A method, device and storage medium for analyzing and verifying transient characteristics of short-circuit current

Abstract

The present invention discloses a method, device and storage medium for analyzing and verifying the transient characteristics of short-circuit current. The method includes: establishing an in-station calculation model of in-station equipment considering the wiring topology through node selection and impedance calculation between nodes; modeling the external system of the substation according to the operation mode of the power grid; establishing a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics according to the action time characteristics corresponding to different fault points; and analyzing and verifying the transient characteristics of short-circuit current according to the in-station calculation model, the external system of the substation and the time-varying impedance model. The present invention obtains the transient change characteristics of the short-circuit current actually borne by the equipment by establishing a refined calculation model of the in-station equipment considering the wiring topology, and a calculation model reflecting the protection action characteristics and the circuit breaker action characteristics, and realizes the refined analysis and verification of the short-circuit current according to different fault forms and the equipment's tolerance to short-circuit current characteristics.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and more specifically, to a method and device for analyzing and verifying transient characteristics of short-circuit current, as well as a storage medium and electronic equipment. Background Art

[0002] With the rapid development of power grids, the scale of power grids is increasing day by day, and the short-circuit current level in my country's power system is increasing year by year. Excessive short-circuit current will harm the safe and stable operation of the power system and the electrical equipment itself. In order to reasonably determine the short-circuit current limiting measures, it is necessary to analyze the transient characteristics of short-circuit current and verify the short-circuit current level that the equipment can withstand.

[0003] At present, the busbar-to-ground short-circuit current level is the main indicator for calculating short-circuit current in power systems and determining short-circuit current limiting measures. Although this calculation and verification method can cover the most serious short-circuit current situation, it cannot accurately evaluate the actual short-circuit current interrupted by the circuit breaker, and the results obtained are often too strict. Some theoretical studies have considered the substation wiring method and calculated the circuit breaker interruption current by calculating the branch current and the busbar-to-ground current, but this method cannot accurately evaluate the actual short-circuit current interrupted by the circuit breaker.

[0004] There is no effective solution to the technical problem in the prior art that the actual short-circuit current interrupted by the circuit breaker cannot be accurately evaluated when calculating the short-circuit current in the power system and determining the short-circuit current limiting measures. Summary of the invention

[0005] In view of the technical problem in the prior art that it is impossible to accurately evaluate the short-circuit current actually broken by the circuit breaker when calculating the short-circuit current in the power system and determining the short-circuit current limiting measures, the present invention provides a method and device for analyzing and verifying the transient characteristics of short-circuit current, as well as a storage medium and an electronic device. By establishing a refined calculation model of the in-station equipment considering the wiring topology, and a calculation model reflecting the protection action characteristics and the circuit breaker action characteristics, the transient change characteristics of the short-circuit current actually borne by the equipment are obtained, and according to different fault forms and the equipment's short-circuit current tolerance characteristics, the short-circuit current is refined and verified, providing a technical basis for further determining suppression measures.

[0006] According to one aspect of the present invention, a method for analyzing and verifying transient characteristics of short-circuit current is provided, comprising:

[0007] Through node selection and impedance calculation between nodes, an in-station calculation model of in-station equipment considering wiring topology is established;

[0008] Modeling substation external systems based on grid operation mode;

[0009] According to the corresponding action time characteristics of different fault points, a time-varying impedance model reflecting the protection action characteristics and circuit breaker action characteristics is established;

[0010] According to the in-station calculation model, substation external system and time-varying impedance model, the short-circuit current transient characteristics analysis and verification are carried out.

[0011] Optionally, an in-station calculation model of in-station equipment considering wiring topology is established through node selection and impedance calculation between nodes, including:

[0012] Obtain substation wiring layout;

[0013] According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, multiple nodes in the substation are determined as the research object;

[0014] Determine the intra-station nodes having a mutual connection relationship among the plurality of intra-station nodes as connection points;

[0015] Calculate the connection line impedance between each connection point according to a preset calculation method;

[0016] According to the impedance of the connection lines between multiple in-station nodes and each connection point, an in-station calculation model of the in-station equipment considering the wiring topology is established.

[0017] Optionally, according to the substation wiring layout and the actual wiring layout of the substation equipment, multiple substation nodes as research objects are determined, including:

[0018] According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, the location points with more than two connecting lines in the substation are determined as the nodes in the substation; and / or

[0019] The locations in the substation that are connected to the two types of equipment are determined as in-station nodes.

[0020] Optionally, calculating the connection line impedance between the connection points according to a preset calculation method includes:

[0021] For overhead leads, calculate the impedance of the overhead leads based on the outer diameter, height above the ground and length of the overhead leads;

[0022] For closed busbars lower than gas-insulated metal, the closed busbar impedance is calculated based on the inner and outer radii of the conductors and the inner and outer radii of the pipes, as well as their lengths;

[0023] For the equipment in the station, the impedance of the equipment in the station is calculated according to the actual parameters of the equipment in the station;

[0024] For switchgear, the switchgear impedance is calculated based on the outer dimensions of the switchgear.

[0025] Optionally, according to the action time characteristics corresponding to different fault points, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including:

[0026] The protection action characteristics and circuit breaker action characteristics are described by three times, wherein the three times include the protection exit time t1 after the fault, the time t2 from the circuit breaker action after the protection exit to the mechanical separation of the circuit breaker contacts, and the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker disconnection;

[0027] According to the corresponding protection action characteristics of different fault points, the value range of each protection exit time t1 is determined respectively, where the protection exit time of the same station takes the same value;

[0028] According to the mechanical characteristics and dispersion of the circuit breaker, determine the time t2 from the circuit breaker action to the mechanical separation of the circuit breaker contacts after the protection outlet;

[0029] According to the current waveform and the arc extinguishing characteristics of the circuit breaker, determine the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker opening;

[0030] According to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established.

