Photovoltaic DC access capacity configuration method and system based on low-voltage flexible interconnection

Abstract

The invention belongs to the field of power systems and automation thereof, and discloses a photovoltaic direct current access capacity configuration method and system based on low-voltage flexible interconnection, and the method comprises the steps: obtaining an input variable of a to-be-configured low-voltage flexible interconnection power distribution area; the photovoltaic direct current access capacity configuration model is input to a low-voltage flexible interconnection power distribution area photovoltaic direct current access capacity configuration model, and corresponding single area photovoltaic direct current access maximum up-sending capacity and low-voltage flexible interconnection system photovoltaic direct current access maximum up-sending total capacity when at least two areas are interconnected are output; the photovoltaic capacity configuration of the direct current access of the low-voltage flexible interconnection power distribution transformer area is realized according to the maximum transmission capacity of the photovoltaic direct current access of a single transformer area and the maximum total transmission capacity of the photovoltaic direct current access of the low-voltage flexible interconnection system. By adopting the method, the problem of load absorption of photovoltaic direct current access in the low-voltage flexible interconnection power distribution area is effectively solved, the overload operation condition of the power distribution line, the transformer and the low-voltage flexible interconnection device is prevented, and an accurate and efficient configuration mode is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems and automation thereof, and specifically relates to a photovoltaic direct current access capacity configuration method and system based on low-voltage flexible interconnection. Background Art

[0002] With the grid connection of large-scale distributed photovoltaic power generation, the power quality and operation control of existing distribution substations are affected; on the other hand, the inconsistent economic structure in the same region leads to large differences in substation loads. Therefore, the interconnection and mutual supply of multiple substations through flexible DC technology in the low-voltage substation system will be a new solution to change the current status of substation operations, improve the power supply level of substations in multiple dimensions, and realize advanced application functions of substations.

[0003] However, under the condition of low-voltage flexible interconnection area access to different loads, due to the maximum transmission capacity limitations of electrical equipment such as distribution lines, transformers and low-voltage flexible interconnection devices, a large number of distributed photovoltaic grid-connected access will result in the phenomenon that the load cannot be fully absorbed, resulting in overload operation of distribution lines, transformers or low-voltage flexible interconnection devices, further leading to the prominent problem of unsafe and stable operation of the power system. Therefore, it is extremely important to plan the capacity configuration of photovoltaic access under the DC microgrid of low-voltage flexible interconnection area. It is necessary to consider the load absorption problem of photovoltaic grid-connected access under different load access conditions, and at the same time ensure the normal operation of electrical equipment such as distribution lines, transformers and low-voltage flexible interconnection devices, so as to ensure the safe and stable operation of the power system.

[0004] It can be seen from this that the capacity configuration problem of photovoltaic DC access in low-voltage flexible interconnected distribution station areas under different load access conditions, as a large number of photovoltaic accesses appear, the load cannot be fully absorbed, resulting in overload operation of distribution lines, transformers or low-voltage flexible interconnected device outgoing lines, further leading to the prominent problem of unsafe and stable operation of the power system. To address the above problems, there is a lack of accurate and efficient capacity configuration methods. Summary of the invention

[0005] The purpose of the present invention is to provide a photovoltaic DC access capacity configuration method and system based on low-voltage flexible interconnection, so as to solve the capacity configuration problem of photovoltaic DC access in low-voltage flexible interconnection distribution station area under different load access conditions. With the access of a large number of photovoltaics, the load cannot be fully absorbed, which leads to the overload operation of the distribution lines, transformers or low-voltage flexible interconnection device outgoing lines, further leading to the outstanding problem of unsafe and stable operation of the power system, and the lack of accurate and efficient capacity configuration methods. Technical problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A photovoltaic direct current access capacity configuration method based on low voltage flexible interconnection, comprising: Obtain input variables of the low voltage flexible interconnection distribution substation area to be configured; The input variables of the low-voltage flexible interconnected distribution station to be configured are input into the pre-built photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution station, and the corresponding maximum upstream transmission capacity of the photovoltaic DC access of a single substation and the maximum total upstream transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnected system when at least two substations are interconnected are output, so as to realize the photovoltaic capacity configuration of the DC access of the low-voltage flexible interconnected distribution station according to the maximum upstream transmission capacity of the photovoltaic DC access of a single substation and the maximum total upstream transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnected distribution station.

