A calculation method for the structural failure of a transformer riser and related equipment

Abstract

The present invention discloses a calculation method for the structural failure of a transformer riser and related equipment, belonging to the technical field of power systems, aiming to accurately simulate the oil pressure change, structural deformation and failure mechanism of extra-high voltage oil-filled equipment under the impact of arc faults. This method overcomes the limitations of traditional finite element methods in dealing with large deformations and ruptures through the finite element - smoothed particle hydrodynamics coupling technology, combined with the pulsation behavior of fault bubbles and the mechanism of multi-physical field coupling, ensuring the conservation of mass, momentum and energy during the calculation process, thereby improving the simulation accuracy of the failure behavior of oil-filled equipment under extreme fault conditions. By analyzing the stress, strain distribution and material failure behavior in the key areas of the equipment, the weak links of the equipment structure are accurately identified, providing a theoretical basis and technical support for optimizing the design of the transformer riser.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems, and particularly relates to a method for calculating the structural failure of a transformer riser and related equipment. Background Art

[0002] A transformer is an important part of a UHV power transmission system. With the continuous increase in the installed capacity of the power grid and the power generation scale, the voltage level and single-unit capacity of the transformer also increase. Once an internal short-circuit fault occurs, the sudden increase in pressure will cause the explosion of oil-filled equipment such as its riser, seriously threatening the safe and stable operation of the power system. In recent years, successive explosions and fires of transformer risers have greatly threatened the safe and stable operation of the power grid, causing serious economic losses and adverse social impacts. Therefore, preventing the explosion of the transformer riser under arc faults is crucial.

[0003] However, the structural failure mechanism of the transformer riser under fault impact has not been fully understood yet, and the related numerical calculation methods are not yet mature. Specifically, existing theoretical models are mostly based on static linear assumptions of gas generation rate and arc energy, and fail to effectively capture the dynamic pulsation behavior of fault bubbles, resulting in a large difference between simulation results and actual test results. In addition, in the study of structural ultimate deformation and rupture behavior, the conventional finite element method relies on deleting elements to simulate structural failure behavior, and this processing method will lead to a significant reduction in calculation accuracy and is difficult to meet the reliability requirements of engineering analysis. Summary of the Invention

[0004] The present invention provides a method for calculating the structural failure of a transformer riser and related equipment, which solves the problem that in the study of structural ultimate deformation and rupture behavior, the conventional finite element method relies on deleting elements to simulate structural failure behavior, and this processing method will lead to a significant reduction in calculation accuracy and is difficult to meet the reliability requirements of engineering analysis.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for calculating the structural failure of a transformer riser, comprising:

[0007] Establishing a solid domain geometric model and a fluid domain geometric model of the transformer riser;

[0008] Importing the solid domain geometric model and the fluid domain geometric model of the transformer riser into ANSYS software, performing mesh division to obtain a solid domain mesh model and a fluid domain mesh model of the transformer riser, and setting the material properties of the solid domain mesh model and the fluid domain mesh model of the transformer riser;

[0009] Configuring a solver and a solution model for the fluid domain mesh model, and calculating the flow field of the fluid domain mesh model based on the fluid domain mesh model;

[0010] Process the solid domain grid model, and use the finite element - smoothed particle hydrodynamics coupling method to perform coupled calculations on the flow field of the fluid domain grid model and the processed solid domain grid model to complete the failure calculation of the transformer riser structure.

[0011] Preferably, the steps of calculating the flow field of the fluid domain grid model are specifically as follows:

[0012] Use the Reynolds - averaged Navier - Stokes equations model to describe the flow field changes, then describe the gas - generation process during arc faults in the fluid domain grid model according to the bubble dynamics equation, then improve the grid quality of the fluid domain grid model, and use the standard turbulence model to describe the turbulence effect of the fluid domain grid model. Based on the coupled calculations of the Reynolds - averaged Navier - Stokes equations model, the bubble dynamics equation, and the standard turbulence model, obtain the flow field of the fluid domain grid model.

