A Method for Generating Cable Length - Short - Circuit Capacity Intervals of Harmonic Amplification in Wind Farms

Abstract

The present invention discloses a method for generating a cable length - short - circuit capacity interval for harmonic amplification in a wind farm, which specifically relates to the technical field of offshore wind power harmonic analysis. The technical key points are as follows: Based on the grid connection voltage level of the offshore wind farm and combined with the actual grid operation status, determine the grid short - circuit capacity interval at the grid connection point, and divide the grid short - circuit capacity interval 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, construct a quantitative analysis model between the harmonic current amplification factor and the cable length and each grid short - circuit capacity; When the harmonic currents at both ends of the cable are equal, use each quantitative analysis model to calculate the cable length interval sequence corresponding to each grid short - circuit capacity, and construct a two - dimensional interval of cable length - short - circuit capacity for offshore wind power harmonic amplification through the cable length interval sequence corresponding to each 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 the cable length and the grid short-circuit capacity on harmonic amplification is not considered in the prior art. The purpose is to provide a method for generating a cable length - short-circuit capacity interval for harmonic amplification in a wind farm. Based on the cable characteristic parameters of an offshore wind farm, a two-dimensional interval of cable length - grid short-circuit capacity where harmonic current generation in the offshore wind farm is amplified is generated. This two-dimensional interval of cable length - grid short-circuit capacity is the high-risk area where harmonic generation is amplified. Compared with the existing method that only analyzes the relationship between harmonic amplification and cable length, the proposed method considers the important influence of grid operation on harmonic current amplification, and promotes the quantitative analysis perspective of harmonic amplification from a one-dimensional perspective to a two-dimensional perspective, that is, from the analysis of the influence of a single variable 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, and thus can truly guide the planning and safe and stable operation of offshore wind farms.

[0006] The present invention is realized through the following technical solutions:

[0007] A method for generating a cable length - short-circuit capacity interval for harmonic amplification in a wind farm, the method includes:

[0008] Based on the grid connection voltage level of the offshore wind farm and combined with the actual grid operation status, determine the grid short-circuit capacity interval at the grid connection point, and divide the grid short-circuit capacity interval according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values;

[0009] Based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values, construct a quantitative analysis model between the harmonic current amplification factor and the cable length and each grid short-circuit capacity;

[0010] When the harmonic currents at both ends of the cable are equal, use each quantitative analysis model to calculate the cable length interval sequence corresponding to each grid short-circuit capacity, and construct a two-dimensional interval of cable length - short-circuit capacity for harmonic amplification in the offshore wind farm through the cable length interval sequence corresponding to each grid short-circuit capacity.

[0011] Further, based on the grid connection voltage level of the offshore wind farm and combined with the actual grid operation status, determine the grid short-circuit capacity interval at the grid connection point, and divide the grid short-circuit capacity interval according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values, specifically:

[0012] Based on the grid connection voltage level of the offshore wind farm, determine the reference grid short-circuit capacity at the grid connection point;

[0013] According to the actual grid operation status and combined with the reference grid short-circuit capacity, determine the grid short-circuit capacity interval at the grid connection point, and divide the grid short-circuit capacity interval according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values.

[0014] Further, based on the distributed parameters of cable characteristics and multiple grid short-circuit capacity values, a quantitative analysis model of the harmonic current amplification factor with respect to the cable length and each grid short-circuit capacity is constructed. Specifically, the quantitative analysis model is as follows: , where represents the harmonic current amplification factor at both ends of the cable; represents the harmonic current at the end of the cable; represents the harmonic current at the head end of the cable; h represents the harmonic order; represents the rated voltage at the grid connection point of the wind farm; represents the grid short-circuit capacity at the grid connection point; represents the angular frequency; represents the capacitance per unit length of the cable; represents the resistance per unit length of the cable; represents the inductance per unit length of the cable; represents the line propagation constant; represents the cable length; represents the imaginary unit.

[0015] Further, the cable length interval sequence corresponding to each grid short-circuit capacity is calculated using each quantitative analysis model. Specifically:

[0016] When the harmonic currents at both ends of the cable are equal, multiple cable length interval endpoints corresponding to the grid short-circuit capacity are calculated using the quantitative analysis model. The multiple cable length interval endpoints include multiple interval left endpoints and multiple interval right endpoints. The multiple interval left endpoints and multiple interval right endpoints are periodically cross-sorted according to the endpoint value sizes, and the interval left endpoints and interval right endpoints in the same period form a cable length interval;

[0017] The cable length interval sequence corresponding to the grid short-circuit capacity is constructed through multiple cable length intervals.

