A three-phase short-circuit fault current calculation method suitable for a distributed new energy access ring-type power distribution network

Abstract

The application discloses a three-phase short-circuit fault current calculation method suitable for a distributed new energy access ring-type power distribution network, and comprises the following steps: determining a bus node connected with a tie switch; identifying whether the bus node is connected with new energy or a synchronous power supply; merging bus nodes not connected with new energy or a synchronous power supply into bus nodes connected with new energy or a synchronous power supply; generating a correction matrix based on bus node information after the merging; and calculating three-phase short-circuit fault currents based on the correction matrix.

Description

Technical Field

[0001] This invention relates to the field of relay protection technology for new energy power systems, and more specifically, to a method for calculating three-phase short-circuit fault current applicable to distributed new energy access ring distribution networks. Background Technology

[0002] Traditional distribution networks typically employ closed-loop design and open-loop operation, with a predominantly radial network topology. For radial distribution networks, mature short-circuit fault current calculation methods exist, primarily involving Thevenin equivalents of the power sources and solving for the fault current distribution of each feeder in a single-source radial network based on the nodal admittance matrix. However, in actual operation, to improve power supply reliability and load transfer capacity, distribution network interconnection switches may be put into operation, forming a ring distribution network with single or multiple ring structures between multiple feeders. In this case, the fault current will flow to the fault point through multiple power supply paths, resulting in significant circulating current effects and multi-source coupling effects within the network, making traditional radial distribution network short-circuit current calculation methods difficult to apply directly. Furthermore, with the integration of distributed renewable energy sources, the fault current is affected by control strategies, current-limiting characteristics, and grid connection location, leading to complex mutual coupling between different renewable energy sources, further increasing the complexity of fault current analysis in ring distribution networks.

[0003] Therefore, there is an urgent need to propose a method for calculating the three-phase short-circuit fault current in distributed renewable energy access ring distribution networks. This method should fully consider the ring topology and the fault response characteristics of renewable energy sources, enabling rapid and accurate calculation of the fault current and providing technical support for distribution network relay protection settings, fault analysis, and operation control. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for calculating three-phase short-circuit fault current applicable to distributed renewable energy access ring distribution networks.

[0005] According to one aspect of the present invention, a method for calculating three-phase short-circuit fault current applicable to distributed renewable energy access in a ring distribution network is provided, comprising: Determine the busbar nodes connected to the tie switch; Identify whether the bus node is connected to a new energy source or synchronous power source; The bus nodes that are not connected to new energy sources or synchronous power sources will be merged into the bus nodes that are connected to new energy sources or synchronous power sources. Based on the merged bus node information, a correction matrix is ​​generated; The three-phase short-circuit fault current is calculated based on the correction matrix.

[0006] Optionally, the merging of bus nodes specifically involves: deleting the rows and columns of the merged bus nodes from the information matrix of the bus nodes, and adding the impedance of the merged bus nodes as parallel branches to the rows and columns of the merged bus nodes.

[0007] Optionally, the correction matrix Y add The expression is: In the formula, Z f1-B The impedance of the line from the fault point to bus B; Z BC The impedance between the BC busbars is denoted as .

[0008] Optionally, based on the correction matrix, the three-phase short-circuit fault current is calculated, including: Based on the correction matrix, construct the node voltage equation; Based on the nodal equations, a set of nonlinear equations for the voltage at each node and the fault current of the photovoltaic output are obtained; Based on the actual voltage of each node and the nonlinear equations, the three-phase short-circuit fault current of each line is obtained.

[0009] Optionally, the expression for the nodal voltage equation is: in, Y add For the correction matrix, Y Let be the nodal admittance matrix, which is symmetric and positive definite. Among them, node voltage U for: I s Injected current for the system's equivalent power source: In the formula, E s , Z s These are the internal potential and internal impedance of the synchronous power supply.

[0010] I PV.f The fault current output by the photovoltaic system is related to the node voltage as follows: In the formula, U C , U EThe voltage at the grid connection point of bus C and bus E; f ( ) is the coupling function between the fault current and the grid connection point voltage under the fault ride-through standard requirements of distributed power sources.

[0011] According to another aspect of the present invention, a three-phase short-circuit fault current calculation device suitable for distributed renewable energy access in a ring distribution network is provided, comprising: The determination module is used to determine the bus node connected to the tie switch; The identification module is used to identify whether the bus node is connected to a new energy source or synchronous power source; The merging module is used to merge bus nodes that are not connected to new energy sources or synchronous power sources into bus nodes that are connected to new energy sources or synchronous power sources. The generation module is used to generate a correction matrix based on the merged bus node information; The calculation module is used to calculate the three-phase short-circuit fault current based on the correction matrix.