[0013] Preferably, the Reynolds - averaged Navier - Stokes equations model is:

[0014]

[0015] where and are spatial coordinates, and are different directions, is the fluid density, is the time, and are the Reynolds - averaged velocity components, represents the partial derivative of the Reynolds - averaged velocity component with respect to time, is the Reynolds - averaged velocity component in the direction with respect to the direction velocity gradient, represents the pressure field, represents the component of the pressure field in the direction, represents the Reynolds stress tensor, represents the divergence of the Reynolds stress tensor, is the dynamic viscosity of the fluid.

[0016] Preferably, the bubble dynamics equation is:

[0017]

[0018] where 、 、 represent the bubble radius, the bubble expansion velocity, and the bubble expansion acceleration respectively, is the initial radius of the bubble, is the specific heat ratio, is the fluid density, is the dynamic viscosity of the fluid, and are the maximum and minimum values of time, is at and for integration within the range, is the arc energy conversion coefficient, is the arc energy, is the pressure at the fluid boundary, represents the bubble surface tension term, is the surface tension coefficient at the gas-liquid interface, is the internal energy of the bubble at the moment of generation, is the surface tension coefficient of the fluid surface, is the integral sign, represents the integration variable.

[0019] Preferably, the standard turbulence model is:

[0020] The turbulent kinetic energy describes the generation, diffusion, and dissipation processes of turbulent energy and is expressed as:

[0021]

[0022] where, represents the velocity components in all directions of the fluid, represents taking the partial derivative in the direction, represents taking the partial derivative in the direction, represents the dynamic viscosity of the fluid, represents the turbulence model viscosity coefficient, is the turbulent Prandtl number of the turbulent kinetic energy, , is the amount of turbulent kinetic energy generation caused by shear stress and velocity gradient, is the turbulence frequency;

[0023] The turbulence frequency describes the change in the turbulence scale and is expressed as:

[0024]

[0025] where, , , is the dissipation term of the turbulence frequency, , k is the turbulent kinetic energy.

[0026] Preferably, the steps of processing the solid domain network model are specifically as follows:

[0027] Based on the BWH failure criterion and the solid domain of the transformer riser, obtain the plastic deformation and failure of the geometric model of the transformer riser solid domain. According to the plastic deformation and failure of the geometric model of the transformer riser solid domain, obtain the failed elements, convert the failed elements into smooth particles, and obtain virtual particles based on the smooth particles;

[0028] The basic form of the BWH failure criterion is:

[0029]

[0030] Where, represents the first principal stress at the failure point, and respectively represent the strength coefficient and hardening index of the material, is the necking strain measured from a uniaxial tensile test, represents the ratio of the two principal strain rates of the plane element.

[0031] Preferably, the steps of completing the structural failure calculation of the transformer riser by using the finite element - smoothed particle hydrodynamics coupling method to couple the flow field of the fluid domain grid model and the processed solid domain grid model are as follows:

[0032] Realize the oil pressure load transfer under the internal arc fault of the transformer riser through the coupling interface, and then obtain the smoothed particle hydrodynamics equation based on the flow field, smooth particles and virtual particles of the fluid domain grid model, and simulate the structural failure behavior of the transformer riser according to the smoothed particle hydrodynamics equation;

[0033] The smoothed particle hydrodynamics equation is:

[0034]

[0035]

[0036]

[0037] Where, represents the particle density, represents the particle density squared, represents the particle density squared, represents the particle mass, represents the number of real particles within the influence domain of the particle ​ Represents particles The number of virtual particles within the influence domain, and respectively represent particles and particles in the direction of the velocity component, = 1, 2, 3 respectively correspond to the direction, is the kernel function, represents the kernel function with respect to the coordinates of particle partial derivative, represents the acceleration of particle in the direction, and respectively represent the stress tensor components of particles and particles is the symbol of the Kronecker function, which is 1 when = and 0 otherwise, represents the rate of change of the internal energy of particle with respect to time, represents the velocity difference between particles and particles in the direction, is the artificial viscosity term.