[0018] Further, a two-dimensional interval of cable length - short-circuit capacity for offshore wind power harmonic amplification is constructed through the cable length interval sequence corresponding to each grid short-circuit capacity. Specifically:

[0019] By integrating the cable length intervals in the same period in the cable length interval sequences corresponding to multiple grid short-circuit capacities, multiple two-dimensional intervals of cable length - short-circuit capacity for offshore wind power harmonic amplification are obtained.

[0020] The present invention also provides a cable length - short-circuit capacity interval generation system for wind farm harmonic amplification. This system is used in the cable length - short-circuit capacity interval generation method for wind farm harmonic amplification described in any one of the above, and the system includes:

[0021] The grid short-circuit capacity acquisition module is used to determine the grid short-circuit capacity range 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 range according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values;

[0022] The quantitative analysis model construction module is used to construct a quantitative analysis model of the harmonic current amplification factor with respect to the cable length and each grid short-circuit capacity based on the cable characteristic distribution parameters and multiple grid short-circuit capacity values;

[0023] The two-dimensional interval construction module is used to calculate the cable length interval sequence corresponding to each grid short-circuit capacity by using each quantitative analysis model when the harmonic currents at both ends of the cable are equal, and construct a two-dimensional interval of cable length - short-circuit capacity for offshore wind power harmonic amplification through the cable length interval sequence corresponding to each grid short-circuit capacity.

[0024] Furthermore, based on the grid connection voltage level of the offshore wind farm and in combination with the actual grid operation status, determine the grid short-circuit capacity range of the grid connection point, where the grid short-circuit capacity range is divided according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values, specifically:

[0025] Based on the grid connection voltage level of the offshore wind farm, determine the reference grid short-circuit capacity of the grid connection point;

[0026] According to the actual grid operation status in combination with the reference grid short-circuit capacity, determine the grid short-circuit capacity range of the grid connection point, and divide the grid short-circuit capacity range according to a preset capacity interval threshold to obtain multiple grid short-circuit capacity values.

[0027] The present invention also provides a computer device, including a system memory and a processor, where the system memory stores a computer program, and when the processor executes the computer program, it implements the steps of the method described in any one of the above.

[0028] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the method described in any one of the above.

[0029] The present invention also provides a computer program product containing instructions, and when the instructions are run by a computer device cluster, the computer device cluster is enabled to execute the method described in any one of the above.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] In the present invention, based on the characteristic parameters of the cables in an offshore wind farm, a two-dimensional interval of cable length - grid short-circuit capacity for the amplification of harmonic current generation in the offshore wind farm is generated. This two-dimensional interval of cable length - grid short-circuit capacity is the high-risk area where harmonic amplification occurs. Compared with the existing method that only analyzes 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 elevates the quantitative analysis perspective of harmonic amplification from a one-dimensional perspective to a two-dimensional perspective, that is, from the analysis of the influence of a single variable of cable length to the simultaneous analysis of cable length and grid capacity, which can reflect the influence of changes in grid operation status on harmonic amplification, and thus can truly guide the planning and safe and stable operation of offshore wind farms. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0033] Figure 1 It is a schematic flow chart of a method for generating a cable length - short-circuit capacity interval for harmonic amplification in a wind farm in this embodiment;

[0034] Figure 2 It is a schematic diagram of the grid connection circuit of an offshore wind farm in a method for generating a cable length - short-circuit capacity interval for harmonic amplification in a wind farm in this embodiment;

[0035] Figure 3 It is a schematic diagram of the generated result of a two-dimensional interval of cable length - grid short-circuit capacity where harmonic current amplification occurs in an offshore wind farm in a method for generating a cable length - short-circuit capacity interval for harmonic amplification in a wind farm in this embodiment;

[0036] Figure 4 It is a schematic structural diagram of a system for generating a cable length - short-circuit capacity interval for harmonic amplification in a wind farm in this embodiment;

[0037] Figure 5 It is a schematic structural diagram of a computer device in this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The following describes exemplary embodiments of the present disclosure with reference to the accompanying drawings. Various details of the embodiments of the present disclosure are included to facilitate understanding, and they should be considered merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope of the present disclosure. Similarly, descriptions of well-known functions and structures are omitted in the following description for clarity and conciseness.

