Cable length-short circuit capacity interval generation method for harmonic amplification of wind power plant

Abstract

The invention discloses a method for generating a cable length-short-circuit capacity interval for harmonic amplification of a wind power plant, and particularly relates to the technical field of offshore wind power harmonic analysis, and the technical key points are as follows: determining a power grid short-circuit capacity interval of a grid-connected point based on a grid-connected voltage level of the offshore wind power plant and in combination with an actual power grid operation state; dividing the power grid short-circuit capacity interval according to a preset capacity interval threshold value to obtain a plurality of power grid short-circuit capacity values; based on the cable characteristic distribution parameters and the plurality of power grid short-circuit capacity values, constructing a quantitative analysis model among the harmonic current amplification factor, the cable length and each power grid short-circuit capacity; and when the harmonic currents at the two ends of the cable are equal, calculating a cable length interval sequence corresponding to each power grid short-circuit capacity by using each quantitative analysis model, and constructing a cable length-short-circuit capacity two-dimensional interval for offshore wind power harmonic amplification through the cable length interval sequence corresponding to each power grid short-circuit capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power harmonic analysis, and in particular to a method for generating a cable length-short-circuit capacity interval for wind farm harmonic amplification. Background Art

[0002] Offshore wind farms are connected to the grid through inverters, and the normal operation of the inverter will generate harmonic currents. The grid-connected lines of offshore wind farms are often long cables. Compared with overhead lines, cables have larger distributed capacitance and may resonate with the inductive grid, causing the harmonics injected into the grid to be amplified, threatening the safe operation of the grid. When the harmonics of offshore wind farms are injected into the grid through cables, the severity of harmonic amplification is affected by the length of the cable and the short-circuit capacity of the grid connected to it. When planning a wind farm, if the cable length and the short-circuit capacity range of the grid for harmonic amplification can be estimated when the offshore wind farm is connected to the grid, the problem of harmonic amplification can be avoided by adjusting the cable length, changing the wind farm grid connection point, or designing harmonic control devices.

[0003] However, the current relevant offshore wind farm harmonic amplification analysis methods only focus on the harmonic resonance amplification frequency and cable length of the wind power grid-connected system, and do not consider the impact of the short-circuit capacity of the grid at the wind farm grid-connected point on harmonic amplification. In fact, the short-circuit capacity characterizes the operating state of the grid and is an important factor affecting harmonic amplification. When the short-circuit capacity of the grid changes, the harmonic amplification value of the wind farm will change significantly. To quantify the severity of harmonic amplification in offshore wind farms, it is necessary to consider the combined effects of cable length and grid short-circuit capacity. If the influence of grid short-circuit capacity is ignored, the results obtained will only reflect the harmonic amplification status under specific grid operation scenarios. However, the actual grid operation state is constantly changing, which leads to a huge deviation between the results obtained based on specific operation scenarios and the actual scenarios, and thus cannot be effectively applied to actual changing scenarios.

[0004] Therefore, the present invention aims to provide a method for generating a cable length-short-circuit capacity interval for harmonic amplification in a wind farm, so as to solve the above-mentioned related problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the influence of cable length and grid short-circuit capacity on harmonic amplification is not considered in the prior art. The purpose is to provide a cable length-short-circuit capacity interval generation method for wind farm harmonic amplification. Based on the characteristic parameters of offshore wind farm cables, a two-dimensional interval of cable length-grid short-circuit capacity where harmonic current amplification occurs in offshore wind farms is generated. This two-dimensional interval of cable length-grid short-circuit capacity is a high-risk area for harmonic amplification. Compared with the existing method of only analyzing the relationship between harmonic amplification and cable length, the proposed method takes into account the important influence of grid operation on harmonic current amplification, and improves the quantitative analysis perspective of harmonic amplification from a one-dimensional perspective to a two-dimensional perspective, that is, from the single variable influence analysis of cable length to the simultaneous influence analysis of cable length and grid capacity, which can reflect the influence of changes in grid operation status on harmonic amplification, thereby truly guiding the planning and safe and stable operation of offshore wind farms.

