Method and device for cleaning grid-side harmonic data of high-voltage direct-current converter station

Abstract

The invention relates to the technical field of power distribution network harmonic impedance identification, and particularly provides a high-voltage direct-current converter station network side harmonic data cleaning method and device, and the method comprises the steps: initializing a data cleaning window length as an initial window length; and performing data cleaning on the harmonic data of the monitoring point in the initial window length based on the correlation coefficient between the harmonic data mean value of the monitoring point in the initial window length and the harmonic data. According to the technical scheme provided by the invention, the linear relation between the harmonic voltage and the harmonic current of the power distribution network is considered, and the linear relation between the harmonic voltage and the harmonic current data is analyzed by adopting a correlation analysis method, so that the usability of the harmonic voltage and the harmonic current data can be improved, the data cleaning quality is improved, and the impedance characteristic analysis of the power distribution network is supported.

Description

Technical Field

[0001] This invention relates to the field of harmonic impedance identification technology in power distribution networks, specifically to a method and apparatus for cleaning harmonic data on the grid side of a high-voltage direct current converter station. Background Technology There is a linear relationship between harmonic voltage and harmonic current in a distribution network, which forms the basis for harmonic impedance identification. However, the widespread integration of large-scale distributed renewable energy sources and electric vehicles has led to randomness, fluctuations, and time-varying characteristics in distribution network harmonic voltage and current. This disrupts the linear relationship between the two, reducing the accuracy of harmonic impedance identification and ultimately affecting the accurate analysis of harmonic interaction characteristics between converter stations and the distribution network.

[0002] Currently, for distribution network harmonic voltage and current data, low-pass filtering and band-pass filtering are commonly used to reduce the impact of white noise on impedance identification. However, because the linear relationship between distribution network harmonic voltage and current is not considered, the filtering accuracy is low and the linear relationship between harmonic voltage and current is disrupted, thus affecting the accuracy of distribution network harmonic impedance identification and its application in practical scenarios. Therefore, for distribution network harmonic impedance identification scenarios, considering the linear relationship between distribution network harmonic voltage and current, and improving the usability of measurement data through data cleaning, has become a key step in improving the accuracy of distribution network harmonic impedance identification and supporting the analysis of distribution network impedance characteristics. Summary of the Invention

[0003] To overcome the above-mentioned defects, this invention proposes a method and apparatus for cleaning harmonic data on the grid side of a high-voltage direct current converter station.

[0004] Firstly, a method for cleaning harmonic data on the grid side of a high-voltage direct current (HVDC) converter station is provided, the method comprising: Initialize the data cleaning window length to the initial window length; Data cleaning is performed on the harmonic data of the monitoring points within the initial window length based on the correlation coefficient between the mean harmonic data of the monitoring points and the harmonic data within the initial window length.

[0005] Preferably, the data cleaning of the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point within the initial window length and the harmonic data includes: Determine the correlation coefficient between the mean harmonic data and the harmonic data at the monitoring point within the initial window length; When the correlation coefficient exceeds the preset upper limit, retain the harmonic data within the initial window length. When the correlation coefficient is less than the preset lower limit, delete the harmonic data within the initial window length. When the correlation coefficient is between the preset lower limit and the preset upper limit, divide the initial window length into a first window length and a second window length, and set the first window length and the second window length as the data cleaning window length respectively, then return to execute the initialization of the data cleaning window length as the initial window length.

[0006] Preferably, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0007] In the above formula, The average value of the h-th harmonic voltage at the monitoring point within the initial window length. The voltage of the h-th harmonic at the n-th data point within the initial window length is used for monitoring. This is the initial window length.

[0008] Furthermore, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0009] In the above formula, The average value of the h-th harmonic current at the monitoring point within the initial window length. To monitor the h-th harmonic current of the nth data point within the initial window length, This is the initial window length.

[0010] Furthermore, the correlation coefficient between the mean value of the harmonic data and the harmonic data at the monitoring point within the initial window length is as follows:

[0011] In the above formula, The correlation coefficient is the mean value of the h-th harmonic data and the h-th harmonic data within the initial window length of the monitoring point.

[0012] Furthermore, the correlation coefficient between the mean value of the harmonic data and the harmonic data within the initial window length of the monitoring point ranges from -1 to 1, with a preset lower limit of -0.3 and a preset upper limit of 0.8.

[0013] Secondly, a harmonic data cleaning device for the grid side of a high-voltage direct current converter station is provided, the high-voltage direct current converter station grid side harmonic data cleaning device comprising: The initialization module is used to initialize the data cleaning window length to the initial window length. The cleaning module is used to clean the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point and the harmonic data within the initial window length.