[0007] Furthermore, the input variables of the low-voltage flexible interconnected distribution substation to be configured include the number of interconnected substations, the rated capacity of each transformer, the maximum photovoltaic transmission capacity of each transformer, the maximum capacity of the line, the rated capacity of each interconnected device, the minimum load of each substation for AC access during the day, and the minimum load of each substation for DC access during the day; The photovoltaic DC access capacity configuration model for the low-voltage flexible interconnected distribution station area is constructed based on the number of interconnected stations, the rated capacity of each transformer, the maximum photovoltaic transmission capacity of each transformer, the maximum capacity of the line, the rated capacity of each interconnected device, the minimum load of AC access in each station during the day, and the minimum load of DC access in each station during the day. It includes a single station photovoltaic DC access maximum transmission capacity configuration model corresponding to when at least two stations are interconnected and a low-voltage flexible interconnected system photovoltaic DC access maximum transmission total capacity configuration model.

[0008] Furthermore, the input variables of the low-voltage flexible interconnection distribution station area to be configured satisfy the following relationship:

[0009]

[0010]

[0011] In the formula, Indicates the rated capacity of each transformer; Indicates the maximum photovoltaic transmission capacity of each transformer; Indicates the maximum capacity of the line; Indicates the rated capacity of each interconnected device; Indicates the minimum load of AC access in each area during the day; Indicates the minimum load of DC access in each substation during the day.

[0012] Furthermore, when the load is not considered, The maximum transmission capacity configuration model of photovoltaic DC access in a single area is expressed as follows: when hour,

[0013] when hour,

[0014] In the formula, It represents the maximum transmission capacity of PV DC access in a single area when n areas are interconnected, where n represents the number of interconnected areas; The maximum total transmission capacity configuration model of photovoltaic DC access in the low-voltage flexible interconnection system is expressed as follows:

[0015] In the formula, It indicates the maximum total upstream transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system.

[0016] Furthermore, when considering the lowest AC load in the area during the day, among them: The maximum transmission capacity configuration model of photovoltaic DC access in a single area is expressed as follows: in, and ; when hour,

[0017] when hour,

[0018] In the formula, It represents the maximum transmission capacity of PV DC access in a single area when n areas are interconnected, where n represents the number of interconnected areas; The maximum total transmission capacity configuration model of photovoltaic DC access in the low-voltage flexible interconnection system is expressed as follows:

[0019] In the formula, It indicates the maximum total upstream transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system.

[0020] Furthermore, when the lowest AC load and the lowest DC load in the daytime are considered at the same time, among which: The maximum transmission capacity configuration model of photovoltaic DC access in a single area is expressed as follows: in, , ; when hour,

[0021] when hour,

[0022] In the formula, It represents the maximum transmission capacity of PV DC access in a single area when n areas are interconnected, where n represents the number of interconnected areas; The maximum total transmission capacity configuration model of photovoltaic DC access in the low-voltage flexible interconnection system is expressed as follows:

[0023] In the formula, It indicates the maximum total upstream transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system.

[0024] A photovoltaic DC access capacity configuration system based on low-voltage flexible interconnection, comprising: A data acquisition module, used to obtain input variables of the low voltage flexible interconnection distribution station area to be configured; The capacity configuration module is used to input the input variables of the low-voltage flexible interconnected distribution station area to be configured into the pre-built low-voltage flexible interconnected distribution station area photovoltaic DC access capacity configuration model, and output the corresponding single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnected system photovoltaic DC access maximum upstream transmission capacity when at least two substations are interconnected, so as to realize the photovoltaic capacity configuration of the DC access of the low-voltage flexible interconnected distribution station area according to the single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnected system photovoltaic DC access maximum upstream transmission capacity.

[0025] A device comprising: Memory for storing computer programs; A processor is used to implement the steps of the above-mentioned photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection when executing the computer program.

[0026] A computer-readable storage medium stores a computer program, which, when executed by a processor, is used to implement the steps of the above-mentioned photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection.

[0027] A computer program product includes a computer program, which, when executed by a processor, implements the steps of the above-mentioned photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection.

