Control sectioning method and device for grid of thermal flow coupling model of distribution transformer

Abstract

This invention provides a method and apparatus for controlling the mesh generation of a thermal-fluid coupling model for a distribution transformer. The method includes establishing a thermal-fluid coupling numerical model of the distribution transformer, dividing the mesh nodes, constructing rectangular mesh nodes for oil passages within the winding, oil passages surrounding the winding, and oil passages on the heat sink, and constructing arbitrary mesh nodes for winding structural components and the main oil passages of the tank. The rectangular mesh nodes are then subjected to rectangular mesh mapping, and the arbitrary mesh nodes are subjected to arbitrary mesh mapping, with the rectangular mesh mapping scale being smaller than the arbitrary mesh mapping scale. A heat source is applied to the winding, and the winding temperature is obtained based on the thermal-fluid coupling numerical model of the distribution transformer. Rectangular mesh nodes are added until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding. This invention can improve the overall mesh quality of the winding, reduce the number of meshes while ensuring the accuracy of the winding temperature rise characteristic solution, and improve mesh quality. It also has strong versatility.

Description

Technical Field

[0001] This invention relates to the field of distribution transformer technology, and more specifically to a method and apparatus for controlling the meshing of a thermal-fluid coupled model of a distribution transformer. Background Technology

[0002] The main function of a distribution transformer is to convert high-voltage electricity into low-voltage electricity for user supply. In the entire power supply system, the distribution transformer is a key component of the distribution network, making it a critical node device in the power system.

[0003] When a transformer is energized, it generates an electromagnetic field within the transformer body, resulting in losses and causing heating of internal components and structures. During normal operation, the current flowing through the windings of a distribution transformer generates resistance heat, which serves as the primary heat source for the entire transformer. This makes the windings highly susceptible to localized overheating. This heat is then transferred to other components of the transformer through conduction, convection, and radiation, potentially accelerating the degradation of insulation materials, reducing insulation performance, and shortening the transformer's lifespan. Therefore, studying the temperature rise of the windings is crucial for ensuring the reliability of distribution transformer operation.

[0004] Current research on the temperature rise characteristics of distribution transformers under thermal-fluid coupling is not uncommon, but most studies focus on two-dimensional models for temperature field coupling simulation. For three-phase transformers, two-dimensional models are insufficient to accurately describe the actual internal temperature and fluid distribution. Furthermore, due to the complex internal structure of transformers, it is difficult to establish a comprehensive three-dimensional model that includes the oil channels within the transformer windings and the oil channels in the heat sinks. Meshing this model can result in tens of millions of meshes, thus affecting the efficiency of accurately solving for temperature rise characteristics. Therefore, constructing thermal-fluid coupling models of distribution transformers based on existing simulation software suffers from problems such as large mesh sizes, difficulty in controlling mesh shapes, and high computational time, thereby hindering the efficient application of numerical simulation technology for thermal-fluid coupling in distribution transformers. Summary of the Invention

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0006] The main purpose of this invention is to solve the aforementioned technical problems in the prior art. It provides a controlled meshing method and device for the thermal-fluid coupling model of distribution transformers, which can improve the overall mesh quality of the windings, reduce the number of meshes while ensuring the accuracy of the winding temperature rise characteristics solution, improve mesh quality, and has strong versatility and broad application prospects.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for controlling the meshing of a thermal-fluid coupled model of a distribution transformer includes:

[0009] Establish a numerical model of thermal-fluid coupling for distribution transformers;

[0010] The steps for dividing the grid nodes are as follows: rectangular grid nodes are constructed for the oil passages inside the winding, the oil passages near the winding, and the oil passages of the heat sink; arbitrary grid nodes are constructed for the winding structural components and the main oil passages of the oil tank.

[0011] Perform rectangular mesh mapping subdivision on rectangular mesh nodes, and perform arbitrary mesh mapping subdivision on arbitrary mesh nodes, with the rectangular mesh mapping subdivision scale being smaller than the arbitrary mesh mapping subdivision scale;

[0012] A heat source is applied to the winding, and the winding temperature is obtained based on a numerical model of heat-fluid coupling of a distribution transformer.

