Low-voltage transformer area topology identification method and system based on distributed photovoltaic power regulation and control

Abstract

The invention discloses a low-voltage transformer area topology identification method and system based on distributed photovoltaic power regulation and control, and the method comprises the steps: sequentially switching off and switching on low-voltage transformer area distributed photovoltaics corresponding to a user in a preset time period, and obtaining a switching-off sequence of distributed photovoltaic inverters; determining a voltage drop sequence of the user according to the voltage rise value and the voltage drop value of the user corresponding to the shutdown sequence; in the voltage drop sequence of the users, matching is carried out according to the voltage rise and drop points of all the users and the closing time periods of the users, and if the proportion of the matched time periods exceeds a preset threshold value, it is confirmed that the users and the distributed photovoltaic devices in the corresponding low-voltage transformer areas are in a strong coupling relation; and on the basis of a graph theory method, taking each user with a strong coupling relationship and the corresponding low-voltage transformer area distributed photovoltaic as nodes in a graph, taking an electrical connection relationship as edge connection points in the graph, and taking connection between the nodes as an electrical path to construct a power grid topological graph of the low-voltage transformer area. And the accuracy and efficiency of topology identification are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power system monitoring and management, and in particular to a method and system for identifying low-voltage area topology based on distributed photovoltaic power regulation. Background Art

[0002] With the acceleration of urbanization and the continuous growth of electricity demand, the management and optimization of low-voltage power grids have become an important part of power system operation and maintenance. Traditional low-voltage power grid management relies on manual on-site surveys to determine the topology of the power grid. This method is not only time-consuming and costly, but also easily affected by subjective judgment. The accuracy and efficiency cannot meet the needs of modern power grid management.

[0003] Although some topology recognition methods based on remote sensing technology and GIS (Geographic Information System) have been developed in recent years, these methods often rely on a large amount of geographic location data and external information, and have high requirements on data quality and update speed. In addition, the flexibility and accuracy of these methods in dealing with complex power grid structures still need to be improved. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a low-voltage area topology identification method based on distributed photovoltaic power control, comprising:

[0005] The distributed photovoltaic power generation in the low-voltage area corresponding to the user is turned off and on in sequence within a preset time period to obtain a shutdown sequence of the distributed photovoltaic inverter;

[0006] Determine a voltage reduction sequence for the user according to the voltage increase value and the voltage reduction value of the user corresponding to the shutdown sequence;

[0007] In the voltage drop sequence of the user, the voltage rise and fall points of each user are matched with the user's shutdown period. If the proportion of the matching period exceeds a preset threshold, it is confirmed that the user and the corresponding low-voltage distributed photovoltaic area are in a strong coupling relationship;

[0008] Based on the graph theory method, each user with a strong coupling relationship and the corresponding low-voltage distributed photovoltaic area are taken as nodes in the graph, the electrical connection relationship is taken as the edge connection point in the graph, and the connection between the nodes is taken as the electrical path to construct the power grid topology diagram of the low-voltage area.

[0009] Furthermore, before the step of sequentially shutting down and opening the distributed photovoltaic power generation in the low-voltage area corresponding to the user within the preset time period, the method further includes:

[0010] Statistics are collected on the files and contract capacities of distributed photovoltaic users in low-voltage areas to obtain users in low-voltage areas.

[0011] Further, determining the voltage reduction sequence of the user according to the voltage increase value and the voltage reduction value of the user corresponding to the shutdown sequence includes:

[0012] Subtract the user voltage from the total meter voltage of the low-voltage area to obtain the difference between the low-voltage area user and the total meter, and the difference is the voltage rise value of the user customer;

[0013] After the distributed photovoltaic inverter is shut down, the user's voltage drop sequence is obtained based on the voltage rise and fall characteristics of the adjacent electric energy meters.

[0014] Furthermore, it also includes: merging users with strong coupling relationship with corresponding low-voltage distributed photovoltaic areas.

[0015] Furthermore, it also includes: according to the power grid topology diagram of the low-voltage area, the distributed photovoltaic in the low-voltage area is taken as the center, and the electrical distance between the user and the distributed photovoltaic is identified through the strong coupling relationship between the user and the distributed photovoltaic.

