the wind farm, which may cause unnecessary wear or stress to some turbines and may also affect the overall frequency regulation effect of the wind farm. Summary of the Invention

[0003] This invention provides a power distribution method, device, and electronic equipment for wind farm overspeed pitch-coordinated load reduction, which solves the defects of the prior art that does not fully consider the differences between different wind turbines in the wind farm, which may cause unnecessary wear or stress to some wind turbines. It achieves more refined power distribution, and the linear programming problem requires less computation time, which is beneficial for its online application in wind farms.

[0004] This invention provides a power allocation method for coordinated load reduction in wind farms using overspeed pitch control, comprising: acquiring structural parameters, wind speed information, pitch angle information, pitch frequency regulation response time limits, and the wind farm's operating load reduction rate requirements of the wind turbines within the wind farm; based on the acquired data, constructing a linear programming problem using the pitch angle variation of the wind turbines within the wind farm as an optimization variable, wherein the constraints of the linear programming problem include the total power of the wind turbines within the wind farm satisfying the operating load reduction rate requirements and the pitch angle variation of the wind turbines within the wind farm satisfying inequality requirements; determining the pitch angle variation of the wind turbines within the wind farm based on the optimization results of the linear programming problem; and outputting a power reference value for the wind turbines within the wind farm based on the determined pitch angle variation.

[0005] According to the power allocation method for wind farm overspeed pitch control and coordinated load reduction provided by the present invention, the step of constructing a linear programming problem based on the acquired data and using the pitch angle change of the wind turbines in the wind farm as an optimization variable includes: calculating the maximum output power of each wind turbine based on the structural parameters and wind speed information of each wind turbine in the wind farm; classifying the wind turbines in the wind farm based on the calculated maximum output power, classifying wind turbines capable of maximum power point tracking as medium-wind-speed turbines, wind turbines with higher wind speeds as high-wind-speed turbines, and wind turbines with lower wind speeds as low-wind-speed turbines; assuming the pitch angle of the high-wind-speed turbines is... All wind turbines are adjusted to the upper limit of the feasible region. It is then determined whether the wind farm load reduction rate is less than the preset load reduction rate. If the wind farm load reduction rate is less than the preset load reduction rate, the high-wind-speed turbines are designated as turbines to be modified. If the wind farm load reduction rate is still less than the preset load reduction rate, the high-wind-speed turbines are designated as turbines to be modified, and the medium-wind-speed turbines are sorted in descending order of wind speed. Based on the sorting result, the medium-wind-speed turbines are sequentially designated as turbines to be modified until the total load reduction of the turbines to be modified can meet the load reduction requirements of the wind farm. The pitch angle change of the turbines to be modified is used as the optimization variable to construct a linear programming problem.

[0006] According to the power allocation method for wind farm overspeed pitch control and coordinated load reduction provided by the present invention, the objective function of the linear programming problem includes minimizing the total pitch angle change of the wind turbine to be controlled; the total power of the wind turbines in the wind farm includes the power of the wind turbine to be controlled and the power of the wind turbines not to be controlled in the wind farm.

[0007] According to the power allocation method for coordinated load reduction in wind farms using overspeed pitch control provided by the present invention, the step of constructing a linear programming problem based on acquired data, using the pitch angle change of the wind turbines in the wind farm as an optimization variable, includes: determining whether the initial power of the wind turbine to be pitched is greater than the difference between the total power of the wind turbines in the wind farm that meets the operating load reduction rate requirement and the power of the wind turbines not to be pitched in the wind farm; if the initial power of the wind turbine to be pitched is greater than the difference between the total power of the wind turbines in the wind farm that meets the operating load reduction rate requirement and the power of the wind turbines not to be pitched in the wind farm, then the actual feasible region of the pitch angle change is a first feasible region, which is from 0 to... The difference between the upper limit of the pitch angle and the current pitch angle is used to connect the two points corresponding to the boundary of the first feasible region, thus obtaining a first linear approximation relationship between the wind energy conversion efficiency coefficient and the pitch angle within the first feasible region. If the initial power of the wind turbine to be changed is not greater than the difference between the total power of the wind turbines in the wind farm that meets the operating load reduction rate requirement and the power of the wind turbines not to be changed in the wind farm, then the actual feasible region of the pitch angle change is the second feasible region. The second feasible region is from the difference between the base pitch angle and the current pitch angle to 0. Connecting the two points corresponding to the boundary of the second feasible region, thus obtaining a second linear approximation relationship between the wind energy conversion efficiency coefficient and the pitch angle within the second feasible region.

