Temperature field acquisition method of transformer winding and related equipment

Abstract

The invention discloses a temperature field obtaining method of a transformer winding and related equipment, and relates to the field of simulation, and the method comprises the steps: calculating the current fluid flow velocity of a fluid in a three-dimensional simulation model after the fluid is affected by the temperature according to the current temperature field of the three-dimensional simulation model; determining the current kinetic energy and the kinetic energy dissipation rate of the fluid according to the current fluid flow velocity, and then determining the current temperature of the fluid and the current temperature of the transformer winding model in contact with the fluid; according to the temperature difference, the current heat flux is calculated to determine the current heat dissipating capacity; updating the current temperature field according to the current heat dissipating capacity; if the updated current temperature field and the current temperature field have a temperature difference value between at least one grid node at the same position, which is not smaller than a set threshold value, taking the updated current temperature field as the current temperature field, and recalculating the current fluid flow velocity; and otherwise, outputting the updated current temperature field as the temperature field in the current time step length. According to the method, the mutual influence of fluid and temperature is considered, and the temperature field with high accuracy can be obtained.

Description

Technical Field

[0001] The present application relates to the field of simulation technology, and in particular to a method for acquiring a temperature field of a transformer winding and related equipment. Background Art

[0002] With the development of economy, the proportion of electricity in people's life is gradually increasing. In order to meet the electricity demand of people's daily life, the power system is developed to convert natural energy into electricity and provide people with stable power support. Among them, the transformer, as the core equipment in the power system, facilitates the transmission of electricity by converting voltage.

[0003] A transformer is an electrical device that works based on the principle of electromagnetic induction. It achieves voltage conversion by winding two or more mutually insulated windings (i.e. coils) on an iron core (or magnetic core). When the transformer is running, the insulating winding will generate a lot of heat due to energy conversion. If it is not dissipated in time, the high temperature caused by a large amount of heat can accelerate the aging of the transformer insulation material, shorten its service life, and even cause the transformer to fail. Therefore, in order to ensure the normal operation of the transformer and extend its service life, the transformer generally has a radiator, and there is a cooling medium between the transformer winding and the radiator. For example, transformer oil is used as a cooling medium for heat dissipation, or natural convection of air or forced wind is used for heat dissipation.

[0004] In order to optimize the heat dissipation design of the transformer, it is necessary to pay close attention to and understand the temperature distribution of the transformer windings. Summary of the invention

[0005] In view of the above problems, the present application provides a method for obtaining the temperature field of a transformer winding and related equipment to achieve the purpose of obtaining the temperature distribution of the transformer winding. The specific scheme is as follows:

[0006] A first aspect of the present application provides a method for acquiring a temperature field of a transformer winding, wherein the temperature simulation method of the transformer winding comprises:

[0007] Calculating a current fluid flow rate of the fluid in the three-dimensional simulation model after the fluid is affected by temperature according to a current temperature field of the three-dimensional simulation model, wherein the three-dimensional simulation model includes a transformer winding model and a radiator model, wherein the fluid is disposed between the transformer winding model and the radiator model, and wherein the three-dimensional simulation model is divided into a plurality of grids, each grid having a plurality of grid nodes;

[0008] determining a current kinetic energy and a kinetic energy dissipation rate of the fluid according to the current fluid flow rate;

[0009] Determining a current temperature of the fluid according to the current kinetic energy and the kinetic energy dissipation rate of the fluid, and determining a current temperature of a transformer winding model in contact with the fluid according to the current temperature of the fluid;

[0010] Calculating a current heat flux density between the fluid and the transformer winding model according to a temperature difference between a current temperature of the fluid and a current temperature of the transformer winding model, and determining a current heat dissipation of the fluid according to the current heat flux density;

[0011] updating the current temperature field according to the current heat dissipation of the fluid;

[0012] If the temperature difference between the updated current temperature field and the current temperature field at least one grid node at the same position is not less than the set threshold, the updated current temperature field is used as the current temperature field, and the step of calculating the current fluid flow rate of the fluid in the three-dimensional simulation model of the transformer and the radiator according to the current temperature field of the three-dimensional simulation model is returned to execute;

[0013] If the temperature difference between the updated current temperature field and each grid node at the same position of the current temperature field is less than the set threshold, the updated current temperature field is output as the temperature field within the current time step.

[0014] In a possible implementation, the method further includes:

[0015] The temperature distribution characteristics and variation rules of the transformer winding model are obtained according to the temperature fields in multiple time steps.

[0016] In a possible implementation, the step of calculating the current fluid flow rate of the fluid in the three-dimensional simulation model after the fluid is affected by temperature according to the current temperature field of the three-dimensional simulation model includes:

[0017] The temperature of the grid nodes in contact with the fluid in the three-dimensional simulation model is substituted into the flow momentum equation of the fluid to calculate the current fluid flow rate after the fluid is affected by the temperature.

[0018] In a possible implementation, determining the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid flow rate includes:

[0019] The current fluid flow rate, dynamic viscosity, turbulent viscosity and average velocity gradient are input as input parameters into a preset turbulence model to obtain the current kinetic energy and kinetic energy dissipation rate of the fluid output by the preset turbulence model. The preset turbulence model is a model for predicting the flow characteristics of the fluid between the transformer winding model and the radiator model.

