Control subdivision method and device for distribution transformer heat flow coupling model grid

Abstract

The invention provides a control subdivision method and device for a distribution transformer heat flow coupling model grid, and the method comprises the steps: building a distribution transformer heat flow coupling numerical model, dividing grid nodes, carrying out the construction of rectangular grid nodes for an inner oil duct of a winding, an oil way wrapping the winding, and a cooling fin oil duct, and carrying out the control subdivision of the distribution transformer heat flow coupling model grid. Any grid node construction is conducted on a winding structural part and an oil tank main oil way, rectangular grid mapping subdivision is conducted on rectangular grid nodes, any grid mapping subdivision is conducted on any grid node, the size of the rectangular grid mapping subdivision is smaller than the size of any grid mapping subdivision, a heat source is applied to a winding, and the winding structure is obtained. And obtaining the winding temperature based on the distribution transformer heat flow coupling numerical model, and increasing rectangular grid nodes until the winding temperature meets the precision requirement to obtain the temperature distribution characteristic of the winding. According to the method, the overall grid quality of the winding can be improved, the number of grids is reduced under the condition that the temperature rise characteristic solving precision of the winding is guaranteed, the grid quality is improved, and the universality is high.

Description

Technical Field

[0001] The invention relates to the technical field of distribution transformers, and in particular to a control partitioning method and a device for a distribution transformer thermal-fluid coupling model grid. Background Art

[0002] The main function of the distribution transformer is to convert high-voltage electricity into low-voltage electricity so that it can be supplied to users. In the entire power supply system, the distribution transformer is the main component of the distribution network, so the distribution transformer is a key node equipment in the power system.

[0003] When the transformer is connected to current, a corresponding electromagnetic field will be generated in the transformer body, which will then cause corresponding losses, causing the internal components and structural parts of the transformer to heat up. During the normal operation of the distribution transformer, the current passing through the winding will generate resistance heat. Resistance heat is the main heat source of the entire transformer, which makes the winding itself very prone to local overheating. This heat is then transferred to other parts of the transformer through heat conduction, heat convection and heat radiation, which may accelerate the performance degradation of other insulating materials, resulting in reduced insulation performance and shortening the service life of the distribution transformer. Therefore, in order to ensure the reliability of the operation of the distribution transformer, it is very important to study the temperature rise of its windings.

[0004] At present, the study of the temperature rise characteristics of the thermal-fluid coupling of distribution transformers is not uncommon, but most of the studies are for the temperature field coupling simulation of two-dimensional models. For three-phase transformers, it is difficult to accurately describe the temperature fluid distribution inside the actual transformer by studying the two-dimensional model. In addition, due to the complex internal structure of the transformer, it is difficult to establish an overall three-dimensional refined model including the oil channel in the transformer winding and the oil channel of the heat sink. When the grid is divided, the number of grids will reach tens of millions, which will affect the efficiency of the accurate solution of the temperature rise characteristics. Therefore, the construction of the thermal-fluid coupling model of the distribution transformer based on the existing simulation software has problems such as large number of grid divisions, difficult to control the grid shape, and time-consuming calculation, which restricts the efficient application of the thermal-fluid coupling numerical simulation technology of the distribution transformer. Summary of the invention

[0005] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0006] The main purpose of the present invention is to solve the above-mentioned technical problems existing in the prior art, and provide a control splitting method and device for the grid of the thermal-fluid coupling model of a distribution transformer, which can improve the overall grid quality of the winding, reduce the number of grids while ensuring the accuracy of solving the temperature rise characteristics of the winding, improve the grid quality, have strong versatility, and have a broad application prospect.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A control partitioning method for a distribution transformer thermal-fluid coupling model grid, comprising:

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

[0010] The grid node division step includes constructing rectangular grid nodes for the oil channel inside the winding, the oil channel around the winding, and the oil channel of the heat sink, and constructing arbitrary grid nodes for the winding structure and the main oil channel of the oil tank;

