Wake assessment method and system for offshore wind farms

Abstract

This application proposes a method and system for evaluating the wake of a group of offshore wind farms. The method includes: based on an actuator disk model, selecting multiple wind farms within the offshore wind power base area for large eddy simulation; combining the results of the large eddy simulation to determine the influence of multiple engineering parameters of the upstream wind farm on the wake of the downstream wind farm; constructing a function between the wake distribution of the downstream wind farm and multiple engineering parameters of the upstream wind farm based on the influence law; dividing the wind direction into multiple sectors, and calculating the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector based on the function. This method analyzes the evolution mechanism of wake between different wind farms and can accurately evaluate the wake loss caused by the upstream wind farm to the downstream wind farm.

Description

Technical Field

[0001] The present application relates to the field of wind power generation technology, and in particular to a wake assessment method and system for an offshore wind farm group. Background Art

[0002] With the development of new energy technologies, wind power continues to account for a growing share of the power supply system. Due to its abundant offshore wind energy resources and proximity to load-absorbing centers, offshore wind power has become a key driver of the wind power industry's upgrade and energy transition in recent years. Grid-connected offshore wind power capacity continues to increase. With the advent of parity for offshore wind power, large-scale, concentrated development has become the only way to reduce costs and achieve high-quality development.

[0003] However, large-scale development can lead to significant wake losses. Offshore wind farms create a barrier to the atmospheric boundary layer, and the wake effect between large wind farms is significant. For closely spaced wind farms, upstream wind farms can severely block downstream wind farms, impacting the distribution of wind resources. Data indicates that the impact of wake from surrounding wind farms can reduce wind farm yields by more than 5%. Therefore, it is necessary to assess the impact of wind farm wakes and implement appropriate measures.

[0004] Wake assessment schemes in related technologies mostly focus on the study of the wake effects within wind turbines and wind farms, and lack analysis of the wake evolution between different wind farms. When designing a wind farm, the wake losses caused by upstream wind farms are usually evaluated using only an empirical reduction coefficient, and accuracy is difficult to guarantee. Summary of the Invention

[0005] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0006] To this end, the first purpose of this application is to propose a wake assessment method for an offshore wind farm group. This method analyzes the wake evolution mechanism between different wind farms and can accurately assess the wake loss caused by the upstream wind farm to the downstream wind farm.

[0007] The second objective of the present application is to provide a wake assessment system for an offshore wind farm group.

[0008] A third object of the present application is to provide a non-transitory computer-readable storage medium.

[0009] To achieve the above objectives, a first embodiment of the present application provides a wake assessment method for an offshore wind farm group, comprising the following steps:

[0010] Based on the actuator disk model, multiple wind farms were selected in the offshore wind power base area for large eddy simulation;

[0011] In combination with the results of the large eddy simulation, determine the influence of multiple engineering parameters of the upstream wind farm on the wake of the downstream wind farm;

[0012] constructing a function between the wake distribution of the downstream wind farm and the plurality of engineering parameters of the upstream wind farm according to the influencing law;

[0013] The wind direction is divided into a plurality of sectors, and the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector is calculated based on the function.

[0014] Optionally, in one embodiment of the present application, based on the actuator disk model, multiple wind farms are selected in the offshore wind power base area for large eddy simulation, including: establishing an actuator disk model for each wind turbine in the wind farm to construct a model of the wind farm; in the process of performing the large eddy simulation on the model of the wind farm, eddy viscosity and eddy diffusion processing is performed through a sub-grid model; and wall flow in the large eddy simulation is processed through a wall function.

[0015] Optionally, in one embodiment of the present application, the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector is calculated based on the function, including: substituting the multiple engineering parameters of each upstream wind farm in the upstream wind farm group into the function to obtain the wake loss of each upstream wind farm to the any position; and superimposing the wake losses corresponding to each upstream wind farm to obtain the total wake loss at the any position.

[0016] Optionally, in one embodiment of the present application, the total wake loss at any position is calculated by the following formula:

[0017]

[0018] Among them, x j represents the wake loss caused by the jth upstream wind farm to any of the locations, y represents the total wake loss, and N represents the number of upstream wind farms.