[0031] Optionally, according to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including:

[0032] For the first time period from the occurrence of the fault to the mechanical separation of the circuit breaker contacts, the circuit breaker is represented by a fixed impedance, and the impedance is determined according to the circuit breaker's own structural parameters, wherein the first time period is the time period from the moment of the fault occurrence to the time t1 plus the time t2;

[0033] For the second time period from mechanical separation of the circuit breaker contacts to the circuit breaker opening, the circuit breaker is represented by a nonlinear resistor, wherein the nonlinear resistor is related to the current value, and the second time period is the time period from the moment when the circuit breaker contacts are mechanically separated to time t3;

[0034] For the third time period after the circuit breaker is opened, the circuit breaker is represented by the break capacitance, wherein the break capacitance value is calculated according to the break voltage-sharing capacitance of the circuit breaker, wherein the third time period is the time period after the circuit breaker is opened.

[0035] Optionally, the short-circuit current transient characteristic analysis and verification is performed based on the in-station calculation model, the substation external system and the time-varying impedance model, including:

[0036] According to the in-station calculation model, substation external system and time-varying impedance model, the electromagnetic transient simulation model of the substation under study is established;

[0037] Based on the electromagnetic transient simulation model, determine the transient characteristics of short-circuit current of each branch when a fault occurs at each node in the station;

[0038] Analyze and verify the transient characteristics of short-circuit current according to the characteristics of the equipment.

[0039] Optionally, based on the electromagnetic transient simulation model, the short-circuit current transient characteristics of each branch when a fault occurs at each node in the station are determined, including:

[0040] Considering the dispersion of protection action characteristics and circuit breaker action characteristics, statistical analysis is performed on the transient waveform of short-circuit current in each branch under different fault moments, protection action moments and circuit breaker opening times;

[0041] According to the statistical analysis results of the short-circuit current transient waveforms of each branch section, the short-circuit current transient characteristics of each branch section when a fault occurs at each node in the station are determined.

[0042] Optionally, the short-circuit current transient characteristics of each branch when a fault occurs at each node in the station include:

[0043] The maximum peak value of the short-circuit current actually borne, the time of occurrence of the maximum peak value and the waveform of the short-circuit current;

[0044] The effective value of the AC component, DC component and decay time constant of the short-circuit current actually borne;

[0045] The actual effective value of the short-circuit current and the duration of the short-circuit current.

[0046] Optionally, the tolerance capability of the equipment is verified according to the transient characteristics of the short-circuit current of each branch, including:

[0047] According to the maximum short-circuit current peak value actually borne by each branch and the time of occurrence of the maximum peak value, check the peak short-circuit current tolerance of the equipment;

[0048] Check the thermal stability of the equipment according to the maximum effective value of the short-circuit current actually borne by each branch;

[0049] For the operated circuit breaker, the maximum values ​​of the AC and DC components of the short-circuit current flowing through the operated circuit breaker after the mechanical separation of the circuit breaker contacts are calculated based on the effective value of the AC component, DC component and attenuation time constant of the short-circuit current actually borne by each branch section, and the breaking short-circuit current level of the operated circuit breaker is checked based on the maximum values ​​of the AC and DC components.

[0050] Optionally, based on the electromagnetic transient simulation model, the short-circuit current transient characteristics of each branch when a fault occurs at each node in the station are determined, including:

[0051] Select a node in the station in the electromagnetic transient simulation model;

[0052] Determine the relay protection and circuit breaker to be operated according to the fault location;

[0053] Randomly generate a failure moment;

[0054] Randomly generate each protection action time and circuit breaker opening time;

[0055] Conduct electromagnetic transient simulation based on each protection action time and circuit breaker opening time;

[0056] Based on electromagnetic transient simulation, the transient change characteristics of short-circuit current in each branch are obtained;

[0057] When the statistical simulation is completed and all nodes in the station are traversed, the statistical analysis of the transient characteristics of the short-circuit current ends.

[0058] According to another aspect of the present invention, there is provided a short-circuit current transient characteristic analysis and verification device, comprising:

[0059] The in-station calculation model establishment module is used to establish an in-station calculation model of in-station equipment taking into account wiring topology through node selection and impedance calculation between nodes;

[0060] Substation external system modeling module, used to model the substation external system according to the grid operation mode;

[0061] The time-varying impedance model building module is used to build a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics according to the action time characteristics corresponding to different fault points;

[0062] The analysis and verification module is used to analyze and verify the transient characteristics of short-circuit current based on the station calculation model, substation external system and time-varying impedance model.

[0063] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0064] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; 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 the above aspects of the present invention.