[0028] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection. The method can accurately output the maximum upstream transmission capacity of photovoltaic direct current access in a single substation and the maximum upstream transmission capacity of photovoltaic direct current access in a low-voltage flexible interconnection distribution station area corresponding to at least interconnection of substations by acquiring input variables of the substation area to be configured and inputting them into a pre-constructed photovoltaic direct current access capacity configuration model of the low-voltage flexible interconnection distribution station area when at least substation areas are interconnected; and then the capacity configuration is divided into the maximum upstream transmission capacity of photovoltaic direct current access in a single substation and the maximum upstream transmission capacity of photovoltaic direct current access in a low-voltage flexible interconnection distribution station area in detail, which effectively solves the load absorption problem of photovoltaic direct current access in low-voltage flexible interconnection distribution station areas, prevents overload operation conditions of distribution lines, transformers and low-voltage flexible interconnection devices, and a reasonable capacity configuration method improves the maximum upstream transmission capacity of photovoltaic direct current access, which not only improves the operation efficiency of the system, but also ensures the safe and stable operation of the system, and provides an accurate and efficient configuration method for the photovoltaic direct current access capacity configuration of low-voltage flexible interconnection distribution station areas.

[0029] Preferably, in the present invention, the construction method of the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution station area is refined, including the maximum upstream capacity configuration model of photovoltaic DC access of a single substation when n (n≥2) substations are interconnected and the maximum total upstream capacity configuration model of photovoltaic DC access of the low-voltage flexible interconnected system, and the models are refined respectively for the cases of not considering the load, considering the minimum AC load during the day, and considering both the minimum AC load during the day and the minimum DC load during the day in the substation. This refined construction method can more accurately reflect the operating conditions of the low-voltage flexible interconnected distribution station area under different scenarios, and provides a capacity configuration method for the low-voltage flexible interconnected distribution station area when no load is connected and when different loads are connected for the photovoltaic DC access capacity of the low-voltage flexible interconnected distribution station area, thereby improving the accuracy and reliability of the calculation.

[0030] Preferably, in the present invention, a method for obtaining input variables of a configuration model for the maximum upstream transmission capacity of photovoltaic DC access in a single substation when n (n≥2) substations are interconnected and a configuration model for the maximum total upstream transmission capacity of photovoltaic DC access in a low-voltage flexible interconnection system is provided, which provides a basis for accurately calculating the maximum upstream transmission capacity of photovoltaic DC access in a single substation when n (n≥2) substations are interconnected and the maximum total upstream transmission capacity of photovoltaic DC access in a low-voltage flexible interconnection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection provided by the present invention; Figure 2 A schematic diagram of the structure of a photovoltaic DC access capacity configuration system based on low-voltage flexible interconnection provided by the present invention; Figure 3A configuration diagram of the maximum transmission capacity of photovoltaic DC access when two substations are interconnected without considering the load provided in an embodiment of the present invention; Figure 4 A configuration diagram of the maximum transmission capacity of photovoltaic DC access under the interconnection of three substations without considering the load provided in an embodiment of the present invention; Figure 5 A configuration diagram of the maximum transmission capacity of photovoltaic DC access under the interconnection of four substations without considering the load provided in an embodiment of the present invention; Figure 6 A configuration diagram of the maximum transmission capacity of photovoltaic DC access under five interconnected areas without considering the load provided by an embodiment of the present invention; Figure 7 A configuration diagram of the maximum transmission capacity of photovoltaic DC access under the interconnection of six substations without considering the load provided in an embodiment of the present invention; Figure 8 A configuration diagram of the maximum transmission capacity of photovoltaic DC access under the interconnection of two substations when the minimum AC load of the substation during the day is considered, provided in an embodiment of the present invention; Fig. 9 A configuration diagram of the maximum transmission capacity of photovoltaic DC access under the interconnection of three substations provided in an embodiment of the present invention when the minimum AC load of the substation during the day is considered; Fig.10 A configuration diagram of the maximum transmission capacity of photovoltaic DC access under the interconnection of two substations provided by an embodiment of the present invention when the minimum AC load and the minimum DC load of the substation during the day are considered; Fig.11 The embodiment of the present invention provides a configuration diagram of the maximum transmission capacity of photovoltaic DC access under the interconnection of three substations when the minimum AC load and the minimum DC load of the substation during the day are considered at the same time. DETAILED DESCRIPTION

[0032] Example 1 like Figure 1 As shown, the present invention provides a photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection, comprising the following steps: S1: Obtain input variables of the low voltage flexible interconnection distribution station area to be configured; S2: Input the input variables of the low-voltage flexible interconnected distribution station to be configured into the pre-built photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution station, and output the corresponding maximum upstream photovoltaic DC access capacity of a single substation and the maximum total upstream photovoltaic DC access capacity of the low-voltage flexible interconnected system when at least two substations are interconnected, so as to realize the photovoltaic capacity configuration of the DC access of the low-voltage flexible interconnected distribution station according to the maximum upstream photovoltaic DC access capacity of a single substation and the maximum total upstream photovoltaic DC access capacity of the low-voltage flexible interconnected distribution station.