[0006] The present invention is achieved through the following technical solutions: A method for generating a cable length-short-circuit capacity interval for harmonic amplification in a wind farm, the method comprising: Based on the grid-connected voltage level of the offshore wind farm and in combination with the actual grid operation status, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values; Based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values, a quantitative analysis model between the harmonic current amplification factor and the cable length and the short-circuit capacity of each grid is constructed; When the harmonic currents at both ends of the cable are equal, each quantitative analysis model is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity, and the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification is constructed through the cable length interval sequence corresponding to each power grid short-circuit capacity.

[0007] Furthermore, based on the grid-connected voltage level of the offshore wind farm and combined with the actual grid operation status, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values, specifically: Determine the benchmark grid short-circuit capacity at the grid connection point based on the grid connection voltage level of the offshore wind farm; According to the actual grid operation status and the benchmark grid short-circuit capacity, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values.

[0008] Furthermore, based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values, a quantitative analysis model between the harmonic current amplification factor and the cable length and each grid short-circuit capacity is constructed, wherein the quantitative analysis model is specifically: ,in, Indicates the harmonic current magnification factor at both ends of the cable; Indicates the harmonic current at the end of the cable; Indicates the harmonic current at the beginning of the cable; h Indicates the harmonic order; Indicates the rated voltage of the wind farm grid connection point; Indicates the short-circuit capacity of the grid at the grid connection point; represents the angular frequency; Indicates the capacitance per unit length of the cable; Indicates the resistance per unit length of the cable; Indicates the inductance per unit length of the cable; represents the line propagation constant; Indicates the cable length; Represents an imaginary unit.

[0009] Furthermore, each quantitative analysis model is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity, specifically: When the harmonic currents at both ends of the cable are equal, a plurality of cable length interval endpoints corresponding to the short-circuit capacity of the power grid are calculated using a quantitative analysis model. The plurality of cable length interval endpoints include a plurality of interval left endpoints and a plurality of interval right endpoints. The plurality of interval left endpoints and the plurality of interval right endpoints are periodically cross-sorted according to the size of the endpoint values. The interval left endpoints and the interval right endpoints of the same period form a cable length interval. A cable length interval sequence corresponding to the short-circuit capacity of the power grid is constructed through multiple cable length intervals.

[0010] Furthermore, the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification is constructed through the cable length interval sequence corresponding to each power grid short-circuit capacity, specifically: By integrating the cable length intervals of the same period in the cable length interval sequences corresponding to the short-circuit capacities of multiple power grids, multiple two-dimensional cable length-short-circuit capacity intervals of offshore wind power harmonic amplification are obtained.

[0011] The present invention also provides a cable length-short-circuit capacity interval generation system for wind farm harmonic amplification, which is used in any one of the above-mentioned cable length-short-circuit capacity interval generation methods for wind farm harmonic amplification, and the system comprises: A power grid short-circuit capacity acquisition module is used to determine the power grid short-circuit capacity interval of the grid connection point based on the grid connection voltage level of the offshore wind farm and the actual grid operation status, and divide the power grid short-circuit capacity interval according to a preset capacity interval threshold to obtain multiple power grid short-circuit capacity values; A quantitative analysis model building module is used to build a quantitative analysis model between the harmonic current amplification factor and the cable length and the short-circuit capacity of each power grid based on the cable characteristic distribution parameters and multiple power grid short-circuit capacity values; The two-dimensional interval construction module is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity using each quantitative analysis model when the harmonic currents at both ends of the cable are equal, and to construct the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification through the cable length interval sequence corresponding to each power grid short-circuit capacity.

[0012] Furthermore, based on the grid-connected voltage level of the offshore wind farm and in combination with the actual grid operation status, the grid short-circuit capacity interval of the grid connection point is determined, wherein the grid short-circuit capacity interval is divided according to a preset capacity interval threshold, and a plurality of grid short-circuit capacity values ​​are obtained, specifically: Determine the benchmark grid short-circuit capacity at the grid connection point based on the grid connection voltage level of the offshore wind farm; According to the actual grid operation status and the benchmark grid short-circuit capacity, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values.