[0013] Determine if the winding temperature meets the accuracy requirements. If it does, obtain the winding temperature distribution characteristics. If not, jump to the mesh node division step and increase the number of rectangular mesh nodes radially and axially until the winding temperature meets the accuracy requirements to obtain the winding temperature distribution characteristics.

[0014] Furthermore, the method for establishing a numerical model of the heat-fluid coupling of a distribution transformer is as follows:

[0015] A numerical model of thermal-fluid coupling for distribution transformers was established, including the core, windings, clamps, oil tank, heat sink, pads, and screws of the distribution transformer.

[0016] Furthermore, the winding temperature is obtained based on a numerical model of thermal-fluid coupling of the distribution transformer:

[0017] Based on the anisotropic heat transfer characteristics, the windings in the numerical model of heat-fluid coupling of distribution transformers are treated as an equivalent process. The winding conductors, surface insulating varnish, and oil-impregnated insulating paper are modeled as a whole, and the thermal parameters of the equivalent windings are solved. The winding temperature is obtained based on the thermal parameters of the equivalent windings. The method for obtaining the equivalent parameters is shown in the following formula:

[0018]

[0019] In the formula, K rThe equivalent thermal conductivity is represented by k1, k2, and k3, which represent the thermal conductivity of three different materials: the winding conductor, the wire enameling layer, and the oil-impregnated insulating paper, respectively. r d represents the total thickness of the material. r1 d r2 d r3 These represent the thicknesses of three different materials: winding conductor, wire enameling layer, and oil-impregnated insulating paper.

[0020] Furthermore, during the process of obtaining the winding temperature based on the thermal parameters of the equivalent winding, the temperature of the equivalent winding region is subjected to Lagrange interpolation.

[0021] Furthermore, the arbitrary grid nodes are arranged with equal or variable arcs and with equal or variable spacing in the axial and radial directions. The arbitrary grid nodes are controlled by manual matching input, configuration file loading, or execution using a parametric design language.

[0022] Furthermore, the method for constructing rectangular mesh nodes for the oil passages within the winding, the oil passages near the winding, and the oil passages of the heat sink is as follows:

[0023] For oil passages within the winding, oil passages near the winding, and oil passages on the heat sink, the height of the first-layer mesh node is determined by the dimensionless wall function y+, where y+ takes a value of 1. The formula for the height of the first-layer mesh node is:

[0024]

[0025] In the formula, y0 represents the height of the first layer of grid nodes, μ is the dynamic viscosity of transformer oil, ρ represents the density of transformer oil, and u τ This indicates that the friction velocity is calculated from the wall shear stress.

[0026] The formula for calculating the growth rate of the rectangular mesh node height for oil passages within the windings and oil passages in the heat sinks is as follows:

[0027]

[0028] In the formula, r represents the growth rate of the rectangular grid node height, d represents the height of the first layer of grid nodes, and N is the number of layers of rectangular grid nodes;

[0029] For the oil passages near the winding, the formula for calculating the growth rate of the rectangular mesh node height is:

[0030]

[0031] Furthermore, the method for arbitrary mesh mapping subdivision of arbitrary mesh nodes is as follows:

[0032] The meshing accuracy is controlled according to the solution requirements, and free meshing using triangles or tetrahedrons is adopted.

[0033] A control mesh generation device for a thermal-fluid coupled model of a distribution transformer includes:

[0034] The model building module is used to build a numerical model of the thermal-fluid coupling of a distribution transformer.

[0035] The mesh generation module is used to divide the mesh nodes. It constructs rectangular mesh nodes for the oil passages inside the winding, the oil passages near the winding, and the oil passages of the heat sink, and constructs arbitrary mesh nodes for the winding structure and the main oil passage of the oil tank.