[0038] A calculation system for the failure of a transformer riser structure, comprising:

[0039] Modeling module: used to establish the solid domain geometric model and fluid domain geometric model of the transformer riser;

[0040] Meshing module: used to import the solid domain geometric model and fluid domain geometric model of the transformer riser into ANSYS software, perform meshing to obtain the solid domain mesh model and fluid domain mesh model of the transformer riser, and set the material properties of the solid domain mesh model and fluid domain mesh model of the transformer riser;

[0041] Solver module: used to configure the solver and solution model for the fluid domain mesh model, and calculate the flow field of the fluid domain mesh model based on the fluid domain mesh model;

[0042] Simulation module: used to process the solid domain mesh model, and perform coupled calculations on the flow field of the fluid domain mesh model and the processed solid domain mesh model using the finite element - smoothed particle hydrodynamics coupling method to complete the calculation of the failure of the transformer riser structure.

[0043] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of a calculation method for the failure of a transformer riser structure are implemented.

[0044] A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps of a calculation method for the failure of a transformer riser structure are implemented.

[0045] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a calculation method for the failure of a transformer riser structure. Through the finite element - smoothed particle hydrodynamics coupling technology, it can accurately simulate the oil pressure change and structural deformation of the transformer riser under arc faults, revealing the internal structure failure mechanism of oil-filled equipment under the action of arcs. The present invention takes into account the dynamic pulsation behavior of fault bubbles and the mechanism of multi-physical field coupling, and can accurately obtain the weak areas and their rupture behaviors of the transformer riser structure under arc faults with different positions and energies, and reproduce its structural failure behavior.

[0046] The present invention effectively overcomes the limitations of the traditional finite element method in dealing with large deformation or even rupture problems. The traditional finite element method usually simulates the failure behavior of a structure by deleting failed elements. However, this processing method inevitably leads to non-conservation of system mass, momentum, and energy, resulting in a significant decrease in calculation accuracy and difficulty in obtaining accurate results. In contrast, the finite element - smoothed particle hydrodynamics coupling method of the present invention converts failed elements into smoothed particles after element failure, inheriting the physical properties of the failed elements, ensuring the conservation of mass, momentum, and energy during the calculation process, and thus significantly improving the simulation accuracy and reliability of the failure behavior of complex structures under extreme conditions. Description of the Drawings

[0047] Figure 1 It is a model diagram of an oil-immersed transformer riser according to an embodiment of the present invention, where Figure a is a geometric model diagram and Figure b is a mesh division diagram.

[0048] Figure 2 It is a calculation flow chart of a calculation method for the failure of a transformer riser structure according to an embodiment of the present invention.

[0049] Figure 3 It is a curve graph of the oil pressure change inside the riser under an arc fault according to an embodiment of the present invention.

[0050] Figure 4 It is the strain distribution of the riser structure at different time points after the fault occurs according to an embodiment of the present invention, where Figure a is at time, and Figure b is at time.

[0051] Figure 5 This is a block diagram of a failure calculation system for the structure of a transformer riser in an embodiment of the present invention. Specific embodiments

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0054] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0055] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0056] See Figure 1 , taking an oil-immersed transformer riser with a diameter of 600 mm and a height of 1000 mm as the research object, the material of the riser barrel wall is structural steel, and the density is 7850 kg / m 3 , the shear modulus is 7.3×10 10 Pa, the Young's modulus is 2.1×10 11 Pa, the Poisson's ratio is 0.3, and the yield strength is 339 MPa.

[0057] As Figure 2 shown, the present invention provides a method for calculating the failure of the transformer riser structure, including the following steps:

[0058] (1) Establish a solid domain geometric model and a fluid domain geometric model of the transformer riser;

[0059] (2) Import the solid domain geometric model and the fluid domain geometric model of the transformer riser into ANSYS software, perform mesh division to obtain the solid domain mesh model and the fluid domain mesh model of the transformer riser, and set the material properties of the solid domain mesh model and the fluid domain mesh model of the transformer riser;

[0060] (3) Configure the solver and solution model for the fluid domain mesh model, and calculate the flow field of the fluid domain mesh model based on the fluid domain mesh model;

[0061] (4) Process the solid domain mesh model, and use the finite element - smoothed particle hydrodynamics coupling method to couple the flow field of the fluid domain mesh model and the processed solid domain mesh model to complete the calculation of the structural failure of the transformer riser.