[0008] According to the power allocation method for wind farm overspeed pitch control and coordinated load reduction provided by the present invention, in the optimization result, at most one wind turbine has a pitch angle change that is not on the boundary of the pitch angle inequality constraint; adjusting the pitch angle change of the wind turbines in the wind farm according to the optimization result of the linear programming problem includes adjusting the pitch angle change of at most one wind turbine.

[0009] According to the power allocation method for wind farm overspeed pitch control and coordinated load reduction provided by the present invention, the step of outputting the power reference value of the wind turbines in the wind farm based on the determined pitch angle change includes: substituting the determined pitch angle change into the power expression to calculate the power reference value of the wind turbine to be controlled; setting the power reference value of the wind turbine in the low wind speed area as the maximum output power; and substituting the pitch angle of zero into the power expression to calculate the power reference value of the wind turbine in the high wind speed area and the wind turbine in the medium wind speed area that is not to be controlled.

[0010] The present invention also provides a power distribution device for wind farm overspeed pitch control and coordinated load reduction, comprising: an acquisition module configured to acquire structural parameters, wind speed information, pitch angle information, pitch frequency regulation response time limit, and the wind farm's operating load reduction rate requirement of the wind turbines within the wind farm; an optimization module configured to construct a linear programming problem based on the acquired data, using the pitch angle change of the wind turbines within the wind farm as the optimization variable, wherein the constraints of the linear programming problem include the total power of the wind turbines within the wind farm satisfying the operating load reduction rate requirement and the pitch angle change of the wind turbines within the wind farm satisfying an inequality requirement; a determination module configured to determine the pitch angle change of the wind turbines within the wind farm based on the optimization result of the linear programming problem; and an output module configured to output a power reference value of the wind turbines within the wind farm based on the determined pitch angle change.

[0011] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the power distribution method for wind farm overspeed pitch coordinated load reduction as described above.

[0012] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the power distribution method for wind farm overspeed pitch coordinated load reduction as described above.

[0013] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the power distribution method for wind farm overspeed pitch coordinated load reduction as described above.

[0014] The power allocation method, device, and electronic equipment for wind farm overspeed pitch-coordinated load reduction provided by this invention, based on the data of wind turbines in the wind farm and the operating load reduction rate requirements of the wind farm, uses the pitch angle change of wind turbines in the wind farm as the optimization variable to construct a linear programming problem, thereby achieving more refined power allocation. At the same time, the computation time required for the linear programming problem is relatively short, which is conducive to its online application in wind farms. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart of the power distribution method for wind farm overspeed pitch-coordinated load reduction provided by the present invention.

[0017] Figure 2 This is a schematic diagram of a system model consisting of a wind farm, a thermal power plant, and a load, provided by the present invention.

[0018] Figure 3 This is a schematic diagram of the wind speed distribution of wind turbines in a wind farm provided by the present invention.

[0019] Figure 4 This is a schematic diagram of the power distribution device for wind farm overspeed pitch coordinated load reduction provided by the present invention.

[0020] Figure 5 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or “connected,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0023] The terminology involved in this invention will be briefly explained below.

[0024] The following is combined with Figures 1-5 The present invention describes a power distribution method, apparatus, and electronic equipment for wind farm overspeed pitch coordinated load reduction.

[0025] Figure 1 This is a flowchart illustrating the power distribution method for wind farm overspeed pitch-coordinated load reduction provided by the present invention, as shown below. Figure 1 As shown, the method includes the following:

[0026] Step 101: Obtain the structural parameters, wind speed information, pitch angle information, pitch frequency regulation response time limit, and wind farm operation load reduction rate requirements of the wind turbines in the wind farm.

[0027] In this embodiment, the structural parameters of the wind turbine may include the blade radius. Gearbox ratio Maximum speed Inertial time constant Wind speed information can include wind speed, etc. air density Etc.; Pitch angle information may include the basic pitch angle. Current pitch angle Upper limit of pitch angle The required operating load factor for a wind farm can include the overall operating load factor that the wind farm needs to achieve. (The ratio of unloaded reserve capacity to actual output power).

[0028] Step 102: Based on the acquired data, the pitch angle change of the wind turbines in the wind farm is used as the optimization variable to construct a linear programming problem.

[0029] In this embodiment, the objective function in the linear programming problem can be set based on considerations such as minimizing cost, minimizing wear, and balancing wear and cost. Constraints in the linear programming problem can also include safety and stability constraints, economic constraints, etc., which can be selected and constructed according to actual needs. By optimizing the pitch angle variation, the power output of the wind turbine can be controlled more precisely, thereby improving the wind farm's response speed and frequency regulation capability to power system frequency changes. Compared with using particle swarm optimization to solve the original pitch angle optimization problem, linear programming is more computationally efficient, and when certain conditions are met (such as the objective function and constraints being linear), linear programming can guarantee finding the global optimum. While particle swarm optimization has global search capabilities, it may converge to a local optimum.