[0019] Optionally, in one embodiment of the present application, after calculating the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector based on the function, it also includes: calculating the wake loss wind speed corresponding to the any position based on the total wake loss; and correcting the annual wind speed distribution of the any position in each sector based on the wake loss wind speed.

[0020] Optionally, in one embodiment of the present application, the annual wind speed distribution at any location in each of the sectors is corrected based on the wake loss wind speed, including: calculating the ratio of the wake loss wind speed at any location to the wind speed when not affected by the wake; calculating the annual wind speed distribution at any location through a wind resource calculation application based on the actual wind speed data of the target downstream wind farm to be evaluated; and multiplying the annual wind speed distribution by the ratio to obtain a corrected value of the annual wind speed distribution in each of the sectors.

[0021] To achieve the above objectives, a second embodiment of the present application provides a wake assessment system for an offshore wind farm group, comprising the following modules:

[0022] A simulation module is used to select multiple wind farms in the offshore wind power base area for large eddy simulation based on the actuator disk model;

[0023] a determination module, configured to determine, based on the results of the large eddy simulation, how multiple engineering parameters of the upstream wind farm affect the wake of the downstream wind farm;

[0024] A construction module, configured to construct a function between the wake distribution of the downstream wind farm and the plurality of engineering parameters of the upstream wind farm according to the influencing law;

[0025] The calculation module is used to divide the wind direction into multiple sectors and calculate, based on the function, the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector.

[0026] Optionally, in one embodiment of the present application, the simulation module is specifically used to: establish an actuator disk model for each wind turbine in the wind farm to construct a model of the wind farm; in the process of performing the large eddy simulation on the model of the wind farm, perform eddy viscosity and eddy diffusion processing through a sub-grid model; and process the wall flow in the large eddy simulation through a wall function.

[0027] Optionally, in one embodiment of the present application, the calculation module is specifically used to: substitute the multiple engineering parameters of each upstream wind farm in the upstream wind farm group into the function to obtain the wake loss of each upstream wind farm at any position; superimpose the wake losses corresponding to each upstream wind farm to obtain the total wake loss at any position.

[0028] In order to implement the above embodiments, the third aspect of the present application further proposes a non-temporary computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the wake assessment method for an offshore wind farm group in the above embodiments is implemented.

[0029] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects: the present application first conducts a large eddy simulation study on the area of the offshore wind power base to determine the influence of various characteristic parameters of the upstream offshore wind farm on the wake of the downstream offshore wind farm. The influence law is then described as a mathematical function that expresses it more clearly and accurately. In the actual evaluation process, the function is used to calculate the influence of the wake on the wind farms in different sectors of a certain downstream wind farm. As a result, the present application analyzes and studies the wake evolution mechanism between wind farms, and can accurately evaluate the wake loss caused by the upstream wind farm to the downstream wind farm, which is helpful for the reasonable design of the wind farm, reduces the wake loss between wind farms, improves the operating efficiency of the wind farm, and is more suitable for the application of wind farms in actual engineering. In addition, the present application also corrects the wind speed distribution based on the calculated wake loss, and can obtain accurate and true annual wind speed distribution at different locations in the wind farm.

[0030] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which

[0032] Figure 1 A flowchart of a wake assessment method for an offshore wind farm group proposed in an embodiment of the present application;

[0033] Figure 2 A flowchart of a method for calculating total wake loss proposed in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of a specific wind farm cluster proposed in an embodiment of the present application;

[0035] Figure 4 This is a flow chart of a method for correcting annual wind speed distribution proposed in an embodiment of the present application;

[0036] Figure 5 This is a schematic structural diagram of a wake assessment system for an offshore wind farm group proposed in an embodiment of the present application. DETAILED DESCRIPTION

[0037] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0038] A method and system for evaluating wakes of an offshore wind farm group according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0039] Figure 1 This is a flow chart of a wake assessment method for an offshore wind farm group proposed in an embodiment of the present application, such as Figure 1 The method comprises the following steps:

[0040] Step S101 : Based on the actuator disk model, multiple wind farms are selected in the offshore wind power base area to perform large eddy simulation.

[0041] It should be noted that after air flows through the rotor of a wind turbine, a wake region forms behind the turbine. Wind speed decreases and turbulence increases within this region, affecting the output and fatigue load of downstream turbines, resulting in a loss of operating efficiency. Therefore, it is necessary to study the wake effects of wind turbines. Computational fluid dynamics (CFD) is one of the main methods for numerically simulating wind turbine flow fields.