[0014] Preferably, the data cleaning of the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point within the initial window length and the harmonic data includes: Determine the correlation coefficient between the mean harmonic data and the harmonic data at the monitoring point within the initial window length; When the correlation coefficient exceeds the preset upper limit, retain the harmonic data within the initial window length. When the correlation coefficient is less than the preset lower limit, delete the harmonic data within the initial window length. When the correlation coefficient is between the preset lower limit and the preset upper limit, divide the initial window length into a first window length and a second window length, and set the first window length and the second window length as the data cleaning window length respectively, then return to execute the initialization of the data cleaning window length as the initial window length.

[0015] Preferably, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0016] In the above formula, The average value of the h-th harmonic voltage at the monitoring point within the initial window length. The voltage of the h-th harmonic at the n-th data point within the initial window length is used for monitoring. This is the initial window length.

[0017] Furthermore, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0018] In the above formula, The average value of the h-th harmonic current at the monitoring point within the initial window length. To monitor the h-th harmonic current of the nth data point within the initial window length, This is the initial window length.

[0019] Furthermore, the correlation coefficient between the mean value of the harmonic data and the harmonic data at the monitoring point within the initial window length is as follows:

[0020] In the above formula, The correlation coefficient is the mean value of the h-th harmonic data and the h-th harmonic data within the initial window length of the monitoring point.

[0021] Thirdly, a computer device is provided, comprising: one or more processors; The processor is used to execute one or more programs; When the one or more programs are executed by the one or more processors, the above-described harmonic data cleaning method for the grid side of the high-voltage direct current converter station is implemented.

[0022] Fourthly, a computer-readable storage medium is provided, on which a computer program is stored, wherein when the computer program is executed, the above-described method for cleaning harmonic data on the grid side of a high-voltage direct current converter station is implemented.

[0023] The above-described technical solutions of the present invention have at least one or more of the following beneficial effects: This invention provides a method and apparatus for cleaning harmonic data on the grid side of a high-voltage direct current converter station, comprising: initializing the data cleaning window length to an initial window length; and cleaning the harmonic data of the monitoring points within the initial window length based on the correlation coefficient between the mean value of the harmonic data and the harmonic data themselves. The technical solution provided by this invention considers the linear relationship between harmonic voltage and harmonic current in the distribution network, and uses correlation analysis to analyze the linear relationship between harmonic voltage and harmonic current data. This can improve the availability of harmonic voltage and harmonic current data, enhance the quality of data cleaning, and support the impedance characteristic analysis of the distribution network. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the main steps of the high-voltage direct current converter station grid-side harmonic data cleaning method according to an embodiment of the present invention; Figure 2 This is a simulation system topology diagram according to an embodiment of the present invention; Figure 3 This is a harmonic current data diagram according to an embodiment of the present invention; Figure 4 This is a harmonic voltage data diagram according to an embodiment of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] 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 embodiments of the present invention, not all embodiments. 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.

[0027] Example 1 See appendix Figure 1 , Figure 1 This is a schematic flowchart illustrating the main steps of a high-voltage direct current converter station grid-side harmonic data cleaning method according to an embodiment of the present invention. Figure 1 As shown, the harmonic data cleaning method for the grid side of a high-voltage direct current converter station in this embodiment of the invention mainly includes the following steps: Step S101: Initialize the data cleaning window length to the initial window length; Step S102: Clean the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point and the harmonic data.

[0028] In this embodiment, the data cleaning of the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point within the initial window length and the harmonic data includes: Determine the correlation coefficient between the mean harmonic data and the harmonic data at the monitoring point within the initial window length; In this embodiment, the relationship between the correlation coefficient and the degree of linear correlation is shown in Table 1: Table 1

[0029] When the correlation coefficient exceeds the preset upper limit, retain the harmonic data within the initial window length. When the correlation coefficient is less than the preset lower limit, delete the harmonic data within the initial window length. When the correlation coefficient is between the preset lower limit and the preset upper limit, divide the initial window length into a first window length and a second window length, and set the first window length and the second window length as the data cleaning window length respectively, then return to execute the initialization of the data cleaning window length as the initial window length.

[0030] In this embodiment, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0031] In the above formula, The average value of the h-th harmonic voltage at the monitoring point within the initial window length. The voltage of the h-th harmonic at the n-th data point within the initial window length is used for monitoring. This is the initial window length.

[0032] In one implementation, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0033] In the above formula, The average value of the h-th harmonic current at the monitoring point within the initial window length. To monitor the h-th harmonic current of the nth data point within the initial window length, This is the initial window length.

[0034] In one implementation, the correlation coefficient between the mean harmonic data and the harmonic data of the monitoring point within the initial window length is as follows:

[0035] In the above formula, The correlation coefficient is the mean value of the h-th harmonic data and the h-th harmonic data within the initial window length of the monitoring point.