[0030] Step 103: Determine the pitch angle variation of the wind turbines in the wind farm based on the optimization results of the linear programming problem.

[0031] In this embodiment, a linear programming solver (such as the simplex method, interior point method, etc.) can be used to find the optimal solution to determine the pitch angle variation of the wind turbines in the wind farm.

[0032] Step 104: Output the power reference value of the wind turbines in the wind farm based on the determined pitch angle change.

[0033] In this embodiment, the pitch angle change of each wind turbine can be determined based on the solution of the linear programming. Using the pitch angle change from the optimization results, the new pitch angle of each wind turbine can be calculated. Using the wind energy conversion efficiency coefficient and other relevant parameters, the power reference value of each wind turbine can be calculated, and then it can be issued as a power command to each wind turbine.

[0034] The power allocation method for wind farm overspeed pitch-coordinated load reduction provided by this invention is based on the data of wind turbines in the wind farm and the operating load reduction rate requirements of the wind farm. It uses the pitch angle change of wind turbines in the wind farm as the optimization variable to construct a linear programming problem, which realizes more refined power allocation. At the same time, the computation time required for the linear programming problem is relatively short, which is conducive to its online application in wind farms.

[0035] In some alternative implementations, based on the acquired data, the pitch angle variation of the wind turbines within the wind farm is used as an optimization variable to construct a linear programming problem, including: calculating the maximum output power of each wind turbine based on its structural parameters and wind speed information. Based on the calculated maximum output power, the wind turbines in the wind farm can be divided into three categories: turbines capable of maximum power point tracking (MPPT) are classified as medium-wind-speed turbines, those with higher wind speeds as high-wind-speed turbines, and those with lower wind speeds as low-wind-speed turbines. Assuming that the pitch angles of all high-wind-speed turbines are adjusted to the upper limit of the feasible region, it is determined whether the wind farm's load shedding rate is less than the preset load shedding rate. If the load shedding rate is less than the preset rate, the high-wind-speed turbines are designated as turbines awaiting pitch adjustment. If the load shedding rate is still less than the preset rate, the high-wind-speed turbines are designated as turbines awaiting pitch adjustment, and the medium-wind-speed turbines are sorted in descending order of wind speed. Based on the sorting result, the medium-wind-speed turbines are sequentially designated as turbines awaiting pitch adjustment until the total load shedding of the turbines awaiting pitch adjustment meets the wind farm's load shedding requirements. The pitch angle change of the turbines awaiting pitch adjustment is used as an optimization variable to construct a linear programming problem.

[0036] The unit load reduction power of a wind turbine is proportional to the cube of the wind speed. Therefore, for high-wind-speed turbines, the load reduction power resulting from a unit change in pitch angle is greater. Furthermore, compared to turbines in low-to-medium wind-speed areas, high-wind-speed turbines have higher power output without load reduction, thus possessing greater load reduction potential. Therefore, pitch angle control should be prioritized for turbines in high-wind-speed areas within the wind farm. However, if the number of turbines in high-wind-speed areas is limited, and the available load reduction capacity cannot meet the wind farm's load reduction requirements, then turbines in medium-wind-speed areas may still need to participate in pitch angle control.

[0037] The feasible region for the wind turbine pitch angle is:

[0038]

[0039] in, for The change in pitch angle of the No. 1 wind turbine.

[0040] Based on the above analysis, the wind turbines to be adjusted for pitch control can be determined through a categorized discussion: Assuming the pitch angles of all turbines in the high-wind-speed zone are adjusted to the upper limit of the feasible region, if the wind farm's load reduction rate is not less than the preset load reduction rate, it means that only the turbines in the high-wind-speed zone can meet the wind farm's load reduction requirements through pitch control, and thus only the turbines in the high-wind-speed zone are designated as turbines to be adjusted for pitch control. Assuming the pitch angles of all turbines in the high-wind-speed zone are adjusted to the upper limit of the feasible region, if the wind farm's load reduction rate is still less than the preset load reduction rate, it means that only the turbines in the high-wind-speed zone cannot meet the wind farm's load reduction requirements through pitch control. In this case, the turbines in the medium-wind-speed zone need to be sorted according to wind speed from highest to lowest, and then sequentially designated as turbines to be adjusted for pitch control, until the total load reduction of all turbines to be adjusted for pitch control can meet the wind farm's load reduction requirements.

