An electromagnetic transient simulation method, apparatus, equipment, medium, and product

Abstract

This application discloses an electromagnetic transient simulation method, apparatus, equipment, medium, and product, relating to the field of electromagnetic transient simulation. Specifically, it relates to a method that includes: using a joint equivalent modeling approach, equipping a transformer time-domain discrete model and a VSC single-arm equivalent circuit model with a joint equivalent model of the transformer and converter; discretizing the joint equivalent model using the Dommel algorithm to determine the discretized equivalent circuit model, writing the node voltage equations, and determining the node admittance matrix; dividing the node admittance matrix into blocks according to node type to determine the block node admittance matrix; eliminating link nodes in the discretized equivalent circuit model based on the block node admittance matrix to determine the updated discretized equivalent circuit model; and performing electromagnetic transient simulation based on the updated discretized equivalent circuit model. This application can significantly improve the accuracy and computational efficiency of electromagnetic transient simulation.

Description

Technical Field

[0001] This application relates to the field of electromagnetic transient simulation, and in particular to an electromagnetic transient simulation method, apparatus, equipment, medium and product. Background Technology

[0002] As the proportion of wind power generation units in the power grid increases, the system will exhibit "dual high" characteristics: a high proportion of clean energy and a high proportion of power electronic devices. The large number of wind power generation units in a wind farm will make the equipment in the power system more complex, thus making electromagnetic transient simulation of the power system more difficult. With the addition of a large number of wind farms, the equipment in the power system will undergo the following changes:

[0003] (1) More complex characteristics. In addition to traditional two-level voltage source converters (VSC), line commutated converters (LCC), and modular multilevel converters (MMC), with the emergence of demands and in-depth research on deep-shore DC wind farms, DC distribution networks, and flexible substations, more complex power electronic devices have appeared, such as high-frequency chain power electronic transformers and multi-port energy routers. These devices exhibit more prominent time-varying and nonlinear characteristics.

[0004] (2) The order of the system matrix is ​​high. As a large number of wind turbines transmit electrical energy to the power grid through converters and transformers, the order of the system matrix increases sharply with the connection of a large number of components, which has a great impact on the simulation speed.

[0005] (3) Multiple time scales. Large wind farms contain a large number of devices with different time constants, ranging from nanoseconds and microseconds to milliseconds and seconds. The multiple time scales pose challenges to the accuracy and efficiency of electromagnetic transient simulation. If a large step size simulation is used, it is impossible to accurately simulate the changes in the system. If a small step size simulation is used, the computational efficiency will be very low.

[0006] Electromagnetic transient simulation needs to be both accurate and fast. However, with the changes brought about by the connection of a large number of wind power generation units to the power grid, the contradiction between the accuracy and speed of electromagnetic transient simulation has become more prominent. Existing methods are no longer applicable, and there is an urgent need to improve or propose new methods.

[0007] To address different practical needs, various electromagnetic transient simulation models exist for voltage source converters in wind power generation, categorized into constant admittance models, dynamic phasor models, and high-efficiency models based on multi-port equivalence. These different models offer varying levels of accuracy, computational speed, and application scenarios.

[0008] (1) Constant Admittance Model. To reduce simulation errors caused by virtual power losses during switching in the inductor-capacitor model, a constant admittance model for the power electronic converter was established. The constant admittance model represents the power electronic switching elements with small inductors and capacitors, whose values ​​ensure that the inductors and capacitors have the same admittance during discretization, thus avoiding changes in the admittance matrix and reducing computational complexity. However, the constant admittance model presents several problems in practical applications. For example, the virtual power losses in high-frequency switching scenarios can cause significant simulation errors. Furthermore, the inability to quickly determine the on / off logic for uncontrollable or semi-controlled devices such as diodes, and the limitation of the simulation step size by model parameters, all severely affect the application scope of the constant admittance model.

[0009] (2) Dynamic phasor model. Theoretically, when sufficient order is considered, the dynamic phasor method can approach the accuracy of the detailed model. However, in practical applications, as the system scale increases, the order of the equations increases due to the limitations of the computing platform's hardware capabilities, resulting in a decrease in computation speed.