[0039] In the present disclosure, unless otherwise specified, the terms "first", "second", etc. are used to describe various elements and are not intended to limit the positional relationship, timing relationship, or importance relationship of these elements. Such terms are only used to distinguish one element from another. In some examples, the first element and the second element may refer to the same instance of the element, and in certain cases, based on the context description, they may also refer to different instances.

[0040] The terms used in the description of various examples in the present 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 may be one or more. In addition, the term "and / or" used in the present disclosure covers any one of the listed items and all possible combinations.

[0041] Embodiment 1

[0042] See 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 includes:

[0043] S1: Based on the grid - connected voltage level of the offshore wind farm and combined with the actual grid operation status, determine the grid short - circuit capacity interval at the grid connection point, and divide the grid short - circuit capacity interval according to a preset capacity interval threshold to obtain multiple grid short - circuit capacity values;

[0044] Specifically, in this embodiment, first, based on the grid - connected voltage level of the offshore wind farm, determine the reference grid short - circuit capacity S N ;

[0045] It should be noted that in this embodiment, the magnitude of the grid short - circuit capacity can reflect the grid operation status. In the national standard "Power Quality - Public Power Grid Harmonics" (GB / T 14549 - 93), the reference short - circuit capacity at the connection point (grid connection point) between users of different voltage levels and the power grid is specified. For example, at the 220 kV voltage level, S N = 2000 MVA; Therefore, determine the reference grid capacity at the grid connection point according to the grid - connected voltage level of the offshore wind farm.

[0046] Then, based on the actual power grid operating state and combined with the benchmark power grid short-circuit capacity, determine the power grid short-circuit capacity range at the grid connection point, and divide the power grid short-circuit capacity range according to the preset capacity interval threshold to obtain multiple power grid short-circuit capacity values.

[0047] It should be noted that in this embodiment, the change in the power grid operating state will cause the change in the power grid short-circuit capacity. However, the change range of the power grid short-circuit capacity of each voltage level bus can be determined with reference to the benchmark short-circuit capacity. The actual power grid short-circuit capacity of the high-voltage bus in the modern power grid is generally greater than the benchmark capacity, and it is only less than the benchmark power grid short-circuit capacity in a few operating states. Therefore, according to the actual power grid operating state and combined with the benchmark power grid short-circuit capacity, set the minimum power grid short-circuit capacity boundary value to 0.5S N and set the maximum power grid short-circuit capacity boundary value to 5S N , that is, the actual power grid short-circuit capacity is not less than half of the benchmark power grid short-circuit capacity and does not exceed 5 times the benchmark power grid short-circuit capacity, so as to obtain the power grid short-circuit capacity range of [0.5S N , 5S N . The setting of the above boundary values basically covers the change range of the power grid short-circuit capacity under all possible actual power grid operating conditions. Therefore, the estimation results based on the above boundary values are no longer limited to specific conditions, but are applicable to the harmonic amplification risk analysis under various operating conditions.

[0048] At the same time, in this embodiment, the power grid short-circuit capacity value characterizes the change in the power grid operating state. Therefore, by traversing the possible values of the power grid short-circuit capacity value, the harmonic amplification state of the power grid operating in different states can be analyzed. At the same time, since the minor changes in reality have little impact on harmonic amplification, the preset capacity interval threshold can be set to 0.1S N , where S N represents the power grid short-circuit capacity value. For example, at the 220 kV voltage level, the preset capacity interval threshold is 200 MVA, so as to obtain 46 power grid short-circuit capacity values for subsequent harmonic cable amplification analysis.