[0041] In some alternative implementations, the objective function of the linear programming problem includes minimizing the total pitch angle variation of the turbines to be controlled; the total power of the turbines in the wind farm includes the power of the turbines to be controlled and the power of the turbines not to be controlled. Pitch angle control of the turbines causes mechanical wear and affects the service life of the turbines. Therefore, in order to reduce the impact of pitch angle control on the service life of the turbines, the pitch angle variation should be minimized. Thus, the objective function of the optimization problem is:

[0042]

[0043] in, For the assembly of pitch wind turbines.

[0044] Under defined operating conditions, wind turbines in low-wind-speed zones do not participate in frequency regulation, and their power is constant. For wind turbines in medium-wind-speed zones that do not participate in pitch angle control, their rotor speeds have reached their upper limits, the pitch angle is 0, and their power is also constant. Therefore, the total power of the wind turbines to be pitched is the total output power of the wind farm minus the two constant values ​​mentioned above. The power equation constraint is:

[0045]

[0046] in, ;

[0047] ; for No. 1 wind turbine blade radius; for Fan speed; for No. 1 fan gearbox ratio; for The maximum output power of the No. 1 fan when operating without load reduction. This is a collection of wind turbines for low wind speed areas.

[0048] Due to the wind energy conversion efficiency coefficient Is it following It is monotonically decreasing, so when the initial power satisfies At that time, it is easy to see that in the optimization results Then the objective function is equivalent to: .

[0049] Similarly, when the initial power satisfies At that time, it is easy to see that in the optimization results Then the objective function is equivalent to: .

[0050] In some alternative implementations, based on the acquired data, the pitch angle change of the wind turbines in the wind farm is used as an optimization variable to construct a linear programming problem, including: determining whether the initial power of the wind turbine to be adjusted is greater than the difference between the total power of the wind turbines in the wind farm that meet the operating load reduction rate requirements and the power of the non-pitch turbines in the wind farm; if the initial power of the wind turbine to be adjusted is greater than the difference between the total power of the wind turbines in the wind farm that meet the operating load reduction rate requirements and the power of the non-pitch turbines in the wind farm, then the actual feasible region of the pitch angle change is the first feasible region, which is from 0 to the upper limit of the pitch angle and the current pitch angle. The difference in pitch angle is used to connect the two points corresponding to the boundary of the first feasible region, yielding a first linear approximation relationship between the wind energy conversion efficiency coefficient and the pitch angle within the first feasible region. If the initial power of the wind turbine to be modified is not greater than the difference between the total power of the wind turbines in the wind farm that meet the operating load reduction rate requirements and the power of the non-pitch wind turbines in the wind farm, then the actual feasible region for the pitch angle change is the second feasible region. The second feasible region is defined as the difference between the base pitch angle and the current pitch angle reaching 0. Connecting the two points corresponding to the boundary of the second feasible region yields a second linear approximation relationship between the wind energy conversion efficiency coefficient and the pitch angle within the second feasible region. When the initial power of the wind turbine to be modified meets the requirements... At that time, the practical feasible region for the change in pitch angle is:

[0051]

[0052] Connecting the two points corresponding to the boundary of the feasible region of the inequality yields a linear approximation of the relationship between the wind energy conversion efficiency coefficient and the pitch angle within the feasible region of the inequality, expressed as:

[0053]

[0054] in, The power equality constraint can be simplified to:

[0055]

[0056] When the initial power of the pitch fan meets the requirements

[0057] At that time, the practical feasible region for the change in pitch angle is:

[0058]

[0059] Connecting the two points corresponding to the boundary of the feasible region of the inequality yields a linear approximation of the relationship between the wind energy conversion efficiency coefficient and the pitch angle within the feasible region of the inequality, expressed as:

[0060]

[0061] in, The power equality constraint can be simplified to:

[0062] .

[0063] By combining the simplified objective function, pitch angle inequality constraints, and simplified power equality constraints, a linear programming problem is constructed for each case. The initial power of the wind turbine to be variable pitched satisfies...

[0064] When the linear programming problem is:

[0065]

[0066] When the initial power of the pitch fan meets the requirements

[0067] When the linear programming problem is:

[0068]

[0069]

[0070] In both cases, this is a standard form linear programming problem, which can be solved using existing mathematical methods for global optimization, or by using solvers in commercial software. The solution time for this optimization problem is much shorter than that for complex non-convex and nonlinear optimization problems using existing methods.

