WO2024082163A1

WO2024082163A1 - Method for electromagnetic transient simulation of transformer, computer device, and storage medium

Info

Publication number: WO2024082163A1
Application number: PCT/CN2022/126082
Authority: WO
Inventors: 彭庆军; 施勇; 邹德旭; 李国友; 王欣; 王浩州
Original assignee: 云南电网有限责任公司电力科学研究院
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2024-04-25

Abstract

The present application relates to a method for electromagnetic transient simulation of a transformer. The method comprises: building a transformer model on the basis of a finite-difference time-domain method, and setting the time step of the transformer model; acquiring a frequency response curve of the transformer; updating an electric field component and a magnetic field component of the transformer model on the basis of the frequency response curve to obtain an electric field component of the current time step and a magnetic field component of the current time step; and if the electric field component of the current time step or the magnetic field component of the current time step converges, ending the simulation. According to the present application, the transformer model is established on the basis of the finite-difference time-domain method, without the need of complex and tedious calculation and on-site tests, so that the calculation efficiency can be greatly improved. In addition, the electric field component and the magnetic field component of the transformer model are updated on the basis of the frequency response curve. In this way, electromagnetic response parameters of a frequency-dependent transformer can be taken into full consideration in the time domain, thereby greatly improving simulation precision.

Description

A transformer electromagnetic transient simulation method, computer equipment and storage medium

Technical Field

The present application relates to the technical field of transformers, and in particular to a transformer electromagnetic transient simulation method, a computer device, and a storage medium.

Background technique

Power transformers are one of the most important equipment in the power system. Once a power transformer fails, it will cause great disturbances to the power system, and even interrupt the power supply of the power system, which will greatly affect industrial production and the normal life of residents. Moreover, the cost of large power transformers is very expensive. If the protection device cannot work correctly when the transformer fails, it may cause different degrees of damage to the transformer or even burn it, which will lead to very serious economic losses. Therefore, it is very necessary to study the transient process of power transformers. By studying the working principles of various transient processes of transformers, it is effective to avoid further expansion of power accidents and damage to transformers. At the same time, it can also improve the design and manufacturing level of power transformers, and provide a theoretical basis for the manufacture of transformers and the mechanism of various operation and fault conditions. However, the existing transformer simulation technology requires a large number of complex and tedious calculations and some complex field tests. It is difficult to consider frequency-varying parameters, the simulation efficiency is low, and it is difficult to consider transient impulse responses with broadband characteristics.

Summary of the invention

Based on this, it is necessary to provide a transformer electromagnetic transient simulation method, computer equipment and storage medium. This solution applies the finite time-domain difference method to the simulation of the electromagnetic transient process of the power transformer, adopts the vector matching method to fit the frequency characteristic curve of the transformer equipment, and combines the time-domain convolution method to fully consider the frequency-varying characteristics of the transformer equipment in the time-domain transient simulation calculation, thereby greatly improving the time-domain simulation accuracy. Compared with the existing technical solutions, this patent has the advantages of high simulation efficiency, high accuracy, good stability, small memory space occupation, one-time calculation of broadband transient processes, explicit calculation without large matrix inversion, and convenient acceleration of calculation through high-performance graphics computing processors, etc., providing computing support for the manufacture of transformers and the analysis of various operation and fault conditions.

In a first aspect, the present application provides a transformer electromagnetic transient simulation method, the method comprising:

Establishing a transformer model based on a finite time-domain difference method, and setting a time step for the transformer model;

Obtain the frequency characteristic curve of the transformer;

Based on the frequency characteristic curve, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step;

If the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends.

In combination with the first aspect, in one achievable manner, the method further includes: if the number of iterations corresponding to the current time step is greater than an iteration number threshold, the simulation ends.

In combination with the first aspect, in one achievable manner, establishing a transformer model based on the finite time-domain difference method includes: determining a target calculation area of the finite time-domain difference method according to the structural size of the transformer; and establishing the transformer model within the target calculation area.

In combination with the first aspect, in an implementable manner, setting the time step of the transformer model includes: setting the time step of the transformer model according to the following time step formula:

Among them, Δx, Δy, Δz are the minimum grid sizes of the finite time-domain difference method grid in the three orthogonal directions of X, Y, and Z, c is the propagation speed of light in the corresponding medium, and Δt is the maximum time step.