[0020] In a possible implementation, calculating the current heat flux density between the fluid and the transformer winding model according to the temperature difference between the current temperature of the fluid and the current temperature of the transformer winding model includes:

[0021] A convection heat transfer coefficient is obtained, and the product of the convection heat transfer coefficient and the temperature difference is used as the current heat flux density between the fluid and the transformer winding model.

[0022] In a possible implementation, the method further includes:

[0023] A first boundary condition is set on the surface of the transformer winding model, a second boundary condition is set on the surface of the radiator model, and a third boundary condition is set on the contact surface between the fluid and the transformer winding model;

[0024] The first boundary condition is used to define the boundary temperature, the second boundary condition is used to define the boundary heat flux density, and the third boundary condition is used to define the boundary convection heat transfer coefficient and the boundary fluid temperature.

[0025] A second aspect of the present application provides a temperature field acquisition system for a transformer winding, wherein the temperature simulation system for the transformer winding comprises:

[0026] a flow rate calculation unit, used for calculating the current fluid flow rate of the fluid in the three-dimensional simulation model after being affected by temperature according to the current temperature field of the three-dimensional simulation model, wherein the three-dimensional simulation model comprises a transformer winding model and a radiator model, wherein the transformer winding model and the radiator model have the fluid therebetween, and the three-dimensional simulation model is divided into a plurality of grids, each grid having a plurality of grid nodes;

[0027] a kinetic energy calculation unit, configured to determine the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid flow rate;

[0028] a temperature calculation unit, configured to determine a current temperature of the fluid according to the current kinetic energy and kinetic energy dissipation rate of the fluid, and determine a current temperature of a transformer winding model in contact with the fluid according to the current temperature of the fluid;

[0029] a heat dissipation calculation unit, configured to calculate a current heat flux density between the fluid and the transformer winding model according to a temperature difference between a current temperature of the fluid and a current temperature of the transformer winding model, and determine a current heat dissipation amount of the fluid according to the current heat flux density;

[0030] A temperature updating unit, used for updating the current temperature field according to the current heat dissipation of the fluid;

[0031] If the temperature difference between the updated current temperature field and the current temperature field at least one grid node at the same position is not less than the set threshold, the updated current temperature field is used as the current temperature field, and the flow velocity calculation unit is triggered again;

[0032] If the temperature difference between the updated current temperature field and each grid node at the same position of the current temperature field is less than the set threshold, the temperature output unit is triggered,

[0033] The temperature output unit is used to output the updated current temperature field as the temperature field within the current time step.

[0034] In a possible implementation, a temperature analysis unit is also included:

[0035] The temperature analysis unit is used to obtain the temperature distribution characteristics and change rules of the transformer winding model according to the temperature field in multiple time steps.

[0036] A third aspect of the present application provides an electronic device, comprising at least one processor and a memory connected to the processor, wherein:

[0037] The memory is used to store computer programs;

[0038] The processor is used to execute the computer program so that the electronic device can implement the method for acquiring the temperature field of the transformer winding according to the first aspect or any implementation manner of the first aspect.

[0039] The fourth aspect of the present application provides a computer program product, including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements the method for acquiring the temperature field of a transformer winding according to the first aspect or any implementation of the first aspect.

[0040] By means of the above technical scheme, the present application provides a method for acquiring the temperature field of a transformer winding and related equipment. The method for acquiring the temperature field of the transformer winding first calculates the current fluid flow rate of the fluid after the fluid is affected by the temperature through the temperature field of the three-dimensional simulation model of the transformer winding and the radiator. The current kinetic energy and kinetic energy dissipation rate of the fluid can be determined according to the current fluid flow rate of the fluid, thereby determining the current temperature of the fluid. Since the fluid and the transformer winding model have a contact portion, the current temperature of the transformer winding model can be determined according to the current temperature of the fluid. The current heat flux density of the transformer winding model can be determined according to the temperature difference between the fluid and the transformer winding model, and the current heat dissipation of the fluid can be determined according to the current heat flux density. Then, the current temperature field is updated according to the heat dissipation, and the node temperature difference of the temperature field is used as the iteration condition. The velocity field of the fluid and the temperature field of the transformer winding are continuously updated until the temperature difference between the updated current temperature field and each grid node at the same position in the current temperature field is less than the set threshold, then the iteration is stopped, and the output updated current temperature field is obtained as the temperature field within the current time step. When determining the temperature field of the transformer winding, this method introduces the flow velocity, kinetic energy and kinetic energy dissipation rate of the fluid to reflect the velocity field of the fluid. Through the simulation calculation between the fluid velocity field and the temperature field of the transformer winding, the influence of the heat absorption of the fluid on the temperature and the influence of the temperature on the fluid flow velocity are considered. The temperature field is continuously iterated by quoting the fluid velocity field, and the temperature difference is used as the stop condition, indicating that the temperature field in the current time step has stabilized under the influence of the fluid heat dissipation capacity. Therefore, this method can obtain the temperature field of the transformer winding with high accuracy under the influence of the heat dissipation fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0042] Figure 1 A schematic flow chart of a method for acquiring a temperature field of a transformer winding provided in an embodiment of the present application;

[0043] Figure 2 A schematic diagram of the structure of a three-dimensional simulation model provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of fluid flow rate in a three-dimensional simulation model provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of an internal transient temperature distribution provided in an embodiment of the present application;

[0046] Figure 5 A schematic diagram of the structure of a temperature field acquisition system for a transformer winding provided in an embodiment of the present application;

[0047] Figure 6 A hardware structure block diagram of an electronic device provided in this application. DETAILED DESCRIPTION

[0048] The following describes the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation method section of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0049] The embodiments of the present application are described below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0050] The terms "first", "second" etc. in the specification of the application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable in appropriate circumstances, and this is only to describe the distinction mode adopted by the objects of the same attributes when describing in the embodiments of the application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0051] With the rapid development of power systems, transformers are core equipment in power systems. The temperature rise of their windings can directly affect the operating performance and service life of transformers. Specifically, high temperature can accelerate the aging of transformer insulation materials, thereby shortening the service life of transformers and even causing transformer failures. Therefore, in order to ensure the normal operation of transformers and extend their service life, transformers generally have radiators to dissipate heat for transformers during operation. The radiator can use transformer oil as a cooling medium to dissipate heat, or it can rely on natural air convection or forced wind to dissipate heat.