[0065] The present invention first considers the influence of the circuit breaker action characteristics, and establishes an in-station calculation model that reflects the wiring topology by selecting node selection and impedance calculation between nodes. Then, in order to reflect the influence of the change in the substation wiring topology, the circuit breaker action characteristics are simulated by time-varying impedance according to the protection action time, circuit breaker opening time, and circuit breaker opening time characteristics. Thus, the present invention obtains the transient change characteristics of the short-circuit current actually borne by the equipment by establishing a refined calculation model of the in-station equipment considering the wiring topology, as well as a calculation model reflecting the protection action characteristics and the circuit breaker action characteristics, and realizes the refined analysis and verification of the short-circuit current according to different fault forms and the equipment's tolerance to short-circuit current characteristics, providing a technical basis for further determining suppression measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0067] Figure 1 It is a flow chart of a short-circuit current transient characteristic analysis and verification method provided by an exemplary embodiment of the present invention;

[0068] Figure 2 It is a schematic diagram of a flow chart of a short-circuit current transient characteristic analysis considering wiring topology and circuit breaker action sequence provided by an exemplary embodiment of the present invention;

[0069] Figure 3 is a wiring diagram of a substation provided by an exemplary embodiment of the present invention;

[0070] Figure 4 is a schematic diagram of an in-station computing model considering wiring topology provided by an exemplary embodiment of the present invention;

[0071] Figure 5 It is a schematic diagram of a flow chart of a statistical analysis of transient characteristics of short-circuit current taking into account the circuit breaker action characteristics provided by an exemplary embodiment of the present invention;

[0072] Figure 6 It is a wiring diagram of a certain substation operation mode provided by an exemplary embodiment of the present invention;

[0073] Figure 7 It is a structural schematic diagram of a short-circuit current transient characteristic analysis and verification device provided by an exemplary embodiment of the present invention;

[0074] Figure 8 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0075] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described here.

[0076] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0077] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0078] It should also be understood that, in the embodiments of the present invention, “plurality” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0079] 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 limited or otherwise indicated in the context.

[0080] In addition, the term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0081] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0082] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0083] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0084] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0085] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0086] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, servers, etc., which can operate with many other general or special computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, servers, etc. 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 personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments including any of the above systems, etc.

[0087] Electronic devices such as terminal devices, computer systems, servers, etc. can be described in the general context of computer system executable instructions (such as program modules) executed by computer systems. Generally, 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 a distributed cloud computing environment, where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media including storage devices.

[0088] Exemplary Methods

[0089] Figure 1 FIG. 1 is a flow chart of a method for analyzing and verifying the transient characteristics of short-circuit current provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the short-circuit current transient characteristic analysis and verification method 100 includes the following steps:

[0090] Step 101 , establishing an in-station calculation model of in-station equipment taking into account wiring topology through node selection and impedance calculation between nodes.

[0091] In the embodiments of the present invention, see Figure 2 As shown, firstly, the in-station equipment modeling is performed considering the wiring topology through node selection and impedance calculation between nodes.

[0092] Optionally, an in-station calculation model of in-station equipment considering the wiring topology is established through node selection and impedance calculation between nodes, including: obtaining the substation wiring layout; determining multiple in-station nodes as research objects according to the substation wiring layout and the actual wiring layout of the in-station equipment; determining the in-station nodes with mutual connection relationships among the multiple in-station nodes as connection points; calculating the connection line impedance between each connection point according to a preset calculation method; and establishing an in-station calculation model of in-station equipment considering the wiring topology according to the connection line impedance between the multiple in-station nodes and each connection point.

[0093] Optionally, based on the wiring layout of the substation and the actual wiring layout of the equipment in the station, multiple in-station nodes are determined as research objects, including: based on the wiring layout of the substation and the actual wiring layout of the equipment in the station, location points in the substation with more than two connecting lines are determined as in-station nodes; and / or location points in the substation connected to two types of equipment are determined as in-station nodes.

[0094] In an embodiment of the present invention, the steps of establishing an in-station computing model of in-station equipment considering wiring topology are as follows:

[0095] 1) Obtain the substation wiring layout, such as one and a half circuit breaker wiring, double busbar wiring, etc.

[0096] 2) According to the substation wiring mode and the actual wiring layout of the substation equipment, multiple in-station nodes are determined as the research object. Among them, the location points with more than two connecting lines in the substation can be determined as in-station nodes, or the location points connected to two types of equipment in the substation can be determined as in-station nodes.

[0097] 3) The in-station nodes that are interconnected among the multiple in-station nodes are determined as connection points, and the connection line impedance between the connection points is calculated.

[0098] Optionally, the impedance of the connecting line between each connection point is calculated according to a preset calculation method, including: for overhead leads, the impedance of the overhead leads is calculated according to the outer diameter, height above the ground and length of the conductor of the overhead leads; for closed busbars lower than gas-insulated metal, the impedance of the closed busbar is calculated according to the inner and outer radii of the conductor of the closed busbar and the inner and outer radii of the pipeline, as well as the length; for equipment within the station, the impedance of the equipment within the station is calculated according to the actual parameters of the equipment within the station; for switchgear, the impedance of the switchgear is calculated according to the outer dimensions of the switchgear.

[0099] In the embodiment of the present invention, the calculation method of the connection line impedance between each connection point is as follows:

[0100] a. For overhead leads, calculate impedance based on the outer diameter of the conductor, height above the ground, length, etc.;

[0101] b. Lower than the gas-insulated metal-enclosed busbar, the impedance is calculated based on the inner and outer radius of its conductors and the inner and outer radius and length of the pipeline;

[0102] c. For in-station equipment, such as reactors and transformers, their impedance is calculated based on their actual parameters;

[0103] d. For switchgear, calculate its impedance based on its external dimensions.

[0104] Among them, in Figure 3 The calculation model of the station established under the typical wiring shown is as follows Figure 4 shown.

[0105] Step 102: Model the substation external system according to the power grid operation mode.

[0106] Usually, the substation external system can be modeled by equivalent simplified modeling according to the operation mode of the power grid. When modeling, the lines directly connected to the substation under study are retained, and the external system is simplified to voltage source and equivalent impedance using the Thevenin equivalent method.

[0107] Step 103: Establish a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics according to the action time characteristics corresponding to different fault points.