[0042] Among them, the actuator disc model (AD) is a simplified model of a wind rotor. By constructing the actuator disc model, the workload in the wake study of a wind farm can be reduced and the implementation is facilitated.

[0043] Among them, large eddy simulation (LES) is a spatial average of turbulent eddies. Large-scale eddies and small-scale eddies are separated by a certain filtering function. Large-scale eddies are simulated directly, and small-scale eddies are closed by a model.

[0044] Specifically, the present application can select multiple wind farms within a certain area of an offshore wind power base for large eddy simulation, which is helpful for studying the influence of wakes. The offshore wind power base can be the base of an offshore wind farm station that is being planned. That is, the wake assessment method of the present application can be executed when the wind farm station is in the design stage and has not yet begun construction, so that the design plan of the wind farm station can be adjusted according to the wake assessment results to reduce the impact of wakes. The wind farm data obtained in this step can be the design data of the wind farm plan, etc.

[0045] This application can arbitrarily select several wind farms in the offshore wind power base for large eddy simulation, focusing on revealing the evolution law of wakes between wind farms through research on the selected wind farms. Therefore, the wind farms selected in this step are not the wind farms where the wake assessment is actually performed.

[0046] In one embodiment of the present application, a large eddy simulation (LES) is performed on multiple wind farms within an offshore wind farm base based on an actuator disk model. The LES includes the following steps: First, an actuator disk model is established for each wind turbine in each wind farm to construct a model of the wind farm. Then, during the LES of the wind farm model, eddy viscosity and eddy diffusion are processed using a subgrid model, and wall functions are used to handle the wall flow in the LES.

[0047] Specifically, in this embodiment, for each wind turbine in each wind farm, an actuator disk model is built using a preset scale (e.g., 1 / 150). This actuator disk model simplifies the rotor into a disk. In actual modeling, this disk does not exist in reality; rather, it replaces the rotor's role in the flow field by identifying the mesh and adding a body force source term. Thus, this embodiment constructs models for multiple selected wind farms and performs large eddy simulations.

[0048] When performing large eddy simulation, turbulent motion is numerically simulated, and only eddies larger than the grid are calculated. The eddies are directly calculated through methods such as the Navier-Stokes equations, and a model is used to represent small-scale eddies, which plays a dissipative role. Among them, a reasonable sub-grid model is selected to construct an eddy viscosity model and an eddy diffusion model for simulation and solution. However, near the wall, due to the existence of the boundary layer, the flow development is insufficient, and the turbulence development is insufficient. Therefore, the embodiment of the present application improves the accuracy of the simulation by selecting a reasonable wall function to deal with the wall flow problem in the large eddy simulation. The specific implementation process of each step of the large eddy simulation can refer to the implementation method in the relevant technology, and will not be repeated here.

[0049] Step S102 , combining the results of the large eddy simulation, determines the influence of multiple engineering parameters of the upstream wind farm on the wake of the downstream wind farm.

[0050] The engineering parameters are characteristic parameters of a wind farm during actual construction. For example, the engineering parameters include but are not limited to: the arrangement of wind turbines in the wind farm, the area of the wind farm, and the capacity of the wind farm.

[0051] Among them, the upstream wind farm is the wind farm located upstream in the wind flow, and the downstream wind farm refers to the wind speed field or wind farm located downstream in the wind flow, that is, the downstream wind farm can be a station with wind turbines for wind power generation, or it can be just an area with local wind speed, and there is no actual power generation equipment in this area.

[0052] It is understandable that during the wake study, even if there are no wind turbines in the downstream area, the upstream wind farm will still cause a wake impact on the downstream. Therefore, when analyzing the wake impact law, this application can select an actual wind farm station for research, or it can study the downstream area, thereby further reducing the work of model construction, data collection and processing, reducing the operational complexity and cost of wake assessment, and facilitating implementation. The specific type of downstream wind farm is determined based on the selection of multiple wind farms for large eddy simulation in the previous step. That is, when selecting multiple wind farms, you can also select a downstream wind farm that does not include a power station.