[0052] In order to optimize the heat dissipation design of the transformer and improve the operating efficiency and safety of the transformer, it is necessary to pay close attention to and understand the temperature distribution of the transformer winding, determine the hot spot temperature and its location in the temperature distribution, and especially reduce the hot spot temperature through the winding structure. Among them, a hot spot refers to a point or area with abnormally high temperature in the temperature field, whose temperature is significantly higher than the temperature or average temperature of the surrounding area. The hot spot is generally confined to a specific spatial range.

[0053] Since the heat dissipation of the transformer will affect the temperature distribution of the transformer winding, it is difficult to obtain a high-accuracy temperature distribution. In addition, the internal structure of the transformer winding is complex, and the installation position of the temperature sensor is limited, making it difficult to install the temperature sensor at a key position inside the transformer winding. In addition, the temperature distribution of the transformer winding is usually uneven, and its hot spots may appear deep in the winding or at a local high-load position, making it difficult to fully capture the temperature distribution of the transformer winding.

[0054] In order to solve the above problems, the embodiment of the present application provides a method for obtaining the temperature field of a transformer winding. This scheme uses a numerical simulation method and computer simulation technology to study the temperature field of the transformer winding, which can avoid using a temperature sensor to measure the temperature field. This method constructs a three-dimensional simulation model of the transformer winding and the radiator, and a fluid for heat dissipation is set between the transformer winding model and the radiator model. Considering the influence of the heat dissipation capacity of the fluid on the temperature of the transformer winding, when determining the temperature field, this method introduces a parameter representing the fluid velocity field to update the temperature field. Considering that the temperature will also affect the fluid, the updated temperature field reversely updates the velocity field, and the updated velocity field updates the temperature field again, and so on. Iterate the temperature field multiple times until the temperature difference between the current temperature field and the temperature of each grid node of the previous temperature field is less than the preset threshold, indicating that the current temperature field has stabilized under the influence of the heat dissipation capacity of the fluid, and then the temperature field of the transformer winding with high accuracy can be obtained under the influence of the heat dissipation fluid. The temperature field with high accuracy is also conducive to analyzing the hot spot temperature and its position. The following is a detailed introduction to the temperature field acquisition method of the transformer winding of the embodiment of the present application in conjunction with the accompanying drawings.

[0055] Reference Figure 1 , Figure 1 A schematic diagram of a method for obtaining a temperature field of a transformer winding provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, a data processing method provided in an embodiment of the present application may include steps S10 to S16, and these steps are described in detail below.

[0056] S10, calculating the current fluid flow rate of the fluid in the three-dimensional simulation model after being affected by temperature according to the current temperature field of the three-dimensional simulation model, the three-dimensional simulation model includes a transformer winding model and a radiator model, there is fluid between the transformer winding model and the radiator model, the three-dimensional simulation model is divided into a plurality of grids, each grid having a plurality of grid nodes;

[0057] S11. Determine the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid flow rate.

[0058] The fluid in this embodiment may refer to insulating oil used for heat dissipation. A three-dimensional simulation model is a virtual environment generated by computer simulation technology. The data such as the geometric shape and physical properties of real objects are acquired through data acquisition equipment, and a three-dimensional model is established based on the acquired data. The three-dimensional model is dynamically simulated and rendered through a physical engine and simulation algorithm. Figure 2 As shown, this embodiment establishes a 1:1 equivalent three-dimensional simulation model of a transformer and its heat sink, and a fluid is arranged between the transformer winding model and the heat sink model. The three-dimensional simulation model in this embodiment is a complex three-dimensional structure composed of multiple grids connected to each other. Among them, the grid is usually composed of triangles, quadrilaterals or other simple polygons, and each grid can have multiple grid nodes, and the grid nodes are located at the intersection or endpoints of the grid.

[0059] After obtaining the three-dimensional simulation model, the three-dimensional simulation model can be imported into the simulation software, the grid information is initialized and loaded, and the solver as the core component of the simulation software is set to a steady-state solver, and relevant parameters such as material properties, boundary conditions, etc. are set in the steady-state solver. Among them, a solver is an algorithm or technology for finding an optimal solution or approximate solution that satisfies preset constraints. The steady-state solver is a solver specifically used to solve problems in which the dependent variables of a physical field do not change over time. It is suitable for solving various steady-state physical fields, such as temperature fields, pressure fields, and electric fields, and can be coupled with other physical fields for solution to simulate more complex physical phenomena. In this embodiment, the steady-state solver can better couple the velocity field of the fluid with the temperature field of the transformer winding model for calculation.