[0036] The mesh mapping and partitioning module is used to perform rectangular mesh mapping and partitioning on rectangular mesh nodes, and arbitrary mesh mapping and partitioning on arbitrary mesh nodes, with the scale of rectangular mesh mapping and partitioning being smaller than the scale of arbitrary mesh mapping and partitioning.

[0037] The temperature acquisition module is used to apply a heat source to the winding and acquire the winding temperature based on the numerical model of thermal-fluid coupling of the distribution transformer.

[0038] The temperature distribution characteristic acquisition module is used to determine whether the winding temperature meets the accuracy requirements. If it does, the temperature distribution characteristics of the winding are obtained. If not, the module jumps to the mesh node division step and increases the number of rectangular mesh nodes in the radial and axial directions until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

[0039] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described control partitioning method for the thermal-fluid coupling model mesh of a distribution transformer.

[0040] A non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described control partitioning method for the mesh of the thermal-fluid coupling model of a distribution transformer.

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0042] This invention can construct rectangular mesh nodes specifically based on the distribution of heat sources in the windings and the required computational accuracy. It allows for flexible adjustment of the number of rectangular mesh nodes in the oil channels within the windings, the oil passages surrounding the windings, the oil channels of the heat sinks, and the winding structural components. Furthermore, it enables the application of varying heat sources to different regions of the transformer windings. Simultaneously, by combining mapping and free mesh generation methods, it reduces the overall mesh size of the transformer thermal-fluid coupling model while improving mesh quality, thereby enhancing the efficiency and accuracy of temperature rise calculations for distribution transformer windings. Attached Figure Description

[0043] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0044] Figure 1 This is a flowchart of a control meshing method for a thermal-fluid coupled model of a distribution transformer according to the present invention;

[0045] Figure 2 This is a schematic diagram of rectangular mesh partitioning in a specific embodiment of the present invention;

[0046] Figure 3 This is a flowchart of a control partitioning device for a thermal-fluid coupling model mesh of a distribution transformer according to the present invention. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] Example 1

[0050] In related technologies, research on the temperature rise characteristics of distribution transformers involving thermal-fluid coupling often focuses on temperature field coupling simulations using two-dimensional models. However, for three-phase transformers, two-dimensional models struggle to accurately describe the actual internal temperature and fluid distribution. Furthermore, due to the complex internal structure of transformers, it is difficult to establish a comprehensive three-dimensional refined model that includes the oil channels within the transformer windings and the oil channels of the heat sinks. Meshing this model can result in tens of millions of meshes, thus affecting the efficiency of accurately solving for temperature rise characteristics. This embodiment uses rectangular mesh node control for the oil channels of the distribution transformer, flexibly adjusting the distribution and number of rectangular mesh nodes according to the required computational accuracy. For other non-critical areas, the mesh subdivision scale can be appropriately increased. This effectively avoids the problem of excessive mesh expansion caused by using free meshing methods when constructing a three-dimensional refined model of the distribution transformer.

[0051] Example 1 provides a control meshing method for a thermal-fluid coupled model of a distribution transformer, such as... Figure 1 As shown, it includes:

[0052] Step S1: Establish a numerical model of thermal-fluid coupling for the distribution transformer.

[0053] In this embodiment, in the step of establishing the thermal-fluid coupling numerical model of the distribution transformer, a thermal-fluid coupling numerical model of the distribution transformer is established based on the actual distribution transformer prototype and operating conditions. The thermal-fluid coupling numerical model of the distribution transformer includes the core, windings, clamps, oil tank, heat sink, pads, and screws of the distribution transformer.

[0054] In this embodiment, the winding includes a high-voltage winding and a low-voltage winding.

[0055] In this embodiment, the thermal-fluid coupling numerical model of the distribution transformer includes the addition of model materials, the setting of boundary conditions, the determination of heat transfer coefficients and environmental parameters. The contact surface between the distribution transformer oil and the solid wall is designated as the coupling wall, and the flow heat transfer coefficient and surface emissivity are set for the surface of the distribution transformer casing.

