A method, apparatus, equipment, and medium for fault point identification in a virtual synchronous machine grid-connected system based on contralateral identification.

Abstract

This invention discloses a method, apparatus, equipment, and medium for fault point identification in a virtual synchronous generator grid-connected system based on contralateral identification. When a fault occurs in the virtual synchronous generator grid-connected system, the method collects the bus voltage at the converter outlet side, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle, and obtains the unit reactance value of the conductors in the grid-connected system. The bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle are input into a fault detection model. The fault detection model then calculates the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data. Based on the measured reactance and the unit reactance value, the location of the fault point in the virtual synchronous generator grid-connected system is determined. By implementing this invention, the fault point in a virtual synchronous generator grid-connected system can be located quickly and accurately.

Description

Technical Field

[0001] This invention relates to the field of power technology, and in particular to a method, apparatus, equipment and medium for identifying fault points in a virtual synchronous machine grid-connected system based on counterpart identification. Background Technology

[0002] In virtual synchronous generator (VSG) grid-connected systems, the rapid development of renewable energy and the large-scale integration of distributed power sources have led to increasingly stringent requirements for system safety and stability. While automated and intelligent monitoring methods are becoming more widespread under current technological conditions, manual measurement and calculation remain crucial for assessing system status in certain situations. However, manual measurement and calculation are time-consuming, involving steps such as data acquisition, processing, analysis, and computation. In rapidly changing power systems, this delay can prevent the timely capture of dynamic system changes, thus impacting real-time assessments of system safety and stability. Summary of the Invention

[0003] This invention provides a method, device, equipment, and medium for identifying fault points in a virtual synchronous generator grid-connected system based on contralateral identification. The method solves for the measured reactance through a fault detection model, and obtains the location of the fault point in the virtual synchronous generator grid-connected system based on the measured reactance and the unit reactance value, so as to achieve the purpose of quickly and accurately locating the fault point.

[0004] One embodiment of the present invention provides a method for fault point identification in a virtual synchronous machine grid-connected system based on contralateral identification, comprising:

[0005] When a fault is detected in the virtual synchronous generator grid-connected system, the bus voltage at the converter outlet side of the virtual synchronous generator grid-connected system, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle are collected, and the unit reactance value of the conductors in the virtual synchronous generator grid-connected system is obtained.

[0006] The bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle are input into the fault detection model so that the fault detection model can solve for the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data; wherein, the fault detection model is composed of the operating parameters of the converter in the virtual synchronous generator grid-connected system and the system characteristic parameters of the virtual synchronous generator grid-connected system;

[0007] Based on the measured reactance and the unit reactance value, the location of the fault point in the virtual synchronous generator grid-connected system is determined.

[0008] Furthermore, the construction process of the fault detection model includes:

[0009] Obtain the operating parameters of the converter in the virtual synchronous generator grid-connected system, the system characteristic parameters of the virtual synchronous generator grid-connected system, and the relational expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system;

[0010] By performing a virtual-real part separation operation on the relational expression, a set of nonlinear equations for solving the measured reactance is obtained;

[0011] The fault detection model is determined based on the operating parameters, the system characteristic parameters, and the nonlinear equations.

[0012] Furthermore, the relational expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system is specifically as follows:

[0013]

[0014] In the formula, This represents the voltage phasor at the converter output side; This represents the current phasor on the converter output side. θ c This indicates the phase angle provided by VSG. Indicates the saturation current angle. R represents the maximum current amplitude after the converter triggers current limiting control. g Indicates the grounding resistance at the fault point; X q =X t -X p X q X represents the line reactance from the system-side outlet to the fault point. t X represents the reactance of the transmission line. p X represents the measured reactance from the converter outlet to the fault point; s Indicates the internal reactance of the system; This represents the system voltage phasor.