[0060] Specifically, this embodiment imports the three-dimensional simulation model into ANSYS software, and sets the solver as a steady-state pressure-based solver. Meshing software is used to re-grid the structure area and fluid area of ​​the transformer winding model step by step. The mesh selected in this embodiment is a tetrahedral mesh with good distribution control capability. The turbulence model, the material properties of the three-dimensional simulation model, and the boundary conditions are set in the steady-state pressure-based solver.

[0061] Among them, the turbulence model is a model used to describe and simulate the characteristics of turbulent flow. Turbulence is an irregular, multi-scale and structured flow, which is composed of vortices of various scales with rotating structures. The flow state of the fluid in this embodiment is mainly turbulent. Specifically, the preset turbulence model set in this embodiment is the standard Model, a model for predicting the flow characteristics of the fluid between the transformer winding model and the heat sink model, can be expressed as follows:

[0062]

[0063]

[0064] in, It can represent the average velocity gradient; It can represent the kinetic energy of the fluid; It can represent the flow along Directional component of flow velocity (flow rate); It can represent the dissipation rate of the fluid kinetic energy; It can represent the effect of pulsating expansion on the dissipation rate in compressible turbulent flow; It can represent the turbulent kinetic energy caused by buoyancy; It can represent the turbulent kinetic energy caused by the mean velocity gradient; and Can represent Cartesian coordinates; It can represent the dynamic viscosity of the fluid; It can represent the turbulent viscosity of the fluid; , and are coefficients, The value of can be 1.44; The value of can be 1.0; The value of can be 1.3; It can represent the buoyancy effect; Can represent fluid density.

[0065] In this embodiment, the boundary conditions include a first boundary condition, a second boundary condition and a third boundary condition. Specifically, in this embodiment, the first boundary condition is set on the surface of the transformer winding model, the second boundary condition is set on the surface of the radiator model, and the third boundary condition is set on the contact surface between the fluid and the transformer winding model.

[0066] The first boundary condition is used to define the boundary temperature and can be expressed as follows:

[0067]

[0068] in, It can represent the boundary of an object, and here it can represent the boundary of the transformer winding model; The surface temperature of a known transformer winding model can be expressed; The surface temperature function of the transformer winding model can be represented.

[0069] The second boundary condition is used to define the boundary heat flux density, which can be expressed as follows:

[0070]

[0071] in, It can represent the boundary of an object, here it represents the boundary of the radiator model; It can represent a constant whose value can be 1.92; Represents the surface temperature function of the heat sink model.

[0072] The third boundary condition is used to define the boundary convection heat transfer coefficient and boundary fluid temperature, which can be expressed as follows:

[0073]

[0074] in, It can represent the boundary of an object, which here represents the boundary of the contact surface between the fluid and the transformer winding model; It can represent the temperature of the fluid around the contact surface; It can represent a coefficient whose value can be 1.44; It can represent a constant whose value can be 1.92.

[0075] This embodiment can calculate the current fluid flow rate of the fluid in the three-dimensional simulation model after being affected by temperature based on the current temperature field of the three-dimensional simulation model. Specifically, this embodiment substitutes the temperature of the grid node in contact with the fluid in the three-dimensional simulation model into the flow momentum equation of the fluid to calculate the current fluid flow rate of the fluid after being affected by temperature, such as Figure 3 The fluid flow velocity diagram shown in Figure 3 It can be seen that the insulating oil flows along the vertical and transverse oil channels as a whole. The high velocity area of ​​the insulating oil is mainly concentrated near the oil outlet at both ends of the transformer winding, while the velocity in the middle area is lower. The flow momentum equation of the fluid is based on the Bussineske assumption and finite pressure, and its specific expression can be shown as follows:

[0076]

[0077] in, Can represent fluid density; It can be expressed as the fluid flow rate Components of coordinate axes; It can be expressed as the fluid flow rate Components of coordinate axes; It can represent the fluid pressure scalar; It can represent the dynamic viscosity of the fluid; It can represent the reference temperature, which is room temperature in this embodiment; It can represent the acceleration due to gravity; Can be expressed The angle between the coordinate axis and the direction of gravitational acceleration; It can represent the coefficient of thermal expansion of the fluid.

[0078] After this embodiment calculates the current fluid flow rate after the fluid is affected by temperature, the current kinetic energy and kinetic energy dissipation rate of the fluid can be obtained according to the turbulence model. Specifically, this embodiment inputs the current fluid flow rate and dynamic viscosity, turbulent viscosity and average velocity gradient as input parameters into the preset turbulence model to obtain the current kinetic energy and kinetic energy dissipation rate of the fluid output by the preset turbulence model. Among them, the current kinetic energy of the fluid refers to the energy possessed by the fluid due to turbulent motion, and the kinetic energy dissipation rate refers to the dissipation rate of the pulsating kinetic energy of unit mass of fluid in turbulence, that is, the rate at which the mechanical energy of isotropic small-scale vortices is converted into thermal energy.

[0079] S12, determining the current temperature of the fluid according to the current kinetic energy and kinetic energy dissipation rate of the fluid, and determining the current temperature of the transformer winding model in contact with the fluid according to the current temperature of the fluid;

[0080] S13. Calculate the current heat flux density between the fluid and the transformer winding model according to the temperature difference between the current temperature of the fluid and the current temperature of the transformer winding model, and determine the current heat dissipation of the fluid according to the current heat flux density.