[0016] The present invention also provides a low-voltage area topology identification system based on distributed photovoltaic power control, including:

[0017] A shutdown sequence acquisition module is used to sequentially shut down and open the distributed photovoltaic power generation in the low-voltage area corresponding to the user within a preset time period to obtain a shutdown sequence of the distributed photovoltaic inverter;

[0018] A descending sequence determination module, used to determine a voltage descending sequence of a user according to a voltage raising value and a voltage descending value of the user corresponding to the shutdown sequence;

[0019] A strong coupling relationship confirmation module is used to match the voltage rise and fall points of each user with the user's shutdown period in the voltage drop sequence of the user. If the proportion of the matching period exceeds a preset threshold, it is confirmed that the user and the corresponding low-voltage distributed photovoltaic area are in a strong coupling relationship;

[0020] The grid topology map construction module is used to construct the grid topology map of the low-voltage area based on the graph theory method, taking each user with a strong coupling relationship and the corresponding low-voltage area distributed photovoltaic as the node in the graph, the electrical connection relationship as the edge connection point in the graph, and the connection between the nodes as the electrical path.

[0021] Furthermore, it also includes:

[0022] The user acquisition module is used to collect statistics on the files and contract capacity of distributed photovoltaic users in low-voltage areas, and obtain users in low-voltage areas.

[0023] Furthermore, the descending sequence determination module includes:

[0024] The voltage rise value acquisition submodule is used to make a difference between the user voltage and the total meter voltage of the low-voltage area to obtain the difference between the low-voltage area user and the total meter, and the difference is the voltage rise value of the user customer;

[0025] The voltage drop sequence acquisition submodule is used to obtain the user's voltage drop sequence according to the voltage rise and fall characteristics of the adjacent electric energy meter after the distributed photovoltaic inverter is shut down.

[0026] Furthermore, it also includes:

[0027] The electrical distance identification module is used to identify the electrical distance between the user and the distributed photovoltaic according to the grid topology diagram of the low-voltage area, taking the distributed photovoltaic in the low-voltage area as the center, and through the strong coupling relationship between the user and the distributed photovoltaic.

[0028] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method described in any one of the above claims.

[0029] The present invention provides a low-voltage area topology identification method and system based on distributed photovoltaic power regulation, which identifies the power grid topology by real-time monitoring of voltage changes caused by distributed photovoltaic systems to improve the real-time and accuracy of identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of a method for identifying low-voltage area topology based on distributed photovoltaic power control according to an embodiment of the present invention;

[0031] Figure 2 The photovoltaic start-stop sequence and the voltage raising sequence for electricity users involved in the embodiment of the present invention;

[0032] Figure 3 It is the coupling association between the electricity customer and the distributed photovoltaic power involved in the embodiment of the present invention;

[0033] Figure 4 It is a structural schematic diagram of a low-voltage area topology identification system based on distributed photovoltaic power control provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0035] The main purpose of the present invention is to provide a low-voltage substation topology identification technology. By installing a photovoltaic collection and monitoring unit in the low-voltage substation and identifying the sequence relationship of distributed photovoltaic changes, the topology identification of the low-voltage substation is realized. The topology of the low-voltage substation is identified by this method to obtain the topological association relationship of the low-voltage substation. This method identifies users in the low-voltage substation that are close to the distributed photovoltaic electrical distance by making planned power changes to the distributed photovoltaics and the association relationship with the voltage changes of the electric meters in the low-voltage substation, so as to support the optimization of the low-voltage substation group adjustment and group control, and solve several problems existing in the current low-voltage power grid topology identification, such as Figure 1 As shown, the specific steps include:

[0036] Step S101, within a preset time period, the distributed photovoltaic power generation in the low-voltage area corresponding to the user is sequentially turned off and on to obtain a shutdown sequence of the distributed photovoltaic inverter.

[0037] Statistics are collected on the files and contract capacities of distributed photovoltaic users in low-voltage areas to obtain users in the low-voltage areas [A, B, C...].

[0038] The time period when distributed photovoltaic power generation is high and the voltage in the low-voltage area is high is selected as the preset time period, which is generally between 10:00 and 15:00 in the morning.