[0056] In this embodiment, after establishing a numerical model of heat-fluid coupling of the distribution transformer, based on the anisotropic heat transfer characteristics, the winding is equivalently processed when establishing the transformer heat transfer model, and the thermal parameters of the equivalent winding are solved.

[0057] In this embodiment, the windings in the numerical model of heat-fluid coupling of the distribution transformer are equivalently treated based on the anisotropic heat transfer characteristics. The winding conductors, surface insulating varnish, oil-impregnated insulating paper, etc., are modeled as a whole, and the thermal parameters of the equivalent winding are solved. The winding temperature is obtained based on the thermal parameters of the equivalent winding. The method for obtaining the equivalent parameters is shown in the following formula:

[0058]

[0059] In the formula, K r The equivalent thermal conductivity is represented by k1, k2, and k3, which represent the thermal conductivity of three different materials: the winding conductor, the wire enameling layer, and the oil-impregnated insulating paper, respectively. r d represents the total thickness of the material. r1 d r2 d r3 These represent the thicknesses of three different materials: winding conductor, wire enameling layer, and oil-impregnated insulating paper.

[0060] By using equivalent processing, the calculation model for winding temperature can be simplified while ensuring calculation accuracy.

[0061] Step S2: Mesh node division step. Rectangular mesh nodes are constructed for the oil passages inside the winding, the oil passages near the winding, and the oil passages of the heat sink. Arbitrary mesh nodes are constructed for the winding structural components and the main oil passages of the oil tank.

[0062] In this embodiment, the oil passage near the wrapping winding is an oil passage 5mm to 10mm away from the wrapping winding.

[0063] In this embodiment, the winding structure includes windings, support bars, insulating ends, etc.

[0064] The arbitrary grid nodes are arranged with equal or variable arcs and with equal or variable spacing in the axial and radial directions. The arbitrary grid nodes are controlled by manual matching input, configuration file loading, or execution by a parametric design language.

[0065] In the process of dividing the grid nodes, the number of grid nodes for windings, support bars, and insulation ends can be flexibly increased or decreased based on the rectangular grid nodes of the distribution transformer oil passage.

[0066] Step S3: Perform rectangular mesh mapping subdivision on rectangular mesh nodes, and perform arbitrary mesh mapping subdivision on arbitrary mesh nodes, wherein the scale of rectangular mesh mapping subdivision is smaller than the scale of arbitrary mesh mapping subdivision.

[0067] In this embodiment, the method for constructing rectangular mesh nodes for the oil passages inside the winding, the oil passages near the winding, and the oil passages of the heat sink is as follows:

[0068] The height of the first-layer grid nodes in the oil passages within the winding, the oil passages near the winding, and the oil passages of the heat sink is determined by the dimensionless wall function y+, where y+ takes a value of 1. The formula for the height of the first-layer grid nodes is:

[0069]

[0070] In the formula, y0 represents the height of the first layer of grid nodes, μ is the dynamic viscosity of transformer oil, ρ represents the density of transformer oil, and u τThis indicates that the friction velocity is calculated from the wall shear stress.

[0071] The formula for calculating the growth rate of the rectangular mesh node height for oil passages within the windings and oil passages in the heat sinks is as follows:

[0072]

[0073] In the formula, r represents the growth rate of the rectangular grid node height, d represents the height of the first layer of grid nodes, and N is the number of layers of rectangular grid nodes;

[0074] For the oil passages near the winding, the formula for calculating the growth rate of the rectangular mesh node height is:

[0075]

[0076] Based on the rectangular grid nodes of the oil passages inside the winding, the oil passages surrounding the winding, and the oil passages of the heat sink, the rectangular grid nodes of the winding structure can be flexibly added or removed.

[0077] In this embodiment, the method for arbitrary mesh mapping subdivision of arbitrary mesh nodes is as follows: control the subdivision accuracy according to the solution requirements, and use triangular or tetrahedral free subdivision.

[0078] Step S4: Apply a heat source to the winding and obtain the winding temperature based on the numerical model of heat-fluid coupling of the distribution transformer.