[0081] Among them, after this embodiment obtains the current kinetic energy and kinetic energy dissipation rate of the fluid output by the preset turbulence model, the current temperature of the fluid can be directly calculated, and the variable conservation principle at the interface between the fluid and the transformer winding is used. The boundary conditions at the interface between the fluid and the transformer winding should satisfy the equality or conservation of variables such as displacement, heat flow and temperature of the fluid and the transformer winding. Therefore, this embodiment can directly determine the current temperature of the transformer winding model in contact with the fluid through the current temperature of the fluid. Among them, the boundary conditions at the interface between the fluid and the transformer winding can be expressed as follows:

[0082]

[0083] in, It can represent the displacement of the fluid; It can represent the displacement of transformer windings; It can represent the heat flow of fluid; It can represent the heat flow of transformer windings; It can represent the temperature of the fluid; It can indicate the temperature of transformer windings; A mesh that can represent the fluid; A mesh that can represent a transformer winding.

[0084] Therefore, for each grid, after the current temperature of the fluid is determined in this embodiment, The current temperature of the grid of the transformer winding in contact with the fluid grid is calculated, thereby obtaining the current temperature of the transformer winding model.

[0085] After the current temperature of the fluid and the current temperature of the transformer winding model in contact with the fluid are determined in this embodiment, the heat flux density between the fluid and the transformer winding model can be calculated according to the temperature difference between the two. Heat flux density is also called heat flux, which is defined as the heat passing through the unit cross-sectional area of ​​an object per unit time. Heat flux density can reflect the transfer rate of heat inside an object or between objects.

[0086] Specifically, this embodiment can obtain the set convection heat transfer coefficient, and use the product of the convection heat transfer coefficient and the temperature difference as the current heat flux density between the fluid and the transformer winding model. The calculation formula of the heat flux density can be as follows:

[0087]

[0088] in, It can represent heat flux density; It can represent the convective heat transfer coefficient; The temperature difference between the fluid and the transformer winding model in contact with the fluid can be represented.

[0089] The value of the convective heat transfer coefficient may be affected by the inherent physical properties of the fluid, the geometric characteristics of the contact interface, and the motion state of the fluid. In this embodiment, the convective heat transfer coefficient between the fluid and the transformer winding model can be directly set, or the convective heat transfer coefficient can be calculated based on the current state between the fluid and the transformer winding model. The calculation formula of the convective heat transfer coefficient can be as follows:

[0090]

[0091] in, It can represent a constant whose value can be 1.92; It can represent the characteristic length of convective heat transfer; It can represent the Nusselt number.

[0092] The calculation formula can be shown as follows:

[0093]

[0094] in, and Both can represent a coefficient, which can be determined according to the actual situation of convective heat transfer; It can represent the Grashof coefficient; can represent the Prandtl number. Further, , It can express the volume expansion coefficient of the fluid; It can represent the acceleration due to gravity; The temperature difference between the fluid and the transformer winding model in contact with the fluid can be represented; It can represent the thermal diffusivity, and its calculation formula can be expressed as: , It can represent a constant whose value can be 1.92. It can represent the specific heat capacity of the fluid; It can represent the kinematic viscosity of the fluid.

[0095] After determining the current heat flux density between the fluid and the transformer winding model, this embodiment directly calculates the current heat dissipation of the fluid according to the unit time or time step based on the first law of thermodynamics. The calculation formula can be as follows:

[0096]

[0097] in, It can indicate the current heat dissipation. It can represent the heat taken away by the fluid due to heat conduction and heat radiation of the transformer winding model. In practical applications, the heat dissipated by heat conduction and heat radiation can be ignored. The value of can be 0; Can represent mass flow rate; It can represent the specific enthalpy brought in when the fluid flows out of the transformer winding model; It can represent the specific enthalpy introduced when the fluid flows into the transformer winding model.

[0098] Among them, specific enthalpy is a physical quantity used to describe the heat released or absorbed when a substance changes per unit mass under constant pressure, and mass flow rate reflects the mass of fluid passing through a certain cross section per unit time. If the specific enthalpy of the fluid changes after contacting the transformer winding model, it means that the fluid absorbs or releases heat when contacting the transformer winding model. Therefore, this embodiment can determine the heat taken away by the fluid, that is, the current heat dissipation, based on the specific enthalpy of the fluid before and after entering the transformer winding model.

[0099] Furthermore, the heat exchange mechanism mainly includes three types: heat convection, heat conduction and heat radiation. The effects of heat conduction and heat radiation on temperature in this embodiment are negligible, and in the fluid, heat conduction often occurs simultaneously with heat convection. Therefore, this embodiment mainly considers the effect of heat convection between the fluid and the transformer winding model on temperature.

[0100] Of course, the effect of heat radiation on the heat transfer can also be considered according to different actual conditions. Specifically, the calculation formula for heat radiation heat transfer can be as follows:

[0101]

[0102] in, It can represent the amount of heat transferred by thermal radiation; Here, the radiation surface blackness can be represented, that is, the blackness of the winding surface in the transformer winding model. The blackness is a physical parameter of the material, and its value range can be (0, 1); can represent the Stefan-Boltzmann constant; It can represent the radiation heat transfer area, that is, the entire area of ​​the transformer winding model; It can represent the temperature of the radiator, that is, the temperature of the winding; It can represent the ambient temperature, which is the temperature set by the simulation software.