[0062] Further, the specific step (1) is as follows:

[0063] Use Spacecliam software to establish the solid domain geometric model and fluid domain geometric model of the 1:1 transformer riser. Note that in order to reduce the calculation amount while meeting the requirements of simulation calculation accuracy, a certain degree of reasonable simplification is made to the original physical model.

[0064] Further, the step (2) includes the following steps:

[0065] Import the established solid domain geometric model and fluid domain geometric model of the transformer riser into ANSYS software, perform mesh division on the solid domain geometric model and fluid domain geometric model of the transformer riser, encrypt the mesh in the key areas, and check and adjust the mesh quality;

[0066] Set the material properties of the solid domain and fluid domain of the transformer riser to structural steel, with a density of 7850 kg / m 3 , a shear modulus of 7.3×10 10 Pa, a Young's modulus of 2.1×10 11 Pa, a Poisson's ratio of 0.3, and a yield strength of 339 MPa.

[0067] Further, the step (3) includes the following steps:

[0068] Set the solver of the fluid domain mesh model to a transient solver;

[0069] Use the Reynolds-averaged Navier-Stokes equations (RANS) model to describe the flow field change of the fluid domain mesh model:

[0070] (1)

[0071] Among them, and are spatial coordinates, and are different directions, ρ is the fluid density, is the time, and are the Reynolds-averaged velocity components, represents the Reynolds-averaged velocity component Partial derivative with respect to time is the Reynolds-averaged velocity component In direction with respect to direction of the velocity gradient represents the pressure field represents the component of the pressure field in i direction represents the Reynolds stress tensor represents the divergence of the Reynolds stress tensor

[0072] Furthermore, according to the bubble dynamics equation, the gas generation process during an arc fault in the fluid domain grid model is described. The bubble dynamics equation is as follows:

[0073]

[0074] Where , , respectively represent the bubble radius, bubble expansion velocity, and bubble expansion acceleration is the initial bubble radius is the specific heat ratio is the fluid density is the fluid dynamic viscosity and are the maximum and minimum values of time is at , is the arc energy conversion coefficient is the arc energy is the pressure at the fluid boundary represents the bubble surface tension term is the surface tension coefficient of the gas-liquid interface is the internal energy of the bubble at the moment of generation is the surface tension coefficient of the fluid surface is the integral symbol represents the integration variable

[0075] Furthermore, when the boundary of the target area changes, to determine the quality of all grids and re-divide the grids with lower quality, the grid diffusion smoothing model is used to determine the movement displacement of the grid nodes, which is specifically expressed as:

[0076] (3)

[0077] In the formula is the vector differential operator is the grid movement velocity is the diffusion coefficient, expressed as:

[0078] (4)

[0079] In the formula, d is the distance between the regularized grid node and the boundary, a is the diffusion parameter in the smoothing setting panel, and its value range is 0 to 2.

[0080] After solving the grid movement speed, the position of the grid node at the next time step is expressed as:

[0081] (5)

[0082] In the formula, and are the positions of the grid node at the next time step and the current time step respectively, is the time difference between the next time and the current time of the grid node.

[0083] Furthermore, based on the coupled calculation of the Reynolds-averaged equation model, the bubble dynamics equation and the standard turbulence model, the flow field of the fluid domain grid model is obtained;

[0084] Standard The turbulence model is:

[0085] The turbulent kinetic energy k describes the generation, diffusion and dissipation processes of turbulent energy, and is expressed as:

[0086] (6)

[0087] Among them, represents taking the partial derivative in the direction, represents taking the partial derivative in the direction, represents the hydrodynamic viscosity, represents the turbulence model viscosity coefficient, is the turbulent Prandtl number of the turbulent kinetic energy, , is the generation amount of turbulent kinetic energy caused by shear stress and velocity gradient, is the turbulence frequency, is obtained from the RANS equation (inside the fluid) and the bubble dynamics equation (fluid boundary).