[0012] According to another aspect of the present invention, a computer-readable storage medium is provided, the storage medium storing a computer program for performing the methods described in any of the above aspects of the present invention.

[0013] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method described in any of the preceding aspects of the present invention.

[0014] Therefore, this invention proposes a method for calculating three-phase short-circuit fault current applicable to distributed renewable energy access in ring distribution networks. This method solves the problem that conventional short-circuit current calculation methods for radial power grids are difficult to apply to distributed power generation access in ring distribution networks, and provides a fault current calculation method for single-ring or multi-ring distribution networks formed after the tie switch is closed in actual engineering projects. Attached Figure Description

[0015] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures: Figure 1 This is a flowchart illustrating an exemplary embodiment of the present invention for calculating the three-phase short-circuit fault current in a ring distribution network for distributed renewable energy access. Figure 2 This is a typical two-feeder radial power distribution system structure provided by an exemplary embodiment of the present invention; Figure 3 This is a schematic diagram of a ring distribution network formed after the BE bus tie switch is closed, according to an exemplary embodiment of the present invention. Figure 4 This is a fault equivalent circuit diagram of a single-loop distribution network under a three-phase short-circuit fault provided by an exemplary embodiment of the present invention; Figure 5 This is a schematic diagram of the process for generating the modified impedance provided in an exemplary embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a three-phase short-circuit fault current calculation device for distributed new energy access ring distribution network provided by an exemplary embodiment of the present invention; Figure 7 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0016] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0017] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0018] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0019] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0020] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0021] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0022] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0023] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0024] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0025] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0027] The embodiments of this invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate together with a wide range of other general-purpose or special-purpose computing system environments or configurations. Well-known examples of terminal devices, computing systems, environments, and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, and servers include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments including any of the above systems, etc.

[0028] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system executable instructions (such as program modules) executed by a computer system. Typically, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in distributed cloud computing environments, where tasks are executed by remote processing devices linked through communication networks. In distributed cloud computing environments, program modules can reside on local or remote computing system storage media, including storage devices.

[0029] Exemplary methods Figure 1 This is a flowchart illustrating a method for calculating three-phase short-circuit fault current in a distributed renewable energy network with access to a ring distribution network, provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as… Figure 1 As shown, the three-phase short-circuit fault current calculation method 100 applicable to distributed renewable energy access in a ring distribution network includes the following steps: Step 101: Determine the bus node connected to the tie switch; Step 102: Identify whether the bus node is connected to a new energy source or synchronous power source; Step 103: Merge bus nodes that are not connected to new energy sources or synchronous power sources into bus nodes that are connected to new energy sources or synchronous power sources. Step 104: Generate a correction matrix based on the merged bus node information; Step 105: Calculate the three-phase short-circuit fault current based on the correction matrix.

[0030] Specifically, for distributed renewable energy access ring distribution networks, this invention proposes a method for calculating three-phase short-circuit fault current applicable to distributed renewable energy access ring distribution networks, providing a fault current calculation method for single-ring or multi-ring distribution networks formed by radial distribution networks after the tie switch is closed in actual engineering.

[0031] Explanation of the principle: After distributed photovoltaic (PV) power is connected to the distribution network, the magnitude and direction of the fault current change. When the tie switch is closed, a ring distribution network is formed. At this time, the fault current will flow to the fault point through multiple power supply paths, resulting in significant circulating current effects and multi-source coupling effects in the network. Existing fault current calculation methods for radial power grids become ineffective. Therefore, this invention proposes a three-phase short-circuit fault current calculation method suitable for distributed renewable energy connected to a ring distribution network.

[0032] Figure 2 This is a structural diagram of a typical two-feeder distribution system. Nodes C and E are connected to distributed photovoltaic systems PV1 and PV2, respectively. CB1~CB5 represent the circuit breakers on each line. After the tie switch between the BE busbars is closed, when a three-phase short-circuit fault occurs (taking f1 as an example), the single-ring distribution network will look like this. Figure 3 As shown. Figure 3 Under the fault conditions shown, the equivalent circuit after the fault is as follows: Figure 4 As shown.