[0010] (3) Multi-port equivalent model. The process of obtaining port characteristics by performing external port equivalence calculations and solving the entire system at the system level, as well as the process of inversely solving the internal characteristics at the device level, both involve matrix operations. A large number of matrix operations can lead to low solution efficiency, especially when the system is complex, resulting in even lower simulation efficiency. Furthermore, this method also uses matrix operations to form the node admittance matrix, failing to utilize the physical nature of the circuit to simplify and speed up the process.

[0011] In summary, the main drawbacks of existing technologies are:

[0012] In the context of large-scale power grids, facing the contradiction between accuracy and computational efficiency in electromagnetic transient simulation, most scholars at home and abroad have focused on converters, ignoring the existence of transformers. While traditional T-type or π-type equivalent circuits are used for transformers, these two equivalent models, although having the advantage of accuracy, increase the number of nodes in the entire system, leading to a decrease in computational efficiency. Moreover, in large-scale wind farms, the number of transformers is numerous, which also causes a sharp drop in the overall simulation speed. Summary of the Invention

[0013] The purpose of this application is to provide an electromagnetic transient simulation method, apparatus, equipment, medium, and product to solve the problem that it is difficult to balance the accuracy and computational efficiency of electromagnetic transient simulation, and that the overall simulation computational efficiency is low.

[0014] To achieve the above objectives, this application provides the following solution:

[0015] Firstly, this application provides an electromagnetic transient simulation method, including:

[0016] Based on the joint equivalent modeling method, the time-domain discrete model of the transformer and the equivalent circuit model of a single VSC arm are converted into a joint equivalent model of the transformer and the converter; the time-domain discrete model of the transformer is generated based on the high-frequency transformer model; the equivalent circuit model of a single VSC arm is generated based on the topology model of a single VSC arm.

[0017] The joint equivalent model is discretized using the Dommel algorithm to determine the discretized equivalent circuit model.

[0018] Based on the discretized equivalent circuit model, the node voltage equations are written, and the node admittance matrix is ​​determined according to the node voltage equations.

[0019] Based on the node type, the node admittance matrix is ​​divided into blocks to determine the block node admittance matrix; the node type includes link nodes and edge nodes;

[0020] Based on the node admittance matrix of the block, the link nodes in the discretized equivalent circuit model are eliminated, and the updated discretized equivalent circuit model is determined.

[0021] Electromagnetic transient simulations were performed based on the updated discretized equivalent circuit model.

[0022] Secondly, this application provides an electromagnetic transient simulation device, comprising:

[0023] The equivalent module is used to convert the transformer time-domain discrete model and the VSC single-arm equivalent circuit model into a joint equivalent model of the transformer and the converter based on the joint equivalent modeling method; the transformer time-domain discrete model is generated based on the high-frequency transformer model; the VSC single-arm equivalent circuit model is generated based on the VSC single-arm topology model.

[0024] The discretization module is used to discretize the joint equivalent model using the Dommel algorithm to determine the discretized equivalent circuit model.

[0025] The node admittance matrix determination module is used to write the node voltage equations based on the discretized equivalent circuit model, and determine the node admittance matrix according to the node voltage equations.

[0026] The block processing module is used to divide the node admittance matrix into blocks according to the node type to determine the block node admittance matrix; the node type includes link nodes and edge nodes.

[0027] The update module is used to eliminate link nodes in the discretized equivalent circuit model based on the node admittance matrix of the block, and determine the updated discretized equivalent circuit model.

[0028] The electromagnetic transient simulation module is used to perform electromagnetic transient simulation based on the updated discretized equivalent circuit model.

[0029] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the electromagnetic transient simulation method described in any one of the above.

[0030] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the electromagnetic transient simulation method described in any one of the above.

[0031] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the electromagnetic transient simulation method described in any one of the above descriptions.