[0039] Arrange time to shut down the distributed photovoltaic in the low-voltage area in sequence, such as: shut down user A at 10:00; turn on user A and shut down user B at 10:15; turn on user B and shut down user C at 10:30; turn on user C and shut down user D at 10:45; get the shutdown sequence of the distributed photovoltaic inverter in sequence, such as Figure 2 As shown;

[0040] Step S102, determining a voltage reduction sequence of the user according to the voltage increase value and the voltage reduction value of the user corresponding to the shutdown sequence.

[0041] The user voltage is subtracted from the total meter voltage of the low-voltage area to obtain the difference between the low-voltage area user and the total meter, and the difference is the voltage rise value of the user customer; after the distributed photovoltaic inverter is shut down, the user's voltage drop sequence is obtained according to the voltage rise and fall characteristics of the adjacent electric energy meters.

[0042] Step S103, in the voltage drop sequence of the user, the voltage rise and fall points of each user are matched with the user's shutdown period. If the matching period ratio exceeds a preset threshold, it is confirmed that the user and the corresponding low-voltage distributed photovoltaic area are in a strong coupling relationship.

[0043] Repeated comparisons are made to obtain the matching of each user's voltage rise and fall points with the photovoltaic user's shutdown period. If the proportion of the matching period exceeds the preset threshold of 80%, it is judged that the user is similar to the distributed photovoltaic electrical topology and can be merged. At the same time, it can be judged that the user and the distributed photovoltaic power are strongly coupled. The specific identification steps are as follows: Figure 3 shown.

[0044] Step S104, based on the graph theory method, each user with a strong coupling relationship and the corresponding low-voltage distributed photovoltaic area are taken as nodes in the graph, the electrical connection relationship is taken as the edge connection point in the graph, and the connection between the nodes is taken as the electrical path to construct a power grid topology diagram of the low-voltage area.

[0045] Based on the matching results, a preliminary electrical connection diagram is generated to show the connection relationship between all users and the corresponding photovoltaics. Using graph theory methods, each user and photovoltaic is regarded as a node in the graph, and the observed electrical connections are used as edges to connect the nodes. Using the connection data, a network graph is constructed in which the connections between nodes represent electrical paths. A clear coupling association diagram between low-voltage areas and distributed photovoltaics is established.

[0046] According to the grid topology diagram of the low-voltage area, the distributed photovoltaic in the low-voltage area is taken as the center, and the electrical distance between the user and the distributed photovoltaic is identified through the strong coupling relationship between the user and the distributed photovoltaic.

[0047] This embodiment provides a technology for identifying the topology of the low-voltage power grid based on real-time monitoring of voltage changes caused by distributed photovoltaic systems. The present invention not only improves the accuracy and efficiency of topology identification, but also reduces the implementation cost of the system and enhances the reliability and flexibility of the power grid.

[0048] User and PV system data collection: First, collect detailed information of all distributed PV users in the low-voltage area, including archival data and contract capacity. For example, the PV installation details and power consumption patterns of users A, B, C, etc.

[0049] Determine the time period of high photovoltaic power generation: select a time period with sufficient sunshine and high photovoltaic power generation efficiency for the experiment, generally from 10:00 to 15:00 every morning.

[0050] Orderly shutdown and startup of distributed photovoltaics:

[0051] At 10:00, the photovoltaic system of user A is turned off.

[0052] At 10:15, the photovoltaic system of user A is turned on, and the photovoltaic system of user B is turned off.

[0053] At 10:30, the photovoltaic system of user B is turned on, and the photovoltaic system of user C is turned off.

[0054] Continue in this way until all users participating in the experiment are included.

[0055] Voltage change monitoring and data recording: Monitor the voltage changes of users and low-voltage area meters every time the photovoltaic system is turned off or on, and record the data. Pay special attention to the obvious voltage changes of users who are close to the operated photovoltaic system.

[0056] Data analysis and topology identification:

[0057] Analyze the voltage variation data of each user when operating different photovoltaic systems.

[0058] By comparing the voltage rise and fall values, users that are electrically close to a specific PV system can be identified.

[0059] If the voltage variation and operation matching degree of a user in a specific photovoltaic shutdown period exceeds 80%, it is considered that the user has a strong coupling relationship with the photovoltaic system.