[0015] Furthermore, the fault detection model is specifically as follows:

[0016]

[0017] In the formula, U p Represents the bus voltage on the converter output side; R g Indicates the grounding resistance at the fault point; X p This represents the measured reactance from the converter outlet to the fault point; θ represents the maximum current amplitude after the converter triggers current limiting control. cThis indicates the phase angle provided by VSG; Indicates the saturation current angle; U s Indicates system voltage; X s Indicates the internal reactance of the system; X t Indicates the reactance of the transmission line; δ p This represents the phase angle of the bus voltage phasor on the converter outlet side.

[0018] Further, determining the location of the fault point in the virtual synchronous generator grid-connected system based on the measured reactance and the unit reactance value includes:

[0019] Divide the measured reactance by the unit reactance value to obtain the fault distance;

[0020] The location of the fault point is determined based on the fault distance.

[0021] An embodiment of the present invention also provides a fault point identification device for a virtual synchronous machine grid-connected system based on contralateral identification, comprising: a data acquisition module, a measurement reactance solving module, and a fault point location module;

[0022] The data acquisition module is used to collect the bus voltage at the converter outlet side of the virtual synchronous generator grid-connected system, the maximum value of the current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle when it is determined that a fault has occurred in the virtual synchronous generator grid-connected system, and to obtain the unit reactance value of the conductor in the virtual synchronous generator grid-connected system.

[0023] The measured reactance solving module is used to input the bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle into the fault detection model, so that the fault detection model can solve for the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data; wherein, the fault detection model is composed of the operating parameters of the converter in the virtual synchronous generator grid-connected system and the system characteristic parameters of the virtual synchronous generator grid-connected system;

[0024] The fault location module is used to determine the location of the fault point in the virtual synchronous generator grid-connected system based on the measured reactance and the unit reactance value.

[0025] Furthermore, the construction process of the fault detection model includes:

[0026] Obtain the operating parameters of the converter in the virtual synchronous generator grid-connected system, the system characteristic parameters of the virtual synchronous generator grid-connected system, and the relational expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system;

[0027] By performing a virtual-real part separation operation on the relational expression, a set of nonlinear equations for solving the measured reactance is obtained;

[0028] The fault detection model is determined based on the operating parameters, the system characteristic parameters, and the nonlinear equations.

[0029] Furthermore, the fault detection model is specifically as follows:

[0030]

[0031] In the formula, U p Represents the bus voltage on the converter output side; R g Indicates the grounding resistance at the fault point; X p This represents the measured reactance from the converter outlet to the fault point; θ represents the maximum current amplitude after the converter triggers current limiting control. c This indicates the phase angle provided by VSG; Indicates the saturation current angle; U s Indicates system voltage; X s Indicates the internal reactance of the system; X t Indicates the reactance of the transmission line; δ p This represents the phase angle of the bus voltage phasor on the converter outlet side.

[0032] This application also provides a terminal device, including:

[0033] One or more processors;

[0034] A memory, coupled to the processor, for storing one or more programs;

[0035] When the one or more programs are executed by the one or more processors, the one or more processors implement the method for identifying fault points in a virtual synchronous grid-connected system based on counterpart identification as described in the above embodiments of the invention.

[0036] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for identifying fault points in a virtual synchronous machine grid-connected system based on counterpart identification as described in the above embodiments of the invention.

[0037] The following benefits can be obtained by implementing the present invention:

[0038] This invention provides a method, apparatus, device, and medium for fault point identification in a virtual synchronous generator grid-connected system based on contralateral identification. The method uses the collected bus voltage and bus current as inputs to a fault detection model. The model, based on these input data and internal parameters and algorithms, calculates the measured reactance and grounding resistance. Then, by measuring the reactance and the unit reactance value, it determines the electrical distance between the fault point and the measured point, thereby pinpointing the location of the fault point in the virtual synchronous generator grid-connected system. Therefore, this method allows for rapid and accurate fault point location, which is of great significance for subsequent fault handling. Attached Figure Description

[0039] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 This is a flowchart illustrating a method for identifying fault points in a virtual synchronous machine grid-connected system based on counterpart identification, according to a certain embodiment of this application.