[0032] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0033] This application uses a joint equivalent modeling method to convert the transformer time-domain discrete model and the VSC single-arm equivalent circuit model into a joint equivalent model of the transformer and converter. After discretizing the joint equivalent model using the Dommel algorithm, the node admittance matrix is ​​determined based on the node voltage equation. The node admittance matrix is ​​then divided into blocks based on the node type. By using the block node admittance matrix, the link nodes in the discretized equivalent circuit model are eliminated, and only the marginal nodes are retained. This results in an updated discretized equivalent circuit model, which reduces the number of nodes in the entire system and the order of the system matrix, thereby improving the overall simulation efficiency. When using the updated discretized equivalent circuit model for electromagnetic transient simulation, the accuracy and computational efficiency of the electromagnetic transient simulation can be significantly improved. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, 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 based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart of an electromagnetic transient simulation method according to an embodiment of this application;

[0036] Figure 2 A schematic diagram of a time-domain discrete model of an inductor provided in an embodiment of this application;

[0037] Figure 3 This is a schematic diagram of a time-domain discrete model of a capacitor provided in an embodiment of this application;

[0038] Figure 4 This is a schematic diagram of a time-domain discrete model of a transformer provided in an embodiment of this application;

[0039] Figure 5 A single bridge arm topology diagram of a VSC with DC-side capacitor grounded, provided in one embodiment of this application;

[0040] Figure 6 Equivalent circuit diagram of a single bridge arm of a VSC with DC-side capacitor grounded, provided in an embodiment of this application;

[0041] Figure 7 A flowchart of an electromagnetic transient simulation method provided in another embodiment of this application. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and 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.

[0043] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] This application provides an electromagnetic transient simulation method, which is executed by a computer device. Specifically, it can be executed by a computer device such as a terminal or a server alone, or it can be executed by both a terminal and a server. In this application embodiment, for example... Figure 1 As shown, the method includes the following steps.

[0045] S101: Based on the joint equivalent modeling method, the time-domain discrete model of the transformer and the equivalent circuit model of a single bridge arm of the VSC are converted into a joint equivalent model of the transformer and the converter; the time-domain discrete model of the transformer is generated based on the high-frequency transformer model; the equivalent circuit model of a single bridge arm of the VSC is generated based on the topology model of a single bridge arm of the VSC.

[0046] S102: Discretize the joint equivalent model using the Dommel algorithm to determine the discretized equivalent circuit model.

[0047] S103: Based on the discretized equivalent circuit model, write the node voltage equations and determine the node admittance matrix according to the node voltage equations.

[0048] S104: Based on the node type, the node admittance matrix is ​​divided into blocks to determine the block node admittance matrix; the node type includes link nodes and edge nodes.

[0049] S105: Based on the node admittance matrix of the block, eliminate the link nodes in the discretized equivalent circuit model and determine the updated discretized equivalent circuit model.

[0050] S106: Perform electromagnetic transient simulation based on the updated discretized equivalent circuit model.

[0051] In an exemplary embodiment, S101 further includes: simplifying the high-frequency transformer model according to the application scenario requirements to generate a transformer T-type equivalent circuit; using the Dommel algorithm to discretize the inductance and capacitance in the transformer T-type equivalent circuit to determine the time-domain discrete model of the transformer; and using a binary resistor model to represent the IGBT switch group in the VSC single-arm topology model to generate a VSC single-arm equivalent circuit model.

[0052] In practical applications, the model of a high-frequency transformer needs to consider nonlinear characteristics such as capacitance, hysteresis, and frequency-dependent effects between the windings and the core. This results in a large amount of parasitic capacitance being included in the model, and the parameters of the transformer change with frequency, making it highly unsuitable for system-level simulations involving numerous wind power generation units. Considering that the frequencies of voltage and current in a system are generally near the fundamental frequency and do not change much, and that the influence of parasitic capacitance can be ignored at lower frequencies (below 20kHz), as can the frequency-dependent changes in transformer parameters, a T-type equivalent circuit of the transformer suitable for simulation of new power systems can be obtained.

[0053] Using the Dommel (trapezoidal integral) algorithm, the inductor and capacitor are discretized to obtain the following: Figure 2-Figure 3 The time-domain discrete model of the inductor and capacitor is shown.