[0049] S2: Based on the cable characteristic distribution parameters and multiple power grid short-circuit capacity values, construct a quantitative analysis model of the harmonic current amplification factor between the cable length and each power grid short-circuit capacity;

[0050] Specifically, in this embodiment, as shown in Figure 2 , since the outgoing cable lines of offshore wind farms are often long, the distribution characteristics of the line parameters have a more significant impact on harmonic amplification. By based on the cable characteristic distribution parameters and multiple power grid short-circuit capacity values, and regarding the cable as a two-port circuit, the harmonic current relationship formula at both ends of the cable can be obtained, specifically: , by converting the harmonic current relationship at both ends of the cable, a quantitative analysis model between the harmonic current amplification factor, cable length, and each grid short-circuit capacity is constructed, specifically as follows: , where represents the harmonic current amplification factor at both ends of the cable; represents the harmonic current at the end of the cable; represents the harmonic current at the head end of the cable; h represents the harmonic order; represents the rated voltage of the grid connection point of the wind farm; represents the grid short-circuit capacity of the grid connection point; represents the angular frequency; represents the capacitance per unit length of the cable; represents the resistance per unit length of the cable; represents the inductance per unit length of the cable; represents the line propagation constant; represents the cable length; represents the imaginary unit.

[0051] It should be noted that in this embodiment, the cable characteristic distribution parameters include the resistance per unit length of the cable, the inductance per unit length of the cable, the cable length, and the capacitance per unit length of the cable.

[0052] S3: When the harmonic currents at both ends of the cable are equal, use each quantitative analysis model to calculate the cable length interval sequence corresponding to each grid short-circuit capacity, and construct a two-dimensional interval of cable length - short-circuit capacity for offshore wind power harmonic amplification through the cable length interval sequence corresponding to each grid short-circuit capacity.

[0053] Specifically, in this embodiment, since represents the amplification factor after the harmonic current flows into the cable, therefore 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;

[0054] Therefore, when the harmonic currents at both ends of the cable are equal, that is, at this time, use the quantitative analysis model to calculate the multiple cable length interval endpoints corresponding to the grid short-circuit capacity , where , the multiple cable length interval endpoints include multiple interval left endpoints and multiple interval right endpoints , the multiple interval left endpoints and multiple interval right endpoints are sorted periodically in ascending order of endpoint values, and the interval left endpoints and interval right endpoints in the same period form a cable length interval ;

[0055] Construct a cable length interval sequence corresponding to the grid short-circuit capacity through multiple cable length intervals .

[0056] It should be noted that in this embodiment, within the same period ( k with equal k values), the cable length between the left endpoint and the right endpoint of the interval is the cable length where harmonic generation is amplified; when the cable is relatively long, multiple intervals may be obtained, that is, there exist k cycles, n which can also refer to the interval number sequence, and the maximum number of intervals is , and is the theoretical maximum power supply distance of the cable under the grid connection point voltage level;

[0057] Meanwhile, the expressions of the left endpoint and the right endpoint of the interval are as follows respectively:

[0058] ; ;

[0059] where .

[0060] Exemplarily, in this embodiment, taking the minimum grid short-circuit capacity as an example, the cable length interval sequence where the first group of cable harmonic current is amplified is solved as: ; Based on this, when the grid operates at the possible minimum short-circuit capacity, multiple cable length intervals where harmonics are amplified can be obtained. If the actual cable length is within the obtained intervals, it indicates that when the grid operates at the possible minimum short-circuit capacity, harmonics will be amplified; then, the cable length interval sequences under 46 grid short-circuit capacities are calculated in sequence. Taking the maximum grid short-circuit capacity as an example, the cable length interval sequence where the last group of cable harmonic current is amplified is solved as: ; A total of 46 groups of cable length interval sequences under different

[0061] can be obtained. Finally, by integrating the cable length intervals with the same period in the cable length interval sequences corresponding to multiple grid short-circuit capacities, multiple two-dimensional intervals of cable length - short-circuit capacity where offshore wind power harmonics are amplified are obtained.

[0062] Specifically, in this embodiment, taking the cable length l as the abscissa and the grid short-circuit capacity as the ordinate, the endpoint values of the cable length intervals where 46 groups of cable harmonic currents are amplified 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 left endpoints of the intervals in the first period ( k =1) in multiple cable length interval sequences are connected , 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.

[0063] 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.

[0064] Meanwhile, in this embodiment, an example of interval generation is given, and the cable characteristic distribution parameters are as shown in Table 1:

[0065] Table 1 Simulation parameter settings

[0066]

[0067] 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.