[0041] Figure 2 This is a schematic diagram of the control structure topology of a virtual synchronous machine grid-connected system provided in a certain embodiment of this application;

[0042] Figure 3 This is a flowchart of the fault detection model construction provided in a certain embodiment of this application;

[0043] Figure 4 This is a flowchart illustrating the calculation process of a method for identifying fault points in a virtual synchronous machine grid-connected system based on counterpart identification, provided in a certain embodiment of this application.

[0044] Figure 5 This is a schematic diagram of the geometric spacing between three-phase conductors provided in a certain embodiment of this application;

[0045] Figure 6 This is a schematic diagram of the structure of a fault point identification device for a virtual synchronous machine grid-connected system based on counterpart identification, provided in a certain embodiment of this application;

[0046] Figure 7 This is a schematic diagram of the structure of a terminal device provided in a certain embodiment of this application. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0049] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0050] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0051] In the description of the embodiments in this application, the term "and / or" 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0052] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0053] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0054] See Figure 1 This is a flowchart illustrating a method for identifying fault points in a virtual synchronous machine grid-connected system based on counterpart identification, according to an embodiment of the present invention, comprising:

[0055] S1. When it is determined that a fault has occurred in the virtual synchronous generator grid-connected system, the bus voltage at the converter outlet side of the virtual synchronous generator grid-connected system, the maximum value of the current amplitude after the converter triggers the current limiting control, the phase angle provided by the VSG, and the saturation current angle are collected, and the unit reactance value of the conductors in the virtual synchronous generator grid-connected system is obtained.

[0056] S2. Input the bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle into the fault detection model, so that the fault detection model can solve for the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data; wherein, the fault detection model is composed of the operating parameters of the converter in the virtual synchronous generator grid-connected system and the system characteristic parameters of the virtual synchronous generator grid-connected system;

[0057] In a preferred embodiment, the process of constructing the fault detection model includes:

[0058] Obtain the operating parameters of the converter in the virtual synchronous generator grid-connected system, the system characteristic parameters of the virtual synchronous generator grid-connected system, and the relational expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system;

[0059] By performing a virtual-real part separation operation on the relational expression, a set of nonlinear equations for solving the measured reactance is obtained;

[0060] The fault detection model is determined based on the operating parameters, the system characteristic parameters, and the nonlinear equations.

[0061] See Figure 2 This is a schematic diagram of the control structure topology of a virtual synchronous machine grid-connected system provided in a certain embodiment of this application;

[0062] Figure 3 This is a flowchart of the fault detection model construction process provided in a certain embodiment of this application. Specifically, the relationship expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system is obtained by the circuit equation after the current is limited due to a fault in the transmission line of the virtual synchronous generator grid-connected system.

[0063] Ignoring the transmission line resistance, the circuit equation after the virtual synchronous generator grid-connected system experiences a transmission line fault and triggers the overcurrent control of the current limiter can be written as:

[0064]

[0065] In the formula, This refers to the voltage phasor at the converter output side; For system voltage phasors; R is the voltage phasor at the fault point; g X is the grounding resistance at the fault point; p X is the measured reactance from the converter outlet to the fault point; q X is the line reactance from the system-side output to the fault point; s The internal reactance of the system; This refers to the current phasor on the converter output side; This refers to the system-side output current phasor. θ represents the maximum current amplitude after the converter triggers current limiting control. c Phase angle provided for VSG; This is the saturation current angle.

[0066] Subsequently, in order to eliminate the other variables in equation (1), the equation (1) is... Substitution From this, we can obtain Then Substitution Solving

[0067] By eliminating variables as described above, we obtain equation (2), the specific expression of which is shown below:

[0068]

[0069] Further elimination of variables The relationship expression used to characterize the relationship between the bus voltage and the bus current on the converter outlet side in the virtual synchronous generator grid-connected system is obtained, namely, equation (3);

[0070] In a preferred embodiment, the relational expression characterizing the relationship between the converter outlet bus voltage and the bus current in the virtual synchronous generator grid-connected system is specifically as follows:

[0071]

[0072] In the formula, This represents the voltage phasor at the converter output side; This represents the current phasor on the converter output side. θ c This indicates the phase angle provided by VSG. Indicates the saturation current angle. R represents the maximum current amplitude after the converter triggers current limiting control. g Indicates the grounding resistance at the fault point; X q =X t -X p X q X represents the line reactance from the system-side outlet to the fault point. t X represents the reactance of the transmission line. p X represents the measured reactance from the converter outlet to the fault point; s Indicates the internal reactance of the system; This represents the system voltage phasor.