[0033] Specifically, the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution station area includes n ( ) When multiple substations are interconnected, the maximum transmission capacity configuration model of photovoltaic DC access in a single substation and the maximum total transmission capacity configuration model of photovoltaic DC access in the low-voltage flexible interconnection system; among which, the maximum photovoltaic transmission capacity of the substation transformer is calculated at 80%; The input variables of the low-voltage flexible interconnected distribution substation to be configured include the number of interconnected substations, the rated capacity of each transformer, the maximum photovoltaic transmission capacity of each transformer, the maximum capacity of the line, the rated capacity of each interconnected device, the minimum load of each substation connected to AC during the day, and the minimum load of each substation connected to DC during the day; The photovoltaic DC access capacity configuration model for the low-voltage flexible interconnected distribution station area is constructed based on the number of interconnected stations, the rated capacity of each transformer, the maximum photovoltaic transmission capacity of each transformer, the maximum capacity of the line, the rated capacity of each interconnected device, the minimum load of AC access in each station during the day, and the minimum load of DC access in each station during the day. It includes a single station photovoltaic DC access maximum transmission capacity configuration model corresponding to when at least two stations are interconnected and a low-voltage flexible interconnected system photovoltaic DC access maximum transmission total capacity configuration model.

[0034] The input variables of the low-voltage flexible interconnection distribution station area to be configured satisfy the following relationship:

[0035]

[0036]

[0037] In the formula, Indicates the rated capacity of each transformer; Indicates the maximum photovoltaic transmission capacity of each transformer; Indicates the maximum capacity of the line; Indicates the rated capacity of each interconnected device; Indicates the minimum load of AC access in each area during the day; Indicates the minimum load of DC access in each substation during the day.

[0038] in, The maximum transmission capacity configuration model for photovoltaic DC access in a single substation is divided into three construction methods: The first method is to build the maximum transmission capacity of photovoltaic DC access in a single substation without considering the load: when hour, ; in, The maximum transmission capacity of photovoltaic DC access in a single area when n areas are interconnected. The rated capacity of each transformer in each substation; when hour, ; in, is the maximum capacity of the line; The second method is to build the maximum transmission capacity of photovoltaic DC access in a single area when the area has the lowest AC load during the day: in, and , The minimum load of AC access in each area during the day. is the rated capacity of each interconnected device; when hour, ; when hour, ; The third method is to build the maximum transmission capacity of photovoltaic DC access in a single area by considering both the lowest AC load and the lowest DC load in the area during the day: in, , ; The minimum load of DC access in each substation during the day; when hour, ; when hour, ; The configuration model of the maximum total transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system is divided into three construction methods: The first method is to build the maximum total transmission capacity of photovoltaic DC access in low-voltage flexible interconnection system without considering the load: , The maximum total transmission capacity of photovoltaic DC access for low-voltage flexible interconnection system; The second method is to consider the construction method of the maximum total transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system when the lowest AC load in the area is during the day: ; The third method: Considering both the lowest AC load and the lowest DC load in the daytime in the substation area, the maximum total transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnection system is constructed: .

[0039] like Figure 2As shown, the present invention also provides a photovoltaic DC access capacity configuration system based on low-voltage flexible interconnection, including: a data acquisition module, used to obtain the input variables of the low-voltage flexible interconnection distribution station to be configured; a capacity configuration module, used to input the input variables of the low-voltage flexible interconnection distribution station to be configured into a pre-built low-voltage flexible interconnection distribution station area photovoltaic DC access capacity configuration model, and output the corresponding single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnection system photovoltaic DC access maximum upstream transmission capacity when at least two substations are interconnected, so as to realize the photovoltaic capacity configuration of DC access in the low-voltage flexible interconnection distribution station area according to the single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnection system photovoltaic DC access maximum upstream transmission capacity.

[0040] The present invention also provides a device, comprising: a memory for storing a computer program; and a processor for implementing the steps of the photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection when executing the computer program.

