Voltage out-of-limit treatment method and device for low-voltage transformer area of power distribution network

Abstract

The invention relates to a voltage out-of-limit treatment method and device for a low-voltage transformer area of a power distribution network. The method comprises the steps of collecting transformer area data of the power distribution network; the power distribution network station area data comprises a power distribution network station area topological structure and monitoring voltage of each node of the power distribution network station area; determining whether voltage out-of-limit occurs in each node according to the monitoring voltage of each node in the distribution network area; determining the voltage out-of-limit problem type of the power distribution network area according to the position of the node where the voltage out-of-limit occurs in the topological structure of the power distribution network area; according to the type of the voltage out-of-limit problem of the power distribution network area and the position of the node where the voltage out-of-limit occurs in the topological structure of the power distribution network area, the setting position of the low-voltage flexible direct current voltage regulation device is determined. According to the technical scheme, the output voltage can be adjusted in real time, the load change is quickly responded, and the grid voltage is kept within a set range. And moreover, data sharing and communication among node equipment are realized, and centralized management and data analysis are performed on data of all nodes of the distribution network area, so that the voltage regulation efficiency can be optimized.

Description

Technical Field

[0001] The present application relates to the field of voltage management technology, and in particular to a method and device for managing voltage over-limit in a low-voltage area of ​​a distribution network. Background Art

[0002] In modern distribution networks, low voltage problems have become an important factor affecting the quality of power supply. The causes of low voltage problems in distribution networks mainly include factors such as load fluctuations, line losses, insufficient transformer capacity, and insufficient reactive power. Concentrated power consumption and sudden loads during peak hours can cause voltage drops, while long-distance transmission and unreasonable equipment configuration increase energy losses. In addition, with the access of renewable energy, its volatility and the instability of inverters will also affect voltage quality. At the same time, structural problems of the power grid and external environmental factors (such as extreme weather and electromagnetic interference) will further aggravate the low voltage phenomenon. This not only affects the user's power experience, but may also cause equipment damage and increased energy consumption, increasing the operation risk of the power system.

[0003] Existing measures and methods for managing voltage over-limit in substations mainly include adding adjustable transformers and reactive compensation equipment, such as capacitors, to improve power supply capacity and stabilize voltage; implementing load management and balancing peak loads through demand response strategies; optimizing distribution line design and reducing line losses; introducing intelligent monitoring and control systems to achieve real-time voltage monitoring and dynamic regulation; encouraging users to adopt distributed power generation, such as solar panels; and applying smart grid technology to improve overall operating efficiency using the Internet of Things and big data analysis. These measures are intended to improve voltage quality and power supply reliability, but in actual applications they have the following defects:

[0004] 1) The existing distribution network is difficult to maintain voltage stability during load peaks or sudden load changes, which easily leads to low voltage phenomena;

[0005] 2) There is a lack of effective data sharing and coordination between different node devices in the existing system, resulting in low overall regulation efficiency. Summary of the invention

[0006] In order to at least to some extent overcome the problems of insufficient voltage stability and information islands in the voltage over-limit management measures in the related art, the present application provides a method and device for voltage over-limit management in a low-voltage area of ​​a distribution network.

[0007] The scheme of this application is as follows:

[0008] According to a first aspect of an embodiment of the present application, a method for over-limit voltage control in a low-voltage area of ​​a distribution network is provided, comprising:

[0009] Collecting distribution network area data; the distribution network area data includes: the distribution network area topology structure and the monitoring voltage of each node in the distribution network area;

[0010] Determine whether the voltage at each node exceeds the limit based on the voltage monitored at each node in the distribution network substation;

[0011] According to the location of the node where the voltage exceeds the limit in the topological structure of the distribution network area, the type of voltage exceeding the limit problem in the distribution network area is determined;

[0012] The location of the low-voltage flexible direct current voltage regulation device is determined based on the type of voltage over-limit problem in the distribution network substation and the location of the node where the voltage over-limit occurs in the topological structure of the distribution network substation.

[0013] Preferably, determining whether voltage exceeds the limit at each node according to the voltage monitored at each node in the distribution network substation includes:

[0014] If the node is powered by a single-phase supply, the node supply voltage is compared with the single-phase supply voltage limit range;

[0015] If the node power supply voltage is higher than the single-phase power supply voltage limit interval, it is determined that the node exceeds the upper limit;

[0016] If the node power supply voltage is lower than the single-phase power supply voltage limit interval, it is determined that the node has crossed the lower limit.