[0013] The present invention also provides a computer device, comprising a system memory and a processor, wherein the system memory stores a computer program, and the processor implements the steps of any one of the above-mentioned methods when executing the computer program.

[0014] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any one of the methods described above are implemented.

[0015] The present invention also provides a computer program product comprising instructions, and when the instructions are executed by a computer device cluster, the computer device cluster executes any of the above methods.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: In the present invention, based on the characteristic parameters of the offshore wind farm cable, a two-dimensional interval of cable length-grid short-circuit capacity where harmonic current amplification occurs in the offshore wind farm is generated. This two-dimensional interval of cable length-grid short-circuit capacity is a high-risk area for harmonic amplification. Compared with the existing method of only analyzing the relationship between harmonic amplification and cable length, the proposed method takes into account the important influence of grid operation on harmonic current amplification, and improves the quantitative analysis perspective of harmonic amplification from a one-dimensional perspective to a two-dimensional perspective, that is, from the single variable influence analysis of cable length to the simultaneous influence analysis of cable length and grid capacity, which can reflect the influence of changes in grid operation status on harmonic amplification, thereby truly guiding the planning and safe and stable operation of offshore wind farms. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings: Figure 1 This is a schematic diagram of a method flow of a method for generating a cable length-short-circuit capacity interval for harmonic amplification in a wind farm in this embodiment; Figure 2 A schematic diagram of an offshore wind farm grid-connected circuit in a method for generating a cable length-short-circuit capacity interval for wind farm harmonic amplification in this embodiment; Figure 3 This is a schematic diagram of the generation result of the two-dimensional interval of cable length-grid short-circuit capacity for harmonic current amplification in an offshore wind farm in a method for generating cable length-short-circuit capacity interval for harmonic amplification in a wind farm in this embodiment; Figure 4 This is a structural schematic diagram of a cable length-short-circuit capacity interval generation system for wind farm harmonic amplification in this embodiment; Figure 5 It is a structural schematic diagram of a computer device in this embodiment. DETAILED DESCRIPTION

[0018] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope of the present disclosure. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0019] In the present disclosure, unless otherwise specified, the use of the terms "first", "second", etc. to describe various elements is not intended to limit the positional relationship, timing relationship, or importance relationship of these elements, and such terms are only used to distinguish one element from another element. In some examples, the first element and the second element may refer to the same instance of the element, and in some cases, based on the description of the context, they may also refer to different instances.

[0020] The terms used in the description of various examples in this disclosure are only for the purpose of describing specific examples and are not intended to be limiting. Unless the context clearly indicates otherwise, if the number of elements is not specifically limited, the element can be one or more. In addition, the term "and / or" used in this disclosure covers any one of the listed items and all possible combinations.

[0021] Example 1

[0022] See also Figure 1 As shown, this embodiment provides a method for generating a cable length-short-circuit capacity interval for harmonic amplification in a wind farm, the method comprising: S1: Based on the grid-connected voltage level of the offshore wind farm and combined with the actual grid operation status, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values; Specifically, in this embodiment, firstly, based on the grid-connected voltage level of the offshore wind farm, the benchmark grid short-circuit capacity S of the grid-connected point is determined. N ; It should be noted that, in this embodiment, the short-circuit capacity of the power grid can reflect the operating status of the power grid. The national standard "Power Quality Public Power Grid Harmonics" (GB / T 14549-93) stipulates the benchmark short-circuit capacity of the public connection point (grid connection point) between users of different voltage levels and the power grid. For example, at the 220kV voltage level, S N =2000MVA; therefore, the benchmark grid capacity of the grid connection point is determined according to the grid connection voltage level of the offshore wind farm.

[0023] Then, according to the actual grid operation status and the benchmark grid short-circuit capacity, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values.