[0011] Performing rectangular grid mapping subdivision on rectangular grid nodes, performing arbitrary grid mapping subdivision on arbitrary grid nodes, and the rectangular grid mapping subdivision scale is smaller than the arbitrary grid mapping subdivision scale;

[0012] Apply heat source to the winding and obtain the winding temperature based on the thermal-fluid coupled numerical model of the distribution transformer;

[0013] Determine whether the winding temperature meets the accuracy requirements? If it does, the temperature distribution characteristics of the winding are obtained. If not, jump to the step of dividing the grid nodes and increase the number of radial and axial rectangular grid nodes until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

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

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

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

[0017] Based on the anisotropic heat transfer characteristics, the winding in the thermal-fluid coupling numerical model of the distribution transformer is treated equivalently. The winding conductor, surface insulating paint, 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:

[0018]

[0019] In the formula, K rrepresents the equivalent thermal conductivity, k 1 , k 2 , k 3 Respectively represent the thermal conductivity of three different materials: winding conductor, wire enameled layer, and oil-impregnated insulating paper, d r Indicates the total thickness of the material, d r1 d r2 d r3 They respectively represent the thickness of three different materials: winding conductor, wire enameling layer and oil-impregnated insulating paper.

[0020] Furthermore, in the process of obtaining the winding temperature based on the thermal parameters of the equivalent winding, Lagrangian interpolation processing is performed on the temperature of the equivalent winding area.

[0021] Furthermore, the arbitrary grid nodes are arranged with equal arc or variable arc and the grid nodes are arranged with equal spacing or variable spacing in the axial and radial directions. The control method of the arbitrary grid nodes is manual matching input, configuration file loading or parameterized design language execution.

[0022] Furthermore, the method for constructing rectangular grid nodes for the oil passage inside the winding, the oil passage near the winding, and the oil passage of the heat sink is as follows:

[0023] For the oil passages in the winding, the oil passages around the winding, and the oil passages on the heat sink, the height of the first-layer grid nodes is determined by the dimensionless wall function y+, where y+ takes the value of 1. The formula for the height of the first-layer grid nodes is:

[0024]

[0025] In the formula, y 0 represents the height of the first-layer grid node, μ is the dynamic viscosity of transformer oil, ρ represents the transformer oil density, and u τ Indicates that the friction velocity is calculated from the wall shear stress;

[0026] For the oil passages in the winding and the heat sink, the calculation formula for the growth rate of the rectangular grid node height is:

[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 circuit around the winding, the growth rate of the rectangular grid node height is calculated as:

[0030]

[0031] Furthermore, the method of performing arbitrary mesh mapping division on any mesh node is as follows:

[0032] Control the segmentation accuracy according to the solution requirements and use triangle or tetrahedron free segmentation.

[0033] A control and partitioning device for a distribution transformer thermal-fluid coupling model grid, comprising:

[0034] Model building module, used to build a thermal-fluid coupling numerical model of distribution transformers;

[0035] The mesh division module is used to divide the mesh node steps, construct rectangular mesh nodes for the oil channel inside the winding, the oil channel near the winding, and the oil channel of the heat sink, and construct arbitrary mesh nodes for the winding structure and the main oil channel of the oil tank;

[0036] A grid mapping subdivision module is used to perform rectangular grid mapping subdivision on rectangular grid nodes and perform arbitrary grid mapping subdivision on arbitrary grid nodes, and the rectangular grid mapping subdivision scale is smaller than the arbitrary grid mapping subdivision scale;

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

[0038] 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 not, the step of dividing the grid nodes is jumped to increase the number of radial and axial rectangular grid nodes until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

[0039] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the control partitioning method of the grid of the thermal-fluid coupling model of the distribution transformer when executing the program.