[0017] Preferably, determining whether voltage exceeds the limit at each node according to the voltage monitored at each node in the distribution network substation includes:

[0018] If the node is powered by three-phase power, the node power supply voltage is compared with the three-phase power supply voltage limit range;

[0019] If the node power supply voltage is higher than the three-phase power supply voltage limit interval, it is determined that the node exceeds the upper limit;

[0020] If the node power supply voltage is lower than the three-phase power supply voltage limit interval, it is determined that the node has crossed the lower limit.

[0021] Preferably, determining the type of voltage over-limit problem in the distribution network area according to the position of the node where the voltage over-limit occurs in the topological structure of the distribution network area includes:

[0022] If the nodes where the voltage exceeds the limit are adjacent in the topological structure of the distribution network substation and belong to the same branch, the voltage exceeding the limit problem of the distribution network substation is determined to be the voltage exceeding the limit of the substation branch area;

[0023] If the nodes where the voltage exceeds the limit are not adjacent, it is determined that the voltage exceeding the limit problem in the distribution network substation is caused by the voltage exceeding the limit of a single user in the substation.

[0024] Preferably, according to the type of voltage over-limit problem in the distribution network area and the location of the node where the voltage over-limit occurs in the topological structure of the distribution network area, the location of the low-voltage flexible direct current voltage regulating device is determined, including:

[0025] If the voltage over-limit problem in the distribution network substation is the voltage over-limit in the substation branch area, the first node on the low-voltage side of the substation distribution transformer shall be determined as the host setting position of the low-voltage flexible direct current voltage regulation device, and the first node of the branch where the voltage over-limit occurs in the substation branch area shall be determined as the slave setting position of the low-voltage flexible direct current voltage regulation device.

[0026] Preferably, according to the type of voltage over-limit problem in the distribution network area and the location of the node where the voltage over-limit occurs in the topological structure of the distribution network area, the setting location of the low-voltage flexible direct current voltage regulating device is determined, and further includes:

[0027] If the voltage over-limit problem in the distribution network substation is caused by the voltage over-limit of a single user in the substation, the first node on the low-voltage side of the substation distribution transformer shall be determined as the host setting position of the low-voltage flexible direct current voltage regulation device, and the node where the voltage over-limit of a single user in the substation occurs shall be determined as the slave position of the low-voltage flexible direct current voltage regulation device.

[0028] Preferably, the method further comprises:

[0029] The host of the low-voltage flexible DC voltage regulator rectifies 380V or 220V AC into ±375V DC;

[0030] The slave machine of the low-voltage flexible DC voltage regulator inverts the ±375V DC power into 380V or 220V AC power.

[0031] Preferably, the method further comprises:

[0032] After rectification and inversion by the low-voltage flexible DC voltage regulation device, the distribution network substation data is collected again to determine whether there are still nodes with voltage exceeding the limit in the current distribution network substation.

[0033] Preferably, after determining whether there are still nodes with voltage exceeding the limit in the current distribution network area, the method further includes:

[0034] Output the governance assessment results based on the judgment results.

[0035] According to a second aspect of an embodiment of the present application, a voltage over-limit management device for a low-voltage area in a distribution network is provided, comprising:

[0036] Processor and memory;

[0037] The processor and the memory are connected via a communication bus:

[0038] Wherein, the processor is used to call and execute the program stored in the memory;

[0039] The memory is used to store a program, and the program is used at least to execute a method for controlling voltage over-limit in a low-voltage area of ​​a distribution network as described in any one of the above items.

[0040] The technical solution provided by the present application may include the following beneficial effects: the voltage over-limit control method of the low-voltage area of ​​the distribution network in the present application includes: collecting distribution network area data; the distribution network area data includes: the distribution network area topology structure and the monitoring voltage of each node in the distribution network area; determining whether the voltage of each node is over-limit according to the monitoring voltage of each node in the distribution network area; determining the type of voltage over-limit problem in the distribution network area according to the position of the node where the voltage is over-limit in the distribution network area topology structure; determining the setting position of the low-voltage flexible direct current voltage regulating device according to the type of voltage over-limit problem in the distribution network area and the position of the node where the voltage is over-limit in the distribution network area topology structure. In the present technical solution, the voltage of each node in the distribution network area is monitored in real time. When a node where the voltage is over-limit occurs, the setting position of the low-voltage flexible direct current voltage regulating device is immediately determined according to the type of voltage over-limit problem in the distribution network area and the position of the node where the voltage is over-limit in the distribution network area topology structure, so that the output voltage can be adjusted in real time, the load change can be quickly responded to, and the grid voltage can be kept within the set range. Furthermore, in this technical solution, the Internet of Things technology is used to realize data sharing and communication between each node device, and the data of all nodes in the distribution network area are centrally managed and analyzed, which can optimize the voltage regulation efficiency.