[0073] This is an illustrative example of performing a virtual-real part separation operation on the relational expression;

[0074] Specifically, Substituting into equation (3) and separating the real and imaginary parts of the relational expression obtained in equation (3), we can obtain equation (4), the specific expression of which is shown below:

[0075]

[0076] Simplify equation (4) to obtain equation (5), the specific expression of which is shown below;

[0077]

[0078] Subsequently, based on the obtained operating parameters of the converter in the virtual synchronous generator grid-connected system and the system characteristic parameters of the virtual synchronous generator grid-connected system, a fault detection model is constructed, namely, Equation (6).

[0079] Specifically, the operating parameters include the phase angle δ of the converter outlet side voltage phasor. p The system characteristic parameters include the system voltage U. s The system's internal reactance X s Transmission line reactance X t ;

[0080] Among them, U s and X s Based on the identified information from the opposite side, the reactance of the transmission line is X.t =X p +X q By X q Represented as X t -X p And because X t It is a known quantity, and therefore the unknown quantity X q Eliminating these, for reactance, only X remains. p An unknown quantity to be determined;

[0081] In a preferred embodiment, the fault detection model is specifically:

[0082]

[0083] In the formula, U p Represents the bus voltage on the converter output side; R g Indicates the grounding resistance at the fault point; X p This represents the measured reactance from the converter outlet to the fault point; θ represents the maximum current amplitude after the converter triggers current limiting control. c This indicates the phase angle provided by VSG; Indicates the saturation current angle; U s Indicates system voltage; X s Indicates the internal reactance of the system; X t Indicates the reactance of the transmission line; δ p The phase angle of the bus voltage phasor on the converter outlet side;

[0084] Specifically, see Figure 4 The bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle are input into the fault detection model so that the fault detection model can solve for the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data and the known quantities in the fault detection model.

[0085] S3. Based on the measured reactance and the unit reactance value, determine the location of the fault point in the virtual synchronous generator grid-connected system;

[0086] In a preferred embodiment, determining the location of the fault point in the virtual synchronous generator grid-connected system based on the measured reactance and the unit reactance value includes:

[0087] Divide the measured reactance by the unit reactance value to obtain the fault distance;

[0088] Based on the fault distance, the location of the fault point is determined;

[0089] Specifically, given that the unit reactance value is a known quantity, the formula for calculating the fault distance is as follows:

[0090]

[0091] In the formula, X p The measured reactance from the converter outlet to the fault point is represented by 'x'; 'x' represents the unit reactance value of the conductor.

[0092] See Figure 5 This is a schematic diagram of the geometric spacing between three-phase conductors. The specific expression for the unit reactance value x of the conductors is as follows:

[0093]

[0094] In the formula, D m Indicates the geometric spacing between the three-phase conductors.

[0095] See Figure 6 This invention provides a fault point identification device for a virtual synchronous machine grid-connected system based on counterpart identification, comprising: a data acquisition module, a measurement reactance solving module, and a fault point location module.

[0096] The data acquisition module is used to collect the bus voltage at the converter outlet side of the virtual synchronous generator grid-connected system, the maximum value of the current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle when it is determined that a fault has occurred in the virtual synchronous generator grid-connected system, and to obtain the unit reactance value of the conductor in the virtual synchronous generator grid-connected system.

[0097] The measured reactance solving module is used to input the bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle into the fault detection model, so that the fault detection model can solve for the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data; wherein, the fault detection model is composed of the operating parameters of the converter in the virtual synchronous generator grid-connected system and the system characteristic parameters of the virtual synchronous generator grid-connected system;

[0098] The fault location module is used to determine the location of the fault point in the virtual synchronous generator grid-connected system based on the measured reactance and the unit reactance value.