[0079] In this embodiment, during the process of obtaining the winding temperature based on the thermal parameters of the equivalent winding, the temperature of the equivalent winding region is subjected to Lagrange interpolation. The processing formula is as follows:

[0080]

[0081] In the formula, T(x,y) represents the temperature at the winding interpolation point (x,y), and x i y j These are the x and y coordinates of the rectangular grid nodes, respectively, T(x) i ,y j ) represents the temperature of the grid node.

[0082] In this embodiment, based on the winding rectangular grid unit, the transformer winding can be subjected to regional heat source loading.

[0083] Step S5: Determine if the winding temperature meets the accuracy requirements. If it does, obtain the winding temperature distribution characteristics. If it does not, jump to the mesh node division step and increase the number of rectangular mesh nodes in the radial and axial directions until the winding temperature meets the accuracy requirements to obtain the winding temperature distribution characteristics.

[0084] Specifically, when determining whether the winding temperature can meet the accuracy requirements, the hot spot temperature of the winding or the temperature at any position of the winding can be selected as the judgment basis. If the accuracy requirements are met, the temperature distribution characteristics of the winding can be output. If the accuracy requirements are not met, the number of rectangular grid nodes of the oil passages in the winding, the oil passages surrounding the winding, and the oil passages of the heat sink can be flexibly increased, and then steps S3 to S6 are repeated. Furthermore, the automatic judgment and result output of step S7 can be achieved by using a programming language.

[0085] The following is a detailed description of a control partitioning method for a thermal-fluid coupled model mesh of a distribution transformer provided by the present invention, using a specific embodiment.

[0086] This invention proposes an efficient control meshing method for a thermal-fluid coupling model of a distribution transformer. First, a thermal-fluid coupling numerical model of the distribution transformer is established. The windings are then equivalently processed, and the equivalent winding thermal parameters are solved to construct rectangular mesh nodes for the transformer windings, support bars, internal winding oil channels, and heat sink oil channels. Rectangular mesh mapping is then applied to the transformer windings, internal winding oil channels, and the oil channels within 5mm of the windings and heat sink oil channels. For the remaining areas around the windings, a suitable meshing method is selected based on the solution requirements. Based on the transformer winding thermal-fluid coupling model, a variable heat source is applied to the windings in different zones to calculate the transformer winding temperature and transformer oil flow distribution characteristics. Finally, the layout and number of rectangular mesh nodes for the transformer windings and oil channels are adjusted according to the calculation results of the transformer winding thermal-fluid coupling model. This invention treats the winding conductor, conductor insulation layer, and insulating oil paper as an equivalent whole, calculates the equivalent thermal parameters, and reduces the complexity of the model. At the same time, it adopts a hybrid meshing method of rectangular meshing and triangular meshing, which reduces the overall number of meshes while ensuring mesh quality. Furthermore, the rectangular mesh nodes of the winding and oil passages can be flexibly adjusted according to calculation needs, thereby improving the overall efficiency of winding temperature rise calculation.

[0087] like Figure 2 The diagram shown is a schematic representation of the rectangular grid partitioning in a specific embodiment of the present invention, illustrating the rectangular grid partitioning of the insulating ends, low-voltage winding, high-voltage winding, and oil passages.

[0088] The efficient controlled meshing method of the thermal-fluid coupling model of the distribution transformer of the present invention is compared with the meshing calculation results of the triangular free meshing method. The comparison of the temperature rise calculation results of the distribution transformer winding is shown in Table 1 below.

[0089] Table 1 Comparison of Calculation Results of Temperature Rise in Distribution Transformer Windings

[0090]

[0091] Table 1 shows that the overall mesh size of the efficient controlled mesh generation method using the thermal-fluid coupled model mesh for distribution transformers is 4.51 million, while the overall mesh size of the mesh generation method using the triangular free mesh generation method is 17.1 million. Simulation analysis was conducted while ensuring consistent boundary conditions. The results show that the simulation time using the triangular free mesh generation method is 2983 minutes, the hot spot temperature of phase B winding is 90.08℃, the experimental temperature is 92.27℃, and the relative error is 2.38%. In contrast, the simulation time using the efficient controlled mesh generation method using the thermal-fluid coupled model mesh is 564 minutes, the hot spot temperature of phase B winding is 91.66℃, and the relative error is 0.663%. The efficient controlled mesh generation method using the thermal-fluid coupled model mesh in this invention improves computational efficiency by 81.1% and computational accuracy by 1.7% compared to the triangular free mesh generation method.

