Electromagnetic transient simulation method, device, equipment, medium and product

Abstract

The invention discloses an electromagnetic transient simulation method, device and equipment, a medium and a product, and relates to the field of electromagnetic transient simulation, in particular to a method which comprises the steps that a transformer time domain discrete model and a VSC single bridge arm equivalent circuit model are equivalent to a combined equivalent model of a transformer and a current converter based on a combined equivalent modeling method; performing discretization processing on the joint equivalent model by using a Dommel algorithm, determining a discretized equivalent circuit model, listing a node voltage equation, and determining a node admittance matrix; according to the node type, performing blocking processing on the node admittance matrix, and determining a blocked node admittance matrix; eliminating link nodes in the discretized equivalent circuit model according to the partitioned node admittance matrix, and determining an updated discretized equivalent circuit model; and performing electromagnetic transient simulation according to the updated discretized equivalent circuit model. According to the application, the precision and the calculation efficiency of the electromagnetic transient simulation can be greatly improved.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic transient simulation, and in particular to an electromagnetic transient simulation method, device, equipment, medium and product. Background Art

[0002] As the capacity of wind power generation units in the power grid increases, the system will present the characteristics of "double high", that is, a high proportion of clean energy and a high proportion of power electronic devices. A wind farm composed of a large number of wind power generation units will make the equipment in the power system more complex, which makes the 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 the traditional two-level voltage source converter (VSC), line commutated converter (LCC), and modular multilevel converter (MMC), with the requirements of deep-coastal DC wind farms, DC distribution networks, and flexible substations, and the deepening of research, more complex power electronic equipment has emerged, such as high-frequency link power electronic transformers, multi-port energy routers, etc. The time-varying and nonlinear characteristics of these devices are more prominent.

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

[0005] (3) Multiple time scales. There are a large number of devices with different time constants in large wind farms, and the time constants range from nanoseconds, microseconds to milliseconds and seconds. Multiple time scales make electromagnetic transient simulation face the test of accuracy and efficiency. If a large step size simulation is used, the changes in the system cannot be accurately simulated. If a small step size simulation is used, the calculation efficiency will be very low.

[0006] Electromagnetic transient simulation must be both accurate and fast. However, with the above three changes brought about by the access of a large number of wind power units to the power grid, the contradiction between the accuracy and speed of electromagnetic transient simulation has become more prominent. The existing methods are no longer applicable and it is urgent to improve or propose new methods.

[0007] In response to different practical needs, there are different electromagnetic transient simulation models of voltage source converters in wind power generation, which are divided into constant admittance model, dynamic phasor model and efficient model based on multi-port equivalence. Different models have different accuracy, calculation speed and application scenarios.

[0008] (1) Constant admittance model. In order to reduce the simulation error caused by the virtual power loss generated by the inductor-capacitor model when switching the switch state, a constant admittance model of the power electronic converter is established. The constant admittance model represents the power electronic switch elements with small inductors and capacitors, and their values ​​are selected so that the inductor and capacitor elements have the same admittance when discretized, thereby avoiding the change of the admittance matrix and reducing the amount of calculation. However, there are many problems in the actual application of the constant admittance model. For example, the virtual power loss of the constant admittance model in high-frequency switching scenarios will cause huge simulation errors. In addition, the problems such as the inability to quickly perform on / off logic judgment on uncontrollable devices such as diodes or semi-controlled devices, and the selection of simulation step size cannot be too large due to model parameter restrictions, will seriously affect the application scope of the constant admittance model.

[0009] (2) Dynamic phasor model. Theoretically, when a sufficient number of orders is taken into account, the dynamic phasor method can approach the accuracy of the detailed model. However, in practical applications, as the scale of the system increases, the order of the equation increases and the calculation speed decreases due to the hardware capabilities of the computing platform.

[0010] (3) Multi-port equivalent model. The process of equalizing the external ports of the converter at the system level, solving the whole system to obtain the port characteristics, and the process of inversely solving its internal characteristics at the device level all involve matrix operations. A large number of matrix operations will reduce the solution efficiency, especially when the system is complex, the simulation efficiency is even lower. In addition, this method also forms the node admittance matrix through matrix operations, and cannot use the physical nature of the circuit to simplify and speed up the process.

[0011] In summary, the shortcomings of the prior art are mainly:

[0012] In the context of large-scale power grids, faced with the contradiction between accuracy and computational efficiency in electromagnetic transient simulation, most domestic and foreign scholars have focused on converters, ignoring the existence of transformers. For transformers, traditional T-type equivalent circuits or π-type equivalent circuits are used. Although these two equivalent models have the advantage of accuracy, they will increase the number of nodes in the entire system, resulting in a decrease in computational efficiency. In addition, the number of transformers in large-scale wind farms is large, which will also cause 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, device, equipment, medium and product to solve the problem that it is difficult to strike a balance between accuracy and computational efficiency in electromagnetic transient simulation and that the overall simulation computational efficiency is low.