[0108] Optionally, according to the action time characteristics corresponding to failures at different fault points, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including: describing the protection action characteristics and the circuit breaker action characteristics by three times, wherein the three times include the protection exit time t1 after the fault, the time t2 from the circuit breaker action after the protection exit to the mechanical separation of the circuit breaker contacts, and the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker opening; according to the protection action characteristics corresponding to failures at different fault points, determining the value range of each protection exit time t1 respectively, wherein the protection exit time for the same station takes the same value; according to the mechanical characteristics and dispersion of the circuit breaker, determining the time t2 from the circuit breaker action after the protection exit to the mechanical separation of the circuit breaker contacts; according to the current waveform and the arc extinguishing characteristics of the circuit breaker, determining the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker opening; according to the time characteristics of time t1, time t2 and time t3, establishing a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics.

[0109] In the embodiment of the present invention, the protection action characteristics and the circuit breaker action characteristics are described by three times, wherein the three times are respectively the protection exit time t1 after the fault, the time t2 from the circuit breaker action after the protection exit to the mechanical separation of the circuit breaker contacts, and the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker disconnection.

[0110] Furthermore, according to the corresponding protection action characteristics of different fault points, the value range of each protection exit time t1 is determined respectively. The same value is taken for the protection exit time of the same station. For example, when the substation bus fails, according to the characteristics of the protection device, the protection exit action time range is 8 to 20ms. When a certain line fails, the protection action time of the substation on this side is 8 to 20ms, and the protection action time of the substation on the opposite side is 10 to 30ms.

[0111] The time t2 from the action of the circuit breaker to the mechanical separation of the circuit breaker contacts after the protection outlet is determined by the mechanical characteristics of the circuit breaker and takes into account a certain degree of dispersion. The typical value range is 25 to 30 ms.

[0112] The time t3 from mechanical separation of the circuit breaker contacts to the circuit breaker opening is determined by the current waveform and the arc extinguishing characteristics of the circuit breaker. The typical range is 10 to 20 ms, and the specific opening time is determined by simulation.

[0113] Finally, based on the above action time characteristics, a time-varying impedance model reflecting the protection action characteristics and circuit breaker action characteristics can be established.

[0114] Optionally, according to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including:

[0115] a. For the period from the occurrence of a fault to the mechanical separation of the circuit breaker contacts (typically 0 to 35 ms after a fault), the circuit breaker is represented by a fixed impedance, which is determined according to the circuit breaker's own structural parameters;

[0116] b. For the time period from mechanical separation of the circuit breaker contacts to the circuit breaker opening (typical value of about 35 to 55ms after a fault), the circuit breaker is represented by a nonlinear resistor, where the nonlinear resistor is related to the current value and is obtained based on the analysis of the short-circuit structure.

[0117] c. After the circuit breaker is opened (typical value 55ms after fault), the break capacitance is used to represent it, where the break capacitance value is calculated based on the break equalizing capacitance of the circuit breaker.

[0118] Step 104, performing short-circuit current transient characteristic analysis and verification based on the in-station calculation model, the substation external system and the time-varying impedance model.

[0119] Optionally, the transient characteristics of short-circuit current are analyzed and verified based on the in-station calculation model, the external system of the substation and the time-varying impedance model, including: establishing an electromagnetic transient simulation model of the substation under study based on the in-station calculation model, the external system of the substation and the time-varying impedance model; determining the transient characteristics of short-circuit current of each branch when a fault occurs at each in-station node based on the electromagnetic transient simulation model; and analyzing and verifying the transient characteristics of short-circuit current according to equipment characteristics.

[0120] Optionally, based on the electromagnetic transient simulation model, the transient characteristics of the short-circuit current of each branch section when a fault occurs at each node within the station are determined, including: considering the dispersion of the protection action characteristics and the circuit breaker action characteristics, and statistically analyzing the transient waveforms of the short-circuit current of each branch section at different fault times, different protection action times and circuit breaker opening times; and determining the transient characteristics of the short-circuit current of each branch section when a fault occurs at each node within the station based on the statistical analysis results of the transient waveforms of the short-circuit current of each branch section.

[0121] In the embodiment of the present invention, the steps of analyzing and verifying the transient characteristics of short-circuit current are as follows:

[0122] 1) Using the above-mentioned in-station and out-station modeling methods, an electromagnetic transient simulation model of the substation under study is established according to the actual power grid operation mode;

[0123] 2) Study the fault current level of each branch when a fault occurs at each node in the station. A statistical method is used to consider the dispersion of protection and action time, and the transient waveform of short-circuit current of each branch is statistically analyzed under the same fault moment, different protection action moments, and circuit breaker opening time. The statistical analysis process is as follows: Figure 5 According to the statistical analysis results, the short-circuit current transient characteristics actually borne by each device (branch) are obtained.

[0124] Optionally, the short-circuit current transient characteristics of each branch when a fault occurs at each node in the station include:

[0125] a. The maximum peak value of the short-circuit current actually borne, the time of occurrence of the maximum peak value and the waveform of the short-circuit current;

[0126] b. The actual short-circuit current AC component effective value, DC component and decay time constant;

[0127] c. The actual effective value of the short-circuit current and the duration of the short-circuit current.

[0128] Optionally, the tolerance capability of the equipment is verified according to the transient characteristics of the short-circuit current of each branch, including:

[0129] a. Verify the peak short-circuit current tolerance of the equipment according to the maximum short-circuit current peak value actually borne by each branch and the time when the maximum peak value occurs;

[0130] b. Check the thermal stability of the equipment according to the maximum effective value of the short-circuit current actually borne by each branch;

[0131] c. For the operated circuit breaker, calculate the maximum values ​​of the AC and DC components of the short-circuit current flowing through the operated circuit breaker after the mechanical separation of the circuit breaker contacts based on the effective value of the AC component, DC component and attenuation time constant of the short-circuit current actually borne by each branch section, and check the short-circuit current breaking level of the operated circuit breaker based on the maximum values ​​of the AC and DC components.