[0041] When the processor executes the computer program, the above-mentioned steps of configuring the photovoltaic DC access capacity based on low-voltage flexible interconnection are implemented, for example: obtaining the input variables of the distribution station area of ​​the low-voltage flexible interconnection to be configured; inputting the input variables of the distribution station area of ​​the low-voltage flexible interconnection to be configured into a pre-built photovoltaic DC access capacity configuration model of the low-voltage flexible interconnection distribution station area, and outputting the corresponding maximum upstream transmission capacity of the photovoltaic DC access of a single substation and the maximum total upstream transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnection system when at least two substations are interconnected, so as to implement the photovoltaic capacity configuration of the DC access of the low-voltage flexible interconnection distribution station area according to the maximum upstream transmission capacity of the photovoltaic DC access of the single substation and the maximum total upstream transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnection system.

[0042] Alternatively, the processor implements the functions of each module in the above system when executing the computer program, for example: a data acquisition module, used to obtain the input variables of the low-voltage flexible interconnected distribution station to be configured; a capacity configuration module, used to input the input variables of the low-voltage flexible interconnected distribution station to be configured into a pre-built low-voltage flexible interconnected distribution station photovoltaic DC access capacity configuration model, and output the corresponding single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnected system photovoltaic DC access maximum upstream transmission capacity when at least two substations are interconnected, so as to realize the photovoltaic capacity configuration of DC access in the low-voltage flexible interconnected distribution station according to the single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnected system photovoltaic DC access maximum upstream transmission capacity.

[0043] Exemplarily, the computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments that can complete preset functions, and the instruction segments are used to describe the execution process of the computer program in the photovoltaic DC access capacity configuration device based on low-voltage flexible interconnection. For example, the computer program can be divided into a data acquisition module and a capacity configuration module; the specific functions of each module are as follows: a data acquisition module, which is used to obtain the input variables of the low-voltage flexible interconnection distribution station area to be configured; a capacity configuration module, which is used to input the input variables of the low-voltage flexible interconnection distribution station area to be configured into a pre-built low-voltage flexible interconnection distribution station area photovoltaic DC access capacity configuration model, and output the corresponding single station area photovoltaic DC access maximum transmission capacity and the low-voltage flexible interconnection system photovoltaic DC access maximum transmission total capacity when at least two stations are interconnected, so as to realize the photovoltaic capacity configuration of the low-voltage flexible interconnection distribution station area DC access according to the single station area photovoltaic DC access maximum transmission capacity and the low-voltage flexible interconnection system photovoltaic DC access maximum transmission total capacity.

[0044] The photovoltaic DC access capacity configuration device based on low-voltage flexible interconnection can be a computing device such as a desktop computer, a notebook, a PDA, and a cloud server. The photovoltaic DC access capacity configuration device based on low-voltage flexible interconnection may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that the above is an example of a photovoltaic DC access capacity configuration device based on low-voltage flexible interconnection, and does not constitute a limitation on the photovoltaic DC access capacity configuration device based on low-voltage flexible interconnection, and may include more components than the above, or a combination of certain components, or different components. For example, the photovoltaic DC access capacity configuration device based on low-voltage flexible interconnection may also include input and output devices, network access devices, buses, etc.

[0045] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The processor is the control center of the photovoltaic DC access capacity configuration based on low-voltage flexible interconnection, and uses various interfaces and lines to connect various parts of the entire photovoltaic DC access capacity configuration device based on low-voltage flexible interconnection.

[0046] The memory can be used to store the computer program and / or module, and the processor implements various functions of the photovoltaic direct current access capacity configuration device based on low-voltage flexible interconnection by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory.

[0047] The memory may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0048] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection are implemented.

[0049] If the module / unit integrated in the photovoltaic direct current access capacity configuration system based on low-voltage flexible interconnection is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0050] Based on such understanding, the present invention implements all or part of the processes in the above-mentioned photovoltaic DC access capacity configuration method based on low-voltage flexible interconnection, and can also be completed by instructing related hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, the steps of the above-mentioned photovoltaic DC access capacity configuration method based on low-voltage flexible interconnection can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or preset intermediate form, etc.

[0051] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0052] It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electrical carrier signals and telecommunication signals.

[0053] The present invention will be further described below in conjunction with the embodiments and drawings: Example 2 This embodiment also provides a method for configuring photovoltaic DC access capacity based on low-voltage flexible interconnection, which specifically includes: The first step is to obtain the input variables of the low-voltage flexible interconnected distribution area to be configured, where the input variables include the number of interconnected areas n, the rated capacity of each transformer The maximum photovoltaic transmission capacity of each transformer is set to 0.8 , maximum line capacity , the rated capacity of each interconnected device , the minimum load of AC access in each area during the day , and the input value must satisfy and , the minimum load of DC access in each area during the day , and the input value must satisfy .