[0041] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0043] Figure 1 It is a flow chart of a method for over-limit voltage control in a low-voltage area of ​​a distribution network provided by an embodiment of the present application;

[0044] Figure 2 This is a schematic diagram of a topological structure of a distribution network area provided by an embodiment of the present application;

[0045] Figure 3 A schematic diagram of a distribution network area topology structure when the voltage of an area branch area exceeds the limit is provided by an embodiment of the present application;

[0046] Figure 4 A schematic diagram of a topological structure of a distribution network area provided by an embodiment of the present application when the voltage of a single user in the area exceeds the limit;

[0047] Figure 5 This is a schematic diagram of the installation position of a low-voltage flexible direct current voltage regulating device provided by an embodiment of the present application;

[0048] Figure 6This is a schematic diagram of the internal structure of a host of a low-voltage flexible direct current voltage regulating device provided by an embodiment of the present application;

[0049] Figure 7 This is a schematic diagram of the internal structure of a slave device of a low-voltage flexible direct current voltage regulation device provided by an embodiment of the present application;

[0050] Figure 8 It is a schematic diagram of an implementation example of a method for over-limit voltage control in a low-voltage area of ​​a distribution network provided by an embodiment of the present application;

[0051] Fig. 9 It is a structural schematic diagram of a voltage over-limit control device for a low-voltage area in a distribution network provided by an embodiment of the present application.

[0052] Reference numerals: processor-21; memory-22. DETAILED DESCRIPTION

[0053] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0054] Figure 1 This is a flow chart of a method for over-limit voltage control in a low-voltage area of ​​a distribution network provided by an embodiment of the present application, with reference to Figure 1 A method for over-limit voltage control in a low-voltage area of ​​a distribution network, comprising:

[0055] S11: Collect distribution network area data; the distribution network area data includes: distribution network area topology structure and monitoring voltage of each node in the distribution network area;

[0056] In actual practice, an intelligent monitoring system can be integrated to collect distribution network substation data in real time, and automatic adjustments can be made through the control unit to ensure rapid response during peak load moments.

[0057] The collected distribution network area data include: distribution network area topology structure and monitoring voltage of each node in the distribution network area. The monitoring voltage of each node is expressed as U ij , i represents phases A, B, and C, i=1 represents phase A, i=2 represents phase B, and i=3 represents phase C; j represents the node position, where j=1 represents the outlet position on the low-voltage side of the distribution transformer in the substation.

[0058] The topological structure of the distribution network area is as follows: Figure 2As shown, the line from node 1 to node 8, the line from node 2 to node 14, the line from node 5 to node 9, the line from node 11 to node 16, the line from node 12 to node 17, and the line from node 13 to node 18 are all branches.

[0059] S12: Determine whether the voltage at each node exceeds the limit according to the voltage monitored at each node in the distribution network substation;

[0060] Specifically, if the node is single-phase powered, the node power supply voltage is compared with the single-phase power supply voltage limit interval;

[0061] If the node power supply voltage is higher than the single-phase power supply voltage limit interval, it is determined that the node exceeds the upper limit;

[0062] If the node power supply voltage is lower than the single-phase power supply voltage limit interval, it is determined that the node has crossed the lower limit.

[0063] The normal voltage range of single-phase power supply is the rated voltage U N =220V[-10%,+7%], that is: U upper =235V, U lower =198V.

[0064] If the node is powered by three-phase power, the node power supply voltage is compared with the three-phase power supply voltage limit range;

[0065] If the node power supply voltage is higher than the three-phase power supply voltage limit interval, it is determined that the node exceeds the upper limit;

[0066] If the node power supply voltage is lower than the three-phase power supply voltage limit interval, it is determined that the node has crossed the lower limit.

[0067] The normal voltage range of single-phase power supply is the rated voltage U N =380V[-7%,+7%], that is: U upper =406V, U lower =353V.