[0132] Alternatively, see Figure 5 As shown, based on the electromagnetic transient simulation model, the transient characteristics of the short-circuit current of each branch when a fault occurs at each node in the station are determined, including:

[0133] 1) Select a node in the station in the electromagnetic transient simulation model;

[0134] 2) Determine the relay protection and circuit breaker to be operated according to the fault location;

[0135] 3) Randomly generate a fault moment; randomly generate each protection action time and circuit breaker opening time;

[0136] 4) Carry out electromagnetic transient simulation according to the action time of each protection and the circuit breaker opening time;

[0137] 5) Based on electromagnetic transient simulation, the transient change characteristics of short-circuit current in each branch are obtained;

[0138] 6) When the statistical simulation is completed and all nodes in the station are traversed, the short-circuit current transient characteristic statistical analysis is terminated;

[0139] 7) When the statistical simulation is not completed, re-execute steps 3) to 6) until the statistical simulation is completed;

[0140] 8) When all nodes have not been traversed, re-execute steps 1) to 7) until all nodes are traversed.

[0141] Best embodiment for specific application:

[0142] Taking a substation as an example, the fault location of the circuit breaker breaking current exceeding the standard is analyzed. The actual operation wiring method of the substation is Figure 6 As shown, the circuit breaker CB8 is in the disconnected state. The substation has 6 circuits and 2 main transformers.

[0143] According to conventional calculation methods, the substation is generally regarded as a single node, and the calculated short-circuit current level of the substation is 64kA, indicating that the short-circuit current exceeds the design value of 63kA, but it is impossible to analyze the short-circuit current characteristics that the equipment actually withstands.

[0144] By adopting the method proposed by the present invention, after establishing a model reflecting the substation wiring topology and circuit breaker action characteristics, the transient characteristics of short-circuit current actually borne by different equipment under different fault modes can be calculated, as shown in Table 1. According to the calculation results, it can be seen that after considering the wiring topology and circuit breaker action characteristics, only the main transformer outgoing branch exceeds the short-circuit current design value of 63kA. The short-circuit current levels of each circuit breaker and line outgoing branch are within the allowable range. Therefore, special measures only need to be taken for the main transformer outgoing branch. The adoption of station-wide measures is avoided.

[0145] Table 1 Calculation comparison

[0146]

[0147] Therefore, the present invention first considers the influence of the circuit breaker action characteristics, and establishes an in-station calculation model that reflects the wiring topology by selecting node selection and impedance calculation between nodes. Then, in order to reflect the impact of the change in the substation wiring topology, the time-varying impedance is used to simulate the circuit breaker action characteristics according to the protection action time, circuit breaker opening time, and circuit breaker breaking time characteristics. A fixed impedance is used in the time period from the occurrence of the fault to the mechanical opening of the circuit breaker, and a nonlinear resistor that changes with the current is used from the mechanical opening of the circuit breaker to the circuit breaker breaking. After the circuit breaker is broken, the fracture capacitance is simulated. Secondly, by considering the statistical analysis of different fault locations, different fault times, circuit breaker action times, etc., the characteristic parameters such as the maximum peak value, effective value, and DC component of the short-circuit current actually borne by the equipment are obtained. Finally, the equipment tolerance capacity is checked according to the characteristics of the equipment, including peak tolerance, thermal stability, and breaking capacity. Therefore, the present invention obtains the transient change characteristics of the short-circuit current actually borne by the equipment by establishing a refined calculation model of the station equipment taking into account the wiring topology, as well as a calculation model that reflects the protection action characteristics and the circuit breaker action characteristics. According to different fault forms and the equipment's short-circuit current tolerance characteristics, refined analysis and verification of the short-circuit current is achieved, providing a technical basis for further determining suppression measures.

[0148] Exemplary Devices

[0149] Figure 7 FIG. 1 is a schematic diagram of a short-circuit current transient characteristic analysis and verification device provided by an exemplary embodiment of the present invention. Figure 7 As shown, the apparatus 700 includes:

[0150] The in-station calculation model establishment module 710 is used to establish an in-station calculation model of the in-station equipment considering the wiring topology through node selection and impedance calculation between nodes;

[0151] The substation external system modeling module 720 is used to model the substation external system according to the power grid operation mode;

[0152] The time-varying impedance model establishment module 730 is used to establish a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics according to the action time characteristics corresponding to the different fault points;

[0153] The analysis and verification module 740 is used to analyze and verify the transient characteristics of the short-circuit current based on the in-station calculation model, the substation external system and the time-varying impedance model.

[0154] Optionally, the in-station computing model building module 710 is specifically used for:

[0155] Obtain substation wiring layout;

[0156] According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, multiple nodes in the substation are determined as the research object;

[0157] Determine the intra-station nodes having a mutual connection relationship among the plurality of intra-station nodes as connection points;

[0158] Calculate the connection line impedance between each connection point according to a preset calculation method;

[0159] According to the impedance of the connection lines between multiple in-station nodes and each connection point, an in-station calculation model of the in-station equipment considering the wiring topology is established.

[0160] Optionally, the in-station computing model building module 710 is further specifically used for:

[0161] According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, the location points with more than two connecting lines in the substation are determined as the nodes in the substation; and / or

[0162] The locations in the substation that are connected to the two types of equipment are determined as in-station nodes.