[0092] Example 2

[0093] Example 2 provides a control meshing device for a thermal-fluid coupled model of a distribution transformer, such as... Figure 3 As shown, it includes:

[0094] The model building module is used to build a numerical model of the thermal-fluid coupling of a distribution transformer.

[0095] The mesh generation module is used to divide the mesh nodes. It constructs rectangular mesh nodes for the oil passages inside the winding, the oil passages near the winding, and the oil passages of the heat sink, and constructs arbitrary mesh nodes for the winding structure and the main oil passage of the oil tank.

[0096] The mesh mapping and partitioning module is used to perform rectangular mesh mapping and partitioning on rectangular mesh nodes, and arbitrary mesh mapping and partitioning on arbitrary mesh nodes, with the scale of rectangular mesh mapping and partitioning being smaller than the scale of arbitrary mesh mapping and partitioning.

[0097] The temperature acquisition module is used to apply a heat source to the winding and acquire the winding temperature based on the numerical model of thermal-fluid coupling of the distribution transformer.

[0098] The temperature distribution characteristic acquisition module is used to determine whether the winding temperature meets the accuracy requirements. If it does, the temperature distribution characteristics of the winding are obtained. If not, the module jumps to the mesh node division step and increases the number of rectangular mesh nodes in the radial and axial directions until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

[0099] Example 3

[0100] Example 3 provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described control partitioning method for the thermal-fluid coupling model mesh of a distribution transformer.

[0101] Example 4

[0102] Example 4 provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described control partitioning method for the mesh of the thermal-fluid coupling model of a distribution transformer.

[0103] The above embodiments are merely illustrative examples of the technical solution of the present invention. The method for predicting the daily attenuation variation of regulating waves in a hydropower station, as described in the present invention, is not limited to the content described in the above embodiments, but is defined by the scope of the claims. Any modifications, additions, or equivalent substitutions made by those skilled in the art based on these embodiments are within the scope of protection claimed by the claims of the present invention.