[0068] Example 2

[0069] See Figure 4 As shown, the present invention also provides a cable length - short - circuit capacity interval generation system for harmonic amplification in a wind farm, which is used in the method for generating a cable length - short - circuit capacity interval for harmonic amplification in a wind farm described in any one of the above. The system includes:

[0070] A grid short - circuit capacity acquisition module 100, which is used to determine the grid short - circuit capacity interval at 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;

[0071] A quantitative analysis model construction module 200, which is used to construct a quantitative analysis model between the harmonic current amplification factor and the cable length and each grid short - circuit capacity based on the cable characteristic distribution parameters and multiple grid short - circuit capacity values;

[0072] A two - dimensional interval construction module 300, which is used to calculate the cable length interval sequence corresponding to each grid short - circuit capacity using each quantitative analysis model when the harmonic currents at both ends of the cable are equal, and construct a two - dimensional interval of cable length - short - circuit capacity for harmonic amplification in offshore wind power through the cable length interval sequence corresponding to each grid short - circuit capacity.

[0073] It should be noted that the modules in the system of Embodiment 2 correspond to the steps in the method of Embodiment 1. The steps in the method of Embodiment 1 have been elaborated in detail in Embodiment 1, and the content of the modules in the system will not be elaborated in detail in this Embodiment 2.

[0074] Embodiment 3

[0075] See Figure 5 As shown, this embodiment also provides a computer device, including a system memory 1005 and a processor 1001. The system memory 1005 stores a computer program, and when the processor 1001 executes the computer program, it implements the steps of the method described in any one of the above.

[0076] It should be noted that the processor 1001 is used to execute the steps in the above - mentioned method embodiments according to the instructions in the program code. Or, when the processor 1001 executes the computer program, it implements the functions of each module / unit in the above - mentioned system / device embodiments.

[0077] Specifically, in this embodiment, the computer program can 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 this application. One or more modules / units can be a series of computer program instruction segments that can complete specific functions, and these instruction segments are used to describe the execution process of the computer program in the terminal device.

[0078] The terminal device can be a computing device such as a desktop computer, a notebook, a handheld computer, and a cloud server. The terminal device may include, but is not limited to, a processor 1001 and a system memory 1005. Those skilled in the art can understand that this does not constitute a limitation on the terminal device, and it may include more or fewer components than shown in the figure, or combine some 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.

[0079] The processor 1001 can be a Central Processing Unit (CPU), or it can also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0080] The system memory 1005 can be an internal storage unit of the terminal device, such as the hard disk or memory of the terminal device. The system memory 1005 can also be a storage device 1004 of the terminal device, such as a plug-in hard disk, a SmartMedia Card (SMC), a Secure Digital (SD) card, a FlashCard, etc. equipped on the terminal device. Further, the system memory 1005 can 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 can also be used to temporarily store data that has been output or will be output.

[0081] Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the above-described systems, systems, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0082] Embodiment 4

[0083] 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 the method in any one of the above are implemented.

[0084] Among them, a computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (non-exhaustive list) of the computer-readable storage medium include: an electrical connection having 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 disc read-only memory (Compact Disc 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.

[0085] An exemplary storage medium is coupled to the processor, enabling the processor to 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, the computer-readable storage medium can be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, apparatus, or device.

[0086] Embodiment 5

[0087] This embodiment also provides a computer program product containing instructions. When the instructions are run by a computer device cluster, the computer device cluster is caused to execute the method described in Embodiment 1.

[0088] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above is only the specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope 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 each grid short-circuit capacity is constructed, wherein the quantitative analysis model is specifically as follows: Among them, HF i 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; U N Indicates the rated voltage of the wind farm grid connection point; S c represents the short-circuit capacity of the grid at the grid connection point; ω represents the angular frequency; C0 represents the capacitance per unit length of the cable; R0 represents the resistance per unit length of the cable; L0 represents the inductance per unit length of the cable; γ represents the line propagation constant; l represents the cable length; j represents the imaginary unit; 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, and a two-dimensional cable length-short-circuit capacity interval for 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: 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.

4. 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 wind farm harmonic amplification according to any one of claims 1 to 3, 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.

5. A cable length-short-circuit capacity interval generation system for wind farm harmonic amplification according to claim 4, 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.

6. 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 3 are implemented.

7. 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 3 are implemented.

8. 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 3.

Images