[0163] Optionally, the in-station computing model building module 710 is further specifically used for:

[0164] For overhead leads, calculate the impedance of the overhead leads based on the outer diameter, height above the ground and length of the overhead leads;

[0165] For closed busbars lower than gas-insulated metal, the closed busbar impedance is calculated based on the inner and outer radii of the conductors and the inner and outer radii of the pipes, as well as their lengths;

[0166] For the equipment in the station, the impedance of the equipment in the station is calculated according to the actual parameters of the equipment in the station;

[0167] For switchgear, the switchgear impedance is calculated based on the outer dimensions of the switchgear.

[0168] Optionally, the time-varying impedance model building module 730 is specifically used for:

[0169] The protection action characteristics and circuit breaker action characteristics are described by three times, wherein the three times include the protection exit time t1 after the fault, the time t2 from the circuit breaker action after the protection exit to the mechanical separation of the circuit breaker contacts, and the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker disconnection;

[0170] According to the corresponding protection action characteristics of different fault points, the value range of each protection exit time t1 is determined respectively, where the protection exit time of the same station takes the same value;

[0171] According to the mechanical characteristics and dispersion of the circuit breaker, determine the time t2 from the circuit breaker action to the mechanical separation of the circuit breaker contacts after the protection outlet;

[0172] According to the current waveform and the arc extinguishing characteristics of the circuit breaker, determine the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker opening;

[0173] According to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established.

[0174] Optionally, the time-varying impedance model building module 730 is further specifically used for:

[0175] For the first time period from the occurrence of the fault to the mechanical separation of the circuit breaker contacts, the circuit breaker is represented by a fixed impedance, and the impedance is determined according to the circuit breaker's own structural parameters, wherein the first time period is the time period from the moment of the fault occurrence to the time t1 plus the time t2;

[0176] For the second time period from mechanical separation of the circuit breaker contacts to the circuit breaker opening, the circuit breaker is represented by a nonlinear resistor, wherein the nonlinear resistor is related to the current value, and the second time period is the time period from the moment when the circuit breaker contacts are mechanically separated to time t3;

[0177] For the third time period after the circuit breaker is opened, the circuit breaker is represented by the break capacitance, wherein the break capacitance value is calculated according to the break voltage-sharing capacitance of the circuit breaker, wherein the third time period is the time period after the circuit breaker is opened.

[0178] Optionally, the analysis and verification module 740 is specifically used for:

[0179] According to the in-station calculation model, substation external system and time-varying impedance model, the electromagnetic transient simulation model of the substation under study is established;

[0180] Based on the electromagnetic transient simulation model, determine the transient characteristics of short-circuit current of each branch when a fault occurs at each node in the station;

[0181] Analyze and verify the transient characteristics of short-circuit current according to the characteristics of the equipment.

[0182] Optionally, the analysis and verification module 740 is further specifically used for:

[0183] Considering the dispersion of protection action characteristics and circuit breaker action characteristics, statistical analysis is performed on the transient waveform of short-circuit current in each branch under different fault moments, protection action moments and circuit breaker opening times;

[0184] According to the statistical analysis results of the short-circuit current transient waveforms of each branch section, the short-circuit current transient characteristics of each branch section when a fault occurs at each node in the station are determined.

[0185] Optionally, the short-circuit current transient characteristics of each branch when a fault occurs at each node in the station include:

[0186] The maximum peak value of the short-circuit current actually borne, the time of occurrence of the maximum peak value and the waveform of the short-circuit current;

[0187] The effective value of the AC component, DC component and decay time constant of the short-circuit current actually borne;

[0188] The actual effective value of the short-circuit current and the duration of the short-circuit current.

[0189] Optionally, the analysis and verification module 740 is further specifically used for:

[0190] According to the maximum short-circuit current peak value actually borne by each branch and the time of occurrence of the maximum peak value, check the peak short-circuit current tolerance of the equipment;

[0191] Check the thermal stability of the equipment according to the maximum effective value of the short-circuit current actually borne by each branch;

[0192] For the operated circuit breaker, the maximum values ​​of the AC and DC components of the short-circuit current flowing through the operated circuit breaker after the mechanical separation of the circuit breaker contacts are calculated based on the effective value of the AC component, DC component and attenuation time constant of the short-circuit current actually borne by each branch section, and the breaking short-circuit current level of the operated circuit breaker is checked based on the maximum values ​​of the AC and DC components.

[0193] Optionally, the analysis and verification module 740 is further specifically used for:

[0194] Select a node in the station in the electromagnetic transient simulation model;

[0195] Determine the relay protection and circuit breaker to be operated according to the fault location;

[0196] Randomly generate a failure moment;

[0197] Randomly generate each protection action time and circuit breaker opening time;

[0198] Conduct electromagnetic transient simulation based on each protection action time and circuit breaker opening time;

[0199] Based on electromagnetic transient simulation, the transient change characteristics of short-circuit current in each branch are obtained;

[0200] When the statistical simulation is completed and all nodes in the station are traversed, the statistical analysis of the transient characteristics of the short-circuit current ends.

[0201] The short-circuit current transient characteristic analysis and verification device 700 of the embodiment of the present invention corresponds to the short-circuit current transient characteristic analysis and verification method 100 of another embodiment of the present invention, and will not be described in detail herein.