[0036] In one embodiment, the correlation coefficient between the mean value of harmonic data and the harmonic data within the initial window length of the monitoring point ranges from -1 to 1, with a preset lower limit of -0.3 and a preset upper limit of 0.8.

[0037] In one specific implementation, to demonstrate the feasibility of correlation screening, in the simulation model, a 1% disturbance is superimposed on the amplitude and phase angle of the system-side harmonic voltage source to simulate system-side fluctuations. At different time periods, disturbances of varying proportions are superimposed on the amplitude and phase angle of the harmonic current source on the user side. For example... Figure 2 As shown in the topology, the third harmonic voltage and current (data points n=1000) are sampled at the PCC point of the simulation experimental circuit. In the data segments 301-500 and 901-1000, the amplitude and phase angle of the harmonic current source on the user side are superimposed with a 1% fluctuation; in other cases, a 5% fluctuation is superimposed. Therefore, in the data segments 301-500 and 901-1000, the fluctuations on the system side and the user side are approximately the same; in the other data segments, the fluctuations on the system side are smaller than those on the user side. Harmonic voltage and current data are collected at the PCC point, as follows... Figure 3 and Figure 4 As shown.

[0038] The simulation data was divided into 10 windows, each containing 100 data points. Pearson correlation calculations were performed within each window. Data from windows with high correlation were retained, thus identifying data with a strong correlation between harmonic voltage and harmonic current. The correlation calculation results are shown in Table 2 below.

[0039] Table 2

[0040] As shown in the table, the correlation coefficients in the 301-500 and 901-1000 data groups are relatively small, all less than 0.3, corresponding to the weak correlation in Table 1. This indicates that both harmonic voltage and harmonic current measurements fluctuate simultaneously, resulting in poor accuracy for impedance identification. The correlation coefficients for the remaining data windows are all greater than 0.8, representing a high positive correlation. This indicates fluctuations in harmonic current and relatively constant harmonic voltage, making these the optimal data segments for parameter identification. Therefore, the 0-300 and 501-900 data groups are suitable for parameter identification. The correlation calculation results demonstrate the feasibility of data cleaning based on correlation.

[0041] Example 2 Based on the same inventive concept, the present invention also provides a harmonic data cleaning device for the grid side of a high-voltage direct current converter station, the harmonic data cleaning device for the grid side of the high-voltage direct current converter station comprising: The initialization module is used to initialize the data cleaning window length to the initial window length. The cleaning module is used to clean the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point and the harmonic data within the initial window length.

[0042] Preferably, the data cleaning of the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point within the initial window length and the harmonic data includes: Determine the correlation coefficient between the mean harmonic data and the harmonic data at the monitoring point within the initial window length; When the correlation coefficient exceeds the preset upper limit, retain the harmonic data within the initial window length. When the correlation coefficient is less than the preset lower limit, delete the harmonic data within the initial window length. When the correlation coefficient is between the preset lower limit and the preset upper limit, divide the initial window length into a first window length and a second window length, and set the first window length and the second window length as the data cleaning window length respectively, then return to execute the initialization of the data cleaning window length as the initial window length.

[0043] Preferably, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0044] In the above formula, The average value of the h-th harmonic voltage at the monitoring point within the initial window length. The voltage of the h-th harmonic at the n-th data point within the initial window length is used for monitoring. This is the initial window length.

[0045] Furthermore, the mean harmonic data of the monitoring point within the initial window length is as follows:

[0046] In the above formula, The average value of the h-th harmonic current at the monitoring point within the initial window length. To monitor the h-th harmonic current of the nth data point within the initial window length, This is the initial window length.

[0047] Furthermore, the correlation coefficient between the mean value of the harmonic data and the harmonic data at the monitoring point within the initial window length is as follows:

[0048] In the above formula, The correlation coefficient is the mean value of the h-th harmonic data and the h-th harmonic data within the initial window length of the monitoring point.

[0049] Example 3 Based on the same inventive concept, this invention also provides a computer device, which includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or 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. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to implement corresponding method flows or corresponding functions, thereby implementing the steps of the high-voltage DC converter station grid-side harmonic data cleaning method in the above embodiments.

[0050] Example 4 Based on the same inventive concept, this invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the high-voltage direct current converter station grid-side harmonic data cleaning method in the above embodiments.

[0051] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention 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.

[0052] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0053] 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.

[0054] 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.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for cleaning harmonic data on the grid side of a high-voltage direct current converter station, characterized in that, The method includes: Initialize the data cleaning window length to the initial window length; Data cleaning is performed on the harmonic data of the monitoring points within the initial window length based on the correlation coefficient between the mean harmonic data of the monitoring points and the harmonic data within the initial window length.