[0053] Specifically, combined with the research results of the large eddy simulation obtained in the previous step, the influence of parameters such as the layout of wind turbines in the upstream wind farm, the wind farm area, the wind farm capacity, and the distance from the downstream wind farm on the wake of the downstream offshore wind farm is studied.

[0054] In one embodiment of the present application, the influence pattern can be the corresponding relationship between changes in a certain engineering parameter and the increase or decrease in the downstream wake. In this embodiment, after analyzing the influence pattern of each engineering parameter of the upstream wind farm on the downstream wind farm wake in sequence, a comprehensive analysis can be performed to determine the influence pattern of the coordinated effect of multiple engineering parameters on the downstream wind farm wake. Furthermore, numerical calculation results at different cross-sections between the upstream wind farm and the downstream wind farm are extracted.

[0055] Step S103 : constructing a function between the wake distribution of the downstream wind farm and a plurality of engineering parameters of the upstream wind farm according to the influence rule.

[0056] Specifically, the influencing patterns determined in the previous step are numerically represented. That is, based on these influencing patterns, the wake distribution downstream of the wind farm is described as a function of multiple engineering parameters, such as the wind farm's length, width, capacity, and distance. It is understood that the area of a wind farm is equal to the product of its length and width. This application, targeting the same engineering parameters or a refinement of a specific engineering parameter, constructs a functional expression based on the influencing patterns between the wake distribution and multiple engineering parameters of the upstream wind farm through various methods, such as curve fitting.

[0057] Therefore, the wake assessment method of the present application selects a portion of wind farms for research, analyzes the wake impact of upstream wind farms on downstream wind farms, and obtains a universal calculation function, which is convenient for calculating the wake impact in the subsequent actual wake assessment.

[0058] Step S104 : dividing the wind direction into multiple sectors, and calculating the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector based on the function.

[0059] Specifically, it is understood that under different wind direction conditions, the upstream wind farm and the downstream wind farm will change. Therefore, in order to more comprehensively analyze the wake losses caused by the upstream wind farm to the downstream wind farm under different wind directions, this application first evenly divides the range from 0° to 360° into a preset number of sectors. Then, in a certain sector, the upstream wind farm group including multiple wind farms and the downstream wind farm are determined according to the wind direction of the sector. Then, a downstream wind farm for which wake loss assessment is required is selected, i.e., the target downstream wind farm. Based on the above-mentioned determination function, the impact of the upstream wind farm's wake on the wind farms in different sectors is calculated for this wind farm.

[0060] Based on the above embodiments, in order to more clearly describe the specific implementation process of calculating the total wake loss at any location in the target downstream wind farm in the present application, an embodiment of the present application is described below in combination with a group of wind farms in a specific offshore wind power base, using a method for calculating the wake loss as an example. Figure 2 This is a flow chart of a method for calculating total wake loss proposed in an embodiment of the present application. Figure 3 This is a schematic diagram of a specific wind farm cluster proposed in an embodiment of the present application.

[0061] like Figure 2 As shown, the method includes the following steps:

[0062] Step S201 : Substitute multiple engineering parameters of each upstream wind farm in the upstream wind farm group into a function to obtain the wake loss of each upstream wind farm at any position.

[0063] Specifically, the upstream wind farms in the upstream wind farm group are determined based on the current sector and may be different from the wind farms selected in step S101. Multiple engineering parameters of each upstream wind farm in the upstream wind farm group are substituted into the generated function to calculate the wake loss caused by each upstream wind farm at any location.

[0064] For example, if Figure 3 As shown in the figure, it is assumed that the range of 0°-360° is evenly divided into 16 sectors. For one of the sectors, if the wind direction corresponding to the sector is from southeast to northwest, a wind farm 1 to be built is selected as the target downstream wind farm, and any position of point A in wind farm 1 is selected for research.

[0065] Furthermore, since there are multiple wind farms upstream, namely wind farm 2 and wind farm 3, the various engineering parameters of upstream wind farm 2 and upstream wind farm 3 are substituted into the generated function in turn, and it is obtained that the wake loss of upstream wind farm 2 to point A of wind farm 1 is x1, and the wake loss of upstream wind farm 3 to point A of wind farm 1 is x2.

[0066] Step S202 : adding the wake losses corresponding to each upstream wind farm to obtain the total wake loss at any location.