[0202] Exemplary Electronic Devices

[0203] Figure 8 The electronic device provided by an exemplary embodiment of the present invention may be any one or both of the first device and the second device, or a stand-alone device independent of them, and the stand-alone device may communicate with the first device and the second device to receive the collected input signals from them. Figure 8 FIG. 2 is a block diagram of an electronic device according to an embodiment of the present invention. Figure 8 As shown, the electronic device 80 includes one or more processors 81 and a memory 82 .

[0204] The processor 81 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0205] The memory 82 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 (cache), etc. 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 81 may run the program instructions to implement the method for information mining of historical change records and / or other desired functions of the software program of each embodiment of the present invention described above. In one example, the electronic device may also include: an input system 83 and an output system 84, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0206] In addition, the input system 83 may also include, for example, a keyboard, a mouse, and the like.

[0207] The output system 84 can output various information to the outside. The output device 84 can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0208] Of course, to simplify, Figure 8 Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, according to specific application conditions, the electronic device may also include any other appropriate components.

[0209] Exemplary computer program products and computer-readable storage media

[0210] In addition to the above-mentioned methods and devices, embodiments of the present invention also provide a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method for performing information mining on historical change records according to various embodiments of the present invention described in the above "Exemplary Method" section of this specification.

[0211] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0212] In addition, an embodiment of the present invention also provides a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, causes the processor to execute the steps of the method for performing information mining on historical change records according to various embodiments of the present invention described in the above “Exemplary Method” section of this specification.

[0213] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0214] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0215] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0216] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0217] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware or any combination of software, hardware, firmware. The above order of steps for the method is only for illustration, and the steps of the method of the present invention are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.

[0218] It should also be noted that in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present invention. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but in accordance with the widest range consistent with the principles and novel features disclosed here.

[0219] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for analyzing and verifying the transient characteristics of short-circuit current, characterized in that: include: Through node selection and impedance calculation between nodes, an in-station calculation model of in-station equipment considering wiring topology is established; Modeling substation external systems based on grid operation mode; According to the corresponding action time characteristics of different fault points, a time-varying impedance model reflecting the protection action characteristics and circuit breaker action characteristics is established; According to the calculation model inside the substation, the external system of the substation and the time-varying impedance model, the transient characteristics of the short-circuit current are analyzed and verified; Among them, through node selection and impedance calculation between nodes, an in-station calculation model of in-station equipment considering wiring topology is established, including: Obtain substation wiring layout; According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, multiple nodes in the substation are determined as the research object; Determine the intra-station nodes having a mutual connection relationship among the plurality of intra-station nodes as connection points; Calculate the connection line impedance between each connection point according to a preset calculation method; According to the impedance of the connection lines between multiple in-station nodes and each connection point, an in-station calculation model of the in-station equipment considering the wiring topology is established; Among them, according to the corresponding action time characteristics of different fault points, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including: The protection action characteristics and circuit breaker action characteristics are described by three times, wherein the three times include the protection exit time t1 after the fault, the time t2 from the circuit breaker action after the protection exit to the mechanical separation of the circuit breaker contacts, and the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker disconnection; According to the corresponding protection action characteristics of different fault points, the value range of each protection exit time t1 is determined respectively, where the protection exit time of the same station takes the same value; According to the mechanical characteristics and dispersion of the circuit breaker, determine the time t2 from the circuit breaker action to the mechanical separation of the circuit breaker contacts after the protection outlet; According to the current waveform and the arc extinguishing characteristics of the circuit breaker, determine the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker opening; According to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established; According to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including: For the first time period from the occurrence of the fault to the mechanical separation of the circuit breaker contacts, the circuit breaker is represented by a fixed impedance, and the impedance is determined according to the circuit breaker's own structural parameters, wherein the first time period is from the moment of the fault occurrence to time t1 plus time t2; For the second time period from mechanical separation of the circuit breaker contacts to the circuit breaker opening, the circuit breaker is represented by a nonlinear resistor, wherein the nonlinear resistor is related to the current value, and the second time period is from the moment when the circuit breaker contacts are mechanically separated to time t3; For the third time period after the circuit breaker is disconnected, the circuit breaker is represented by the break capacitance, wherein the break capacitance value is calculated based on the break voltage-sharing capacitance of the circuit breaker, wherein the third time period is the time period after the circuit breaker is disconnected; Among them, the transient characteristics analysis and verification of short-circuit current are carried out according to the in-station calculation model, substation external system and time-varying impedance model, including: According to the in-station calculation model, substation external system and time-varying impedance model, the electromagnetic transient simulation model of the substation under study is established; Based on the electromagnetic transient simulation model, determine the transient characteristics of short-circuit current of each branch when a fault occurs at each node in the station; The tolerance capacity of the equipment is verified based on the transient characteristics of the short-circuit current of each branch.

2. The method according to claim 1, characterized in that According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, multiple nodes in the substation are determined as the research object, including: According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, the location points with more than two connecting lines in the substation are determined as the nodes in the substation; and / or The locations in the substation that are connected to the two types of equipment are determined as in-station nodes.

3. The method according to claim 1, characterized in that According to the preset calculation method, the connection line impedance between each connection point is calculated, including: For overhead leads, calculate the impedance of the overhead leads based on the outer diameter, height above the ground and length of the overhead leads; For closed busbars lower than gas-insulated metal, the closed busbar impedance is calculated based on the inner and outer radii of the conductors and the inner and outer radii of the pipes, as well as their lengths; For the equipment in the station, the impedance of the equipment in the station is calculated according to the actual parameters of the equipment in the station; For switchgear, the switchgear impedance is calculated based on the outer dimensions of the switchgear.