Claims

1. A method for controlling the mesh generation of a thermal-fluid coupled model of a distribution transformer, characterized in that, include: Establish a numerical model of thermal-fluid coupling for distribution transformers; The steps for dividing the grid nodes are as follows: rectangular grid nodes are constructed for the oil passages inside the winding, the oil passages near the winding, and the oil passages of the heat sink; arbitrary grid nodes are constructed for the winding structural components and the main oil passages of the oil tank. Perform rectangular mesh mapping subdivision on rectangular mesh nodes, and perform arbitrary mesh mapping subdivision on arbitrary mesh nodes, with the rectangular mesh mapping subdivision scale being smaller than the arbitrary mesh mapping subdivision scale; A heat source is applied to the winding, and the winding temperature is obtained based on a numerical model of heat-fluid coupling of a distribution transformer. Determine whether the winding temperature meets the accuracy requirements. If it does, obtain the temperature distribution characteristics of the winding. If it does not, jump to the mesh node division step and increase the number of rectangular mesh nodes in the radial and axial directions until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding. A numerical model of the heat-fluid coupling of the distribution transformer is established, specifically as follows: Establish a numerical model of thermal-fluid coupling for distribution transformers, including the core, windings, clamps, oil tank, heat sink, pads, and screws of the distribution transformer. The winding temperature is obtained based on a numerical model of thermal-fluid coupling of a distribution transformer, specifically as follows: Based on the anisotropic heat transfer characteristics, the windings in the numerical model of heat-fluid coupling of distribution transformers are treated as an equivalent process. The winding conductors, surface insulating varnish, and oil-impregnated insulating paper are modeled as a whole, and the thermal parameters of the equivalent windings are solved. The winding temperature is obtained based on the thermal parameters of the equivalent windings. The method for obtaining the equivalent parameters is shown in the following formula: In the formula, Indicates equivalent thermal conductivity. , , These represent the thermal conductivity of three different materials: winding conductor, wire enameling layer, and oil-impregnated insulating paper. Indicates the total thickness of the material. , , These represent the thicknesses of three different materials: winding conductor, wire enameling layer, and oil-impregnated insulating paper. Rectangular mesh nodes are constructed for the oil passages within the winding, the oil passages near the winding, and the oil passages of the heat sink, specifically as follows: For oil passages within the winding, oil passages near the winding, and oil passages on the heat sink, the height of the first-layer mesh node is determined by the dimensionless wall function y+, where y+ takes a value of 1. The formula for the height of the first-layer mesh node is: In the formula, Indicates the height of the first layer of mesh nodes. The dynamic viscosity of transformer oil. Indicates the density of transformer oil. This indicates that the friction velocity is calculated from the wall shear stress. The formula for calculating the growth rate of the rectangular mesh node height for oil passages within the windings and oil passages in the heat sinks is as follows: In the formula, This represents the growth rate of the height of the rectangular grid nodes. Indicates the height of the first layer of mesh nodes. The number of layers for the rectangular grid nodes; For the oil passages near the winding, the formula for calculating the growth rate of the rectangular mesh node height is: 。 2. The control meshing method for the thermal-fluid coupling model of distribution transformers according to claim 1, characterized in that: In the process of obtaining the winding temperature based on the thermal parameters of the equivalent winding, the temperature of the equivalent winding region is subjected to Lagrange interpolation.

3. The control meshing method for the thermal-fluid coupled model of distribution transformers according to claim 1, characterized in that: The arbitrary grid nodes are arranged with equal or variable arcs and with equal or variable spacing in the axial and radial directions. The arbitrary grid nodes are controlled by manual matching input, configuration file loading, or execution by a parametric design language.

4. The control meshing method for the thermal-fluid coupled model of a distribution transformer according to claim 1, characterized in that, Perform arbitrary mesh mapping and subdivision on arbitrary mesh nodes, specifically as follows: The meshing accuracy is controlled according to the solution requirements, and free meshing using triangles or tetrahedrons is adopted.

5. A control meshing device for a thermal-fluid coupled model of a distribution transformer, characterized in that, A control meshing method for performing the distribution transformer thermal-fluid coupled model mesh as described in any one of claims 1 to 4, comprising: The model building module is used to build a numerical model of the thermal-fluid coupling of a distribution transformer. The mesh generation module is used to divide the mesh nodes. It constructs rectangular mesh nodes for the oil passages inside the winding, the oil passages near the winding, and the oil passages of the heat sink, and constructs arbitrary mesh nodes for the winding structure and the main oil passage of the oil tank. The mesh mapping and partitioning module is used to perform rectangular mesh mapping and partitioning on rectangular mesh nodes, and arbitrary mesh mapping and partitioning on arbitrary mesh nodes, with the scale of rectangular mesh mapping and partitioning being smaller than the scale of arbitrary mesh mapping and partitioning. The temperature acquisition module is used to apply a heat source to the winding and acquire the winding temperature based on the numerical model of thermal-fluid coupling of the distribution transformer. The temperature distribution characteristic acquisition module is used to determine whether the winding temperature can meet the accuracy requirements. If it does, the temperature distribution characteristics of the winding are obtained. If it does not, the module jumps to the grid node division step and increases the number of rectangular grid nodes in the radial and axial directions until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

6. An electronic 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 program, it implements the controlled partitioning method for the thermal-fluid coupling model mesh of the distribution transformer as described in any one of claims 1 to 4.

7. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the controlled partitioning method for the thermal-fluid coupling model mesh of the distribution transformer as described in any one of claims 1 to 4.

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