In combination with the first aspect, in an achievable manner, the electric field component and the magnetic field component of the transformer model are updated based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step, including: using a vector matching method to fit the frequency-varying function corresponding to the frequency characteristic curve to obtain a first-order rational function; based on the first-order rational function, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step.

In combination with the first aspect, in an achievable manner, the electric field component of the transformer model is updated based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step, including: inputting the convolution form of the first-order rational function into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step.

In combination with the first aspect, in an achievable manner, updating the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step includes: inputting the convolution form of the first-order rational function into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.

In a second aspect, the present application provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

Obtain the frequency characteristic curve of the transformer;

In combination with the second aspect, in one achievable manner, the method further includes: if the number of iterations corresponding to the current time step is greater than an iteration number threshold, the simulation ends.

In combination with the second aspect, in one achievable manner, establishing a transformer model based on the finite time-domain difference method includes: determining a target calculation area of the finite time-domain difference method according to the structural size of the transformer; and establishing a transformer model within the target calculation area.

In conjunction with the second aspect, in an implementable manner, setting the time step of the transformer model includes: setting the time step of the transformer model according to the following time step formula:

In combination with the second aspect, in an achievable manner, the electric field component and the magnetic field component of the transformer model are updated based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step, including: using a vector matching method to fit the frequency-varying function corresponding to the frequency characteristic curve to obtain a first-order rational function; based on the first-order rational function, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step.

In combination with the second aspect, in an achievable manner, the electric field component of the transformer model is updated based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step, including: inputting the convolution form of the first-order rational function into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step.

In combination with the second aspect, in an achievable manner, updating the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step includes: inputting the convolution form of the first-order rational function into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.

In a third aspect, the present application provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor performs the following steps:

Obtain the frequency characteristic curve of the transformer;

In combination with the third aspect, in one achievable manner, the method further includes: if the number of iterations corresponding to the current time step is greater than an iteration number threshold, the simulation ends.

In combination with the third aspect, in an achievable manner, establishing a transformer model based on the finite time-domain difference method includes: determining a target calculation area of the finite time-domain difference method according to the structural size of the transformer; and establishing a transformer model within the target calculation area.

In conjunction with the third aspect, in an implementable manner, setting the time step of the transformer model includes: setting the time step of the transformer model according to the following time step formula:

In combination with the third aspect, in an achievable manner, the electric field component and the magnetic field component of the transformer model are updated based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step, including: using a vector matching method to fit the frequency-varying function corresponding to the frequency characteristic curve to obtain a first-order rational function; based on the first-order rational function, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step.

In combination with the third aspect, in an achievable manner, the electric field component of the transformer model is updated based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step, including: inputting the convolution form of the first-order rational function into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step.

In combination with the third aspect, in an achievable manner, updating the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step includes: inputting the convolution form of the first-order rational function into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.

The present invention provides a transformer electromagnetic transient simulation method, the method comprising: establishing a transformer model based on a finite time-domain difference method, and setting a time step for the transformer model; obtaining a frequency characteristic curve of the transformer; based on the frequency characteristic curve, updating the electric field component and the magnetic field component of the transformer model, and obtaining the electric field component of the current time step and the magnetic field component of the current time step; if the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends. The present application establishes a transformer model based on a finite time-domain difference method, does not require complex and tedious calculations and field tests, and can greatly improve the calculation efficiency; and the present application updates the electric field component and the magnetic field component of the transformer model based on the frequency characteristic curve, and can fully consider the frequency-varying transformer electromagnetic characteristic parameters in the time domain, greatly improving the simulation accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

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 or the description of the prior art 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 the structures shown in these drawings without paying any creative work.

FIG1 is a schematic diagram of a flow chart of a transformer electromagnetic transient simulation method provided in an embodiment of the present application;

FIG2 is a schematic diagram of an electric field vector in a grid provided in an embodiment of the present application;

FIG3 is a schematic diagram of a magnetic field vector in a grid provided in an embodiment of the present application;

FIG4 is a schematic diagram of an electromagnetic field vector in a grid provided in an embodiment of the present application;

FIG5 is a magnetic field frequency characteristic curve of a long straight conductor with a rectangular cross section and a vector matching method fitting curve thereof provided in an embodiment of the present application;

FIG6 is a current frequency characteristic curve of a long straight conductor with a rectangular cross section and a vector matching method fitting curve thereof provided in an embodiment of the present application;