2. The method as described in claim 1, characterized in that, The data cleaning of harmonic data within the initial window length based on the correlation coefficient between the mean value of harmonic data at the monitoring point and the harmonic data includes: Determine the correlation coefficient between the mean harmonic data and the harmonic data at the monitoring point within the initial window length; When the correlation coefficient exceeds the preset upper limit, retain the harmonic data within the initial window length. When the correlation coefficient is less than the preset lower limit, delete the harmonic data within the initial window length. When the correlation coefficient is between the preset lower limit and the preset upper limit, divide the initial window length into a first window length and a second window length, and set the first window length and the second window length as the data cleaning window length respectively, then return to execute the initialization of the data cleaning window length as the initial window length.

3. The method as described in claim 1, characterized in that, The mean harmonic data of the monitoring points within the initial window length are as follows: In the above formula, The average value of the h-th harmonic voltage at the monitoring point within the initial window length. The voltage of the h-th harmonic at the n-th data point within the initial window length is used for monitoring. This is the initial window length.

4. The method as described in claim 3, characterized in that, The mean harmonic data of the monitoring points within the initial window length are as follows: In the above formula, The average value of the h-th harmonic current at the monitoring point within the initial window length. To monitor the h-th harmonic current of the nth data point within the initial window length, This is the initial window length.

5. The method as described in claim 4, characterized in that, The correlation coefficients between the mean harmonic data and the harmonic data at the monitoring points within the initial window length are as follows: In the above formula, The correlation coefficient is the mean value of the h-th harmonic data and the h-th harmonic data within the initial window length of the monitoring point.

6. The method as described in claim 2, characterized in that, The correlation coefficient between the mean value of harmonic data and the harmonic data within the initial window length of the monitoring point ranges from -1 to 1, with a preset lower limit of -0.3 and a preset upper limit of 0.

8.

7. A harmonic data cleaning device for the grid side of a high-voltage direct current converter station, characterized in that, The device includes: The initialization module is used to initialize the data cleaning window length to the initial window length. The cleaning module is used to clean the harmonic data of the monitoring point within the initial window length based on the correlation coefficient between the mean value of the harmonic data of the monitoring point and the harmonic data.

8. The apparatus as claimed in claim 7, characterized in that, The data cleaning of harmonic data within the initial window length based on the correlation coefficient between the mean value of harmonic data at the monitoring point and the harmonic data includes: Determine the correlation coefficient between the mean harmonic data and the harmonic data at the monitoring point within the initial window length; When the correlation coefficient exceeds the preset upper limit, retain the harmonic data within the initial window length. When the correlation coefficient is less than the preset lower limit, delete the harmonic data within the initial window length. When the correlation coefficient is between the preset lower limit and the preset upper limit, divide the initial window length into a first window length and a second window length, and set the first window length and the second window length as the data cleaning window length respectively, then return to execute the initialization of the data cleaning window length as the initial window length.

9. The apparatus as claimed in claim 7, characterized in that, The mean harmonic data of the monitoring points within the initial window length are as follows: In the above formula, The average value of the h-th harmonic voltage at the monitoring point within the initial window length. The voltage of the h-th harmonic at the n-th data point within the initial window length is used for monitoring. This is the initial window length.

10. The apparatus as claimed in claim 9, characterized in that, The mean harmonic data of the monitoring points within the initial window length are as follows: In the above formula, The average value of the h-th harmonic current at the monitoring point within the initial window length. To monitor the h-th harmonic current of the nth data point within the initial window length, This is the initial window length.

11. The apparatus as claimed in claim 10, characterized in that, The correlation coefficients between the mean harmonic data and the harmonic data at the monitoring points within the initial window length are as follows: In the above formula, The correlation coefficient is the mean value of the h-th harmonic data and the h-th harmonic data within the initial window length of the monitoring point.

12. The apparatus as claimed in claim 8, characterized in that, The correlation coefficient between the mean value of harmonic data and the harmonic data within the initial window length of the monitoring point ranges from -1 to 1, with a preset lower limit of -0.3 and a preset upper limit of 0.

8.

13. A computer device, characterized in that, include: One or more processors; The processor is used to execute one or more programs; When the one or more programs are executed by the one or more processors, the method for cleaning harmonic data on the grid side of a high-voltage direct current converter station as described in any one of claims 1 to 6 is implemented.

14. A computer-readable storage medium, characterized in that, It contains a computer program, which, when executed, implements the harmonic data cleaning method for the grid side of a high-voltage direct current converter station as described in any one of claims 1 to 6.

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