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

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

[0042] The present invention can construct rectangular grid nodes in a targeted manner in combination with the distribution of the winding heat source and the calculation accuracy, and can flexibly adjust the number of rectangular grid nodes of the oil channel in the winding, the oil channel near the winding, the heat sink oil channel, and the winding structure, and can realize the regional variable heat source loading of the transformer winding. At the same time, by combining the mapping and free meshing methods, the overall number of grids in the transformer thermal flow coupling model is reduced while the grid quality is improved, thereby improving the efficiency and accuracy of the temperature rise calculation of the distribution transformer winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0044] Figure 1 A flow chart of a control partitioning method of a distribution transformer thermal-fluid coupling model grid according to the present invention;

[0045] Figure 2 A schematic diagram of a rectangular grid division in a specific embodiment of the present invention;

[0046] Figure 3 The present invention is a flow chart of a control and segmentation device for a distribution transformer thermal-fluid coupling model grid. DETAILED DESCRIPTION

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

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0049] Example 1

[0050] In the related art, the temperature rise characteristics of the thermal-fluid coupling of the distribution transformer are mostly studied by the temperature field coupling simulation of the two-dimensional model. However, for the three-phase transformer, the two-dimensional model is difficult to accurately describe the temperature fluid distribution inside the actual transformer, and due to the complex internal structure of the transformer, it is difficult to establish an overall three-dimensional refined model including the oil channel in the transformer winding and the oil channel of the heat sink, and the number of grids will reach tens of millions when the grid is divided, thereby affecting the efficiency of the accurate solution of the temperature rise characteristics. This embodiment performs rectangular grid node control on the oil channel of the distribution transformer, flexibly adjusts the distribution and number of rectangular grid nodes according to the calculation accuracy requirements, and appropriately increases the grid division scale for other non-critical areas, thereby effectively avoiding the problem of excessive expansion of the number of grids caused by using the free division method for grid refinement when constructing the three-dimensional refined model of the distribution transformer.

[0051] Embodiment 1 provides a control partitioning method for a distribution transformer thermal-fluid coupling model grid, such as Figure 1 As shown, including:

[0052] Step S1: Establish a thermal-fluid coupled numerical model of 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 according to the actual distribution transformer prototype and operating conditions, and a thermal-fluid coupling numerical model of the distribution transformer including the core, windings, clamps, oil tank, heat sink, spacers, and screws of the distribution transformer is established.

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

[0055] In this embodiment, the heat-flow 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 set as a coupling wall, and the heat transfer coefficient and surface radiation emissivity are set for the surface of the distribution transformer shell.

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

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

[0058]

[0059] In the formula, K r represents the equivalent thermal conductivity, k 1 , k 2 , k 3 Respectively represent the thermal conductivity of three different materials: winding conductor, wire enameled layer, and oil-impregnated insulating paper, d r Indicates the total thickness of the material, d r1 d r2 d r3 They respectively represent the thickness of three different materials: winding conductor, wire enameling layer and oil-impregnated insulating paper.

[0060] Through equivalent processing, the calculation model of winding temperature can be simplified while ensuring the calculation accuracy.

[0061] Step S2: grid node division step, rectangular grid nodes are constructed for the oil channel inside the winding, the oil channel near the winding, and the oil channel of the heat sink, and arbitrary grid nodes are constructed for the winding structural parts and the main oil channel of the oil tank.

[0062] In this embodiment, the oil path around the wrapped winding is an oil path of 5 mm to 10 mm around the wrapped winding.

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

[0064] The arbitrary grid nodes are arranged with equal arc or variable arc and the grid nodes are arranged with equal spacing or variable spacing in the axial and radial directions. The control method of the arbitrary grid nodes is manual matching input, configuration file loading or parameterized design language execution.

[0065] In the step of dividing the grid nodes, based on the rectangular grid nodes of the oil channel of the distribution transformer, the number of the winding, stay and insulation end grid nodes can be flexibly increased or decreased.

[0066] Step S3: performing rectangular grid mapping division on the rectangular grid nodes, performing arbitrary grid mapping division on the arbitrary grid nodes, and the rectangular grid mapping division scale is smaller than the arbitrary grid mapping division scale.