[0088] The turbulence frequency describes the change of the turbulence scale, and is expressed as:

[0089]

[0090] Among them, , , is the dissipation term of the turbulent frequency, , k is the turbulent kinetic energy.

[0091] Furthermore, step (4) includes the following steps:

[0092] Based on the BWH failure criterion and the solid domain mesh model, obtain the plastic deformation and failure of the solid domain mesh model. Based on the plastic deformation and failure of the solid domain mesh model, obtain the failed elements and convert the failed elements into smooth particles. Based on the smooth particles, obtain virtual particles. The core idea is that the failure of materials not only depends on a single stress component (such as the maximum principal stress or the maximum shear stress), but is related to the comprehensive stress state under the multiaxial stress state. This criterion transforms the complex multiaxial stress state into an equivalent uniaxial stress state by introducing the concept of equivalent stress, so as to judge whether the material will fail. Its basic form is:

[0093] (8)

[0094] In the formula, represents the first principal stress at the failure point, and represent the strength coefficient and the hardening index of the material respectively, usually takes the necking strain measured in the uniaxial tensile test, represents the ratio of the two principal strain rates of the plane element, that is: .

[0095] Assume that the yield function and the plastic flow potential are consistent, then the relationship between the strain rate and the stress can be expressed as:

[0096] (9)

[0097] Among them, represents the plastic strain rate, represents the stress tensor, represents the plastic multiplier, f represents the yield function, represents the yield function f corresponding to the stress tensor partial derivative of.

[0098] The relationship between the strain rate and the principal stresses and is expressed as:

[0099] (10)

[0100] Among them, represents the ratio of the principal stresses, Represents the ratio of the two principal strain rates of the plane element.

[0101] Furthermore, the finite element - smoothed particle hydrodynamics coupling method is used to couple the flow field of the fluid domain grid model and the processed solid domain grid model to complete the failure calculation of the transformer bushing structure.

[0102] The oil pressure load transfer under internal arc fault in the solid domain grid model is realized through the coupling interface. When the finite element satisfies the failure criterion, the failed element becomes a smoothed particle through the transformation algorithm and continues to participate in the calculation. These particles will inherit the information such as the mass, velocity, position, and stress tensor of the failed element to ensure the conservation of mass, momentum, and energy during the calculation process.

[0103] Use the following formula to judge whether it is regarded as a virtual particle:

[0104] (11)

[0105] In the formula, is the distance between the centroid of the finite element and the center of the smoothed particle center, is the expansion coefficient, is the radius of the influence domain of the smoothed particle, and , where, is the particle smoothing length. If the formula (11) is satisfied, then this finite element is regarded as a virtual particle.

[0106] After generating the virtual particle, the mass and density satisfy the following formula:

[0107] (12)

[0108] Among them, the subscripts and respectively represent the virtual particle and the finite element number, and the subscripts and respectively represent the virtual particle and the finite element number.

[0109] The stress of the virtual particle is the same as that of the finite element, expressed as:

[0110] (13)

[0111] Among them, the superscript represents the components of the stress tensor in different directions, and the subscripts and respectively represent the virtual particle and the finite element number, and the subscripts and respectively represent the virtual particle and the finite element number.

[0112] After including virtual particles, the smoothed particle hydrodynamics equation can be transformed into:

[0113] (14)

[0114] (15)

[0115] (16)

[0116] Among them, for the density update equation (14), represents the density of particle , represents the square of the density of particle , represents the square of the density of particle , represents the mass of particle , represents the number of real particles within the influence domain of particle , represents the number of virtual particles within the influence domain of particle , and respectively represent the velocity components of particle and particle in the direction ([[]] = 1, 2, 3 correspond to the direction respectively), and the kernel function is used to describe the interaction between particle and particle , represents the partial derivative of the kernel function with respect to the coordinate of particle .