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

[0015] In a first aspect, the present application provides an electromagnetic transient simulation method, comprising:

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

[0017] Discretizing the joint equivalent model using the Dommel algorithm to determine a discretized equivalent circuit model;

[0018] Based on the discretized equivalent circuit model, a node voltage equation is written, and a node admittance matrix is ​​determined according to the node voltage equation;

[0019] According to the node type, the node admittance matrix is ​​processed in blocks to determine the node admittance matrix of the blocks; the node type includes link nodes and edge nodes;

[0020] Eliminating link nodes in the discretized equivalent circuit model according to the node admittance matrix of the blocks, and determining an updated discretized equivalent circuit model;

[0021] Electromagnetic transient simulation is performed according to the updated discretized equivalent circuit model.

[0022] In a second aspect, the present application provides an electromagnetic transient simulation device, comprising:

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

[0024] A discretization processing module, used for discretizing the joint equivalent model using a Dommel algorithm to determine a discretized equivalent circuit model;

[0025] A node admittance matrix determination module, used to write a node voltage equation based on the discretized equivalent circuit model, and determine a node admittance matrix according to the node voltage equation;

[0026] A block processing module, used for performing block processing on the node admittance matrix according to the node type, and determining the node admittance matrix of the block; the node type includes link nodes and edge nodes;

[0027] An updating module, used to eliminate link nodes in the discretized equivalent circuit model according to the node admittance matrix of the blocks, and determine an updated discretized equivalent circuit model;

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

[0029] In a third aspect, the present application provides a computer device, comprising: 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 any of the electromagnetic transient simulation methods described above.

[0030] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the electromagnetic transient simulation methods described above.

[0031] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any of the electromagnetic transient simulation methods described above.

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

[0033] This application is based on a joint equivalent modeling method, which equates the transformer time-domain discrete model and the VSC single bridge arm equivalent circuit model to a joint equivalent model of a transformer and a converter. After the joint equivalent model is discretized using the Dommel algorithm, the node admittance matrix is ​​determined according to the node voltage equation, and the node admittance matrix is ​​divided into blocks based on the node type. The block node admittance matrix is ​​used to eliminate the link nodes in the discretized equivalent circuit model, and only the marginal nodes are retained to determine the updated discretized equivalent circuit model, thereby reducing the number of nodes in the entire system and the order of the system matrix, thereby improving the overall simulation calculation efficiency. When the updated discretized equivalent circuit model is used for electromagnetic transient simulation, the accuracy and calculation efficiency of the electromagnetic transient simulation can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 This is a flow chart of an electromagnetic transient simulation method in one embodiment of the present application;

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

[0037] Figure 3 A schematic diagram of a time-domain discrete model of a capacitor provided in an embodiment of the present application;

[0038] Figure 4 A schematic diagram of a transformer time-domain discrete model provided in an embodiment of the present application;

[0039] Figure 5 A topology diagram of a single bridge arm of a VSC with a DC side capacitor grounded provided in an embodiment of the present application;

[0040] Figure 6 An equivalent circuit diagram of a single bridge arm of a VSC with a grounded DC side capacitor provided in an embodiment of the present application;

[0041] Figure 7 A flow chart of an electromagnetic transient simulation method provided in another embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0044] The present application embodiment provides an electromagnetic transient simulation method, which is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or by a terminal and a server together. In the present application embodiment, Figure 1 As shown, the method includes the following steps.

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

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

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

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

[0049] S105: Eliminate link nodes in the discretized equivalent circuit model according to the node admittance matrix of the blocks, and determine an updated discretized equivalent circuit model.

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

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

[0052] In practical applications, the model of high-frequency transformer needs to consider nonlinear characteristics such as capacitance effect between winding and core, hysteresis effect, frequency variation effect, etc., which leads to the inclusion of a large number of parasitic capacitances in its modeling, and its parameters will change with the frequency, which is very incompatible with the system-level simulation containing a large number of wind power generation units. Considering that in the system, the frequency of voltage and current is generally near the base frequency and does not change much, and when the frequency is low (less than 20KHz), the influence of parasitic capacitance can be ignored, and the change of transformer parameters with frequency can be ignored, thus obtaining a transformer T-type equivalent circuit suitable for simulation of new power systems.