[0103] S14, updating the current temperature field according to the current heat dissipation of the fluid;

[0104] S15, if the temperature difference between the updated current temperature field and the current temperature field at least one grid node at the same position is not less than the set threshold, the updated current temperature field is used as the current temperature field, and the step of calculating the current fluid flow rate of the fluid in the three-dimensional simulation model of the transformer and the radiator according to the current temperature field of the three-dimensional simulation model is returned;

[0105] S16. If the temperature difference between the updated current temperature field and each grid node at the same position of the current temperature field is less than the set threshold, the updated current temperature field is output as the temperature field within the current time step.

[0106] Among them, the execution order of step S15 and step S16 can be in no particular order. The threshold value can be set according to the actual situation. When the current temperature field is updated in this embodiment, the current temperature field of the transformer winding model is first determined according to the current heat flux density, and then the temperature change value is determined according to the heat dissipation, thereby updating the current temperature field. Specifically, the calculation formula for determining the current temperature field of the transformer winding model according to the current heat flux density can be as follows:

[0107]

[0108] in, Can represent fluid density; It can represent the specific heat capacity of the fluid; This can indicate the current temperature. Can be expressed Coordinate axis; Can be expressed Coordinate axis; Can be expressed Coordinate axis; It can represent a constant whose value can be 1.92; It can represent the current heat flux.

[0109] The constraints of the above calculation formula can be expressed as:

[0110]

[0111] In this embodiment, for each grid node of the transformer winding model in contact with the fluid, the current temperature of each grid node is determined according to the above formula, and the temperature change of each grid node is determined according to the current heat dissipation, and the temperature after the change of each grid node is obtained, thereby obtaining the updated temperature field of the transformer winding model. In this embodiment, the temperature field of the transformer winding model is continuously iteratively updated according to the velocity field of the fluid until a stable temperature field within the current time step is obtained.

[0112] Furthermore, the temperature field acquisition process described above in this embodiment is a temperature field acquisition process within a time step, and there may be multiple time steps in the entire simulation process. Therefore, this embodiment can count the temperature fields within multiple time steps to obtain the changes in the temperature field of the transformer winding model during the simulation process. Specifically, this embodiment can use the CFD-POST software that comes with the ANSYS software to analyze the temperature field within multiple time steps, obtain the temperature distribution characteristics and change laws of the transformer winding model, and generate a cloud map of the internal temperature distribution of the transformer winding model, providing reliable dynamic evolution data of the internal temperature field and fluid velocity field, facilitating a more detailed analysis of the temperature field change trend and key areas in the fluid heat dissipation process, and recording relevant analysis results, such as internal temperature distribution, internal transient temperature distribution, internal transient fluid flow diagram, and hot spot temperature change results, which can provide important reference and guidance for technical personnel in related fields. Figure 4 The schematic diagram of the internal transient temperature distribution is shown in Figure 1. Among them, CFD-POST is the post-processing software that comes with ANSYS, which is a software that can perform data processing, analysis and visualization.

[0113] The embodiment of the present application provides a method for obtaining the temperature field of a transformer winding. The method first calculates the current fluid flow rate of the fluid after being affected by the temperature through the temperature field of the three-dimensional simulation model of the transformer winding and the radiator. The current kinetic energy and kinetic energy dissipation rate of the fluid can be determined according to the current fluid flow rate of the fluid, thereby determining the current temperature of the fluid. Since the fluid and the transformer winding model have a contact portion, the current temperature of the transformer winding model can be determined according to the current temperature of the fluid. The current heat flux density of the transformer winding model can be determined according to the temperature difference between the fluid and the transformer winding model, and the current heat dissipation of the fluid can be determined according to the current heat flux density. Then, the current temperature field is updated according to the heat dissipation, and the node temperature difference of the temperature field is used as the iteration condition. The velocity field of the fluid and the temperature field of the transformer winding are continuously updated until the temperature difference between the updated current temperature field and each grid node at the same position in the current temperature field is less than the set threshold, then the iteration is stopped, and the output updated current temperature field is obtained as the temperature field within the current time step. When determining the temperature field of the transformer winding, this method introduces the flow velocity, kinetic energy and kinetic energy dissipation rate of the fluid to reflect the velocity field of the fluid. Through the simulation calculation between the fluid velocity field and the temperature field of the transformer winding, the influence of the heat absorption of the fluid on the temperature and the influence of the temperature on the fluid flow velocity are considered. The temperature field is continuously iterated by quoting the fluid velocity field, and the temperature difference is used as the stop condition, indicating that the temperature field in the current time step has stabilized under the influence of the fluid heat dissipation capacity. Therefore, this method can obtain the temperature field of the transformer winding with high accuracy under the influence of the heat dissipation fluid.

[0114] A method for acquiring the temperature field of a transformer winding provided in an embodiment of the present application is introduced above. A system applying the method for acquiring the temperature field of a transformer winding will be introduced below.