[0060] Generation of topology map: Using graph theory principles, each user and photovoltaic system is taken as a node, and the electrical connection relationship obtained from voltage change data is used as an edge to draw a grid topology map of the low-voltage area. This map clearly shows the connection relationship between users and distributed photovoltaics, providing valuable data support for grid management.

[0061] Based on the same inventive concept, the present invention also provides a low-voltage area topology identification system 400 based on distributed photovoltaic power regulation, such as Figure 4 As shown, including:

[0062] The shutdown sequence acquisition module 410 is used to sequentially shut down and start the distributed photovoltaic power generation in the low-voltage area corresponding to the user within a preset time period to obtain a shutdown sequence of the distributed photovoltaic inverter;

[0063] A decreasing sequence determining module 420, configured to determine a voltage decreasing sequence of a user according to a voltage raising value and a voltage decreasing value of the user corresponding to the shutdown sequence;

[0064] A strong coupling relationship confirmation module 430 is used to match the voltage rise and fall points of each user with the user's shutdown period in the voltage drop sequence of the user. If the proportion of the matching period exceeds a preset threshold, it is confirmed that the user and the corresponding low-voltage distributed photovoltaic area are in a strong coupling relationship;

[0065] The power grid topology map construction module 440 is used to construct a power grid topology map of the low-voltage substation based on a graph theory method, taking each user with a strong coupling relationship and the corresponding low-voltage substation distributed photovoltaic as a node in the graph, the electrical connection relationship as the edge connection point in the graph, and the connection between the nodes as the electrical path.

[0066] Furthermore, it also includes:

[0067] The user acquisition module is used to collect statistics on the files and contract capacity of distributed photovoltaic users in low-voltage areas, and obtain users in low-voltage areas.

[0068] Furthermore, the descending sequence determination module includes:

[0069] The voltage rise value acquisition submodule is used to make a difference between the user voltage and the total meter voltage of the low-voltage area to obtain the difference between the low-voltage area user and the total meter, and the difference is the voltage rise value of the user customer;

[0070] The voltage drop sequence acquisition submodule is used to obtain the user's voltage drop sequence according to the voltage rise and fall characteristics of the adjacent electric energy meter after the distributed photovoltaic inverter is shut down.

[0071] Furthermore, it also includes:

[0072] The electrical distance identification module is used to identify the electrical distance between the user and the distributed photovoltaic according to the grid topology diagram of the low-voltage area, taking the distributed photovoltaic in the low-voltage area as the center, and through the strong coupling relationship between the user and the distributed photovoltaic.

[0073] The present invention uses an innovative low-voltage area topology identification technology to effectively solve several technical problems existing in traditional topology identification methods and brings significant beneficial effects:

[0074] This method can accurately identify users with close electrical distances by making planned power changes to distributed photovoltaics in low-voltage areas and monitoring the voltage changes of related low-voltage area meters. This method directly observes the results through actual operational influences, greatly improving the accuracy of topology identification. Compared with traditional methods that rely on static data or simulated data, they are easily affected by incomplete or unupdated data. The present invention provides more accurate topology information through dynamic real-time data analysis.

[0075] With a clear topology diagram, grid operation can be better managed, load distribution can be optimized, and energy consumption can be reduced. For example, a clear topology helps implement more effective group dispatching and group control strategies, improving the efficiency and reliability of the overall grid.

[0076] Technical problem to be solved: Without knowing the specific topology structure, power grid management is often reactive and inefficient. The present invention provides a method for actively acquiring topology information, making power grid management more active and accurate.

[0077] In addition, the present invention utilizes the already installed distributed photovoltaic and standard voltage measurement equipment to achieve topology identification, without the need for additional high-cost equipment investment. By identifying and applying the actual topological information of the power grid, it is possible to respond more quickly to power grid failures or demand changes, such as load adjustment under the influence of distributed photovoltaics.

[0078] In summary, the present invention not only improves the accuracy and reliability of low-voltage area topology identification through a simple and effective real-time monitoring and control method, but also enhances the management efficiency and responsiveness of the entire power grid, while reducing the need to rely on high-cost equipment. These technical effects together support a more economical, efficient and reliable power grid operation environment.

[0079] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented 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.