FIG7 is a schematic structural diagram of a transformer electromagnetic transient simulation device provided in an embodiment of the present application;

FIG8 is a schematic diagram of the structure of a computer device provided in an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

In order to facilitate the understanding of this solution, the technical solution of this application is first introduced as a whole. This application establishes a transformer model based on the finite time-domain difference method, and sets the grid size, time step, and material properties of the transformer model; through experimental or theoretical analysis, the material parameter characteristic curve of the transformer that changes nonlinearly with frequency is obtained, and the characteristic curve is fitted into a set of rational functions based on frequency domain analysis; based on the rational function, the Laplace transform technology is applied to convert it into a time domain update equation, and replace the classic update equations of the electric field component and the magnetic field component that need to consider the frequency-varying material characteristics in the transformer model; after the iterative calculation starts, the electric field vector and the magnetic field vector in the transformer model are calculated based on the Maxwell equations or based on the rational function time domain update equation to obtain the electric field component of the current time step and the magnetic field component of the current time step; after multiple iterative calculations, if the electric field component of the current time step or the magnetic field component of the current time step converges or reaches the preset number of iterations, the simulation ends.

Next, this solution is introduced step by step.

In one embodiment, the present application proposes a transformer electromagnetic transient simulation method, as shown in FIG1 , which is a flow chart of a transformer electromagnetic transient simulation method provided in an embodiment of the present application, and the method includes:

Step 101: Establish a transformer model based on a finite difference time domain method, and set a time step for the transformer model.

Among them, the finite-difference time-domain method (FDTD) is a global discrete time-domain simulation algorithm. Its calculation area includes not only all simulated models, but also the areas between simulated objects and their adjacent areas.

The transformer model is completed based on the model building software. Specifically, the transformer model is built in the calculation area of the finite time-domain difference method according to the transformer parameters.

In one embodiment, the establishment of a transformer model based on the finite time-domain difference method includes: determining a target calculation area of the finite time-domain difference method according to the structure size of the transformer; and establishing the transformer model in the target calculation area.

Among them, when establishing a transformer model based on the finite time difference method, the calculation area of the finite time difference method needs to be gridded first, that is, in this application, the calculation area of the finite time difference method is composed of multiple FDTD orthogonal grid arrangements.

Specifically, the calculation domain of the finite time-domain difference method is discretized into a set of parallelepiped grids through FDTD orthogonal grids, and the electromagnetic field in each grid is set to be uniformly distributed. As shown in Figures 2-3, Figure 2 is a schematic diagram of an electric field vector in a grid provided in an embodiment of the present application; Figure 3 is a schematic diagram of a magnetic field vector in a grid provided in an embodiment of the present application. Specifically, as shown in Figure 2, the lower left vertex of each parallelepiped grid is taken as the origin, and the three edges connected to the origin are respectively defined to point to the three orthogonal directions of XYZ. The electric field vector Ex, Ey, and Ez; as shown in Figure 3, the lower left vertex of each parallelepiped grid is taken as the origin, and the three faces connected to the origin are respectively defined to point to the three orthogonal directions of XYZ. , Hy, Hz. Among them, the electric field and magnetic field vectors in each direction need to set the corresponding material parameters according to the relative spatial position, including conductivity σ, dielectric constant ε, and magnetic permeability μ. Material parameters refer to the parameters of transformer electrical materials. It should be noted that when the computational domain of the finite time-domain difference method is discretized into a set of parallelepipedal grids through FDTD orthogonal grids, the grid size can be encrypted in areas where the electromagnetic field changes dramatically, such as the air-conductor interface, the conductor-dielectric interface, etc.; large-size grids can be used in areas where the electromagnetic field changes slowly, such as the inside of the dielectric. By increasing the number of grids and reducing the grid size in key areas, and reducing the number of grids in air or large-volume dielectric areas, on the one hand, the simulated objects that may contain fine structures can be discretized to obtain simulation accuracy that meets the requirements; on the other hand, it can also avoid unnecessary computational burdens caused by overly dense grids, reducing the overall computational implementation efficiency of the solution.