[0024] It should be noted that, in this embodiment, the change of the grid operation state will cause the grid short-circuit capacity to change, but the actual change range of the grid short-circuit capacity of each voltage level bus can be determined by referring to the benchmark short-circuit capacity. The actual grid short-circuit capacity of the modern grid high-voltage bus is generally greater than the benchmark capacity, and only in a few operating states will it be less than the benchmark grid short-circuit capacity; therefore, according to the actual grid operation state combined with the benchmark grid short-circuit capacity, the minimum grid short-circuit capacity boundary value is set to 0.5S N , set the maximum grid short-circuit capacity boundary value to 5S N , that is, the actual grid short-circuit capacity is not less than half of the benchmark grid short-circuit capacity and not more than five times of the benchmark grid short-circuit capacity, thus obtaining a grid short-circuit capacity interval of [0.5S N ,5S N]. The setting of the above boundary values ​​basically covers the variation range of the grid short-circuit capacity under all possible actual grid operating conditions. Therefore, the estimation results based on the above boundary values ​​are no longer limited to specific conditions, but are suitable for harmonic amplification risk analysis under various operating conditions.

[0025] At the same time, in this embodiment, the short-circuit capacity value of the power grid represents the change in the operating state of the power grid. Therefore, by traversing the possible values ​​of the short-circuit capacity value of the power grid, the harmonic amplification state of the power grid under different operating states can be analyzed; at the same time, since the slight changes in practice have little effect on the harmonic amplification, the preset capacity interval threshold can be set to 0.1S N , where S N It represents the short-circuit capacity value of the power grid. For example, at the 220kV voltage level, the preset capacity interval threshold is 200MVA, thereby obtaining 46 short-circuit capacity values ​​of the power grid for subsequent harmonic cable amplification analysis.

[0026] S2: Based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values, a quantitative analysis model between the harmonic current amplification factor and the cable length and the short-circuit capacity of each grid is constructed; Specifically, in this embodiment, see Figure 2 As shown in the figure, since the transmission cable lines of offshore wind farms are often long, the distribution characteristics of line parameters have a significant impact on harmonic amplification. Based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values, and considering the cable as a two-port circuit, the relationship between the harmonic currents at both ends of the cable is obtained, which is: , the harmonic current relationship between the two ends of the cable is transformed to construct a quantitative analysis model between the harmonic current amplification factor and the cable length and the short-circuit capacity of each power grid, specifically: ,in, Indicates the harmonic current magnification at both ends of the cable; Indicates the harmonic current at the end of the cable; Indicates the harmonic current at the beginning of the cable; h Indicates the harmonic order; Indicates the rated voltage of the wind farm grid connection point; Indicates the short-circuit capacity of the grid at the grid connection point; represents the angular frequency; Indicates the capacitance per unit length of the cable; Indicates the resistance per unit length of the cable; Indicates the inductance per unit length of the cable; represents the line propagation constant; Indicates the cable length; Represents an imaginary unit.

[0027] It should be noted that, in this embodiment, the cable characteristic distribution parameters include the cable resistance per unit length, the cable inductance per unit length, the cable length, and the cable capacitance per unit length.

[0028] S3: When the harmonic currents at both ends of the cable are equal, each quantitative analysis model is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity, and the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification is constructed through the cable length interval sequence corresponding to each power grid short-circuit capacity.

[0029] Specifically, in this embodiment, due to Characterizes the amplification factor of harmonics after they flow into the cable, so When it is greater than 1, the harmonic current is amplified, and The corresponding cable length and grid short-circuit capacity are the critical values ​​for harmonic amplification; Therefore, when the harmonic currents at both ends of the cable are equal, that is, When the short-circuit capacity of the power grid is calculated, the endpoints of multiple cable length intervals corresponding to the short-circuit capacity of the power grid are obtained by using the quantitative analysis model. ,in, , multiple cable length interval endpoints include multiple interval left endpoints and multiple right endpoints of intervals Multiple interval left endpoints and multiple interval right endpoints are periodically cross-sorted according to the size of the endpoint values, and the interval left endpoints and interval right endpoints of the same period form a cable length interval ; Constructing a cable length interval sequence corresponding to the short-circuit capacity of the power grid through multiple cable length intervals .

[0030] It should be noted that, in this embodiment, within the same cycle ( k The length of the cable where harmonics are amplified is between the left end point of the interval (values ​​are equal) and the right end point of the interval; when the cable is long, multiple intervals may be obtained, that is, there is k cycles, k It can also refer to the interval number sequence number, the maximum interval number is n ,and , It is the theoretical maximum power supply distance of the cable at the voltage level of the grid connection point; At the same time, the expressions for the left endpoint and the right endpoint of the interval are as follows: ; ; in, .