[0068] In practice, the following formula is used to compare the voltage of each node with the voltage over-limit value to determine whether the voltage of each node of the phase exceeds the limit:

[0069]

[0070] S13: determining the type of voltage over-limit problem in the distribution network area according to the location of the node where the voltage over-limit occurs in the topological structure of the distribution network area;

[0071] Specifically, refer to Figure 3 , if the nodes where the voltage exceeds the limit are adjacent in the topological structure of the distribution network substation and belong to the same branch, then the voltage exceeding the limit problem of the distribution network substation is determined to be the voltage exceeding the limit of the substation branch area;

[0072] Figure 3 In the figure, the nodes where voltage exceeds the limit are 5, 6, 7, 8, 9, and 11, 12, 13, 14, 15, 16, 17, and 18. Nodes 5, 6, 7, 8, and 9 are adjacent to each other in the topology of the distribution network area and belong to the same branch. Nodes 11, 12, 13, 14, 15, 16, 17, and 18 are adjacent to each other in the topology of the distribution network area and belong to the same branch. Therefore, Figure 3 Two branch areas where voltage exceeds the limit are formed.

[0073] Reference Figure 4 If the nodes where the voltage exceeds the limit are not adjacent, it is determined that the voltage exceeding the limit problem in the distribution network substation is the voltage exceeding the limit of a single user in the substation.

[0074] Figure 4 In the example, the nodes where voltage exceeds the limit are 4 and 18, and nodes 4 and 18 are not adjacent to each other. Therefore, it is determined that the voltage exceeding the limit problem in the distribution network area is the voltage exceeding the limit of a single user at nodes 4 and 18.

[0075] S14: Determine the location of the low voltage flexible direct current voltage regulating device according to the type of voltage over-limit problem in the distribution network substation and the location of the node where the voltage over-limit occurs in the topological structure of the distribution network substation.

[0076] Specifically include:

[0077] Reference Figure 5 If the voltage over-limit problem in the distribution network substation is the voltage over-limit in the substation branch area, the first node on the low-voltage side of the substation distribution transformer shall be determined as the host setting position of the low-voltage flexible direct current voltage regulation device, and the first node of the branch where the voltage over-limit occurs in the substation branch area shall be determined as the slave setting position of the low-voltage flexible direct current voltage regulation device.

[0078] In order to solve the problem of over-limit voltage in the branch area of ​​the substation, the host of the low-voltage flexible direct current voltage regulating device (i.e. AC / DC module) is installed at the first node of the low-voltage side of the substation distribution transformer. Figure 5 Slave machines (i.e., DC / AC modules) of low-voltage flexible direct current voltage regulation devices are arranged at nodes 5 and 11 in the figure.

[0079] If the voltage over-limit problem in the distribution network substation is caused by the voltage over-limit of a single user in the substation, the first node on the low-voltage side of the substation distribution transformer shall be determined as the host setting position of the low-voltage flexible direct current voltage regulation device, and the node where the voltage over-limit of a single user in the substation occurs shall be determined as the slave position of the low-voltage flexible direct current voltage regulation device.

[0080] To solve the problem of voltage exceeding the limit for a single user in the substation, a host of low-voltage flexible direct current voltage regulating device (i.e. AC / DC module) is installed at the first node of the low-voltage side of the substation distribution transformer. Figure 4Nodes 4 and 18 in the figure are used to set a slave (i.e., a DC / AC module) of a low-voltage flexible direct current voltage regulating device.

[0081] The internal structure diagram of the host of the low-voltage flexible direct current voltage regulating device is shown in the figure below. Figure 6 , refer to the internal structure diagram of the slave unit of the low voltage flexible direct current voltage regulating device Figure 7 .

[0082] It should be noted that the method also includes:

[0083] The host of the low-voltage flexible DC voltage regulator rectifies 380V or 220V AC into ±375V DC;

[0084] The slave machine of the low-voltage flexible DC voltage regulator inverts the ±375V DC power into 380V or 220V AC power.

[0085] In practice, the main unit (AC / DC rectifier module) of the low-voltage flexible direct current voltage regulator at the first node of the distribution transformer in the substation rectifier converts the AC 380V or 220V into DC ±375V. Function: Increase the transmission voltage and reduce the transmission current under the same power condition, thereby reducing the loss on the line and increasing the transmission distance. On the low-voltage user side, the slave unit (DC / AC inverter module) is used to invert the DC ±375V into AC 380V or 220V to supply power to the user.

[0086] It should be noted that the method also includes:

[0087] After rectification and inversion by the low-voltage flexible DC voltage regulation device, the distribution network substation data is collected again to determine whether there are still nodes with voltage exceeding the limit in the current distribution network substation.

