Wind power plant harmonic source positioning method, system, equipment and medium

Abstract

The invention discloses a wind power plant harmonic source positioning method, system and device and a medium. The method comprises the steps that standard-exceeding voltage and current harmonics of all nodes in a wind power plant and corresponding harmonic frequencies of the voltage and current harmonics are determined; according to the method, the system, the equipment and the medium, all-node instantaneous power calculation is carried out on the harmonic frequency of the standard exceeding frequency, the instantaneous active power of the standard exceeding harmonic at each node is determined, the position of the harmonic source is determined according to the direction of the instantaneous active power, and the method, the system, the equipment and the medium can carry out positioning analysis on the harmonic source.

Description

Technical Field

[0001] This invention belongs to the field of power quality harmonic analysis technology for centralized wind power plants, and relates to a method, system, equipment and medium for locating harmonic sources in wind farms. Background Technology

[0002] Wind farms contain numerous power electronic devices, which are prone to generating harmonics or interharmonics. Harmonics cause voltage fluctuations and energy waste, and in severe cases, can damage equipment connected to the power grid. Wind farms monitor harmonics using online power quality monitoring devices. These devices are connected to the PCC (Point of Common Coupling) and other critical nodes to monitor the voltage and current, and to track harmonic components in the current and voltage in real time. Once a harmonic source is generated, all monitoring points within the farm can detect it. However, because the primary equipment in a wind farm is often asymmetrical, it is difficult to pinpoint a specific line based on the harmonic amplitude, making harmonic mitigation challenging. Furthermore, for multiple users connected to the PCC, harmonic mitigation follows the principle of "whoever pollutes, mitigates," making it crucial for wind farms to determine whether the harmonic source is on the farm side or the user side. Currently, most wind farms only monitor harmonics at key nodes within the farm, and very few perform harmonic source localization analysis. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, system, device and medium for locating harmonic sources in wind farms. This method, system, device and medium can perform harmonic source location analysis.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: In one aspect, the present invention provides a method for locating harmonic sources in a wind farm, comprising: Identify the voltage and current harmonics exceeding the limits at each node in the wind farm and their corresponding harmonic frequencies; The instantaneous power of the harmonic frequencies exceeding the standard is calculated at all nodes to determine the instantaneous active power of the exceeding harmonics at each node, and the location of the harmonic source is determined based on the direction of the instantaneous active power.

[0005] The wind farm harmonic source location method described in this invention is further improved in that: Furthermore, before determining the excessive voltage and current harmonics and their corresponding harmonic frequencies at each node in the wind farm, the following steps are also included: Voltage and current information of each node in the wind farm is obtained through voltage transformers and current transformers. Discrete Fourier transform is performed on the voltage and current signals at each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components.

[0006] Furthermore, the process of obtaining voltage and current information of each node in the wind farm through voltage transformers and current transformers is as follows: Obtain voltage information for the outgoing lines and the collecting bus, and obtain current information for each branch of the outgoing lines and the collecting bus.

[0007] Furthermore, in the process of determining the position of the harmonic source based on the direction of the instantaneous active power of the harmonic, when the instantaneous active power of the harmonic is positive, the direction of the harmonic power flow is consistent with the reference direction, and the harmonic source is located above the reference direction; otherwise, the harmonic source is located below the reference direction.

[0008] In a second aspect, the present invention provides a wind farm harmonic source location system, comprising: The first determining module is used to determine the voltage and current harmonics exceeding the standard at each node in the wind farm and their corresponding harmonic frequencies. The second determining module is used to perform instantaneous power calculations for all nodes of the harmonic frequencies exceeding the standard, determine the instantaneous active power of the exceeding harmonics at each node, and determine the location of the harmonic source based on the direction of the instantaneous active power.

[0009] The wind farm harmonic source location system of the present invention is further improved in that: Furthermore, it also includes: The acquisition module is used to acquire voltage and current information of each node in the wind farm through voltage transformers and current transformers. The separation module is used to perform discrete Fourier processing on the voltage and current signals of each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components.

[0010] Furthermore, the process of obtaining voltage and current information of each node in the wind farm through voltage transformers and current transformers is as follows: Obtain voltage information for the outgoing lines and the collecting bus, and obtain current information for each branch of the outgoing lines and the collecting bus.

[0011] Furthermore, in the process of determining the position of the harmonic source based on the direction of the instantaneous active power of the harmonic, when the instantaneous active power of the harmonic is positive, the direction of the harmonic power flow is consistent with the reference direction, and the harmonic source is located above the reference direction; otherwise, the harmonic source is located below the reference direction.