[0115] See also Figure 5 , Figure 5 This is a schematic diagram of the structure of a temperature field acquisition system for a transformer winding provided in an embodiment of the present application. Figure 5 As shown, the temperature field acquisition system of the transformer winding includes:

[0116] The flow rate calculation unit 100 is used to calculate the current fluid flow rate of the fluid in the three-dimensional simulation model after being affected by the temperature according to the current temperature field of the three-dimensional simulation model, the three-dimensional simulation model includes a transformer winding model and a radiator model, there is a fluid between the transformer winding model and the radiator model, and the three-dimensional simulation model is divided into a plurality of grids, each grid having a plurality of grid nodes;

[0117] A kinetic energy calculation unit 110, for determining the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid flow rate;

[0118] a temperature calculation unit 120, for determining a current temperature of the fluid according to the current kinetic energy and kinetic energy dissipation rate of the fluid, and determining a current temperature of a transformer winding model in contact with the fluid according to the current temperature of the fluid;

[0119] The heat dissipation calculation unit 130 is used to calculate the current heat flux density between the fluid and the transformer winding model according to the temperature difference between the current temperature of the fluid and the current temperature of the transformer winding model, and determine the current heat dissipation of the fluid according to the current heat flux density;

[0120] A temperature updating unit 140, used to update the current temperature field according to the current heat dissipation of the fluid;

[0121] If the temperature difference between the updated current temperature field and the current temperature field at least one grid node at the same position is not less than the set threshold, the updated current temperature field is used as the current temperature field and returned to the trigger flow rate calculation unit 100;

[0122] If the temperature difference between the updated current temperature field and each grid node at the same position of the current temperature field is less than the set threshold, the temperature output unit 150 is triggered.

[0123] The temperature output unit 150 is used to output the updated current temperature field as the temperature field within the current time step.

[0124] In a possible implementation, the temperature field acquisition system of the transformer winding may further include a temperature analysis unit:

[0125] The temperature analysis unit is used to obtain the temperature distribution characteristics and change rules of the transformer winding model according to the temperature field in multiple time steps.

[0126] In a possible implementation, the flow rate calculation unit 100 may be specifically configured as follows:

[0127] The temperature of the grid nodes in contact with the fluid in the three-dimensional simulation model is substituted into the flow momentum equation of the fluid to calculate the current fluid flow rate after the fluid is affected by the temperature.

[0128] In a possible implementation, the kinetic energy calculation unit 110 may be specifically configured as follows:

[0129] The current fluid flow rate and dynamic viscosity, turbulent viscosity and average velocity gradient are input as input parameters into the preset turbulence model to obtain the current kinetic energy and kinetic energy dissipation rate of the fluid output by the preset turbulence model. The preset turbulence model is a model for predicting the flow characteristics of the fluid between the transformer winding model and the radiator model.

[0130] In a possible implementation, the heat dissipation calculation unit 130 calculates the current heat flux density between the fluid and the transformer winding model according to the temperature difference between the current temperature of the fluid and the current temperature of the transformer winding model, which can be specifically configured as follows:

[0131] The convection heat transfer coefficient is obtained, and the product of the convection heat transfer coefficient and the temperature difference is taken as the current heat flux density between the fluid and the transformer winding model.

[0132] In a possible implementation, the temperature field acquisition system of the transformer winding may further include a boundary setting unit, and the boundary setting unit may be specifically configured as follows:

[0133] A first boundary condition is set on the surface of the transformer winding model, a second boundary condition is set on the surface of the radiator model, and a third boundary condition is set on the contact surface between the fluid and the transformer winding model;

[0134] The first boundary condition is used to define the boundary temperature, the second boundary condition is used to define the boundary heat flux density, and the third boundary condition is used to define the boundary convection heat transfer coefficient and the boundary fluid temperature.

[0135] The present application also provides an electronic device in an embodiment. Figure 6 As shown, it shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiment of the present application. The electronic device in the embodiment of the present application may include but is not limited to fixed terminals such as mobile phones, laptops, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Figure 6 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0136] like Figure 6 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage device 608 to a random access memory (RAM) 603. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 603. The processing device 601, the ROM 602, and the RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0137] Typically, the following devices may be connected to the I / O interface 605: an input device 606 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 607 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 608 including, for example, a memory card, a hard disk, etc.; and a communication device 609. The communication device 609 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although Figure 6 An electronic device having various devices is shown, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead.

[0138] An embodiment of the present application also provides a computer program product including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements any method for acquiring the temperature field of a transformer winding provided in the embodiment of the present application.

[0139] A computer-readable storage medium is also provided in an embodiment of the present application. The storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any of the temperature field acquisition methods for transformer windings provided in the embodiments of the present application.

[0140] It should also be noted that the system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the drawings of the system embodiments provided by the present application, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines.

[0141] Through the description of the above implementation mode, the technicians in the field can clearly understand that the present application can be implemented by means of software plus necessary general hardware, and of course, it can also be implemented by special hardware including special integrated circuits, special CPUs, special memories, special components, etc. In general, all functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be various, such as analog circuits, digital circuits or special circuits. However, for the present application, software program implementation is a better implementation mode in more cases. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, a U disk, a mobile hard disk, a ROM, a RAM, a disk or an optical disk, etc., including a number of instructions to enable a computer device (which can be a personal computer, a training device, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0142] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0143] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a training device, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, training device, or data center. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device, a data center, etc. that includes one or more available media integrations. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

[0144] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0145] It is understandable that before using the technical solutions disclosed in the embodiments of the present disclosure, the types, scope of use, usage scenarios, etc. of the personal information involved in the present disclosure should be informed to the user and the user's authorization should be obtained in an appropriate manner in accordance with relevant laws and regulations.