[0053] Using the Dommel (trapezoidal integration method) algorithm, the inductance and capacitance are discretized to obtain the following Figure 2-Figure 3 Discrete time domain model of the inductor and capacitor 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) is the historical current source of the inductor; iC_History(t) is the historical current source of the capacitor; i L (t-Δt), v L (t-Δt) and R L are 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 They are the current, voltage, and equivalent resistance flowing through the inductor and capacitor in the previous step.

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

[0056] Its discretized state equation is:

[0057]

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

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

[0060] Take the VSC converter with ungrounded DC side capacitor as an example. Figure 5 In the figure, L is the VSC AC side reactor, T1~T6 is the switch group composed of IGBT and diode on the VSC bridge arm, and C is the capacitor on the DC side. x Indicates the phase voltage on the AC side (x = A, B, C, indicating three phases ABC, the same below), u d Indicates the DC side capacitor voltage, i x Indicates the input current on the AC side, i cap represents the current flowing through the capacitor, i d Indicates the DC side input current.

[0061] The binary resistance model is used to represent the IGBT switch group, whose on-state resistance is R on , the resistance when turned off is R off , the equivalent circuit diagram is as follows Figure 6 shown.

[0062] By writing the state equation with the inductor current and capacitor voltage in the equivalent circuit diagram as state variables, we can get its state space expression:

[0063]

[0064] Among them, R1-R6 are resistance values.

[0065] That is:

[0066]

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

[0068]

[0069] Since the actual turn-off process can be considered as infinite resistance, R sum =R on +R off ≈∞, so the above iterative formula can be further simplified, that is, G eq =3 / R sum =0, G eq For the equivalent admittance on the DC side, the model will be further simplified.

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

[0071] In practical applications, the joint modeling equivalent algorithm is mainly used to list the node voltage equations through the circuit, and then the nodes connected to the converter and transformer are eliminated by matrix block changes, leaving only the external marginal nodes of the two, thereby obtaining an equivalent model for the marginal nodes, thereby turning the converter and transformer into a joint equivalent model. By eliminating the nodes connected to the converter and transformer, the scale and complexity of matrix operations are reduced, thereby improving computational efficiency.

[0072] The node voltage equation is written for the joint equivalent model of the converter and transformer in the form of:

[0073] YU=J; where Y is the node admittance matrix, U is the node voltage, and J is the injected node current. According to the node type, it is divided into link nodes and marginal nodes, and the matrix can be divided into blocks, as shown in the following formula:

[0074]

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

[0076] Expanding the node voltage equations of the above blocks according to the equations gives:

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

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

[0079] From this, we can get the solution formula for the link node voltage:

[0080]

[0081] Going back and eliminating the link nodes, we can get the node admittance matrix after elimination:

[0082] Y EXEQ U EX =J EXEQ

[0083] in:

[0084] The combined equivalent model of transformer and converter is obtained by analytical method, which reduces the model order without affecting the efficiency of simulation calculation by processing the link nodes.

[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 the converter to obtain a discretized equivalent model circuit, and based on this, the node voltage equation of the equivalent model is formed. From this, the voltage UEX of all marginal nodes can be solved, and the voltage UIN of the link node can be obtained through the solution formula of the link node voltage. Finally, the historical quantity is updated and the next step of calculation can be carried out. The flow chart is shown in Figure 7.

[0086] Based on the same inventive concept, the embodiment of the present application also provides an electromagnetic transient simulation device for implementing the electromagnetic transient simulation method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more electromagnetic transient simulation device embodiments provided below can refer to the limitations on the electromagnetic transient simulation method above, and will not be repeated here.

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

[0088] The equivalent module is used to equate the transformer time domain discrete model and the VSC single bridge 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 bridge arm equivalent circuit model is generated based on the VSC single bridge arm topology model.

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

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

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

[0092] The updating module is used to eliminate the link nodes in the discretized equivalent circuit model according to the node admittance matrix of the blocks, and determine the updated discretized equivalent circuit model.

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

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

[0095] For the converter model: This application uses R on With R offTo describe its conduction and shutdown, thus forming a state space equation, and based on the understanding of its actual physical state, a certain simplification is made, so that it can be adapted to the next step of the joint equivalent modeling method.

[0096] Joint equivalence method for transformers and converters: Based on the models of transformers and converters, the two are equivalent to one model through the joint equivalence modeling method. Matrix block calculation is used to retain only marginal nodes and eliminate 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 computing efficiency will be.

[0097] In the context of "double highs" in large-scale power grids, it is difficult to strike a balance between accuracy and computational efficiency in electromagnetic transient simulation. By considering the transformer and converter as a whole, the defect that most methods only improve one of the two is overcome. This method reduces the order of the system through a joint equivalent modeling method without reducing the simulation accuracy, thereby improving computational efficiency.