[0054] Figure 2 in i L_History(t) =-i L (t-Δt)-v L (t-Δt) / R L , Figure 3 in i C_History(t) =-i C (t-Δt)-v C (t-Δt) / R C ;where i L_History(t) The historical current source of the inductor; iC_History(t) The historical current source of the capacitor; i L (t-Δt), v L (t-Δt) and R L These represent the current, voltage, and equivalent resistance flowing through the inductor and capacitor in the previous step, respectively; i C (t-Δt), v C (t-Δt) and R C These are the current, voltage, and equivalent resistance flowing through the inductor and capacitor in the previous step, respectively.

[0055] Based on this, a time-domain discrete model of the transformer can be obtained, such as Figure 4 As shown, j T1_HIS and j T2_HIS For historical current sources; Y T11 and Y T22 Y is the self-admittance, representing the sum of the conductances of all branches connected to the primary and secondary nodes of the transformer; T12 and Y T21 It is mutual admittance, reflecting the coupling effect of the primary and secondary sides.

[0056] Its discretized state equation is:

[0057]

[0058] in, Let be the current and voltage on the primary and secondary sides at the current time step t.

[0059] Let be the current and voltage on the primary and secondary sides at the previous time step t-Δt.

[0060] Taking a VSC converter with an ungrounded DC-side capacitor as an example, such as Figure 5 In the diagram, L represents the AC side reactor of the VSC, T1 to T6 are the switching groups composed of IGBTs and diodes on the VSC bridge arms, and C is the DC side capacitor. x Indicates the phase voltage on the AC side (x = A, B, C, representing the three phases A, B, and C, the same below), u d Indicates the DC-side capacitor voltage, i x Indicates the AC input current, i cap i represents the current flowing through the capacitor. d This indicates the DC input current.

[0061] The IGBT switching group is represented using a binary resistor model, where its resistance is R when it is turned on. on The resistance when turned off is R. off The equivalent circuit diagram is as follows: Figure 6 As shown.

[0062] By writing the state equations using the inductor current and capacitor voltage in the equivalent circuit diagram as state variables, we can obtain its state-space expression:

[0063]

[0064] Where R1-R6 are resistance values.

[0065] That is:

[0066]

[0067] Where: L x To measure the inductance value of an AC reactor, R eqx R is the equivalent resistance of the bridge arm. sum It is the sum of the on-resistance and the off-resistance.

[0068]

[0069] Since the resistance can be considered infinite during the actual turn-off process, R sum =R on +R off Since ≈∞, the above iterative formula can be further simplified, i.e., G eq =3 / R sum =0, G eq The model will be further simplified by using the DC-side equivalent admittance.

[0070] In an exemplary embodiment, S105 specifically includes: determining the solution formula for the link node voltage based on the node admittance matrix of the block; eliminating link nodes in the discretized equivalent circuit model based on the solution formula for the link node voltage, and determining the eliminated node admittance matrix; and determining the updated discretized equivalent circuit model based on the eliminated node admittance matrix.

[0071] In practical applications, the joint modeling equivalent algorithm mainly derives the nodal voltage equations through the circuit. Then, through matrix block transformation and other methods, the nodes connecting the converter and transformer are eliminated, leaving only the external boundary nodes. This yields an equivalent model for the boundary nodes, thus transforming the converter and transformer into a joint equivalent model. Eliminating the nodes connecting the converter and transformer reduces the scale and complexity of matrix operations, thereby improving computational efficiency.

[0072] The nodal voltage equations for the joint equivalent model of the converter and transformer are written in the following form:

[0073] YU = J; where Y is the node admittance matrix, U is the node voltage, and J is the injected node current. Based on node type, nodes are categorized as linked nodes and edge nodes, and the matrix can be divided into blocks as shown in the following equation:

[0074]

[0075] Where Y is the node admittance matrix, and the subscripts 11, 12, 21, 22 are used to represent the block node admittance matrix, U EX J is the marginal node voltage; EX Inject current into the edge node; U IN For the link node voltage; J IN Inject current into the link node.

[0076] Expanding the above block-specific nodal voltage equations yields:

[0077] Y 11 U EX +Y 12 U IN =J EX .