[0146] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for obtaining the temperature field of a transformer winding, characterized in that: The temperature simulation method of the transformer winding comprises: Calculating a current fluid flow rate of the fluid in the three-dimensional simulation model after the fluid is affected by temperature according to a current temperature field of the three-dimensional simulation model, wherein the three-dimensional simulation model includes a transformer winding model and a radiator model, wherein the fluid is disposed between the transformer winding model and the radiator model, and wherein the three-dimensional simulation model is divided into a plurality of grids, each grid having a plurality of grid nodes; determining a current kinetic energy and a kinetic energy dissipation rate of the fluid according to the current fluid flow rate; Determining a current temperature of the fluid according to the current kinetic energy and the kinetic energy dissipation rate of the fluid, and determining a current temperature of a transformer winding model in contact with the fluid according to the current temperature of the fluid; Calculating a current heat flux density between the fluid and the transformer winding model according to a temperature difference between a current temperature of the fluid and a current temperature of the transformer winding model, and determining a current heat dissipation of the fluid according to the current heat flux density; updating the current temperature field according to the current heat dissipation of the fluid; If the temperature difference between the updated current temperature field and the current temperature field at least one grid node at the same position is not less than the set threshold, the updated current temperature field is used as the current temperature field, and the step of calculating the current fluid flow rate of the fluid in the three-dimensional simulation model of the transformer and the radiator according to the current temperature field of the three-dimensional simulation model is returned to execute; If the temperature difference between the updated current temperature field and each grid node at the same position of the current temperature field is less than the set threshold, the updated current temperature field is output as the temperature field within the current time step.

2. The method for obtaining the temperature field of a transformer winding according to claim 1, characterized in that: Also includes: The temperature distribution characteristics and variation rules of the transformer winding model are obtained according to the temperature fields in multiple time steps.

3. The method for obtaining the temperature field of a transformer winding according to claim 1, characterized in that: The step of calculating the current fluid flow rate of the fluid in the three-dimensional simulation model after the fluid is affected by the temperature according to the current temperature field of the three-dimensional simulation model comprises: The temperature of the grid nodes in contact with the fluid in the three-dimensional simulation model is substituted into the flow momentum equation of the fluid to calculate the current fluid flow rate after the fluid is affected by the temperature.

4. The method for obtaining the temperature field of a transformer winding according to claim 1, characterized in that: Determining the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid flow rate includes: The current fluid flow rate, dynamic viscosity, turbulent viscosity and average velocity gradient are input as input parameters into a preset turbulence model to obtain the current kinetic energy and kinetic energy dissipation rate of the fluid output by the preset turbulence model. The preset turbulence model is a model for predicting the flow characteristics of the fluid between the transformer winding model and the radiator model.

5. The method for obtaining the temperature field of a transformer winding according to claim 1, characterized in that: The calculating the current heat flux density between the fluid and the transformer winding model according to the temperature difference between the current temperature of the fluid and the current temperature of the transformer winding model comprises: A convection heat transfer coefficient is obtained, and the product of the convection heat transfer coefficient and the temperature difference is used as the current heat flux density between the fluid and the transformer winding model.

6. The method for obtaining the temperature field of a transformer winding according to claim 1, characterized in that: Also includes: A first boundary condition is set on the surface of the transformer winding model, a second boundary condition is set on the surface of the radiator model, and a third boundary condition is set on the contact surface between the fluid and the transformer winding model; The first boundary condition is used to define the boundary temperature, the second boundary condition is used to define the boundary heat flux density, and the third boundary condition is used to define the boundary convection heat transfer coefficient and the boundary fluid temperature.

7. A temperature field acquisition system for transformer windings, characterized in that: The temperature simulation system of the transformer winding comprises: a flow rate calculation unit, used for calculating the current fluid flow rate of the fluid in the three-dimensional simulation model after being affected by temperature according to the current temperature field of the three-dimensional simulation model, wherein the three-dimensional simulation model comprises a transformer winding model and a radiator model, wherein the transformer winding model and the radiator model have the fluid therebetween, and the three-dimensional simulation model is divided into a plurality of grids, each grid having a plurality of grid nodes; a kinetic energy calculation unit, configured to determine the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid flow rate; a temperature calculation unit, configured to determine a current temperature of the fluid according to the current kinetic energy and kinetic energy dissipation rate of the fluid, and determine a current temperature of a transformer winding model in contact with the fluid according to the current temperature of the fluid; a heat dissipation calculation unit, configured to calculate a current heat flux density between the fluid and the transformer winding model according to a temperature difference between a current temperature of the fluid and a current temperature of the transformer winding model, and determine a current heat dissipation amount of the fluid according to the current heat flux density; A temperature updating unit, used for updating the current temperature field according to the current heat dissipation of the fluid; If the temperature difference between the updated current temperature field and the current temperature field at least one grid node at the same position is not less than the set threshold, the updated current temperature field is used as the current temperature field, and the flow velocity calculation unit is triggered again; If the temperature difference between the updated current temperature field and each grid node at the same position of the current temperature field is less than the set threshold, the temperature output unit is triggered, The temperature output unit is used to output the updated current temperature field as the temperature field within the current time step.

8. The temperature field acquisition system of transformer winding according to claim 7, characterized in that: Also includes temperature analysis unit: The temperature analysis unit is used to obtain the temperature distribution characteristics and change rules of the transformer winding model according to the temperature field in multiple time steps.

9. An electronic device, characterized in that: The method comprises at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs; The processor is used to execute the computer program so that the electronic device can implement the method for acquiring the temperature field of the transformer winding as described in any one of claims 1 to 6.

10. A computer program product, characterized in that It comprises computer-readable instructions, and when the computer-readable instructions are executed on an electronic device, the electronic device implements the method for acquiring the temperature field of a transformer winding as claimed in any one of claims 1 to 6.

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