[0088] After determining whether there are still nodes with voltage exceeding the limit in the current distribution network area, the method further includes:

[0089] Output the governance assessment results based on the judgment results.

[0090] The specific evaluation method of the governance evaluation results is as follows: voltage after governance Within the limit and away from the rated voltage U N The closer the better, that is, the smaller ε is, the better the effect is.

[0091] It can be evaluated by the following formula: and

[0092] Figure 8 This is a schematic diagram of an implementation example of a method for over-limit voltage control in a low-voltage area of ​​a distribution network provided by an embodiment of the present application, with reference to Figure 8A certain area is powered by No. 1 distribution transformer with a capacity of 400kVA. The main line of the low-voltage 380 / 220V power supply overhead line adopts 300mm 2 Steel core aluminum stranded wire (model LGJ-300), line length is 600m, the end branch line diameter is also LGJ-300, the branch line length is 180m. Figure 8 The main line current is 600A, and the branch line load decreases by 200A every 200m. Before treatment, the voltage loss of the terminal branch line is 15.77%, that is, the voltage at node 12 is low.

[0093] The voltage loss of the terminal branch line is 15.77%, that is, when the line voltage at the head end of the substation is 380V, the voltage sent to the end of the line is 380*(1-15.77%)=320V. The lower the voltage limit, the lower the voltage.

[0094] A host flexible DC management device is set at the head end of the low-voltage side of the substation, and a slave is set at node 12. The voltage loss at the end of the branch line is 6.17%, that is, the voltage is 356.6V, which achieves an increase in the terminal voltage and solves the low voltage problem.

[0095] The method for managing voltage over-limit in the low-voltage area of ​​the distribution network in this embodiment includes: collecting data of the distribution network area; the distribution network area data includes: the topological structure of the distribution network area and the monitored voltage of each node in the distribution network area; determining whether the voltage of each node is over-limit according to the monitored voltage of each node in the distribution network area; determining the type of voltage over-limit problem in the distribution network area according to the position of the node where the voltage is over-limit in the topological structure of the distribution network area; determining the setting position of the low-voltage flexible direct current voltage regulating device according to the type of voltage over-limit problem in the distribution network area and the position of the node where the voltage is over-limit in the topological structure of the distribution network area. In this technical solution, the voltage of each node in the distribution network area is monitored in real time. When a node where the voltage is over-limit occurs, the setting position of the low-voltage flexible direct current voltage regulating device is immediately determined according to the type of voltage over-limit problem in the distribution network area and the position of the node where the voltage is over-limit in the topological structure of the distribution network area. The output voltage can be adjusted in real time, the load change can be quickly responded to, and the grid voltage can be kept within the set range. In addition, in this technical solution, the Internet of Things technology is used to achieve data sharing and communication between each node device, and the data of all nodes in the distribution network area are centrally managed and analyzed, which can optimize the voltage regulation efficiency, improve the quality of power supply, reduce the impact of voltage fluctuations on user power consumption, and provide more reliable power services. This technical solution also reduces overall operating costs by improving the operating efficiency of equipment and reducing failure rates, thereby reducing maintenance requirements.

[0096] In specific practice, smart capacitors and synchronous motors can also be configured to dynamically adjust reactive power output and enhance the system's resistance to voltage fluctuations.

[0097] In actual practice, flexible access solutions can also be designed to support the grid connection of renewable energy sources such as wind and solar power, and balance their fluctuations through flexible direct current technology.

[0098] This technical solution is applicable to urban and rural distribution networks, especially in areas with large load fluctuations, and can effectively improve the intelligence level of the power system and power supply reliability.

[0099] Embodiment 2

[0100] A voltage over-limit control device for low-voltage distribution network, referring to Fig. 9 ,include:

[0101] Processor 21 and memory 22;

[0102] The processor 21 and the memory 22 are connected via a communication bus:

[0103] The processor 21 is used to call and execute the program stored in the memory 22;

[0104] The memory 22 is used to store a program, and the program is used to execute at least one of the above methods for controlling voltage over-limit in a low-voltage area of ​​a distribution network.