[0067] In this embodiment, the method for constructing rectangular grid nodes for the oil passages in the winding, the oil passages around the winding, and the oil passages on the heat sink is as follows:

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

[0069]

[0070] In the formula, y 0represents the height of the first-layer grid node, μ is the dynamic viscosity of transformer oil, ρ represents the transformer oil density, and u τ Indicates that the friction velocity is calculated from the wall shear stress;

[0071] For the oil passages in the winding and the heat sink, the calculation formula for the growth rate of the rectangular grid node height is:

[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 circuit around the winding, the growth rate of the rectangular grid node height is calculated as:

[0075]

[0076] Based on the rectangular grid nodes of the oil channel inside the winding, the oil channel near the winding, and the oil channel of the heat sink, the rectangular grid nodes of the winding structural parts can be flexibly increased or decreased.

[0077] In this embodiment, the method for performing arbitrary mesh mapping division on any mesh node is: controlling the division accuracy according to the solution requirement, and using triangle or tetrahedron free division.

[0078] Step S4: applying a heat source to the winding, and obtaining the winding temperature based on the thermal-fluid coupled numerical model of the distribution transformer.

[0079] In this embodiment, in the process of obtaining the winding temperature based on the thermal parameters of the equivalent winding, Lagrange interpolation processing is performed on the temperature of the equivalent winding area, and the processing formula is:

[0080]

[0081] Where T(x,y) represents the temperature of the winding interpolation point (x,y), x i ,y j are the horizontal and vertical coordinates of the rectangular grid nodes, respectively. i ,y j ) is 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 variable heat source loading.

[0083] Step S5: Determine whether the winding temperature can meet the accuracy requirements. If it does, the temperature distribution characteristics of the winding are obtained. If not, jump to the grid node division step to increase the number of radial and axial rectangular grid nodes until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

[0084] Specifically, when judging whether the winding temperature can meet the accuracy requirement, the hot spot temperature of the winding or the temperature at any position of the winding can be selected as the basis for judgment. If the accuracy requirement is met, the temperature distribution characteristics of the winding can be output. If the accuracy requirement is not met, the number of rectangular grid nodes of the oil channel inside the winding, the oil channel near the winding, and the heat sink oil channel can be flexibly increased, and then steps S3 to S6 are repeated; and the automatic judgment and result output of step S7 can be realized by using a programming language.

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

[0086] The present invention proposes a high-efficiency control and partitioning method for the grid of a distribution transformer thermal-fluid coupling model. First, a distribution transformer thermal-fluid coupling numerical model is established; the winding is equivalently processed and the equivalent winding thermal parameters are solved to construct rectangular grid nodes of the distribution transformer winding, stays, oil channels in the winding, heat sink oil channels, etc.; the distribution transformer winding, the oil channels in the winding, and the oil channels and heat sink oil channels within 5 mm of the winding are partitioned by rectangular grid mapping, and the remaining areas around the winding are partitioned by a suitable grid partitioning method according to the solution requirements; based on the numerical value of the transformer winding thermal-fluid coupling model, a variable heat source is applied to the winding partitions to calculate the distribution transformer winding temperature and the transformer oil flow distribution characteristics; the layout and number of the transformer winding and oil channel rectangular grid nodes are adjusted according to the calculation results of the transformer winding thermal-fluid coupling model. The present invention equates the winding conductor, the conductor insulation layer and the insulating oil paper into a whole, calculates the equivalent thermal parameters, reduces the complexity of the model, and adopts a mixed meshing method of rectangular meshing and triangular meshing. While ensuring the mesh quality, the overall number of meshes is reduced, and the rectangular mesh nodes of the winding and the oil channel can be flexibly adjusted according to the calculation requirements, thereby improving the efficiency of the winding temperature rise calculation as a whole.

[0087] like Figure 2 , which is a schematic diagram of rectangular grid division in a specific embodiment of the present invention, showing the rectangular grid division of the insulation end, the low-voltage winding, the high-voltage winding and the oil channel.