[0078] Y 21 U EX +Y 22 U IN =J IN .

[0079] Therefore, the formula for solving the link node voltage can be obtained:

[0080]

[0081] Going back further and eliminating the linked nodes, we can obtain the node admittance matrix after elimination:

[0082] Y EXEQ U EX =J EXEQ

[0083] in:

[0084] A joint equivalent model of the transformer and converter was obtained through analytical methods. By processing the chain and connection nodes, the model order was reduced without affecting the simulation calculation efficiency.

[0085] First, the system is initialized and the initial time is set to 0. The Dommel algorithm is used to discretize the joint equivalent model of the transformer and converter, thereby obtaining the discretized equivalent model circuit. Based on this, the node voltage equations of the equivalent model are formed, and the voltage UEX of all marginal nodes can be calculated. Then, the voltage UIN of the linked nodes can be obtained by solving the formula for the linked node voltage. Finally, the historical values ​​are updated, and the next step of calculation can be performed. The flowchart is shown in Figure 7.

[0086] Based on the same inventive concept, this application also provides an electromagnetic transient simulation device for implementing the electromagnetic transient simulation method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more electromagnetic transient simulation device embodiments provided below can be found in the limitations of the electromagnetic transient simulation method described above, and will not be repeated here.

[0087] In one exemplary embodiment, an electromagnetic transient simulation device is provided, comprising:

[0088] The equivalent module is used to convert the time-domain discrete model of the transformer and the equivalent circuit model of a single arm of the VSC into a joint equivalent model of the transformer and the converter based on the joint equivalent modeling method. The time-domain discrete model of the transformer is generated based on the high-frequency transformer model. The equivalent circuit model of a single arm of the VSC is generated based on the topology model of a single arm of the VSC.

[0089] The discretization module is used to discretize the joint equivalent model using the Dommel algorithm to determine the discretized equivalent circuit model.

[0090] The node admittance matrix determination module is used to write the node voltage equations based on the discretized equivalent circuit model, and determine the node admittance matrix according to the node voltage equations.

[0091] The block processing module is used to divide the node admittance matrix into blocks according to the node type and determine the block node admittance matrix; the node type includes link nodes and edge nodes.

[0092] The update module is used to eliminate link nodes in the discretized equivalent circuit model based on the node admittance matrix of the block, and determine the updated discretized equivalent circuit model.

[0093] The electromagnetic transient simulation module is used to perform electromagnetic transient simulation based on the updated discretized equivalent circuit model.

[0094] Regarding the transformer model: This application simplifies the high-frequency transformer model based on the needs of practical application scenarios, thereby obtaining a transformer T-type equivalent circuit suitable for simulation of new power systems. Furthermore, using the Dommel algorithm, a time-domain discrete model of the transformer is obtained, which can intuitively reflect the coupling relationship between the primary and secondary sides.

[0095] Regarding the converter model: This application uses R to replace the equivalent topology change behavior of the converter switch. on With R offThis is used to describe its on and off states, thus forming a state-space equation. Based on our understanding of its actual physical state, we have simplified it to some extent, which allows it to be adapted to the next step of joint equivalent modeling.

[0096] For the joint equivalent method of transformer and converter: Based on the models of transformer and converter, the two are equivalent to a single model through joint equivalent modeling. The matrix is ​​used for block calculation, retaining only the edge nodes and eliminating the link nodes, thereby reducing the order of the system matrix. Theoretically, the larger the scale of the wind farm, the more significant the improvement in calculation efficiency of this method will be.

[0097] In the context of large-scale power grids with "high speed and high efficiency," electromagnetic transient simulation faces the challenge of balancing accuracy and computational efficiency. By treating transformers and converters as a whole, this approach overcomes the shortcomings of most methods that only improve one of them. It achieves the goal of reducing the system order through joint equivalent modeling without compromising simulation accuracy, thereby improving computational efficiency.

[0098] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal. The computer device includes a processor, memory, input / output interfaces (I / O), and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is connected to the system bus via the I / O interfaces. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database of the computer device stores electromagnetic transient simulation data. The I / O interfaces of the computer device are used for exchanging information between the processor and external devices. The communication interface of the computer device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements an electromagnetic transient simulation method.