[0054] The second step is to input the input variables of the low-voltage flexible interconnected distribution area to be configured into the pre-built photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area, and output n ( ) When multiple substations are interconnected, the maximum transmission capacity of PV DC access in a single substation Maximum total transmission capacity of photovoltaic DC access in low-voltage flexible interconnection system , according to n ( ) When individual substations are interconnected, the maximum upstream transmission capacity of photovoltaic DC access in a single substation and the maximum total upstream transmission capacity of photovoltaic DC access in the low-voltage flexible interconnected distribution station system are used to realize the photovoltaic capacity configuration of DC access in the low-voltage flexible interconnected distribution station area.

[0055] For the PV capacity configuration of DC access in low-voltage flexible interconnected distribution areas, the specific calculation method is further explained below with reference to the attached figure: In this embodiment, the photovoltaic capacity configuration method for DC access in low-voltage flexible interconnected distribution station area includes n ( ) The calculation method of the maximum transmission capacity of photovoltaic DC access in a single area when multiple areas are interconnected and the calculation method of the maximum total transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system are as follows: n( ) The calculation method for the maximum upstream transmission capacity of photovoltaic DC access in a single substation when multiple substations are interconnected includes: the calculation method for the maximum upstream transmission capacity of photovoltaic DC access in a single substation when the load is not considered, the calculation method for the maximum upstream transmission capacity of photovoltaic DC access in a single substation when the minimum AC load of the substation during the day is considered, and the calculation method for the maximum upstream transmission capacity of photovoltaic DC access in a single substation when both the minimum AC load of the substation during the day and the minimum DC load of the substation during the day are considered.

[0056] n( ) The calculation method for the maximum total upstream capacity of photovoltaic DC access in the low-voltage flexible interconnected system when the substations are interconnected, including: the calculation method for the maximum total upstream capacity of photovoltaic DC access in the low-voltage flexible interconnected system without considering the load, the calculation method for the maximum total upstream capacity of photovoltaic DC access in the low-voltage flexible interconnected system when the minimum AC load in the substation during the day is considered, and the calculation method for the maximum total upstream capacity of photovoltaic DC access in the low-voltage flexible interconnected system when the minimum AC load in the substation during the day and the minimum DC load in the substation during the day are considered at the same time.

[0057] First, n ( ) Calculation method for the maximum transmission capacity of photovoltaic DC access in a single area when multiple areas are interconnected: (1) Calculation method for the maximum transmission capacity of photovoltaic DC access in a single grid area without considering the load: Take the interconnection of two substations (i.e., when n=2) as an example. Figure 3 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines , the maximum transmission capacity of photovoltaic DC access in a single area when the load is not taken into account =1.6 ; Take the interconnection of three substations (i.e., when n=3) as an example. Figure 4 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines , the maximum transmission capacity of photovoltaic DC access in a single area when the load is not taken into account =2.4 ; Take the interconnection of four substations (i.e., when n=4) as an example. Figure 5 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines ,set up , the maximum transmission capacity of photovoltaic DC access in a single area when the load is not taken into account 2.6 ; Take five areas interconnected (i.e. n=5) as an example. Figure 6 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines ,set up , the maximum transmission capacity of photovoltaic DC access in a single area when the load is not taken into account ; Take six areas interconnected (i.e. n=6) as an example. Figure 7 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines ,set up , the maximum transmission capacity of photovoltaic DC access in a single area when the load is not taken into account ; and so on; (2) Calculation method for the maximum transmission capacity of photovoltaic DC access in a single substation considering the lowest AC load in the substation during the day: Take the interconnection of two substations (i.e., when n=2) as an example. Figure 8 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines that n=2, and then the output is the maximum transmission capacity of photovoltaic DC access in a single area when the area has the lowest AC load during the day. ; Take the interconnection of three substations (i.e., when n=3) as an example. Fig. 9As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines , then the output considers the maximum transmission capacity of photovoltaic DC access in a single substation when the substation has the lowest AC load during the day ; and so on; (3) Calculation method for the maximum uplink capacity of photovoltaic DC access in a single substation when considering both the minimum AC load and the minimum DC load during the day: Take the interconnection of two substations (i.e., when n=2) as an example. Fig.10 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines that n=2, and then the output is the maximum transmission capacity of photovoltaic DC access in a single area when both the minimum AC load and the minimum DC load of the area during the day are considered. ; Take the interconnection of three substations (i.e., when n=3) as an example. Fig.11 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution area. The photovoltaic DC access capacity configuration system of the low-voltage flexible interconnected distribution area determines , then the output is the maximum transmission capacity of photovoltaic DC access in a single substation when the minimum AC load and the minimum DC load of the substation during the day are considered simultaneously. ; and so on; Second, n ( ) Calculation method for the maximum total transmission capacity of photovoltaic DC access in low-voltage flexible interconnection system when interconnecting multiple substations: (1) Calculation method for the maximum total transmission capacity of photovoltaic DC access in low-voltage flexible interconnection system without considering load: Take five areas interconnected (i.e. n=5) as an example. Figure 6 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnection distribution area, and the maximum total transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnection system without considering the load is output. ; and so on; (2) Calculation method for the maximum total transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system when the lowest AC load in the area during the day is considered: Take five interconnected areas (i.e. n=3) as an example. Fig. 9 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution station area, and the output is the maximum total transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnected system when the area has the lowest AC load during the day. ; and so on; (3) Calculation method for the maximum total transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system when considering both the lowest AC load and the lowest DC load in the daytime: Take the interconnection of three substations (i.e., when n=3) as an example. Fig.11 As shown in the figure, the input variables are input into the photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution station area, and the output is the maximum total transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnected system when the lowest AC load and the lowest DC load in the daytime are considered. ; and so on.