[0099] In a preferred embodiment, the process of constructing the fault detection model includes:

[0100] Obtain the operating parameters of the converter in the virtual synchronous generator grid-connected system, the system characteristic parameters of the virtual synchronous generator grid-connected system, and the relational expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system;

[0101] By performing a virtual-real part separation operation on the relational expression, a set of nonlinear equations for solving the measured reactance is obtained;

[0102] The fault detection model is determined based on the operating parameters, the system characteristic parameters, and the nonlinear equations.

[0103] In a preferred embodiment, the fault detection model is specifically:

[0104]

[0105] In the formula, U p Represents the bus voltage on the converter output side; R g Indicates the grounding resistance at the fault point; X p This represents the measured reactance from the converter outlet to the fault point; θ represents the maximum current amplitude after the converter triggers current limiting control. c This indicates the phase angle provided by VSG; Indicates the saturation current angle; U s Indicates system voltage; X s Indicates the internal reactance of the system; X t Indicates the reactance of the transmission line; δ p This represents the phase angle of the bus voltage phasor on the converter outlet side.

[0106] See Figure 7 One embodiment of this application also provides a terminal device, including:

[0107] One or more processors;

[0108] A memory, coupled to the processor, for storing one or more programs;

[0109] When the one or more programs are executed by the one or more processors, the one or more processors implement the method for identifying fault points in a virtual synchronous grid-connected system based on counterpart identification as described above.

[0110] The processor controls the overall operation of the terminal device to complete all or part of the steps of the aforementioned method for identifying fault points in a virtual synchronous grid-connected system based on counterpart identification. The memory stores various types of data to support the operation of the terminal device. This data may include, for example, instructions for any application or method operating on the terminal device, as well as application-related data. The memory can be implemented using any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0111] In an exemplary embodiment, the terminal device may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the virtual synchronous machine grid-connected system fault point identification method based on counterpart identification as described in any of the above embodiments, and achieve the same technical effect as the above method.

[0112] In another exemplary embodiment, a computer-readable storage medium including a computer program is also provided. When executed by a processor, the computer program implements the steps of the method for identifying fault points in a virtual synchronous machine grid-connected system based on counterpart identification as described in any of the foregoing embodiments. For example, the computer-readable storage medium may be the aforementioned memory including the computer program, which may be executed by a processor of a terminal device to complete the method for identifying fault points in a virtual synchronous machine grid-connected system based on counterpart identification as described in any of the foregoing embodiments, and achieve the same technical effects as the aforementioned method.

[0113] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for fault point identification in a virtual synchronous machine grid-connected system based on contralateral identification, characterized in that, include: When a fault is detected in the virtual synchronous generator grid-connected system, the bus voltage at the converter outlet side of the virtual synchronous generator grid-connected system, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle are collected, and the unit reactance value of the conductors in the virtual synchronous generator grid-connected system is obtained. The bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle are input into the fault detection model so that the fault detection model can solve for the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data. The fault detection model is composed of the operating parameters of the converter in the virtual synchronous generator grid-connected system and the system characteristic parameters of the virtual synchronous generator grid-connected system. Specifically, the fault detection model is as follows: ； In the formula, This represents the bus voltage on the converter output side; Indicates the grounding resistance at the fault point; This represents the measured reactance from the converter outlet to the fault point; This indicates the maximum current amplitude after the converter triggers current limiting control. This indicates the phase angle provided by VSG; Indicates the saturation current angle; Indicates system voltage; Indicates the internal reactance of the system; Indicates the reactance of the transmission line; The phase angle of the bus voltage phasor on the converter outlet side; Based on the measured reactance and the unit reactance value, the location of the fault point in the virtual synchronous generator grid-connected system is determined.