[0099] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described above.

[0100] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the methods described above.

[0101] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the methods described above.

[0102] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0103] In this application, all actions to acquire signals, information, or data are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with the authorization granted by the owner of the relevant device.

[0104] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An electromagnetic transient simulation method, characterized in that, The electromagnetic transient simulation method includes: Based on the joint equivalent modeling method, the time-domain discrete model of the transformer and the equivalent circuit model of a single VSC arm are converted into a joint equivalent model of the transformer and the converter; the time-domain discrete model of the transformer is generated based on the high-frequency transformer model; the equivalent circuit model of a single VSC arm is generated based on the topology model of a single VSC arm. The joint equivalent model is discretized using the Dommel algorithm to determine the discretized equivalent circuit model. Based on the discretized equivalent circuit model, the node voltage equations are written, and the node admittance matrix is ​​determined according to the node voltage equations. Based on the node type, the node admittance matrix is ​​divided into blocks to determine the block node admittance matrix; the node type includes link nodes and edge nodes; The node admittance matrix of the segment is: Among them, Y ij U is the node admittance matrix of the block in the i-th row and j-th column, where i = j = 1, 2; EX J is the marginal node voltage; EX Inject current into the edge node; U IN For the link node voltage; J IN Inject current into the link node; Based on the node admittance matrix of the segment, the linked nodes in the discretized equivalent circuit model are eliminated, and the updated discretized equivalent circuit model is determined, specifically including: The formula for solving the link node voltage is determined based on the node admittance matrix of the block; the formula for solving the link node voltage is: Based on the formula for solving the linked node voltage, the linked nodes in the discretized equivalent circuit model are eliminated, and the node admittance matrix after elimination is determined; the node admittance matrix after elimination is: Y EXEQ U EX *J EXEQ ; in, Based on the eliminated node admittance matrix, the updated discretized equivalent circuit model is determined; Electromagnetic transient simulations were performed based on the updated discretized equivalent circuit model.

2. The electromagnetic transient simulation method according to claim 1, characterized in that, Based on the joint equivalent modeling method, the time-domain discrete model of the transformer and the equivalent circuit model of a single arm of the VSC are converted into a joint equivalent model of the transformer and the converter. This previously included: The high-frequency transformer model is simplified according to the application scenario requirements to generate the transformer T-type equivalent circuit; The inductance and capacitance in the transformer T-equivalent circuit are discretized using the Dommel algorithm to determine the time-domain discrete model of the transformer. The IGBT switch group in a single bridge arm topology model of VSC is represented by a binary resistor model, and an equivalent circuit model of a single bridge arm of VSC is generated.

3. An electromagnetic transient simulation device, characterized in that, The electromagnetic transient simulation device employs the electromagnetic transient simulation method according to any one of claims 1-2, and the electromagnetic transient simulation device comprises: The equivalent module is used to convert the transformer time-domain discrete model and the VSC single-arm equivalent circuit model into a joint equivalent model of the transformer and the converter based on the joint equivalent modeling method; the transformer time-domain discrete model is generated based on the high-frequency transformer model; the VSC single-arm equivalent circuit model is generated based on the VSC single-arm topology model. The discretization module is used to discretize the joint equivalent model using the Dommel algorithm to determine the discretized equivalent circuit model. The node admittance matrix determination module is used to write the node voltage equations based on the discretized equivalent circuit model, and determine the node admittance matrix according to the node voltage equations. The block processing module is used to divide the node admittance matrix into blocks according to the node type to determine the block node admittance matrix; the node type includes link nodes and edge nodes. The update module is used to eliminate link nodes in the discretized equivalent circuit model based on the node admittance matrix of the block, and determine the updated discretized equivalent circuit model. The electromagnetic transient simulation module is used to perform electromagnetic transient simulation based on the updated discretized equivalent circuit model.

4. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the electromagnetic transient simulation method according to any one of claims 1-2.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the electromagnetic transient simulation method according to any one of claims 1-2.

6. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the electromagnetic transient simulation method according to any one of claims 1-2.

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