[0031] For example, in this embodiment, the minimum short-circuit capacity of the power grid is Taking the example, the cable length interval sequence of the first group of cable harmonic current amplification is solved as follows: Based on this, we can get multiple cable length intervals where harmonics are amplified when the power grid operates at the possible minimum short-circuit capacity. If the actual cable length is within the required interval, it means that when the power grid operates at the possible minimum short-circuit capacity, harmonics will be amplified; then calculate the cable length interval sequence under 46 power grid short-circuit capacities in turn, and use the maximum power grid short-circuit capacity as the starting point. For example, the cable length interval sequence of the last group of cable harmonic current amplification is solved as follows: ; A total of 46 groups of different cable length interval sequences can be obtained.

[0032] Finally, by integrating the cable length intervals of the same period in the cable length interval sequences corresponding to the short-circuit capacities of multiple power grids, multiple two-dimensional intervals of cable length-short-circuit capacity for offshore wind power harmonic amplification are obtained.

[0033] Specifically, in this embodiment, the cable length l As the horizontal axis, the short-circuit capacity of the power grid is the vertical axis, and 46 groups of cable length interval endpoint values ​​of cable harmonic current amplification are plotted in the rectangular coordinate system. The left endpoints of the intervals with the same period are connected to obtain the first curve. For example, the first period ( k =1) , and obtain the first curve L(1); connect the right endpoints of the intervals with the same period to obtain the second curve, for example, connect the first period ( k =1) , the second curve R(1) is obtained by integrating the cable length intervals of the same period. n The cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification; considering the actual cable length limitation, n Usually no more than 3.

[0034] Specifically, in this embodiment, based on the characteristic parameters of the offshore wind farm cable, a two-dimensional interval of cable length-grid short-circuit capacity where harmonic current amplification occurs in the offshore wind farm is generated. This two-dimensional interval of cable length-grid short-circuit capacity is a high-risk area for harmonic amplification. Compared with the existing method of only analyzing the relationship between harmonic amplification and cable length, the proposed method takes into account the important influence of grid operation on harmonic current amplification, and improves the quantitative analysis perspective of harmonic amplification from a one-dimensional perspective to a two-dimensional perspective, that is, from the single variable influence analysis of cable length to the simultaneous influence analysis of cable length and grid capacity, which can reflect the influence of changes in grid operation status on harmonic amplification, thereby truly guiding the planning and safe and stable operation of offshore wind farms.

[0035] Meanwhile, in this embodiment, an example of interval generation is given, and the cable characteristic distribution parameters are as shown in Table 1: Table 1 Simulation parameter settings

[0036] As shown in Table 1, the grid-connected voltage level of offshore wind farms is 220kV. The standard grid short-circuit capacity at the grid-connected point under the current voltage level is 2000MVA, and the maximum cable length is 300km. Taking the 11th harmonic generated by offshore wind farms as an example, simulation analysis shows the cable length-grid short-circuit capacity interval where harmonics are amplified when transmitted to the grid-connected point. The results are as follows: Figure 3 As shown. Figure 3 It can be seen that after considering the cable length and the short-circuit capacity of the power grid at the same time, the two-dimensional interval of cable length-power grid short-circuit capacity where harmonic current amplification occurs can be obtained. When the wind farm is in this area, the harmonic current will be amplified. This interval can be used to guide the planning of offshore wind power cable length, the selection of grid connection points and the adjustment of operation mode. Figure 3 Analysis shows that for a cable of a specific length, when the short-circuit capacity is small, the harmonic current may not be amplified, but when the short-circuit capacity is large, amplification will occur. That is, the larger the short-circuit capacity of the power grid, the higher the risk of harmonic current amplification.