[0012] In three aspects, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the wind farm harmonic source location method.

[0013] In four aspects, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the wind farm harmonic source location method.

[0014] The present invention has the following beneficial effects: The wind farm harmonic source location method, system, equipment, and medium described in this invention, in practical operation, acquire raw current and voltage data through the measuring stations PT and CT at each node of the wind farm's PCC (Power Process Control Center). The raw data undergoes DFT processing, and the harmonic content is analyzed based on the raw data to determine if it exceeds the standard. The instantaneous active power of the exceeding frequency harmonics is calculated, and the harmonic source is identified based on the direction of the instantaneous active power of the harmonics at each node. The operation is simple and highly practical. This invention addresses the difficulty of locating wind farm harmonic sources by proposing a method for determining harmonic sources based on the direction of harmonic active power and designing related equipment. This comprehensively improves the efficiency of wind farm harmonic source location, provides a basis for wind farm harmonic mitigation, and has practical application value. Attached Figure Description

[0015] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the method principle of the present invention; Figure 3 This is a system structure diagram of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0018] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0019] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0020] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0021] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0024] Example 1 refer to Figure 1 and Figure 2 The wind farm harmonic source location method of the present invention includes: 1) Obtain voltage and current information of each node in the PCC of the wind farm through voltage transformers (PT) and current transformers (CT); Specifically, obtain the voltage information of the power supply (PT) of the transmission line and the collection bus, and obtain the current information of each branch of the transmission line and the collection bus. All voltage and current transformers are of the measurement grade to ensure that the accuracy requirements for harmonic extraction are met.

[0025] 2) Perform Discrete Fourier Transform (DFT) processing on the voltage and current signals of each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components.

[0026] Specifically, Fourier analysis is performed on the voltage and current signals corresponding to the transmitting and receiving lines to obtain the phase angle and amplitude of each harmonic. 3) Determine the voltage and current harmonics exceeding the limits at each node and their corresponding harmonic frequencies; Specifically, the voltage and current signals corresponding to the sending and receiving lines are compared with the standard voltage and current signals to determine the harmonic frequencies that exceed the standard. 4) Perform instantaneous power calculations for all nodes of the harmonic frequencies exceeding the standard, determine the instantaneous active power of the exceeding harmonics at each node, and determine the location of the harmonic source based on the direction of the instantaneous active power of the harmonics.

[0027] Specifically, such as Figure 2 As shown, the specific process for calculating the instantaneous active power of excessive harmonics is as follows: 41) Convert the current and voltage signals of harmonics exceeding the standard frequency using Clark converter. In the coordinate system, that is: ,in

[0028] 42) According to The instantaneous active power is calculated based on the harmonic current and voltage in the coordinate system, i.e., the instantaneous active power is:

[0029] 43) Determine the location of harmonic sources based on the sign of instantaneous active power.

[0030] Specifically, when the instantaneous active power of the harmonic is positive, the harmonic power flow direction is consistent with the reference direction, and the harmonic source is located above the reference direction. Otherwise, the harmonic source is located below the reference direction. By performing the above operation on each node, the specific location of the harmonic source can be determined.

[0031] Example 2 Accordingly, refer to Figure 3 The wind farm harmonic source location system of the present invention includes: The first determining module is used to determine the voltage and current harmonics exceeding the standard at each node in the wind farm and their corresponding harmonic frequencies. The second determining module is used to perform instantaneous power calculations for all nodes of the harmonic frequencies exceeding the standard, determine the instantaneous active power of the exceeding harmonics at each node, and determine the location of the harmonic source based on the direction of the instantaneous active power.

[0032] This embodiment also includes: The acquisition module is used to acquire voltage and current information of each node in the wind farm through voltage transformers and current transformers. The separation module is used to perform discrete Fourier processing on the voltage and current signals of each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components.

[0033] In this embodiment, the process of obtaining voltage and current information of each node in the wind farm through voltage transformers and current transformers is as follows: Obtain voltage information for the outgoing lines and the collecting bus, and obtain current information for each branch of the outgoing lines and the collecting bus.

[0034] In this embodiment, during the process of determining the location of the harmonic source based on the direction of the instantaneous active power of the harmonics, when the instantaneous active power of the harmonics is positive, the direction of the harmonic power flow is consistent with the reference direction, and the harmonic source is located above the reference direction; otherwise, the harmonic source is located below the reference direction.