[0058] In summary, the present invention provides a photovoltaic DC access capacity configuration method based on low-voltage flexible interconnection, which has the following advantages over the existing capacity configuration method: First, accurate and efficient configuration: This method constructs a photovoltaic DC access capacity configuration model for low-voltage flexible interconnected distribution station areas, which can accurately calculate and output the maximum photovoltaic DC access transmission capacity of a single area and the entire low-voltage flexible interconnected system under different area interconnection conditions; this precise calculation method effectively solves the problems of inability to fully absorb loads caused by a large number of photovoltaic accesses, overload operation of electrical equipment, and unsafe and stable operation of the power system.

[0059] Second, comprehensive consideration of variables: When constructing the model, this method fully considers various factors that affect the photovoltaic access capacity, including the number of interconnected areas, the rated capacity of the transformer and the maximum photovoltaic transmission capacity, the maximum capacity of the line, the rated capacity of the interconnected device, and the minimum load of the AC and DC access in the area during the day. This comprehensive consideration of variables makes the configuration results more in line with the actual situation and improves the accuracy and practicality of the configuration.

[0060] Third, flexible adaptation to different working conditions: This method can be flexibly adjusted according to different load access conditions. Whether it is considering only the transformer and line capacity, or considering the minimum AC load and DC load in the substation during the day, it can provide a corresponding configuration model; this flexibility makes this method widely applicable to various low-voltage flexible interconnected distribution substations, improving its applicability and promotion value.

[0061] Fourth, ensure safe and stable operation of the system: By accurately calculating the photovoltaic access capacity, this method ensures that electrical equipment such as distribution lines, transformers and low-voltage flexible interconnection devices operate within the normal capacity range, thereby effectively avoiding the prominent problem of unsafe and stable operation of the power system due to overload operation, which is of great significance for ensuring the long-term stable operation of the power system.

[0062] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A photovoltaic DC access capacity configuration method based on low-voltage flexible interconnection, characterized in that: include: Obtain input variables of the low voltage flexible interconnection distribution substation area to be configured; The input variables of the low-voltage flexible interconnected distribution station to be configured are input into the pre-built photovoltaic DC access capacity configuration model of the low-voltage flexible interconnected distribution station, and the corresponding maximum upstream transmission capacity of the photovoltaic DC access of a single substation and the maximum total upstream transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnected system when at least two substations are interconnected are output, so as to realize the photovoltaic capacity configuration of the DC access of the low-voltage flexible interconnected distribution station according to the maximum upstream transmission capacity of the photovoltaic DC access of a single substation and the maximum total upstream transmission capacity of the photovoltaic DC access of the low-voltage flexible interconnected distribution station.