[0037] Example 2

[0038] See also Figure 4 As shown, the present invention also provides a cable length-short-circuit capacity interval generation system for wind farm harmonic amplification, which is used in any one of the above-mentioned cable length-short-circuit capacity interval generation methods for wind farm harmonic amplification, and the system includes: The grid short-circuit capacity acquisition module 100 is used to determine the grid short-circuit capacity interval of the grid connection point based on the grid connection voltage level of the offshore wind farm and in combination with the actual grid operation status, and divide the grid short-circuit capacity interval according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values; A quantitative analysis model building module 200 is used to build a quantitative analysis model between the harmonic current amplification factor and the cable length and each power grid short-circuit capacity based on the cable characteristic distribution parameters and multiple power grid short-circuit capacity values; The two-dimensional interval construction module 300 is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity using each quantitative analysis model when the harmonic currents at both ends of the cable are equal, and to construct the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification through the cable length interval sequence corresponding to each power grid short-circuit capacity.

[0039] It should be noted that the modules in the system of Example 2 correspond to the steps in the method of Example 1. The steps in the method of Example 1 have been described in detail in Example 1, and the contents of the modules in the system will not be described in detail in this Example 2.

[0040] Example 3

[0041] See also Figure 5 As shown, this embodiment further provides a computer device, including a system memory 1005 and a processor 1001, wherein the system memory 1005 stores a computer program, and the processor 1001 implements the steps of any of the above methods when executing the computer program.

[0042] It should be noted that the processor 1001 is used to execute the steps in the above method embodiments according to the instructions in the program code. Alternatively, the processor 1001 implements the functions of each module / unit in the above system / device embodiments when executing the computer program.

[0043] Specifically, in this embodiment, the computer program may be divided into one or more modules / units, one or more modules / units are stored in the system memory 1005, and are executed by the processor 1001 to complete the present application. One or more modules / units may be a series of computer program instruction segments that can complete specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal device.

[0044] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor 1001 and a system memory 1005. Those skilled in the art will appreciate that this does not constitute a limitation on the terminal device, and may include more or less components than shown in the figure, or combine certain components, or different components. For example, the terminal device may also include an input / output device 1003, a network access device 1002, a bus 1006, etc.

[0045] The processor 1001 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0046] The system memory 1005 may be an internal storage unit of the terminal device, such as a hard disk or memory of the terminal device. The system memory 1005 may also be a storage device 1004 of the terminal device, such as a plug-in hard disk, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (FlashCard), etc. equipped on the terminal device. Further, the system memory 1005 may also include both the internal storage unit of the terminal device and the storage device 1004. The system memory 1005 is used to store computer programs and other programs and data required by the terminal device. The system memory 1005 may also be used to temporarily store data that has been output or is to be output.

[0047] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, systems and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0048] Example 4

[0049] This embodiment provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of any one of the above methods are implemented.

[0050] Among them, the computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared or semiconductor system, system or device, or any combination of the above. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection with one or more wires, a portable computer disk, a hard disk. Random Access Memory (RAM), Read-Only Memory (ROM), Erasable Programmable Read Only Memory (EPROM), registers, hard disks, optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above, or any other form of computer-readable storage medium known in the art.

[0051] An exemplary storage medium is coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an application-specific integrated circuit (ASIC). In an embodiment of the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system, or device.

[0052] Example 5

[0053] This embodiment also provides a computer program product including instructions. When the instructions are executed by a computer device cluster, the computer device cluster executes the method described in Embodiment 1.

[0054] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for generating cable length-short-circuit capacity interval for wind farm harmonic amplification, characterized in that the method include: Based on the grid-connected voltage level of the offshore wind farm and in combination with the actual grid operation status, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values; Based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values, a quantitative analysis model between the harmonic current amplification factor and the cable length and the short-circuit capacity of each grid is constructed; When the harmonic currents at both ends of the cable are equal, each quantitative analysis model is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity, and the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification is constructed through the cable length interval sequence corresponding to each power grid short-circuit capacity.

2. A method for generating cable length-short-circuit capacity interval for wind farm harmonic amplification according to claim 1, characterized in that: Based on the grid-connected voltage level of the offshore wind farm and combined with the actual grid operation status, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values, specifically: Determine the benchmark grid short-circuit capacity at the grid connection point based on the grid connection voltage level of the offshore wind farm; According to the actual grid operation status and the benchmark grid short-circuit capacity, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values.