[0067] Specifically, if there are multiple wind farms upstream, a wake superposition model can be used to calculate the wake loss experienced by the target downstream wind farm. Specifically, the wake loss corresponding to each upstream wind farm is superimposed to calculate the total wake loss experienced by all upstream wind farms.

[0068] As an implementation, the total wake loss at any location is calculated using the following formula:

[0069]

[0070] Among them, x j represents the wake loss caused by the jth upstream wind farm at any location, y represents the total wake loss, and N represents the number of upstream wind farms.

[0071] Continuing with the above example, at point A in wind farm 1, x1 and x2 can be substituted into the above formula to calculate the total wake loss y.

[0072] Similarly, this application can refer to the above method to carry out calculations on the influence of wake on the wind field downwind of different sectors.

[0073] In one embodiment of the present application, after obtaining the wake effects at different locations in the wind farm area, the wind speed distribution calculation can also be corrected based on the calculated wake effects. Specifically, after calculating the total wake loss caused by the upstream wind farm group to any location in the target downstream wind farm to be evaluated in each sector based on a function, the present application also includes: calculating the wake loss wind speed corresponding to any location based on the total wake loss; and correcting the annual wind speed distribution of any location in each of the sectors based on the wake loss wind speed.

[0074] Specifically, the wake loss wind speed can be calculated by multiplying the total wake loss calculated at any position by the incoming wind speed. For example, in the above example, the wake loss at point A of wind farm 1 is y, and the wake loss wind speed corresponding to point A of wind farm 1 is y*U0, where U0 is the incoming wind speed, which can be obtained through actual measurement.

[0075] Furthermore, when the annual wind speed distribution is corrected according to the wake loss wind speed, in order to more clearly describe the specific implementation of the process, a wind speed correction method is exemplified in an embodiment of the present application. Figure 4 This is a flow chart of a method for correcting annual wind speed distribution proposed in an embodiment of the present application.

[0076] like Figure 4As shown, the method includes the following steps:

[0077] Step S401 : Calculate the ratio of the wake loss wind speed at any location to the wind speed when not affected by the wake.

[0078] Continue to refer to Figure 3 As shown in the example, after evenly dividing the range from 0° to 360° into 16 sectors, the wake loss at different locations in wind farm 1 is calculated under each sector, and the ratio of the wake loss to the wake loss at different locations in the wind farm area is obtained. For example, in the 0° to 25° sector, the ratio of the wake loss to the wake loss at point A in wind farm 1 is c (0 < c ≤ 1).

[0079] Step S402 : calculating the annual wind speed distribution at any location using a wind resource calculation application based on actual wind speed data of the target downstream wind farm to be evaluated.

[0080] Among them, the actual wind speed data can be the historical wind speed time within one year actually measured by the wind speed measuring equipment in the target downstream wind farm. The wind speed measuring equipment stores the wind speed data in the database after measuring it in real time. When wake assessment is required, the actual wind speed data of the target downstream wind farm pre-stored can be read from the database.

[0081] The wind resource calculation application may be Windsim or WT, etc., which are commercial wind resource calculation software that generates wind speed distribution data within a time period based on wind speed data at different times.

[0082] Continuing with the above example, the annual wind speed distribution in the 0° to 25° sector at point A of wind farm 1 is calculated using the measured data recorded by the wind tower in wind farm 1 using the commercial wind resource calculation software Windsim or WT.

[0083] Step S403: multiply the annual wind speed distribution by the ratio to obtain a correction value of the annual wind speed distribution in each sector.

[0084] Continuing with the above example, the initial annual wind speed distribution in the 0° to 25° sector is multiplied by the coefficient c calculated in step S401 to obtain the corrected annual wind speed distribution in the 0° to 25° sector. The wind speed correction calculation for other sectors at point A is similar, and for other locations in wind farm 1, the wind speed correction calculation can be performed referring to this method.

[0085] Therefore, this application can make corrections based on the measured data from the wind tower within the wind farm and the annual wind speed distribution at different locations throughout Wind Farm 1 calculated using the commercial wind resource calculation software Windsim or WT. The calculation process for other downstream wind farms can refer to Wind Farm 1 and will not be repeated here. This application can correct the annual wind speed distribution at various locations in different downstream wind farms.