[0117] For the momentum update equation (15), represents the acceleration of particle in the direction ([[]] = 1, 2, 3 correspond to the direction respectively), and respectively represent the stress tensor components of particle and particle , is the Kronecker delta symbol, which is 1 when = and 0 otherwise, is the artificial viscosity term.

[0118] For the energy update equation (16), which represents the rate of change of the internal energy of particle with respect to time, and represents the velocity difference between particle and particle in the a direction.

[0119] Replace the nodal load in the finite element motion equation with the nodal contact force:

[0120] (18)

[0121] where is the finite element contact force matrix, K , C , M represent the stiffness matrix, damping matrix, and mass matrix respectively, represents the displacement at time .

[0122] Through the finite element - smoothed particle hydrodynamics coupling technology and simulation calculations, the present invention successfully simulates the internal oil pressure change and structural failure process of the equipment when an arc fault occurs in the transformer riser. This method reproduces the impact of the sudden increase in oil pressure caused by the arc fault on the structure of the oil - filled equipment, and deeply reveals the weak areas and structural damage mechanisms of the equipment under the impact of high - energy faults. This technology provides accurate mechanical analysis and dynamic response data support for the explosion - proof design of the transformer riser, and can effectively quantify the pressure change and equipment failure risk under fault conditions.

[0123] Figure 3 and Figure 4 The simulation calculation results based on the finite element - smoothed particle hydrodynamics coupling method in the specific embodiments of the present invention reveal the oil pressure change and structural strain distribution of the transformer riser under the impact of an arc fault. Figure 3 It shows the curves of the oil pressure change with time at measuring point 1 (located in the middle of the bushing) and measuring point 2 (located at the geometric center of the manhole of the transformer riser). Figure 3 It shows that the oil pressure at measuring point 2 rises rapidly after the fault and reaches a peak value of nearly 1.7 MPa at about 10 ms, while the oil pressure at measuring point 1 rises more slowly and has a lower peak value, indicating that the transformer riser area bears a greater pressure impact. This difference also reflects the uneven pressure distribution in different structural areas under the arc fault. Figure 4 It shows the strain distribution of the transformer riser structure at different time points after the fault. It can be seen that at time t = 5 ms, the strain of the structure is concentrated in the middle area of the transformer riser, and the strain value is relatively low at this time. At time tWhen t = 11.9 ms, the strain in the riser area of the transformer increased significantly, and a large range of plastic deformation and rupture occurred, indicating that the structure of the transformer riser had failed under high voltage at this time. The above quantitative analysis results not only verified the effectiveness of the finite element - smoothed particle hydrodynamics coupling method in simulating the structural failure behavior under arc faults, but also provided a reliable numerical basis for evaluating the safety of key parts of the transformer riser and improving the design.

[0124] As Figure 5 shown, the present invention provides a calculation system for the structural failure of a transformer riser, including:

[0125] Modeling module: used to establish the geometric model of the solid domain and the geometric model of the fluid domain of the transformer riser;

[0126] Meshing module: used to import the geometric models of the solid domain and the fluid domain of the transformer riser into ANSYS software, perform meshing to obtain the mesh models of the solid domain and the fluid domain of the transformer riser, and set the material properties of the mesh models of the solid domain and the fluid domain of the transformer riser;

[0127] Solver module: used to configure the solver and the solution model of the fluid domain mesh model, and calculate the flow field of the fluid domain mesh model based on the fluid domain mesh model;

[0128] Simulation module: used to process the solid domain mesh model, and perform coupling calculation on the flow field of the fluid domain mesh model and the processed solid domain mesh model by using the finite element - smoothed particle hydrodynamics coupling method to complete the calculation of the structural failure of the transformer riser.

[0129] The terminal device provided by an embodiment of the present invention. The terminal device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above - mentioned method embodiments are implemented. Or, when the processor executes the computer program, the functions of each module / unit in the above - mentioned device embodiments are implemented.

[0130] The computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention.

[0131] The terminal device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory.