[0071] In some alternative implementations, the pitch angle change of at most one wind turbine in the optimization result is not on the boundary of the pitch angle inequality constraint; the pitch angle changes of wind turbines in the wind farm are adjusted according to the optimization result of the linear programming problem, including adjusting the pitch angle change of at most one wind turbine. Based on the mathematical properties of the linear programming problem, in the optimization result, the pitch angle change of at most one wind turbine is not on the boundary of the pitch angle inequality constraint.

[0072] Since the specific method of linear approximation is "connecting two points on the boundary of the feasible region," for the vast majority of wind turbines whose pitch angle changes are on the boundary, the linear approximation of their wind energy conversion efficiency coefficient does not introduce errors into the original power equation constraint. At most, only one wind turbine whose pitch angle change is not on the boundary introduces an error into the original power equation constraint. Therefore, it is only necessary to adjust the pitch angle change of this one wind turbine to make the original power equation constraint hold. The original power equation is:

[0073]

[0074] Since only the pitch angle change of this single wind turbine needs to be adjusted, this is a single-variable equation, which can be solved using existing mathematical methods. Given current algorithms and computing power, the solution time for this single-variable equation is extremely short.

[0075] In some optional implementations, the power reference value of the wind turbines in the wind farm is output based on the determined pitch angle change. This includes: calculating the power reference value of the turbine to be modified based on the determined pitch angle change by substituting it into the power expression; setting the power reference value of the turbines in the low wind speed area as the maximum output power; and calculating the power reference value of the turbines not to be modified in the high wind speed area and the medium wind speed area by substituting the pitch angle as zero into the power expression. The turbines in the low wind speed area do not reduce load, and the power reference value is the maximum output power. .

[0076] The power reference value for the variable pitch fan is:

[0077]

[0078] The power reference values ​​for other fans are:

[0079]

[0080] The obtained power reference value can be used as a power command to send to each wind turbine.

[0081] To verify the application effect of the above implementation method, a system was built as follows: Figure 2 The system model shown consists of a wind farm, a thermal power plant, and loads. Figure 2 The medium-sized wind farm comprises 30 doubly-fed induction generator (DFIG) wind turbines with a rated capacity of 5MW each (typical wind turbine units), and the thermal power plant comprises 5 thermal power units with a rated capacity of 60MW each, for a total load of 300MW. The inertial time constant of the three DFIG wind turbines is 7s, the inertial time constant of the thermal power units is 10s, and the power-frequency static characteristic coefficient of the thermal power units is 20. and All are 150MW, and the frequency regulation effect coefficient of the load is 3. The wind speed distribution of the 30 wind turbines is as follows: Figure 3As shown, each wind speed zone has corresponding wind turbines operating within the wind farm. The total load shedding power of the wind farm is set at 6% of the operating power.

[0082] Referring to Table 1, which shows the calculation effects of the three pitch reduction power allocation methods, this invention provides a comparison with the method described above, which uses a particle swarm optimization algorithm to solve the original pitch angle optimization problem and calculates the power reference value of the wind turbine to be pitched based on the pitch angle optimization result. The traditional method, which sets the same load reduction power for all wind turbines to be pitched in the wind farm, and the pitch angle of each wind turbine is determined by its actual operating power, is also compared with the traditional method.

[0083]

[0084] Compared to the particle swarm optimization (PSO) method, the pitch angle optimization results obtained by the method of this invention are very similar. However, under the same computing power, the computation time of the method of this invention is in the hundreds of milliseconds, which is much shorter than the min time of the PSO method. Compared to traditional methods, both have computation times in the hundreds of milliseconds, but the total change in pitch angle obtained by the method of this invention is much smaller than that of the traditional method, and the mechanical wear caused by pitch reduction is significantly less than that of the traditional method. In summary, the method of this invention can not only greatly shorten the computation time of the optimization problem, but also accurately meet the operating load reduction rate requirements of the wind farm, and significantly reduce the total change in pitch angle of the wind farm, which is beneficial for online application in actual wind farms.

[0085] The power distribution device for wind farm overspeed pitch coordinated load reduction provided by the present invention will be described below. The power distribution device for wind farm overspeed pitch coordinated load reduction described below can be referred to in correspondence with the power distribution method for wind farm overspeed pitch coordinated load reduction described above.

[0086] Figure 4 This is a schematic diagram of the power distribution device for wind farm overspeed pitch coordinated load reduction provided in the embodiments of this application, as shown below. Figure 4 As shown, the specific components include: an acquisition module 401, configured to acquire structural parameters, wind speed information, pitch angle information, pitch frequency regulation response time limits, and wind farm operating load reduction rate requirements of the wind turbines within the wind farm; an optimization module 402, configured to construct a linear programming problem based on the acquired data, using the pitch angle change of the wind turbines within the wind farm as the optimization variable, wherein the constraints of the linear programming problem include that the total power of the wind turbines within the wind farm meets the operating load reduction rate requirements; a determination module 403, configured to determine the pitch angle change of the wind turbines within the wind farm based on the optimization results of the linear programming problem; and an output module 404, configured to output a power reference value of the wind turbines within the wind farm based on the determined pitch angle change.