4. The method according to claim 1, characterized in that: Based on the electromagnetic transient simulation model, determine the transient characteristics of short-circuit current of each branch when a fault occurs at each node in the station, including: Considering the dispersion of protection action characteristics and circuit breaker action characteristics, statistical analysis is performed on the transient waveform of short-circuit current in each branch under different fault moments, protection action moments and circuit breaker opening times; According to the statistical analysis results of the short-circuit current transient waveforms of each branch section, the short-circuit current transient characteristics of each branch section when a fault occurs at each node in the station are determined.

5. The method according to claim 4, characterized in that The transient characteristics of short-circuit current of each branch when a fault occurs at each node in the station include: The maximum peak value of the short-circuit current actually borne, the time of occurrence of the maximum peak value and the waveform of the short-circuit current; The effective value of the AC component, DC component and decay time constant of the short-circuit current actually borne; The actual effective value of the short-circuit current and the duration of the short-circuit current.

6. The method according to claim 5, characterized in that According to the transient characteristics of short-circuit current of each branch, the tolerance capacity of the equipment is verified, including: According to the maximum short-circuit current peak value actually borne by each branch and the time of occurrence of the maximum peak value, check the peak short-circuit current tolerance of the equipment; Check the thermal stability of the equipment according to the maximum effective value of the short-circuit current actually borne by each branch; For the operated circuit breaker, the maximum values ​​of the AC and DC components of the short-circuit current flowing through the operated circuit breaker after the mechanical separation of the circuit breaker contacts are calculated based on the effective value of the AC component, DC component and attenuation time constant of the short-circuit current actually borne by each branch section, and the breaking short-circuit current level of the operated circuit breaker is checked based on the maximum values ​​of the AC and DC components.

7. The method according to claim 1, characterized in that Based on the electromagnetic transient simulation model, determine the transient characteristics of short-circuit current of each branch when a fault occurs at each node in the station, including: Select a node in the station in the electromagnetic transient simulation model; Determine the relay protection and circuit breaker to be operated according to the fault location; Randomly generate a failure moment; Randomly generate each protection action time and circuit breaker opening time; Conduct electromagnetic transient simulation based on each protection action time and circuit breaker opening time; Based on electromagnetic transient simulation, the transient change characteristics of short-circuit current in each branch are obtained; When the statistical simulation is completed and all nodes in the station are traversed, the statistical analysis of the transient characteristics of the short-circuit current ends.

8. A short-circuit current transient characteristic analysis and verification device, characterized in that: include: The in-station calculation model establishment module is used to establish an in-station calculation model of in-station equipment taking into account wiring topology through node selection and impedance calculation between nodes; Substation external system modeling module, used to model the substation external system according to the grid operation mode; The time-varying impedance model building module is used to build a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics according to the action time characteristics corresponding to different fault points; The analysis and verification module is used to analyze and verify the transient characteristics of short-circuit current based on the in-station calculation model, substation external system and time-varying impedance model; Among them, through node selection and impedance calculation between nodes, an in-station calculation model of in-station equipment considering wiring topology is established, including: Obtain substation wiring layout; According to the wiring layout of the substation and the actual wiring layout of the equipment in the substation, multiple nodes in the substation are determined as the research object; Determine the intra-station nodes having a mutual connection relationship among the plurality of intra-station nodes as connection points; Calculate the connection line impedance between each connection point according to a preset calculation method; According to the impedance of the connection lines between multiple in-station nodes and each connection point, an in-station calculation model of the in-station equipment considering the wiring topology is established; Among them, according to the corresponding action time characteristics of different fault points, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including: The protection action characteristics and circuit breaker action characteristics are described by three times, wherein the three times include the protection exit time t1 after the fault, the time t2 from the circuit breaker action after the protection exit to the mechanical separation of the circuit breaker contacts, and the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker disconnection; According to the corresponding protection action characteristics of different fault points, the value range of each protection exit time t1 is determined respectively, where the protection exit time of the same station takes the same value; According to the mechanical characteristics and dispersion of the circuit breaker, determine the time t2 from the circuit breaker action to the mechanical separation of the circuit breaker contacts after the protection outlet; According to the current waveform and the arc extinguishing characteristics of the circuit breaker, determine the time t3 from the mechanical separation of the circuit breaker contacts to the circuit breaker opening; According to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established; According to the time characteristics of time t1, time t2 and time t3, a time-varying impedance model reflecting the protection action characteristics and the circuit breaker action characteristics is established, including: For the first time period from the occurrence of the fault to the mechanical separation of the circuit breaker contacts, the circuit breaker is represented by a fixed impedance, and the impedance is determined according to the circuit breaker's own structural parameters, wherein the first time period is from the moment of the fault occurrence to time t1 plus time t2; For the second time period from mechanical separation of the circuit breaker contacts to the circuit breaker opening, the circuit breaker is represented by a nonlinear resistor, wherein the nonlinear resistor is related to the current value, and the second time period is from the moment when the circuit breaker contacts are mechanically separated to time t3; For the third time period after the circuit breaker is disconnected, the circuit breaker is represented by the break capacitance, wherein the break capacitance value is calculated based on the break voltage-sharing capacitance of the circuit breaker, wherein the third time period is the time period after the circuit breaker is disconnected; Among them, the transient characteristics analysis and verification of short-circuit current are carried out according to the in-station calculation model, substation external system and time-varying impedance model, including: According to the in-station calculation model, substation external system and time-varying impedance model, the electromagnetic transient simulation model of the substation under study is established; Based on the electromagnetic transient simulation model, determine the transient characteristics of short-circuit current of each branch when a fault occurs at each node in the station; The tolerance capacity of the equipment is verified based on the transient characteristics of the short-circuit current of each branch.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 7.

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