[0132] The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0133] The memory can be used to store the computer program and / or modules. By running or executing the computer program and / or modules stored in the memory, and by invoking the data stored in the memory, the processor implements various functions of the terminal device.

[0134] If the modules / units integrated in the terminal device are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-described various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0135] Although the embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields. The above specific embodiments are merely illustrative and guiding, rather than restrictive. Under the inspiration of the specification, those of ordinary skill in the art can also make many forms without departing from the scope protected by the claims of the present invention, and all of these fall within the scope of protection of the present invention.

Claims

1. A calculation method for the failure of the elevated seat structure of a transformer, characterized in that, Including: Establish a solid domain geometric model and a fluid domain geometric model of the transformer riser; Import the solid domain geometric model and the fluid domain geometric model of the transformer riser into ANSYS software, perform mesh generation to obtain the solid domain mesh model and the fluid domain mesh model of the transformer riser, and set the material properties of the solid domain mesh model and the fluid domain mesh model of the transformer riser; Configure the solver and the solution model of the fluid domain mesh model, and calculate the flow field of the fluid domain mesh model based on the fluid domain mesh model; Process the solid domain mesh model, and use the finite element - smoothed particle hydrodynamics coupling method to couple and calculate the flow field of the fluid domain mesh model and the processed solid domain mesh model to complete the structural failure calculation of the transformer riser; The steps for processing the solid domain network model are specifically as follows: Based on the BWH failure criterion and the solid domain network model, obtain the plastic deformation and failure of the solid domain network model, obtain the failed elements according to the plastic deformation and failure of the solid domain network model, convert the failed elements into smoothed particles, and obtain virtual particles based on the smoothed particles; The steps for using the finite element - smoothed particle hydrodynamics coupling method to couple and calculate the flow field of the fluid domain mesh model and the processed solid domain mesh model to complete the structural failure calculation of the transformer riser are specifically as follows: Realize the oil pressure load transfer under the internal arc fault of the solid domain mesh model through the coupling interface, then obtain the smoothed particle hydrodynamics equation based on the flow field, smoothed particles and virtual particles of the fluid domain mesh model, and simulate the structural failure behavior of the transformer riser according to the smoothed particle hydrodynamics equation.

2. The failure calculation method of a transformer riser structure according to claim 1, characterized in that The steps for calculating the flow field of the fluid domain mesh model are specifically as follows: The Reynolds-averaged Navier-Stokes equations model is used to describe the flow field changes. Then, according to the bubble dynamics equation, the gas generation process during arc faults in the fluid domain grid model is described. Next, the grid quality of the fluid domain grid model is improved, and the standard turbulence model is used to describe the turbulence effect of the fluid domain grid model. Based on the coupled calculations of the Reynolds-averaged Navier-Stokes equations model, the bubble dynamics equation, and the standard turbulence model, the flow field of the fluid domain grid model is obtained.

3. A calculation method for the failure of the structure of a transformer riser according to claim 2, characterized in that, The Reynolds-averaged equation model is: wherein, and are spatial coordinates, and are different directions, is the fluid density, is the time, and are the Reynolds-averaged velocity components, represents the partial derivative of the Reynolds-averaged velocity component with respect to time, is the Reynolds-averaged velocity component in the direction with respect to the direction velocity gradient, represents the pressure field, represents the component of the pressure field in the direction, represents the Reynolds stress tensor, represents the divergence of the Reynolds stress tensor, is the dynamic viscosity of the fluid.

4. A calculation method for the failure of the structure of a transformer riser according to claim 2, characterized in that, The bubble dynamics equation is: Among them, , , represent the bubble radius, the bubble expansion velocity, and the bubble expansion acceleration respectively, is the initial radius of the bubble, is the specific heat ratio, is the fluid density, is the dynamic viscosity of the fluid, and are the maximum and minimum values of time, is the integral within the range of and , is the arc energy conversion coefficient, is the arc energy, is the pressure at the fluid boundary, represents the bubble surface tension term, is the surface tension coefficient of the gas-liquid interface, is the internal energy of the bubble at the moment of generation, is the surface tension coefficient of the fluid surface, is the integral sign, represents the integration variable.