[0087] In some optional implementations, the optimization module 402 is further configured to: calculate the maximum output power of each wind turbine based on its structural parameters and wind speed information; classify the wind turbines in the wind farm based on the calculated maximum output power, classifying those capable of maximum power point tracking as medium-wind-speed turbines, those with higher wind speeds as high-wind-speed turbines, and those with lower wind speeds as low-wind-speed turbines; and, assuming that the pitch angles of all high-wind-speed turbines are adjusted to the upper limit of the feasible region, determine when to reduce the load on the wind farm. If the wind farm's load reduction rate is less than the preset load reduction rate, then the high-wind-speed turbines are designated as turbines to be adjusted for pitch control. If the wind farm's load reduction rate is still less than the preset load reduction rate, then the high-wind-speed turbines are designated as turbines to be adjusted for pitch control, and the medium-wind-speed turbines are sorted in descending order of wind speed. Based on the sorting results, the medium-wind-speed turbines are sequentially designated as turbines to be adjusted for pitch control until the total load reduction of the turbines to be adjusted for pitch control meets the wind farm's load reduction requirements. The pitch angle change of the turbines to be adjusted for pitch control is used as the optimization variable to construct a linear programming problem.

[0088] In some alternative implementations, the objective function of the linear programming problem includes minimizing the total pitch angle change of the wind turbine to be pitched; the total power of the wind turbines in the wind farm includes the power of the wind turbine to be pitched and the power of the wind turbines not to be pitched in the wind farm.

[0089] In some optional implementations, the optimization module 402 is further configured to: determine whether the initial power of the wind turbine to be adjusted is greater than the difference between the total power of the wind turbines in the wind farm that meet the operating load reduction rate requirements and the power of the non-wind turbines in the wind farm; if the initial power of the wind turbine to be adjusted is greater than the difference between the total power of the wind turbines in the wind farm that meet the operating load reduction rate requirements and the power of the non-wind turbines in the wind farm, then the actual feasible region of the pitch angle change is the first feasible region, which is from 0 to the difference between the upper limit of the pitch angle and the current pitch angle, and the boundary of the first feasible region is defined. Connecting the two corresponding points yields the first linear approximation relationship between the wind energy conversion efficiency coefficient and the pitch angle within the first feasible region. If the initial power of the wind turbine to be pitched is not greater than the difference between the total power of the wind turbines in the wind farm that meet the operating load reduction rate requirements and the power of the non-pitch wind turbines in the wind farm, then the actual feasible region for the pitch angle change is the second feasible region. The second feasible region is the difference between the base pitch angle and the current pitch angle up to 0. Connecting the two points corresponding to the boundary of the second feasible region yields the second linear approximation relationship between the wind energy conversion efficiency coefficient and the pitch angle within the second feasible region.

[0090] In some alternative implementations, at most one wind turbine's pitch angle change is not on the boundary of the pitch angle inequality constraint in the optimization result; the pitch angle change of wind turbines in the wind farm is adjusted according to the optimization result of the linear programming problem, including adjusting the pitch angle change of at most one wind turbine.

[0091] In some optional implementations, the output module 404 is further configured to: calculate the power reference value of the wind turbine to be modified based on the determined pitch angle change by substituting it into the power expression; set the power reference value of the wind turbine in the low wind speed zone as the maximum output power; and calculate the power reference value of the wind turbine in the high wind speed zone and the wind turbine in the medium wind speed zone that is not the wind turbine to be modified by substituting the pitch angle as zero into the power expression.

[0092] The power distribution device for wind farm overspeed pitch coordinated load reduction provided by this invention uses the data of wind turbines in the wind farm and the operating load reduction rate requirements of the wind farm as the optimization variable to construct a linear programming problem, thereby achieving more refined power distribution. At the same time, the computation time required for the linear programming problem is relatively short, which is conducive to its online application in wind farms.