[0033] according to Figure 4 At the moment of closing the circuit, the original 7th-order nodal admittance matrix of the radial power grid will instantly decrease to a 6th-order nodal admittance matrix due to the merging of the BE nodes. To maintain the original short-circuit current calculation form of the radial power grid, an additional correction matrix is ​​required. Y add The correction process is as follows: Figure 5 As shown, it can be represented as: (1) Therefore, the node voltage equation can be expressed as: (2) YLet be the nodal admittance matrix, which is symmetric and positive definite. (3) The node voltage equation U is: (4) I s The injected current is the equivalent power supply current of the system, in this example only node A is not zero: (5) I PV.f The fault current of the photovoltaic output is related to the node voltage as follows: (6) By combining equations (1) to (6), we can obtain a set of nonlinear equations related to the voltage of each node and the fault current of the photovoltaic output. Solving these equations will give us the voltage of each node and the fault current of the photovoltaic output. Based on the voltage of each node, we can obtain the current of each line.

[0034] Calculation process: In summary, after distributed generation is connected to a radial power grid, and the tie switch is closed, causing the distribution network to evolve into a ring distribution network, the calculation process for short-circuit current under a three-phase fault is as follows: Step 1: Determine the bus nodes connected to the tie switch, j and k; Step 2: Identify whether new energy sources or synchronous power sources are connected at bus J and bus K; Step 3: Prioritize merging unconnected power supplies to connected power supply nodes. For example, if bus j has no power supply but bus k has power supply, then merge bus j to bus k, ultimately retaining only bus k. Step 4: Generate the correction matrix, which includes: the original self-impedance and mutual impedance of bus j are reversed, and the mutual impedance and self-impedance are transferred from node j to node k respectively; Therefore, after distributed photovoltaic (PV) power is connected to the distribution network, the magnitude and direction of the fault current will change, forming a ring distribution network when the tie switch is closed. At this point, the fault current will flow to the fault point through multiple power supply paths, resulting in significant circulating current effects and multi-source coupling effects in the network. Existing fault current calculation methods for radial power grids become ineffective. To address this, this invention proposes a three-phase short-circuit fault current calculation method suitable for distributed renewable energy connected to a ring distribution network. This method solves the problem that conventional short-circuit current calculation methods for radial power grids are difficult to apply to distributed power sources connected to a ring distribution network, providing a fault current calculation method for single-ring or multi-ring distribution networks formed after the tie switch is closed in practical engineering projects.

[0035] Exemplary device Figure 6This is a schematic diagram of the structure of a three-phase short-circuit fault current calculation device for distributed new energy access ring distribution networks provided by an exemplary embodiment of the present invention. Figure 6 As shown, the device 600 includes: The determination module 610 is used to determine the bus node connected to the tie switch; The identification module 620 is used to identify whether the bus node is connected to a new energy source or synchronous power source. The merging module 630 is used to merge bus nodes that are not connected to new energy sources or synchronous power sources into bus nodes that are connected to new energy sources or synchronous power sources. The generation module 640 is used to generate a correction matrix based on the merged bus node information; The calculation module 650 is used to calculate the three-phase short-circuit fault current based on the correction matrix.

[0036] Optionally, the merging of bus nodes specifically involves: deleting the rows and columns of the merged bus nodes from the information matrix of the bus nodes, and adding the impedance of the merged bus nodes as parallel branches to the rows and columns of the merged bus nodes.

[0037] Optionally, the correction matrix Y add The expression is: In the formula, Z f1-B The impedance of the line from the fault point to bus B; Z BC The impedance between the BC busbars is denoted as .

[0038] Optionally, based on the correction matrix, the three-phase short-circuit fault current is calculated, including: Based on the correction matrix, construct the node voltage equation; Based on the nodal equations, a set of nonlinear equations for the voltage at each node and the fault current of the photovoltaic output are obtained; Based on the actual voltage of each node and the nonlinear equations, the three-phase short-circuit fault current of each line is obtained.

[0039] Optionally, the expression for the nodal voltage equation is: in, Y add For the correction matrix, Y Let be the nodal admittance matrix, which is symmetric and positive definite. Among them, node voltage U for: I s Injected current for the system's equivalent power source: In the formula, E s , Z s These are the internal potential and internal impedance of the synchronous power supply.

[0040] I PV.f The fault current output by the photovoltaic system is related to the node voltage as follows: In the formula, U C , U E The voltage at the grid connection point of bus C and bus E; f ( ) is the coupling function between the fault current and the grid connection point voltage under the fault ride-through standard requirements of distributed power sources.

[0041] Exemplary electronic devices Figure 7 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. For example... Figure 7 As shown, the electronic device 70 includes one or more processors 71 and a memory 72.

[0042] The processor 71 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0043] The memory 72 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 71 may execute the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above, and / or other desired functions. In one example, the electronic device may also include an input device 73 and an output device 74, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0044] In addition, the input device 73 may also include, for example, a keyboard, a mouse, etc.

[0045] The output device 74 can output various information to the outside. The output device 74 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0046] Of course, for the sake of simplicity, Figure 7 Only some of the components of this electronic device relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device may include any other suitable components depending on the specific application.