[0035] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0036] Example 3 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a wind farm harmonic source location method. For example, the method includes: acquiring voltage and current information of each node in the wind farm using voltage and current transformers; performing Discrete Fourier Transform processing on the voltage and current signals of each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components; determining the voltage and current harmonics exceeding the standard at each node and their corresponding harmonic frequencies; calculating the instantaneous power of the exceeding harmonic frequencies at all nodes to determine the instantaneous active power of the exceeding harmonics at each node; and determining the location of the harmonic source based on the direction of the instantaneous active power. In the process of determining the location of the harmonic source based on the direction of the instantaneous active power, when the instantaneous active power is positive, the harmonic power flow direction is consistent with the reference direction, and the harmonic source is located above the reference direction; otherwise, the harmonic source is located below the reference direction. The memory may include main memory, such as high-speed random access memory (RAM), or non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which may be an industry-standard architecture bus, a peripheral component interconnection standard bus, or an extended industry-standard architecture bus. The bus can be categorized as an address bus, data bus, or control bus. The memory stores programs; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0037] Example 4 A computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a wind farm harmonic source localization method. For example, the method includes: acquiring voltage and current information of each node in the wind farm using voltage and current transformers; performing Discrete Fourier Transform processing on the voltage and current signals of each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components; determining the voltage and current harmonics exceeding the standard at each node in the wind farm and their corresponding harmonic frequencies; calculating the instantaneous power of the exceeding harmonic frequencies at all nodes to determine the instantaneous active power of the exceeding harmonics at each node; and determining the location of the harmonic source based on the direction of the instantaneous active power. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0038] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0039] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0040] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0041] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0042] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0043] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0044] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for locating harmonic sources in a wind farm, characterized in that, include: Identify the voltage and current harmonics exceeding the limits at each node in the wind farm and their corresponding harmonic frequencies; The instantaneous power of the harmonic frequencies exceeding the standard is calculated at all nodes to determine the instantaneous active power of the exceeding harmonics at each node, and the location of the harmonic source is determined based on the direction of the instantaneous active power.

2. The wind farm harmonic source location method according to claim 1, characterized in that, Before determining the excessive voltage and current harmonics and their corresponding harmonic frequencies at each node in the wind farm, the following steps are also included: Voltage and current information of each node in the wind farm is obtained through voltage transformers and current transformers. Discrete Fourier transform is performed on the voltage and current signals at each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components.

3. The wind farm harmonic source location method according to claim 1, characterized in that, The process of obtaining voltage and current information of each node in the wind farm through voltage transformers and current transformers is as follows: Obtain voltage information for the outgoing lines and the collecting bus, and obtain current information for each branch of the outgoing lines and the collecting bus.

4. The wind farm harmonic source location method according to claim 1, characterized in that, In the process of determining the location of the harmonic source based on the direction of the instantaneous active power of the harmonic, when the instantaneous active power of the harmonic is positive, the direction of the harmonic power flow is consistent with the reference direction, and the harmonic source is located above the reference direction; otherwise, the harmonic source is located below the reference direction.

5. A wind farm harmonic source location system, characterized in that, include: The first determining module is used to determine the voltage and current harmonics exceeding the standard at each node in the wind farm and their corresponding harmonic frequencies. The second determining module is used to perform instantaneous power calculations for all nodes of the harmonic frequencies exceeding the standard, determine the instantaneous active power of the exceeding harmonics at each node, and determine the location of the harmonic source based on the direction of the instantaneous active power.

6. The wind farm harmonic source location system according to claim 5, characterized in that, Also includes: The acquisition module is used to acquire voltage and current information of each node in the wind farm through voltage transformers and current transformers. The separation module is used to perform discrete Fourier processing on the voltage and current signals of each node in the wind farm to separate the fundamental wave and obtain the harmonic and interharmonic components.

7. The wind farm harmonic source location system according to claim 5, characterized in that, The process of obtaining voltage and current information of each node in the wind farm through voltage transformers and current transformers is as follows: Obtain voltage information for the outgoing lines and the collecting bus, and obtain current information for each branch of the outgoing lines and the collecting bus.

8. The wind farm harmonic source location system according to claim 5, characterized in that, In the process of determining the location of the harmonic source based on the direction of the instantaneous active power of the harmonic, when the instantaneous active power of the harmonic is positive, the direction of the harmonic power flow is consistent with the reference direction, and the harmonic source is located above the reference direction; otherwise, the harmonic source is located below the reference direction.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the wind farm harmonic source location method as described in any one of claims 1-4.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the wind farm harmonic source location method as described in any one of claims 1-4.

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