[0093] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5 As shown, the electronic device may include a processor 510, a communication interface 520, a memory 530, and a communication bus 540. The processor 510, communication interface 520, and memory 530 communicate with each other via the communication bus 540. The processor 510 can call logical instructions in the memory 530 to execute a power allocation method for coordinated load reduction in wind farms using overspeed pitch control. This method includes: acquiring the structural parameters of the wind turbines in the wind farm, wind speed information, pitch angle information, pitch frequency regulation response time limits, and the wind farm's operating load reduction rate requirements; based on the acquired data, constructing a linear programming problem using the pitch angle change of the wind turbines in the wind farm as an optimization variable, the constraints of which include ensuring the total power of the wind turbines in the wind farm meets the operating load reduction rate requirements; determining the pitch angle change of the wind turbines in the wind farm based on the optimization results of the linear programming problem; and outputting a power reference value for the wind turbines in the wind farm based on the determined pitch angle change.

[0094] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0095] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the power allocation method for wind farm overspeed pitch coordinated load reduction provided by the above methods. The method includes: acquiring the structural parameters, wind speed information, pitch angle information, pitch frequency regulation response time limit, and wind farm operation load reduction rate requirements of the wind turbines in the wind farm; constructing a linear programming problem based on the acquired data, using the pitch angle change of the wind turbines in the wind farm as an optimization variable, wherein the constraints of the linear programming problem include that the total power of the wind turbines in the wind farm meets the operation load reduction rate requirements; determining the pitch angle change of the wind turbines in the wind farm based on the optimization result of the linear programming problem; and outputting a power reference value of the wind turbines in the wind farm based on the determined pitch angle change.

[0096] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements a power allocation method for wind farm overspeed pitch-coordinated load reduction provided by the methods described above. The method includes: acquiring structural parameters, wind speed information, pitch angle information, pitch frequency regulation response time limits, and wind farm operating load reduction rate requirements of the wind turbines within the wind farm; constructing a linear programming problem based on the acquired data, using the pitch angle change of the wind turbines within the wind farm as an optimization variable, wherein the constraints of the linear programming problem include that the total power of the wind turbines within the wind farm meets the operating load reduction rate requirements; determining the pitch angle change of the wind turbines within the wind farm based on the optimization results of the linear programming problem; and outputting a power reference value of the wind turbines within the wind farm based on the determined pitch angle change.

[0097] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0098] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power distribution method for coordinated load reduction via overspeed pitch control in wind farms, characterized in that, include: Obtain the structural parameters, wind speed information, pitch angle information, pitch frequency regulation response time limit of the wind turbines in the wind farm, and the operating load reduction rate requirements of the wind farm; Based on the acquired data, the pitch angle change of the wind turbines in the wind farm is used as the optimization variable to construct a linear programming problem. The constraints of the linear programming problem include that the total power of the wind turbines in the wind farm meets the operating load reduction rate requirement and that the pitch angle change of the wind turbines in the wind farm meets the inequality requirement. The pitch angle variation of the wind turbines in the wind farm is determined based on the optimization results of the linear programming problem. The power reference value of the wind turbines in the wind farm is output based on the determined pitch angle change. Based on the acquired data, the variation in the pitch angle of the wind turbines within the wind farm is used as an optimization variable to construct a linear programming problem, including: The maximum output power of each wind turbine is calculated based on the structural parameters and wind speed information of each wind turbine in the wind farm. Based on the calculated maximum output power, the wind turbines in the wind farm are divided into medium wind speed zone turbines, wind turbines with higher wind speeds are divided into high wind speed zone turbines, and wind turbines with lower wind speeds are divided into low wind speed zone turbines. Assuming that the pitch angle of all wind turbines in the high wind speed area is adjusted to the upper limit of the feasible region, determine whether the wind farm load reduction rate is less than the preset load reduction rate at this time; If the wind farm load reduction rate is less than the preset load reduction rate at this time, the wind turbine in the high wind speed area will be set as the wind turbine to be modified. If the wind farm load reduction rate is still less than the preset load reduction rate, the wind turbines in the high wind speed area are set as wind turbines to be pitched, and the wind turbines in the medium wind speed area are sorted in order of wind speed from large to small. According to the sorting result, the wind turbines in the medium wind speed area are set as wind turbines to be pitched in turn until the total load reduction of the wind turbines to be pitched can meet the load reduction requirements of the wind farm. The pitch angle change of the wind turbine to be modified is used as the optimization variable to construct a linear programming problem.

2. The power distribution method for wind farm overspeed pitch-coordinated load reduction according to claim 1, characterized in that, The objective function of the linear programming problem includes minimizing the total pitch angle change of the wind turbine to be modified; the total power of the wind turbines in the wind farm includes the power of the wind turbine to be modified and the power of the wind turbines not to be modified in the wind farm.