3. The cable length-short-circuit capacity interval generation method for wind farm harmonic amplification according to claim 1, characterized in that: Based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values, a quantitative analysis model between the harmonic current amplification factor and the cable length and each grid short-circuit capacity is constructed, wherein the quantitative analysis model is specifically as follows: ,in, Indicates the harmonic current magnification factor at both ends of the cable; Indicates the harmonic current at the end of the cable; Indicates the harmonic current at the beginning of the cable; h Indicates the harmonic order; Indicates the rated voltage of the wind farm grid connection point; Indicates the short-circuit capacity of the grid at the grid connection point; represents the angular frequency; Indicates the capacitance per unit length of the cable; Indicates the resistance per unit length of the cable; Indicates the inductance per unit length of the cable; represents the line propagation constant; Indicates the cable length; Represents an imaginary unit.

4. The cable length-short-circuit capacity interval generation method for wind farm harmonic amplification according to claim 1, characterized in that: Each quantitative analysis model is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity, specifically: When the harmonic currents at both ends of the cable are equal, a plurality of cable length interval endpoints corresponding to the short-circuit capacity of the power grid are calculated using a quantitative analysis model. The plurality of cable length interval endpoints include a plurality of interval left endpoints and a plurality of interval right endpoints. The plurality of interval left endpoints and the plurality of interval right endpoints are periodically cross-sorted according to the size of the endpoint values. The interval left endpoints and the interval right endpoints of the same period form a cable length interval. A cable length interval sequence corresponding to the short-circuit capacity of the power grid is constructed through multiple cable length intervals.

5. The cable length-short-circuit capacity interval generation method for wind farm harmonic amplification according to claim 1, characterized in that: The cable length interval sequence corresponding to each grid short-circuit capacity is used to construct the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification, specifically: By integrating the cable length intervals of the same period in the cable length interval sequences corresponding to the short-circuit capacities of multiple power grids, multiple two-dimensional cable length-short-circuit capacity intervals of offshore wind power harmonic amplification are obtained.

6. A cable length-short-circuit capacity interval generation system for wind farm harmonic amplification, characterized in that: The system is used in a method for generating a cable length-short-circuit capacity interval for harmonic amplification in a wind farm as described in any one of claims 1 to 5, and the system comprises: A power grid short-circuit capacity acquisition module is used to determine the power grid short-circuit capacity interval of the grid connection point based on the grid connection voltage level of the offshore wind farm and the actual grid operation status, and divide the power grid short-circuit capacity interval according to a preset capacity interval threshold to obtain multiple power grid short-circuit capacity values; A quantitative analysis model building module is used to build a quantitative analysis model between the harmonic current amplification factor and the cable length and the short-circuit capacity of each power grid based on the cable characteristic distribution parameters and multiple power grid short-circuit capacity values; The two-dimensional interval construction module is used to calculate the cable length interval sequence corresponding to each power grid short-circuit capacity using each quantitative analysis model when the harmonic currents at both ends of the cable are equal, and to construct the cable length-short-circuit capacity two-dimensional interval of offshore wind power harmonic amplification through the cable length interval sequence corresponding to each power grid short-circuit capacity.

7. A cable length-short-circuit capacity interval generation system for wind farm harmonic amplification according to claim 6, characterized in that: Based on the grid-connected voltage level of the offshore wind farm and combined with the actual grid operation status, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values, specifically: Determine the benchmark grid short-circuit capacity at the grid connection point based on the grid connection voltage level of the offshore wind farm; According to the actual grid operation status and the benchmark grid short-circuit capacity, the grid short-circuit capacity interval of the grid connection point is determined, and the grid short-circuit capacity interval is divided according to the preset capacity interval threshold to obtain multiple grid short-circuit capacity values.

8. A computer device comprising a system memory and a processor, wherein the system memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

10. A computer program product comprising instructions, characterized in that When the instructions are executed by a computer device cluster, the computer device cluster executes the method according to any one of claims 1 to 5.

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