[0086] In summary, the wake assessment method for an offshore wind farm group in the embodiment of the present application first conducts a large eddy simulation study on the area of the offshore wind power base to determine the influence of various characteristic parameters of the upstream offshore wind farm on the wake of the downstream offshore wind farm. The influence law is then described as a mathematical function that is expressed more clearly and accurately. In the actual assessment process, the influence of the wake on the wind farms in different sectors is calculated for a certain downstream wind farm based on the function. Thus, the method analyzes and studies the wake evolution mechanism between wind farms, and can accurately assess the wake loss caused by the upstream wind farm to the downstream wind farm, which is helpful for the reasonable design of the wind farm, reduces the wake loss between wind farms, improves the operating efficiency of the wind farm, and is more suitable for the application of wind farms in actual engineering. In addition, the method also corrects the wind speed distribution based on the calculated wake loss, and can obtain accurate and true annual wind speed distribution at different locations in the wind farm.

[0087] In order to implement the above embodiment, the present application also proposes a wake assessment system for an offshore wind farm group. Figure 5 This is a schematic structural diagram of a wake assessment system for an offshore wind farm group proposed in an embodiment of the present application.

[0088] like Figure 5 As shown, the system includes a simulation module 100 , a determination module 200 , a construction module 300 and a calculation module 400 .

[0089] The simulation module 100 is used to select a plurality of wind farms in the offshore wind power base area to perform large eddy simulation based on the actuator disk model.

[0090] The determination module 200 is used to determine the influence of multiple engineering parameters of the upstream wind farm on the wake of the downstream wind farm based on the results of the large eddy simulation.

[0091] The construction module 300 is used to construct a function between the wake distribution of the downstream wind farm and multiple engineering parameters of the upstream wind farm according to the influence law.

[0092] The calculation module is used to divide the wind direction into multiple sectors and calculate the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector based on the function.

[0093] Optionally, in one embodiment of the present application, the simulation module 100 is specifically used to: establish an actuator disk model for each wind turbine in a wind farm to construct a model of the wind farm; in the process of performing large eddy simulation on the model of the wind farm, perform eddy viscosity and eddy diffusion processing through a sub-grid model; and process the wall flow in the large eddy simulation through a wall function.

[0094] Optionally, in one embodiment of the present application, the calculation module 400 is specifically used to: substitute multiple engineering parameters of each upstream wind farm in the upstream wind farm group into the function to obtain the wake loss of each upstream wind farm at any position; and superimpose the wake losses corresponding to each upstream wind farm to obtain the total wake loss at any position.

[0095] Optionally, in one embodiment of the present application, the calculation module 400 is specifically configured to calculate the total wake loss at any location using the following formula:

[0096]

[0097] Among them, x j represents the wake loss caused by the jth upstream wind farm at any location, y represents the total wake loss, and N represents the number of upstream wind farms.

[0098] Optionally, in one embodiment of the present application, the system includes: a correction module, the correction module being used to calculate the wake loss wind speed corresponding to any location based on the total wake loss; and to correct the annual wind speed distribution of any location in each sector based on the wake loss wind speed.

[0099] Optionally, in one embodiment of the present application, the correction module is specifically used to: calculate the ratio of the wake loss wind speed at any location to the wind speed when not affected by the wake; calculate the annual wind speed distribution at any location through a wind resource calculation application based on the actual wind speed data of the target downstream wind farm to be evaluated; multiply the annual wind speed distribution by the ratio to obtain a corrected value of the annual wind speed distribution in each sector.

[0100] It should be noted that the description of the embodiment of the wake assessment method for an offshore wind farm group mentioned above is also applicable to the system of this embodiment, and the implementation principle is the same, which will not be repeated here.

[0101] In summary, the wake assessment system for the offshore wind farm group of the embodiment of the present application first conducts a large eddy simulation study on the area of the offshore wind power base to determine the influence of various characteristic parameters of the upstream offshore wind farm on the wake of the downstream offshore wind farm. The influence law is then described as a mathematical function that is expressed more clearly and accurately. In the actual evaluation process, the function is used to calculate the influence of the wake on the wind farms in different sectors of a certain downstream wind farm. As a result, the system analyzes and studies the wake evolution mechanism between wind farms, and can accurately assess the wake loss caused by the upstream wind farm to the downstream wind farm, which helps to reasonably design the wind farm, reduce the wake loss between wind farms, improve the operating efficiency of the wind farm, and is more suitable for the application of wind farms in actual engineering. In addition, the system also corrects the wind speed distribution based on the calculated wake loss, and can obtain accurate and true annual wind speed distribution at different locations in the wind farm.