2. The photovoltaic direct current access capacity configuration method based on low voltage flexible interconnection according to claim 1 is characterized in that: The input variables of the low-voltage flexible interconnected distribution substation to be configured include the number of interconnected substations, the rated capacity of each transformer, the maximum photovoltaic transmission capacity of each transformer, the maximum capacity of the line, the rated capacity of each interconnected device, the minimum load of each substation connected to AC during the day, and the minimum load of each substation connected to DC during the day; The photovoltaic DC access capacity configuration model for the low-voltage flexible interconnected distribution station area is constructed based on the number of interconnected stations, the rated capacity of each transformer, the maximum photovoltaic transmission capacity of each transformer, the maximum capacity of the line, the rated capacity of each interconnected device, the minimum load of AC access in each station during the day, and the minimum load of DC access in each station during the day. It includes a single station photovoltaic DC access maximum transmission capacity configuration model corresponding to when at least two stations are interconnected and a low-voltage flexible interconnected system photovoltaic DC access maximum transmission total capacity configuration model.

3. The photovoltaic direct current access capacity configuration method based on low voltage flexible interconnection according to claim 2 is characterized in that: The input variables of the low-voltage flexible interconnection distribution station area to be configured satisfy the following relationship: In the formula, Indicates the rated capacity of each transformer; Indicates the maximum photovoltaic transmission capacity of each transformer; Indicates the maximum capacity of the line; Indicates the rated capacity of each interconnected device; Indicates the minimum load of AC access in each area during the day; Indicates the minimum load of DC access in each substation during the day.

4. The photovoltaic direct current access capacity configuration method based on low voltage flexible interconnection according to claim 3 is characterized in that: When the load is not considered, the following: The maximum transmission capacity configuration model of photovoltaic DC access in a single area is expressed as follows: when hour, when hour, In the formula, It represents the maximum transmission capacity of PV DC access in a single area when n areas are interconnected, where n represents the number of interconnected areas; The maximum total transmission capacity configuration model of photovoltaic DC access in the low-voltage flexible interconnection system is expressed as follows: In the formula, It indicates the maximum total upstream transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system.

5. The photovoltaic direct current access capacity configuration method based on low voltage flexible interconnection according to claim 3 is characterized in that: When considering the lowest AC load in the area during the day, among which: The maximum transmission capacity configuration model of photovoltaic DC access in a single area is expressed as follows: in, and ; when hour, when hour, In the formula, It represents the maximum transmission capacity of PV DC access in a single area when n areas are interconnected, where n represents the number of interconnected areas; The maximum total transmission capacity configuration model of photovoltaic DC access in the low-voltage flexible interconnection system is expressed as follows: In the formula, It indicates the maximum total upstream transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system.

6. The photovoltaic direct current access capacity configuration method based on low voltage flexible interconnection according to claim 3 is characterized in that: When considering both the lowest AC load and the lowest DC load during the daytime in the substation area, among which: The maximum transmission capacity configuration model of photovoltaic DC access in a single area is expressed as follows: in, , ; when hour, when hour, In the formula, It represents the maximum transmission capacity of PV DC access in a single area when n areas are interconnected, where n represents the number of interconnected areas; The maximum total transmission capacity configuration model of photovoltaic DC access in the low-voltage flexible interconnection system is expressed as follows: In the formula, It indicates the maximum total upstream transmission capacity of photovoltaic DC access in the low-voltage flexible interconnection system.

7. A photovoltaic DC access capacity configuration system based on low-voltage flexible interconnection, characterized in that: include: A data acquisition module, used to obtain input variables of the low voltage flexible interconnection distribution station area to be configured; The capacity configuration module is used to input the input variables of the low-voltage flexible interconnected distribution station area to be configured into the pre-built low-voltage flexible interconnected distribution station area photovoltaic DC access capacity configuration model, and output the corresponding single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnected system photovoltaic DC access maximum upstream transmission capacity when at least two substations are interconnected, so as to realize the photovoltaic capacity configuration of the DC access of the low-voltage flexible interconnected distribution station area according to the single substation photovoltaic DC access maximum upstream transmission capacity and the low-voltage flexible interconnected system photovoltaic DC access maximum upstream transmission capacity.

8. A device, characterized in that include: Memory for storing computer programs; A processor is used to implement the steps of the method for configuring photovoltaic direct current access capacity based on low-voltage flexible interconnection as described in any one of claims 1 to 6 when executing the computer program.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it is used to implement the steps of the photovoltaic direct current access capacity configuration method based on low-voltage flexible interconnection as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for configuring photovoltaic direct current access capacity based on low-voltage flexible interconnection as described in any one of claims 1 to 6 are implemented.

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