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

[0089] Table 1 Comparison of calculation results of temperature rise of distribution transformer windings

[0090]

[0091] As can be seen from Table 1, the number of overall grids of the efficient control partitioning method using the distribution transformer thermal-fluid coupling model grid is 4.51 million, and the number of overall grids of the triangular free partitioning method is 17.1 million. The simulation analysis is carried out under the condition of ensuring the consistency of boundary conditions, etc. The results show that the simulation time of the triangular free partitioning method is 2983 minutes, the hot spot temperature of the B-phase winding is 90.08°C, the test temperature is 92.27°C, and the relative error is 2.38%; while the simulation time of the efficient control partitioning using the thermal-fluid coupling model grid is 564 minutes, the hot spot temperature of the B-phase winding is 91.66°C, and the relative error is 0.663%. Compared with the triangular free partitioning method, the efficient control partitioning method of the thermal-fluid coupling model grid adopted by the present invention has an 81.1% improvement in calculation efficiency and a 1.7% improvement in calculation accuracy.

[0092] Example 2

[0093] Embodiment 2 provides a control and segmentation device for a distribution transformer thermal-fluid coupling model grid, such as Figure 3 As shown, including:

[0094] Model building module, used to build a thermal-fluid coupling numerical model of distribution transformers;

[0095] The mesh division module is used to divide the mesh node steps, construct rectangular mesh nodes for the oil channel inside the winding, the oil channel near the winding, and the oil channel of the heat sink, and construct arbitrary mesh nodes for the winding structure and the main oil channel of the oil tank;

[0096] A grid mapping subdivision module is used to perform rectangular grid mapping subdivision on rectangular grid nodes and perform arbitrary grid mapping subdivision on arbitrary grid nodes, and the rectangular grid mapping subdivision scale is smaller than the arbitrary grid mapping subdivision scale;

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

[0098] 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 not, the step of dividing the grid nodes is jumped to increase the number of radial and axial rectangular grid nodes until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

[0099] Example 3

[0100] Embodiment 3 provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the control partitioning method of the grid of the thermal-fluid coupling model of the distribution transformer when executing the program.

[0101] Example 4

[0102] Embodiment 4 provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the control partitioning method of the grid of the thermal-fluid coupling model of the distribution transformer is implemented.

[0103] The above embodiments are merely examples of the technical solutions of the present invention. The method for predicting the attenuation change of the daily regulation wave of a hydropower station involved in the present invention is not limited to the contents described in the above embodiments, but is subject to the scope defined by the claims. Any modification, supplement or equivalent replacement made by a technician in the field of the present invention based on the embodiment is within the scope of protection required by the claims of the present invention.

Claims

1. A control partitioning method for a distribution transformer thermal-fluid coupling model grid, characterized in that: include: Establish a thermal-fluid coupled numerical model for distribution transformers; The grid node division step includes constructing rectangular grid nodes for the oil channel inside the winding, the oil channel around the winding, and the oil channel of the heat sink, and constructing arbitrary grid nodes for the winding structure and the main oil channel of the oil tank; Performing rectangular grid mapping subdivision on rectangular grid nodes, performing arbitrary grid mapping subdivision on arbitrary grid nodes, and the rectangular grid mapping subdivision scale is smaller than the arbitrary grid mapping subdivision scale; Apply heat source to the winding and obtain the winding temperature based on the thermal-fluid coupled numerical model of the distribution transformer; Determine whether the winding temperature meets the accuracy requirements? If it does, the temperature distribution characteristics of the winding are obtained. If not, jump to the step of dividing the grid nodes and increase the number of radial and axial rectangular grid nodes until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

2. The control partitioning method of the distribution transformer thermal-fluid coupling model grid according to claim 1 is characterized in that: The method to establish the thermal-fluid coupling numerical model of distribution transformer is as follows: A thermal-fluid coupling numerical model of the distribution transformer is established, including the core, windings, clamps, oil tank, heat sink, spacers and screws of the distribution transformer.