[0047] Exemplary computer program products and computer-readable storage media In addition to the methods and apparatus described above, embodiments of the present invention may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0048] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of the present invention. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0049] Furthermore, embodiments of the present invention may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps of the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0050] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0051] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0053] The block diagrams of devices, systems, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, systems, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0054] The methods and systems of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0055] It should also be noted that in the systems, apparatus, and methods of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered equivalents of the present invention. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0056] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for calculating three-phase short-circuit fault current applicable to distributed renewable energy access in a ring distribution network, characterized in that, include: Determine the busbar nodes connected to the tie switch; Identify whether the bus node is connected to a new energy source or synchronous power source; The bus nodes that are not connected to new energy sources or synchronous power sources will be merged into the bus nodes that are connected to new energy sources or synchronous power sources. Based on the merged bus node information, a correction matrix is ​​generated; Based on the correction matrix, the three-phase short-circuit fault current is calculated.

2. The method according to claim 1, characterized in that, The merging of the bus nodes specifically involves deleting the rows and columns of the merged bus nodes from the information matrix of the bus nodes, and adding the impedance of the merged bus nodes as parallel branches to the rows and columns of the merged bus nodes.

3. The method according to claim 1, characterized in that, The correction matrix Y add The expression is: In the formula, Z f1-B The impedance of the line from the fault point to bus B; Z BC The impedance between the BC busbars is denoted as .

4. The method according to claim 1, characterized in that, Based on the correction matrix, the three-phase short-circuit fault current is calculated, including: Based on the correction matrix, the node voltage equations are constructed; Based on the node equations, a set of nonlinear equations for the voltage at each node and the fault current of the photovoltaic output are obtained. Based on the actual voltage of each node and the aforementioned nonlinear equations, the three-phase short-circuit fault current of each line is obtained.

5. The method according to claim 4, characterized in that, The expression for the node voltage equation is as follows: in, Y add For the correction matrix, Y Let be the nodal admittance matrix, which is symmetric and positive definite. Among them, node voltage U for: I s Injected current for the system's equivalent power source: In the formula, E s , Z s The internal potential and internal impedance of the synchronous power supply; I PV.f The fault current output by the photovoltaic system is related to the node voltage as follows: In the formula, U C , U E The voltage at the grid connection point of bus C and bus E; f ( ) is the coupling function between the fault current and the grid connection point voltage under the fault ride-through standard requirements of distributed power sources.

6. A three-phase short-circuit fault current calculation device suitable for distributed renewable energy access to a ring distribution network, characterized in that, include: The determination module is used to determine the bus node connected to the tie switch; The identification module is used to identify whether the bus node is connected to a new energy source or a synchronous power source; The merging module is used to merge bus nodes that are not connected to new energy sources or synchronous power sources into bus nodes that are connected to new energy sources or synchronous power sources. The generation module is used to generate a correction matrix based on the merged bus node information; The calculation module is used to calculate the three-phase short-circuit fault current based on the correction matrix.

7. The apparatus according to claim 6, characterized in that, The merging of the bus nodes specifically involves deleting the rows and columns of the merged bus nodes from the information matrix of the bus nodes, and adding the impedance of the merged bus nodes as parallel branches to the rows and columns of the merged bus nodes.

8. The apparatus according to claim 6, characterized in that, The correction matrix Y add The expression is: In the formula, Z f1-B The impedance of the line from the fault point to bus B; Z BC The impedance between the BC busbars is denoted as .

9. The apparatus according to claim 6, characterized in that, Based on the correction matrix, the three-phase short-circuit fault current is calculated, including: Based on the correction matrix, the node voltage equations are constructed; Based on the node equations, a set of nonlinear equations for the voltage at each node and the fault current of the photovoltaic output are obtained. Based on the actual voltage of each node and the aforementioned nonlinear equations, the three-phase short-circuit fault current of each line is obtained.

10. The apparatus according to claim 9, characterized in that, The expression for the node voltage equation is as follows: in, Y add For the correction matrix, Y Let be the nodal admittance matrix, which is symmetric and positive definite. Among them, node voltage U for: I s Injected current for the system's equivalent power source: In the formula, E s , Z s The internal potential and internal impedance of the synchronous power supply; I PV.f The fault current output by the photovoltaic system is related to the node voltage as follows: In the formula, U C , U E The voltage at the grid connection point of bus C and bus E; f ( ) is the coupling function between the fault current and the grid connection point voltage under the fault ride-through standard requirements of distributed power sources.

11. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for performing the method described in any one of claims 1-5.

12. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1-5.

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