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

[0099] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the above method is implemented when the processor executes the computer program.

[0100] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which implements the above method when executed by a processor.

[0101] In an exemplary embodiment, a computer program product is provided, including a computer program, which implements the above method when executed by a processor.

[0102] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ReadOnlyMemory, ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (Magnetoresistive RandomAccess Memory, MRAM), ferroelectric random access memory (Ferroelectric RandomAccess Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (RandomAccess Memory, RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0103] In this application, all actions to obtain signals, information or data are carried out in compliance with the relevant data protection laws and policies of the country where they are located and with the authorization given by the owner of the corresponding device.

[0104] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0105] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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 article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An electromagnetic transient simulation method, characterized in that: The electromagnetic transient simulation method comprises: Based on the joint equivalent modeling method, the transformer time domain discrete model and the VSC single bridge arm equivalent circuit model are equivalent to a joint equivalent model of a transformer and a converter; the transformer time domain discrete model is generated based on the high-frequency transformer model; the VSC single bridge arm equivalent circuit model is generated based on the VSC single bridge arm topology model; Discretizing the joint equivalent model using the Dommel algorithm to determine a discretized equivalent circuit model; Based on the discretized equivalent circuit model, a node voltage equation is written, and a node admittance matrix is ​​determined according to the node voltage equation; According to the node type, the node admittance matrix is ​​processed in blocks to determine the node admittance matrix of the blocks; the node type includes link nodes and edge nodes; Eliminating link nodes in the discretized equivalent circuit model according to the node admittance matrix of the blocks, and determining an updated discretized equivalent circuit model; Electromagnetic transient simulation is performed according to 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 transformer time-domain discrete model and the VSC single bridge arm equivalent circuit model are equivalent to a joint equivalent model of the transformer and the converter, which also includes: The high-frequency transformer model is simplified according to the application scenario requirements to generate a T-type equivalent circuit of the transformer; The inductance and capacitance in the T-type equivalent circuit of the transformer are discretized by using the Dommel algorithm to determine a discrete model of the transformer in the time domain; The binary resistance model is used to represent the IGBT switch group in the VSC single bridge arm topology model, and the VSC single bridge arm equivalent circuit model is generated.

3. The electromagnetic transient simulation method according to claim 1, characterized in that: The node admittance matrix of the block is: Among them, Y ij is the node admittance matrix of the block in row i and column j, i=j=1,2; U EX is the marginal node voltage; J EX Inject current into the edge node; U IN is the link node voltage; J IN Injects current into the link node.

4. The electromagnetic transient simulation method according to claim 3, characterized in that: Eliminating link nodes in the discretized equivalent circuit model according to the node admittance matrix of the blocks to determine an updated discretized equivalent circuit model specifically includes: Determine a solution formula for link node voltage according to the node admittance matrix of the blocks; Eliminate link nodes in the discretized equivalent circuit model according to the solution formula for link node voltage, and determine the node admittance matrix after elimination; An updated discretized equivalent circuit model is determined according to the eliminated node admittance matrix.

5. The electromagnetic transient simulation method according to claim 4, characterized in that: The solution formula for the link node voltage is:

6. The electromagnetic transient simulation method according to claim 5, characterized in that: The node admittance matrix after the elimination is: Y EXEQ U EX =J EXEQ ; in, 7. An electromagnetic transient simulation device, characterized in that: The electromagnetic transient simulation device comprises: An equivalent module is used to convert the transformer time-domain discrete model and the VSC single bridge arm equivalent circuit model into a joint equivalent model of a transformer and a converter based on a joint equivalent modeling method; the transformer time-domain discrete model is generated based on a high-frequency transformer model; the VSC single bridge arm equivalent circuit model is generated based on a VSC single bridge arm topology model; A discretization processing module, used for discretizing the joint equivalent model using a Dommel algorithm to determine a discretized equivalent circuit model; A node admittance matrix determination module, used to write a node voltage equation based on the discretized equivalent circuit model, and determine a node admittance matrix according to the node voltage equation; A block processing module, used for performing block processing on the node admittance matrix according to the node type, and determining the node admittance matrix of the block; the node type includes link nodes and edge nodes; An updating module, used to eliminate link nodes in the discretized equivalent circuit model according to the node admittance matrix of the blocks, and determine an updated discretized equivalent circuit model; The electromagnetic transient simulation module is used to perform electromagnetic transient simulation according to the updated discretized equivalent circuit model.

8. A computer device comprising: 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 according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the electromagnetic transient simulation method described in any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the electromagnetic transient simulation method described in any one of claims 1 to 6 is implemented.

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