2. The method for fault point identification in a virtual synchronous grid-connected system based on contralateral identification as described in claim 1, characterized in that, The process of constructing the fault detection model includes: Obtain the operating parameters of the converter in the virtual synchronous generator grid-connected system, the system characteristic parameters of the virtual synchronous generator grid-connected system, and the relational expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system; By performing a virtual-real part separation operation on the relational expression, a set of nonlinear equations for solving the measured reactance is obtained; The fault detection model is determined based on the operating parameters, the system characteristic parameters, and the nonlinear equations.

3. The method for fault point identification in a virtual synchronous grid-connected system based on contralateral identification as described in claim 2, characterized in that, The relational expression used to characterize the relationship between the converter outlet bus voltage and the bus current in a virtual synchronous generator grid-connected system is as follows: ； In the formula, This represents the voltage phasor at the converter output side; This represents the current phasor on the converter output side. , This indicates the phase angle provided by VSG. Indicates the saturation current angle. This indicates the maximum current amplitude after the converter triggers current limiting control. Indicates the grounding resistance at the fault point; , This indicates the line reactance from the system-side output to the fault point. Indicates the reactance of the transmission line. This represents the measured reactance from the converter outlet to the fault point; Indicates the internal reactance of the system; This represents the system voltage phasor.

4. The method for fault point identification in a virtual synchronous grid-connected system based on contralateral identification as described in claim 1, characterized in that, The step of determining the location of the fault point in the virtual synchronous generator grid-connected system based on the measured reactance and the unit reactance value includes: Divide the measured reactance by the unit reactance value to obtain the fault distance; The location of the fault point is determined based on the fault distance.

5. A fault point identification device for a virtual synchronous machine grid-connected system based on contralateral identification, characterized in that, include: Data acquisition module, reactance measurement module, and fault location module; The data acquisition module is used to collect the bus voltage at the converter outlet side of the virtual synchronous generator grid-connected system, the maximum value of the current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle when it is determined that a fault has occurred in the virtual synchronous generator grid-connected system, and to obtain the unit reactance value of the conductor in the virtual synchronous generator grid-connected system. The measured reactance solving module is used to input the bus voltage, the maximum current amplitude after the converter triggers current limiting control, the phase angle provided by the VSG, and the saturation current angle into the fault detection model, so that the fault detection model can solve for the measured reactance and grounding resistance of the virtual synchronous generator grid-connected system based on the input data; wherein, the fault detection model is composed of the operating parameters of the converter in the virtual synchronous generator grid-connected system and the system characteristic parameters of the virtual synchronous generator grid-connected system; the fault detection model is specifically as follows: ； In the formula, This represents the bus voltage on the converter output side; Indicates the grounding resistance at the fault point; This represents the measured reactance from the converter outlet to the fault point; This indicates the maximum current amplitude after the converter triggers current limiting control. This indicates the phase angle provided by VSG; Indicates the saturation current angle; Indicates system voltage; Indicates the internal reactance of the system; Indicates the reactance of the transmission line; The phase angle of the bus voltage phasor on the converter outlet side; The fault location module is used to determine the location of the fault point in the virtual synchronous generator grid-connected system based on the measured reactance and the unit reactance value.

6. The fault point identification device for a virtual synchronous grid-connected system based on contralateral identification as described in claim 5, characterized in that, The process of constructing the fault detection model includes: Obtain the operating parameters of the converter in the virtual synchronous generator grid-connected system, the system characteristic parameters of the virtual synchronous generator grid-connected system, and the relational expression used to characterize the relationship between the converter outlet side bus voltage and the bus current in the virtual synchronous generator grid-connected system; By performing a virtual-real part separation operation on the relational expression, a set of nonlinear equations for solving the measured reactance is obtained; The fault detection model is determined based on the operating parameters, the system characteristic parameters, and the nonlinear equations.

7. A device, characterized in that, include: One or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method for identifying fault points in a virtual synchronous grid-connected system based on counterpart identification as described in any one of claims 1-4.

8. A medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for identifying fault points in a virtual synchronous grid-connected system based on counterpart identification as described in any one of claims 1-4.

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