Specifically, when a group of FDTD grids are arranged together to form an FDTD calculation area, the electromagnetic field vectors are spaced apart by half a spatial step (i.e., the grid size), and the electromagnetic vectors surround and surround each other, that is, the electric field vector in a certain direction is surrounded by four magnetic field vectors, and vice versa. The electromagnetic field vectors are also spaced apart by half a time step in time, that is, the overall electric field vector and the overall magnetic field vector are always 0.5Δt apart. As shown in Figure 4, Figure 4 is a schematic diagram of electromagnetic field vectors in a grid provided in an embodiment of the present application. It should be noted that the above space-time characteristics meet the characteristics of solving Maxwell's discrete equations, because alternating step-by-step solutions of electric field vectors and magnetic field vectors can be achieved.

Specifically, after the calculation area of the finite time-domain difference method is gridded, the target calculation area of the finite time-domain difference method is determined according to the structural size of the transformer, that is, the model construction area of the transformer model is determined. The structural size of the transformer can be the transformer body and the adjacent area (which can be 50% of the transformer size), and the target calculation area of the finite time-domain difference method is not less than the structural size of the transformer.

In one embodiment, setting the time step of the transformer model includes: setting the time step of the transformer model according to the following time step formula:

The selection of the maximum time step is determined by the minimum FDTD discrete grid size and should satisfy the Courant-Friedrich-Levy (CFL) criterion to prevent data divergence, oscillation, non-convergence and other problems that may occur in time domain calculations, that is,

Where Δx, Δy, Δz are the minimum grid sizes of the FDTD grid in the three orthogonal directions of X, Y, and Z, and c is the propagation speed of light in the corresponding medium.

In this embodiment, a transformer model is established based on the finite time-domain difference method, that is, the transformer body and the adjacent area (generally 50% of the transformer size) are modeled in the FDTD calculation area, and the transformer and the adjacent area are discretized using the FDTD grid. In an achievable manner, for areas where material parameters do not change with frequency (frequency invariant), the FDTD classical update equation is used to solve the electromagnetic field distribution in the time domain. For areas where material parameters change nonlinearly with frequency (frequency variable), the frequency characteristic curve of the transformer is first obtained, and then the electromagnetic field distribution is solved based on the frequency characteristic curve of the transformer and the classical FDTD update equation. The scheme of nonlinear change of material parameters with frequency is described below.

Step 102: Obtain a frequency characteristic curve of the transformer.

Among them, the frequency-varying characteristic curve of the key structure of the power transformer is obtained through experiments, theoretical formula calculations or numerical algorithms, and the frequency range must cover all frequency bands of concern in the electromagnetic transient process.

Specifically, the theoretical formula can be Bessel Function, etc., and the numerical algorithm can be Method of Moment (MoM), Partial Element Equivalent Circuit (PEEC), etc.

In one embodiment, the frequency characteristic curve of the key components of the transformer (such as copper loss considering the frequency-varying characteristics) is not only related to the material, but also to the geometric structure size of the key components, so even for the same material, they need to be obtained separately. Since the internal structure of the transformer is relatively complex and the accuracy of the detection equipment is limited, in order to improve the accuracy of the frequency characteristic curve, this application uses theoretical formulas or numerical algorithms to obtain the corresponding characteristic curves. For example, to solve the frequency-varying loss of solid, hollow, and coaxial conductors with circular cross-sections, the Bessel function can be used to obtain the current density distribution of the circular conductor, and then derive the frequency-varying loss. The form of the Bessel function is as follows:

Wherein, Z is impedance, R _d = _mrd , m ² =jωμ(σ+jωε), r _d is the conductor radius, μ is the magnetic permeability, ε is the dielectric constant, σ is the conductivity, j represents a complex number, ω is the angular frequency, I ₀ and I ₁ are the 0th and 1st order first kind modified form Bessel functions respectively.

For the frequency-dependent loss of a long straight conductor with a non-circular cross section, the two-dimensional MoM algorithm can be used to discretize the two-dimensional cross section, obtain the current distribution on each discrete unit, and then obtain the overall frequency-dependent loss of the long straight conductor. For key conductor structures with complex structures, the three-dimensional PEEC algorithm can be used to discretize the conductor in space according to the accuracy requirements, and each discrete unit is equivalent to a circuit element, and then combined with the circuit solving algorithm to obtain its frequency characteristic curve.

Step 103: based on the frequency characteristic curve, update the electric field component and the magnetic field component of the transformer model to obtain the electric field component of the current time step and the magnetic field component of the current time step.

Specifically, based on the frequency characteristic curve, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step, including: using a vector matching method to fit the frequency-varying function corresponding to the frequency characteristic curve to obtain a first-order rational function; based on the first-order rational function, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step.