3. The control partitioning method of the distribution transformer thermal-fluid coupling model grid according to claim 1 is characterized in that: Obtain winding temperature based on the thermal-fluid coupling numerical model of distribution transformer: Based on the anisotropic heat transfer characteristics, the winding in the thermal-fluid coupling numerical model of the distribution transformer is treated equivalently. The winding conductor, surface insulating paint, 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: In the formula, K r represents the equivalent thermal conductivity, k1, k2, and k3 represent the thermal conductivity of three different materials: winding conductor, wire enameled layer, and oil-impregnated insulating paper, respectively. r Indicates the total thickness of the material, d r1 ,d r2 ,d r3 They respectively represent the thickness of three different materials: winding conductor, wire enameling layer and oil-impregnated insulating paper.

4. The control partitioning method of the distribution transformer thermal-fluid coupling model grid according to claim 3 is characterized in that: In the process of obtaining the winding temperature based on the thermal parameters of the equivalent winding, Lagrangian interpolation processing is performed on the temperature of the equivalent winding area.

5. The control partitioning method of the distribution transformer thermal-fluid coupling model grid according to claim 1 is characterized in that: The arbitrary grid nodes are arranged with equal arc or variable arc and the grid nodes are arranged with equal spacing or variable spacing in the axial and radial directions. The control method of the arbitrary grid nodes is manual matching input, configuration file loading or parameterized design language execution.

6. The control partitioning method of the distribution transformer thermal-fluid coupling model grid according to claim 1 is characterized in that: The method for constructing rectangular grid nodes for the oil passages inside the winding, the oil passages around the winding, and the oil passages on the heat sink is as follows: For the oil passages in the winding, the oil passages around the winding, and the oil passages on the heat sink, the height of the first-layer grid nodes is determined by the dimensionless wall function y+, where y+ takes the value of 1. The formula for the height of the first-layer grid nodes is: Where y0 represents the height of the first-layer grid node, μ is the dynamic viscosity of transformer oil, ρ represents the density of transformer oil, and u τ Indicates that the friction velocity is calculated from the wall shear stress; For the oil passages in the winding and the heat sink, the calculation formula for the growth rate of the rectangular grid node height is: 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; For the oil circuit around the winding, the growth rate of the rectangular grid node height is calculated as:

7. The control partitioning method of the distribution transformer thermal-fluid coupling model grid according to claim 1 is characterized in that: The method of performing arbitrary mesh mapping division on any mesh node is: Control the segmentation accuracy according to the solution requirements and use triangle or tetrahedron free segmentation.

8. A control and partitioning device for a distribution transformer thermal-fluid coupling model grid, characterized in that: include: Model building module, used to build a thermal-fluid coupling numerical model of distribution transformers; The mesh division module is used to divide the mesh node steps, construct rectangular mesh nodes for the oil channel inside the winding, the oil channel near the winding, and the oil channel of the heat sink, and construct arbitrary mesh nodes for the winding structure and the main oil channel of the oil tank; A grid mapping subdivision module is used to perform rectangular grid mapping subdivision on rectangular grid nodes and perform arbitrary grid mapping subdivision on arbitrary grid nodes, and the rectangular grid mapping subdivision scale is smaller than the arbitrary grid mapping subdivision scale; A temperature acquisition module is used to apply a heat source to the winding and obtain the winding temperature based on a thermal-fluid coupling numerical model 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 not, the step of dividing the grid nodes is jumped to increase the number of radial and axial rectangular grid nodes until the winding temperature meets the accuracy requirements to obtain the temperature distribution characteristics of the winding.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the control partitioning method of the distribution transformer thermal-fluid coupling model grid is implemented as claimed in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the control partitioning method of the distribution transformer thermal-fluid coupling model grid is implemented as claimed in any one of claims 1 to 7.

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