5. A calculation method for the failure of the riser structure of a transformer according to claim 2, characterized in that, Standard The turbulence model is as follows: Turbulent kinetic energy Describes the generation, diffusion, and dissipation processes of turbulent energy, expressed as: Among them, represents the velocity components of the fluid in all directions, represents taking the partial derivative in the direction, represents taking the partial derivative in the direction, represents the dynamic viscosity of the fluid, represents the viscosity coefficient of the turbulence model, is the turbulent Prandtl number of the turbulent kinetic energy, , is the generation amount of turbulent kinetic energy caused by shear stress and velocity gradient, is the turbulence frequency; Turbulence frequency Describes the variation of the turbulence scale and is expressed as: Among them, , , is the dissipation term of the turbulent frequency, , k is the turbulent kinetic energy.

6. A calculation method for the failure of the structure of a transformer riser according to claim 1, characterized in that The basic form of the BWH failure criterion is: Among them, represents the first principal stress at the failure point, and represent the strength coefficient and the hardening index of the material respectively, is the necking strain measured from the uniaxial tensile test, represents the ratio of the two principal strain rates of the plane element.

7. A method for calculating the structural failure of a transformer riser according to claim 1, characterized in that The smoothed particle hydrodynamics equation is: Among them, represents the density of the particle , represents the square of the density of the particle , represents the square of the density of the particle , represents the mass of the particle , represents the number of real particles within the influence domain of the particle , represents the number of virtual particles within the influence domain of the particle , and respectively represent the velocity components of the particle and the particle in the direction, = 1, 2, 3 respectively correspond to the direction, is the kernel function, represents the partial derivative of the kernel function with respect to the coordinates of the particle , represents the acceleration of the particle in the direction, and respectively represent the stress tensor components of the particle and the particle , is the symbol of the Kronecker function, which is 1 when = and 0 otherwise, represents the rate of change of the internal energy of the particle with respect to time, represents the velocity difference between the particle and the particle in the direction, is the artificial viscosity term.

8. A calculation system for the failure of the elevated seat structure of a transformer, characterized in that, Including: A modeling module: used for establishing a solid domain geometric model and a fluid domain geometric model of the transformer riser; A meshing module: used for importing the solid domain geometric model and the fluid domain geometric model of the transformer riser into ANSYS software, performing mesh generation to obtain the solid domain mesh model and the fluid domain mesh model of the transformer riser, and setting the material properties of the solid domain mesh model and the fluid domain mesh model of the transformer riser; A solution module: used for configuring the solver and the solution model of the fluid domain mesh model, and calculating the flow field of the fluid domain mesh model based on the fluid domain mesh model; A simulation module: used for processing the solid domain mesh model, and using the finite element - smoothed particle hydrodynamics coupling method to couple and calculate the flow field of the fluid domain mesh model and the processed solid domain mesh model to complete the structural failure calculation of the transformer riser; The steps for processing the solid domain network model are specifically as follows: Based on the BWH failure criterion and the solid domain network model, obtain the plastic deformation and failure of the solid domain network model, obtain the failed elements according to the plastic deformation and failure of the solid domain network model, convert the failed elements into smoothed particles, and obtain virtual particles based on the smoothed particles; The steps for completing the failure calculation of the transformer riser structure by using the finite element - smoothed particle hydrodynamics coupling method to couple the flow field of the fluid domain grid model and the processed solid domain grid model are as follows: The oil pressure load transfer under the internal arc fault of the solid domain grid model is realized through the coupling interface, and then the smoothed particle hydrodynamics equation is obtained based on the flow field, smoothed particles and virtual particles of the fluid domain grid model. The failure behavior of the transformer riser structure is simulated according to the smoothed particle hydrodynamics equation.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of a transformer riser structure failure calculation method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the steps of a transformer riser structure failure calculation method according to any one of claims 1 to 7 are implemented.

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