Among them, after obtaining the frequency-variant characteristic curve of the key structure of the power transformer through experiments, theoretical formula calculations or numerical algorithms, the corresponding frequency-variant function is fitted using the vector fitting technique (VFT), and the complex frequency-variant function is fitted into a first-order rational function, and then the rational function is substituted into the FDTD solution equation in the form of convolution to achieve the purpose of considering the frequency-variant parameters in the time domain calculation. Using the vector matching method to fit the corresponding frequency-variant function can effectively reduce the complexity of the function, thereby reducing the difficulty of solving the time domain simulation.

Specifically, the vector matching method has the advantages of high stability, few iterations, and fast convergence. Through the vector matching method, the frequency characteristic curve of the key components of the transformer can be approximately fitted in the frequency domain as a first-order rational function and. Among them, the first-order rational function of the frequency characteristic curve fitted by the vector matching method is (the frequency-dependent impedance Z can be fitted in the complex frequency domain as):

Wherein, s represents the complex frequency domain, d is the DC component, h is the inductive component, _cm is the residue, _am is the pole, and N is the vector matching order. It has been verified that the relative error between the frequency characteristic curve fitted by the vector matching method and the frequency characteristic curve of the original transformer key component is less than 0.1%. As shown in Figures 5-6, Figure 5 is a magnetic field frequency characteristic curve of a long straight conductor with a rectangular cross-section and its vector matching method fitting curve provided in an embodiment of the present application, and Figure 6 is a current frequency characteristic curve of a long straight conductor with a rectangular cross-section and its vector matching method fitting curve provided in an embodiment of the present application. It should be noted that as many frequency points as possible should be uniformly selected within each frequency order of magnitude of the original characteristic frequency curve to improve the accuracy of curve fitting.

In one embodiment, the updating of the electric field component of the transformer model based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step includes: inputting the convolution form of the first-order rational function into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step. The updating of the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step includes: inputting the convolution form of the first-order rational function into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.

Specifically, the classic FDTD update equation is applied to iteratively solve the electric field vector in the calculation area. In each iterative solution process, the first-order rational function needs to be substituted into the FDTD electric field update equation in the form of convolution, so as to fully consider the influence of the electric frequency-dependent characteristic parameters on the electromagnetic transient simulation results. The iterative process involves the electric field vector value of the previous time step and the four magnetic field vectors surrounding the electric field vector. The specific update equation is as follows:

Where _Ex , _Ey , and _Ez are the electric field vectors in three orthogonal directions, i, j, and k are the position numbers of the electric field vector based on the FDTD grid numbering, q represents the number of time steps, σ and ε represent the equivalent conductivity and dielectric constant in the corresponding space, respectively, and Δt represents the FDTD time step.

Among them, based on the vector matching method, the frequency characteristic curve of the impedance can be fitted into the form of a first-order rational function, and then the first-order rational function can be transformed into a time domain convolution form by an inverse Laplace transform, and then the electric field vector update equation in the time domain convolution form is replaced by the electric field vector update equation at the corresponding position in formula (4). Exemplarily, the update equation of the electric field vector E at the spatial position of the frequency-dependent characteristic material can be replaced by the following equation:

Where, _Kp = d + h / Δt, _Kn = -h / Δt,

is the convolution term, Δt represents the FDTD time step, ^Iq is the current, d is the DC component, and h is the inductive component;

Where _cm is the residue, _am is the pole, and N is the vector matching order.

Specifically, to ensure the stability of the simulation, the time step can be appropriately reduced when combined with the time domain convolution calculation. Each iteration needs to reduce the time step to between 0.8 and 0.9 times the time step of the previous iteration. Since such convolution calculations are performed in local areas, they do not affect the parallel computing capabilities of the FDTD program. The electromagnetic transient time domain simulation of power transformers can still use high-performance graphics processing units (GPUs) to improve computing efficiency.

Specifically, the classic FDTD update equation is used to iteratively solve the magnetic field vector in the calculation area. In each iterative solution process, the first-order rational function mentioned above needs to be substituted into the FDTD magnetic field update equation in the form of convolution, so as to fully consider the influence of the magnetic frequency-variable characteristic parameters on the electromagnetic transient simulation results. The magnetic field vector of the entire calculation domain is iteratively calculated using the classic FDTD magnetic field vector update equation. The specific equation is expressed as follows:

Where μ and σ _m are magnetic permeability and permeability, and the permeability is generally set to 0. Substitute the first-order rational function of the magnetic frequency-variable material parameters into the FDTD equation for calculation. The process is the same as that of the electrical material parameters, which will not be repeated here.