[0080] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0081] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0082] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalents that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for identifying low-voltage area topology based on distributed photovoltaic power control, characterized in that: include: The distributed photovoltaic power generation in the low-voltage area corresponding to the user is turned off and on in sequence within a preset time period to obtain a shutdown sequence of the distributed photovoltaic inverter; Determine a voltage reduction sequence for the user according to the voltage increase value and the voltage reduction value of the user corresponding to the shutdown sequence; In the voltage drop sequence of the user, the voltage rise and fall points of each user are matched with the user's shutdown period. If the proportion of the matching period exceeds a preset threshold, it is confirmed that the user and the corresponding low-voltage distributed photovoltaic area are in a strong coupling relationship; Based on the graph theory method, each user with a strong coupling relationship and the corresponding low-voltage distributed photovoltaic area are taken as nodes in the graph, the electrical connection relationship is taken as the edge connection point in the graph, and the connection between the nodes is taken as the electrical path to construct the power grid topology diagram of the low-voltage area.

2. The method according to claim 1, characterized in that Before the step of sequentially shutting down and opening up the distributed photovoltaic power generation in the low-voltage area corresponding to the user within the preset time period, the method further includes: Statistics are collected on the files and contract capacities of distributed photovoltaic users in low-voltage areas to obtain users in low-voltage areas.

3. The method according to claim 1, characterized in that Determining a voltage reduction sequence of a user according to a voltage increase value and a voltage reduction value of the user corresponding to the shutdown sequence includes: Subtract the user voltage from the total meter voltage of the low-voltage area to obtain the difference between the low-voltage area user and the total meter, and the difference is the voltage rise value of the user customer; After the distributed photovoltaic inverter is shut down, the user's voltage drop sequence is obtained based on the voltage rise and fall characteristics of the adjacent electric energy meters.

4. The method according to claim 1, characterized in that: Also includes: Merge users with strong coupling relationships with corresponding low-voltage distributed photovoltaics.

5. The method according to claim 1, characterized in that Also includes: According to the grid topology diagram of the low-voltage area, the distributed photovoltaic in the low-voltage area is taken as the center, and the electrical distance between the user and the distributed photovoltaic is identified through the strong coupling relationship between the user and the distributed photovoltaic.

6. A low-voltage area topology identification system based on distributed photovoltaic power control, characterized in that: include: A shutdown sequence acquisition module is used to sequentially shut down and open the distributed photovoltaic power generation in the low-voltage area corresponding to the user within a preset time period to obtain a shutdown sequence of the distributed photovoltaic inverter; A descending sequence determination module, used to determine a voltage descending sequence of a user according to a voltage raising value and a voltage descending value of the user corresponding to the shutdown sequence; A strong coupling relationship confirmation module is used to match the voltage rise and fall points of each user with the user's shutdown period in the voltage drop sequence of the user. If the proportion of the matching period exceeds a preset threshold, it is confirmed that the user and the corresponding low-voltage distributed photovoltaic area are in a strong coupling relationship; The grid topology map construction module is used to construct the grid topology map of the low-voltage area based on the graph theory method, taking each user with a strong coupling relationship and the corresponding low-voltage area distributed photovoltaic as the node in the graph, the electrical connection relationship as the edge connection point in the graph, and the connection between the nodes as the electrical path.

7. The system according to claim 6, characterized in that Also includes: The user acquisition module is used to collect statistics on the files and contract capacity of distributed photovoltaic users in low-voltage areas and obtain users in low-voltage areas.

8. The system according to claim 6, characterized in that The descending sequence determination module comprises: The voltage rise value acquisition submodule is used to make a difference between the user voltage and the total meter voltage of the low-voltage area to obtain the difference between the low-voltage area user and the total meter, and the difference is the voltage rise value of the user customer; The voltage drop sequence acquisition submodule is used to obtain the user's voltage drop sequence according to the voltage rise and fall characteristics of the adjacent electric energy meter after the distributed photovoltaic inverter is shut down.

9. The system according to claim 6, characterized in that Also includes: The electrical distance identification module is used to identify the electrical distance between the user and the distributed photovoltaic according to the grid topology diagram of the low-voltage area, taking the distributed photovoltaic in the low-voltage area as the center, and through the strong coupling relationship between the user and the distributed photovoltaic.

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

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