[0105] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0106] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0107] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0108] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0109] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0110] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0111] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0112] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0113] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for controlling voltage over-limit in a low-voltage area of ​​a distribution network, characterized in that: include: Collect distribution network area data; The distribution network area data includes: the distribution network area topology structure and the monitoring voltage of each node in the distribution network area; Determine whether the voltage at each node exceeds the limit based on the voltage monitored at each node in the distribution network substation; According to the location of the node where the voltage exceeds the limit in the topological structure of the distribution network area, the type of voltage exceeding the limit problem in the distribution network area is determined; The location of the low-voltage flexible direct current voltage regulation device is determined based on the type of voltage over-limit problem in the distribution network substation and the location of the node where the voltage over-limit occurs in the topological structure of the distribution network substation.

2. The method according to claim 1, characterized in that Determine whether the voltage at each node exceeds the limit based on the voltage monitoring at each node in the distribution network substation, including: If the node is powered by a single-phase supply, the node supply voltage is compared with the single-phase supply voltage limit range; If the node power supply voltage is higher than the single-phase power supply voltage limit interval, it is determined that the node exceeds the upper limit; If the node power supply voltage is lower than the single-phase power supply voltage limit interval, it is determined that the node has crossed the lower limit.

3. The method according to claim 1, characterized in that Determine whether the voltage at each node exceeds the limit based on the voltage monitoring at each node in the distribution network substation, including: If the node is powered by three-phase power, the node power supply voltage is compared with the three-phase power supply voltage limit range; If the node power supply voltage is higher than the three-phase power supply voltage limit interval, it is determined that the node exceeds the upper limit; If the node power supply voltage is lower than the three-phase power supply voltage limit interval, it is determined that the node has crossed the lower limit.

4. The method according to claim 1, characterized in that: According to the location of the node where the voltage exceeds the limit in the topological structure of the distribution network area, the type of voltage exceeding the limit problem in the distribution network area is determined, including: If the nodes where the voltage exceeds the limit are adjacent in the topological structure of the distribution network substation and belong to the same branch, the voltage exceeding the limit problem of the distribution network substation is determined to be the voltage exceeding the limit of the substation branch area; If the nodes where the voltage exceeds the limit are not adjacent, it is determined that the voltage exceeding the limit problem in the distribution network substation is caused by the voltage exceeding the limit of a single user in the substation.

5. The method according to claim 4, characterized in that According to the type of voltage over-limit problem in the distribution network area and the location of the node where the voltage over-limit occurs in the topological structure of the distribution network area, the location of the low-voltage flexible direct current voltage regulation device is determined, including: If the voltage over-limit problem in the distribution network substation is the voltage over-limit in the substation branch area, the first node on the low-voltage side of the substation distribution transformer shall be determined as the host setting position of the low-voltage flexible direct current voltage regulation device, and the first node of the branch where the voltage over-limit occurs in the substation branch area shall be determined as the slave setting position of the low-voltage flexible direct current voltage regulation device.

6. The method according to claim 4, characterized in that According to the type of voltage over-limit problem in the distribution network area and the location of the node where the voltage over-limit occurs in the topological structure of the distribution network area, the location of the low-voltage flexible direct current voltage regulating device is determined, which also includes: If the voltage over-limit problem in the distribution network substation is caused by the voltage over-limit of a single user in the substation, the first node on the low-voltage side of the substation distribution transformer shall be determined as the host setting position of the low-voltage flexible direct current voltage regulation device, and the node where the voltage over-limit of a single user in the substation occurs shall be determined as the slave position of the low-voltage flexible direct current voltage regulation device.

7. The method according to any one of claims 5 or 6, characterized in that: The method further comprises: The host of the low-voltage flexible DC voltage regulator rectifies 380V or 220V AC into ±375V DC; The slave machine of the low-voltage flexible DC voltage regulator inverts the ±375V DC power into 380V or 220V AC power.

8. The method according to claim 7, characterized in that The method further comprises: After rectification and inversion by the low-voltage flexible DC voltage regulation device, the distribution network substation data is collected again to determine whether there are still nodes with voltage exceeding the limit in the current distribution network substation.

9. The method according to claim 8, characterized in that After determining whether there are still nodes with voltage exceeding the limit in the current distribution network area, the method further includes: Output the governance assessment results based on the judgment results.

10. A voltage over-limit control device for low-voltage areas in a distribution network, characterized in that: include: Processor and memory; The processor and the memory are connected via a communication bus: Wherein, the processor is used to call and execute the program stored in the memory; The memory is used to store a program, and the program is used at least to execute a method for controlling voltage over-limit in a low-voltage area of ​​a distribution network as described in any one of claims 1-9.

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