[0102] In order to implement the above embodiments, the present invention also proposes a non-temporary computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, it implements the wake assessment method for an offshore wind farm group described in the first aspect of the embodiment of the present application.

[0103] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, if schematic expressions of the above terms are used in multiple embodiments or examples, it does not mean that these embodiments or examples are the same. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0104] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0105] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0106] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0107] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0108] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0109] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0110] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for evaluating the wake of an offshore wind farm group, characterized in that: The following steps are involved: Based on the actuator disk model, a plurality of wind farms are selected in an offshore wind power base area for large eddy simulation, including: establishing an actuator disk model for each wind turbine in the wind farm to construct a model of the wind farm; in the process of performing the large eddy simulation on the model of the wind farm, performing eddy viscosity and eddy diffusion processing using a subgrid model; and processing the wall flow in the large eddy simulation using a wall function; In combination with the results of the large eddy simulation, determine the influence of multiple engineering parameters of the upstream wind farm on the wake of the downstream wind farm; constructing a function between the wake distribution of the downstream wind farm and the plurality of engineering parameters of the upstream wind farm according to the influencing law; The wind direction is divided into a plurality of sectors, and the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector is calculated based on the function.

2. The wake assessment method according to claim 1, characterized in that: The calculating, based on the function, in each sector, the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated comprises: Substituting the plurality of engineering parameters of each upstream wind farm in the upstream wind farm group into the function to obtain the wake loss of each upstream wind farm at any one location; The wake losses corresponding to each upstream wind farm are superimposed to obtain the total wake loss at any location.

3. The wake assessment method according to claim 2, characterized in that: The total wake loss at any location is calculated by the following formula: in, x j Representative j The wake loss caused by the upstream wind farm at any of the above locations, y represents the total wake loss, N Represents the number of upstream wind farms.

4. The wake assessment method according to claim 1, characterized in that: After calculating the total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated in each sector based on the function, the method further includes: Calculating the wake loss wind speed corresponding to any position according to the total wake loss; The annual wind speed distribution of any location in each sector is corrected based on the wake loss wind speed.

5. The wake assessment method according to claim 4, characterized in that: The correcting the annual wind speed distribution of any location in each sector based on the wake loss wind speed includes: Calculating the ratio of the wake loss wind speed at any one of the locations to the wind speed when not affected by the wake; calculating the annual wind speed distribution at any location using a wind resource calculation application based on actual wind speed data of the target downstream wind farm to be evaluated; The annual wind speed distribution is multiplied by the ratio to obtain a corrected value of the annual wind speed distribution in each sector.

6. A wake assessment system for an offshore wind farm group, characterized in that: Includes the following modules: A simulation module is used to select multiple wind farms in the offshore wind power base area for large eddy simulation based on the actuator disk model; a determination module, configured to determine, based on the results of the large eddy simulation, how multiple engineering parameters of the upstream wind farm affect the wake of the downstream wind farm; A construction module, configured to construct a function between the wake distribution of the downstream wind farm and the plurality of engineering parameters of the upstream wind farm according to the influencing law; a calculation module, configured to divide the wind direction into a plurality of sectors, and calculate, based on the function, in each sector, a total wake loss caused by the upstream wind farm group to any position in the target downstream wind farm to be evaluated; The simulation module is specifically used for: Establishing an actuator disc model for each wind turbine in the wind farm to construct a model of the wind farm; During the large eddy simulation of the wind farm model, eddy viscosity and eddy diffusion processing are performed using a subgrid model; The wall flow in the large eddy simulation is handled by the wall function.

7. The wake assessment system according to claim 6, characterized in that: The computing module is specifically configured to: Substituting the plurality of engineering parameters of each upstream wind farm in the upstream wind farm group into the function to obtain the wake loss of each upstream wind farm at any one location; The wake losses corresponding to each upstream wind farm are superimposed to obtain the total wake loss at any location.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for evaluating the wake of an offshore wind farm group according to any one of claims 1 to 5 is implemented.

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