3. The power distribution method for wind farm overspeed pitch-coordinated load reduction according to claim 2, characterized in that, Based on the acquired data, the variation in the pitch angle of the wind turbines within the wind farm is used as an optimization variable to construct a linear programming problem, including: Determine whether the initial power of the wind turbine to be modified is greater than the difference between the total power of the wind turbines in the wind farm that meets the operating load reduction rate requirement and the power of the wind turbines in the wind farm that are not the wind turbine to be modified. If the initial power of the wind turbine to be modified is greater than the difference between the total power of the wind turbines in the wind farm that meets the operating load reduction rate requirement and the power of the wind turbines not to be modified in the wind farm, then the actual feasible region of the pitch angle change is the first feasible region. The first feasible region is from 0 to the difference between the upper limit of the pitch angle and the current pitch angle. Connecting the two points corresponding to the boundary of the first feasible region, we obtain the first linear approximate relationship between the wind energy conversion efficiency coefficient and the pitch angle in the first feasible region. If the initial power of the wind turbine to be modified is not greater than the difference between the total power of the wind turbines in the wind farm that meets the operating load reduction rate requirement and the power of the wind turbines not to be modified in the wind farm, then the actual feasible region of the pitch angle change is the second feasible region. The second feasible region is the difference between the base pitch angle and the current pitch angle up to 0. Connecting the two points corresponding to the boundary of the second feasible region, we obtain the second linear approximate relationship between the wind energy conversion efficiency coefficient and the pitch angle in the second feasible region.

4. The power distribution method for wind farm overspeed pitch-coordinated load reduction according to claim 3, characterized in that, In the optimization results, at most one wind turbine's pitch angle change is not on the boundary of the pitch angle inequality constraint; adjusting the pitch angle change of the wind turbines in the wind farm based on the optimization results of the linear programming problem includes adjusting the pitch angle change of at most one wind turbine.

5. The power distribution method for wind farm overspeed pitch-coordinated load reduction according to claim 1, characterized in that, The step of outputting the power reference value of the wind turbines in the wind farm based on the determined pitch angle change includes: The power reference value of the wind turbine to be modified is calculated by substituting the determined pitch angle change into the power expression; Set the power reference value of the fan in the low wind speed zone to the maximum output power; Substituting the pitch angle of zero into the power expression, calculate the power reference value of the non-variable pitch wind turbine in the high wind speed zone and the medium wind speed zone wind turbine.

6. A power distribution device for coordinated load reduction in wind farms using overspeed pitch control, characterized in that, include: The acquisition module is configured to acquire the structural parameters of the wind turbines in the wind farm, wind speed information, pitch angle information, pitch frequency regulation response time limit, and the operating load reduction rate requirements of the wind farm. The optimization module is configured to construct a linear programming problem based on the acquired data, using the pitch angle change of the wind turbines in the wind farm as the optimization variable. The constraints of the linear programming problem include that the total power of the wind turbines in the wind farm meets the operating load reduction rate requirement and that the pitch angle change of the wind turbines in the wind farm meets the inequality requirement. The determination module is configured to determine the pitch angle variation of the wind turbines in the wind farm based on the optimization results of the linear programming problem. The output module is configured to output a power reference value of the wind turbines in the wind farm based on the determined pitch angle change. Based on the acquired data, the variation in the pitch angle of the wind turbines within the wind farm is used as an optimization variable to construct a linear programming problem, including: The maximum output power of each wind turbine is calculated based on the structural parameters and wind speed information of each wind turbine in the wind farm. Based on the calculated maximum output power, the wind turbines in the wind farm are divided into medium wind speed zone turbines, wind turbines with higher wind speeds are divided into high wind speed zone turbines, and wind turbines with lower wind speeds are divided into low wind speed zone turbines. Assuming that the pitch angle of all wind turbines in the high wind speed area is adjusted to the upper limit of the feasible region, determine whether the wind farm load reduction rate is less than the preset load reduction rate at this time; If the wind farm load reduction rate is less than the preset load reduction rate at this time, the wind turbine in the high wind speed area will be set as the wind turbine to be modified. If the wind farm load reduction rate is still less than the preset load reduction rate, the wind turbines in the high wind speed area are set as wind turbines to be pitched, and the wind turbines in the medium wind speed area are sorted in order of wind speed from large to small. According to the sorting result, the wind turbines in the medium wind speed area are set as wind turbines to be pitched in turn until the total load reduction of the wind turbines to be pitched can meet the load reduction requirements of the wind farm. The pitch angle change of the wind turbine to be modified is used as the optimization variable to construct a linear programming problem.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the power distribution method for wind farm overspeed pitch coordinated load reduction as described in any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the power distribution method for wind farm overspeed pitch coordinated load reduction as described in any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the power distribution method for wind farm overspeed pitch coordinated load reduction as described in any one of claims 1 to 5.

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