Step 104: If the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends.

The electric field component and the magnetic field component are iteratively calculated until the electric field component or the magnetic field component of the current time step converges, and the simulation ends.

In one embodiment, if the number of iterations corresponding to the current time step is greater than an iteration number threshold, the simulation ends.

In one embodiment, the present application provides a transformer electromagnetic transient simulation device, as shown in FIG7 , which is a schematic diagram of the structure of a transformer electromagnetic transient simulation device provided in an embodiment of the present application, the device comprising:

The model building module 701 is used to build a transformer model based on the finite time-domain difference method and set the time step of the transformer model.

The characteristic curve acquisition module 702 is used to acquire the frequency characteristic curve of the transformer.

The first simulation module 703 is used to update the electric field component and the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step.

The second simulation module 704 is used to end the simulation if the electric field component of the current time step or the magnetic field component of the current time step converges.

As shown in FIG8, in one embodiment, it is an internal structure diagram of a computer device. The computer device may be a transformer electromagnetic transient simulation device, or a terminal or server connected to a transformer electromagnetic transient simulation device. As shown in FIG8, the computer device includes a processor, a memory, and a network interface connected via a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor may implement a transformer electromagnetic transient simulation method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor may execute a transformer electromagnetic transient simulation method. The network interface is used to communicate with an external device. Those skilled in the art may understand that the structure shown in FIG8 is only a block diagram of a partial structure related to the present application scheme, and does not constitute a limitation on the computer device to which the present application scheme is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

In one embodiment, a transformer electromagnetic transient simulation method provided by the present application can be implemented in the form of a computer program, and the computer program can be run on a computer device as shown in FIG8. The memory of the computer device can store various program templates constituting the transformer electromagnetic transient simulation device. For example, a model building module 701, a characteristic curve acquisition module 702, a first simulation module 703, and a second simulation module 704.

A computer device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the following steps: establishing a transformer model based on a finite time-domain difference method, and setting a time step for the transformer model; obtaining a frequency characteristic curve of the transformer; updating an electric field component and a magnetic field component of the transformer model based on the frequency characteristic curve to obtain an electric field component of a current time step and a magnetic field component of a current time step; if the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends.

In one embodiment, when the computer program is executed by the processor, the processor further executes the following steps: if the number of iterations corresponding to the current time step is greater than an iteration number threshold, the simulation ends.

In one embodiment, the updating of the electric field component and the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step includes: fitting the frequency-varying function corresponding to the frequency characteristic curve using a vector matching method to obtain a first-order rational function; updating the electric field component and the magnetic field component of the transformer model based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step.

In one embodiment, the updating of the electric field component of the transformer model based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step includes: inputting the convolution form of the first-order rational function into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step.

In one embodiment, updating the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step includes: inputting the convolution form of the first-order rational function into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.

A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor performs the following steps: establishing a transformer model based on a finite time-domain difference method, and setting a time step for the transformer model; obtaining a frequency characteristic curve of the transformer; updating an electric field component and a magnetic field component of the transformer model based on the frequency characteristic curve to obtain an electric field component of a current time step and a magnetic field component of a current time step; if the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends.

Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

A transformer electromagnetic transient simulation method, characterized in that the method comprises:

Establishing a transformer model based on a finite time-domain difference method, and setting a time step for the transformer model;

Obtain the frequency characteristic curve of the transformer;

Based on the frequency characteristic curve, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step;

If the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends.
The method according to claim 1, characterized in that the method further comprises:

If the number of iterations corresponding to the current time step is greater than the iteration number threshold, the simulation ends.
The method according to claim 1, characterized in that the transformer model is established based on the finite time-domain difference method, comprising:

Determine the target calculation area of the finite time-domain difference method according to the transformer structure size;

A transformer model is established in the target calculation area.
The method according to claim 1, characterized in that the step of setting the time step of the transformer model comprises:

The time step of the transformer model is set according to the following time step formula:

Among them, Δx, Δy, Δz are the minimum grid sizes of the finite time-domain difference method grid in the three orthogonal directions of X, Y, and Z, c is the propagation speed of light in the corresponding medium, and Δt is the maximum time step.
The method according to claim 1, characterized in that the updating of the electric field component and the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step comprises:

Using a vector matching method to fit the frequency-dependent function corresponding to the frequency characteristic curve to obtain a first-order rational function;

The electric field component and the magnetic field component of the transformer model are updated based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step.
The method according to claim 5, characterized in that the updating of the electric field component of the transformer model based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step comprises:

The convolution form of the first-order rational function is input into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step.
The method according to claim 5, characterized in that the updating of the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step comprises:

The convolution form of the first-order rational function is input into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.
A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

Establishing a transformer model based on a finite time-domain difference method, and setting a time step for the transformer model;

Obtain the frequency characteristic curve of the transformer;

Based on the frequency characteristic curve, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step;

If the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends.
The computer device according to claim 8, wherein the method further comprises:

If the number of iterations corresponding to the current time step is greater than the iteration number threshold, the simulation ends.
The computer device according to claim 8, characterized in that the transformer model is established based on the finite time-domain difference method, comprising:

Determine the target calculation area of the finite time-domain difference method according to the transformer structure size;

A transformer model is established in the target calculation area.
The computer device according to claim 8, characterized in that the time step setting of the transformer model comprises:

The time step of the transformer model is set according to the following time step formula:

Among them, Δx, Δy, Δz are the minimum grid sizes of the finite time-domain difference method grid in the three orthogonal directions of X, Y, and Z, c is the propagation speed of light in the corresponding medium, and Δt is the maximum time step.
The computer device according to claim 8, characterized in that the updating of the electric field component and the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step comprises:

Using a vector matching method to fit the frequency-dependent function corresponding to the frequency characteristic curve to obtain a first-order rational function;

The electric field component and the magnetic field component of the transformer model are updated based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step.
The computer device according to claim 12, characterized in that the updating of the electric field component of the transformer model based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step comprises:

The convolution form of the first-order rational function is input into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step.
The computer device according to claim 12, characterized in that the updating of the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step comprises:

The convolution form of the first-order rational function is input into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.
A computer-readable storage medium stores a computer program, which, when executed by a processor, causes the processor to perform the following steps:

Establishing a transformer model based on a finite time-domain difference method, and setting a time step for the transformer model;

Obtain the frequency characteristic curve of the transformer;

Based on the frequency characteristic curve, the electric field component and the magnetic field component of the transformer model are updated to obtain the electric field component of the current time step and the magnetic field component of the current time step;

If the electric field component of the current time step or the magnetic field component of the current time step converges, the simulation ends.
The computer-readable storage medium according to claim 15, wherein the method further comprises:

If the number of iterations corresponding to the current time step is greater than the iteration number threshold, the simulation ends.
The computer-readable storage medium according to claim 15, wherein the step of establishing a transformer model based on a finite difference time domain method comprises:

Determine the target calculation area of the finite time-domain difference method according to the transformer structure size;

A transformer model is established in the target calculation area.
The computer-readable storage medium according to claim 15, wherein the step of setting the time step of the transformer model comprises:

The time step of the transformer model is set according to the following time step formula:

Among them, Δx, Δy, Δz are the minimum grid sizes of the finite time-domain difference method grid in the three orthogonal directions of X, Y, and Z, c is the propagation speed of light in the corresponding medium, and Δt is the maximum time step.
The computer-readable storage medium according to claim 15, characterized in that the updating of the electric field component and the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the electric field component of the current time step and the magnetic field component of the current time step comprises:

Using a vector matching method to fit the frequency-dependent function corresponding to the frequency characteristic curve to obtain a first-order rational function;

The electric field component and the magnetic field component of the transformer model are updated based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step.
The computer-readable storage medium according to claim 19, characterized in that the updating of the electric field component of the transformer model based on the first-order rational function to obtain the electric field component of the current time step and the magnetic field component of the current time step comprises:

The convolution form of the first-order rational function is input into the electric field update equation of the finite time-domain difference method in the transformer model to determine the electric field component of the current time step.
The computer-readable storage medium according to claim 19, wherein the updating of the magnetic field component of the transformer model based on the frequency characteristic curve to obtain the magnetic field component of the current time step comprises:

The convolution form of the first-order rational function is input into the magnetic field update equation of the finite time-domain difference method in the transformer model to determine the magnetic field component of the current time step.