A method for obtaining the temperature field of a transformer winding and related equipment

Abstract

The present application discloses a method for obtaining the temperature field of a transformer winding and related equipment, which relates to the field of simulation and includes: calculating the current fluid velocity 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; determining the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid velocity, and then determining the current temperature of the fluid and the current temperature of the transformer winding model in contact with the fluid; and calculating the current heat flux density according to the temperature difference to determine the current heat dissipation; updating the current temperature field with the current heat dissipation; if the temperature difference between the grid nodes at at least one same position between the updated current temperature field and the current temperature field is not less than the set threshold, then taking the updated current temperature field as the current temperature field and recalculating the current fluid velocity; otherwise, outputting the updated current temperature field as the temperature field within the current time step. The present application considers the mutual influence of the fluid and temperature and can obtain a temperature field with higher accuracy.

Description

Technical Field

[0001] This application relates to the field of simulation technology, and particularly to a method for obtaining the temperature field of a transformer winding and related equipment. Background Art

[0002] With the development of the economy, the proportion of electricity used in people's lives has gradually increased. To meet the electricity demand in people's daily lives, the power system is developed to convert the energy in nature into electricity and provide stable power support for people. Among them, as a core device in the power system, the transformer facilitates the transmission of electrical energy by changing the voltage.

[0003] A transformer is an electrical device that works based on the principle of electromagnetic induction. By winding two or more mutually insulated windings (i.e., coils) around an iron core (or magnetic core), the transformation of voltage is achieved. Since the transformer generates a large amount of heat due to energy conversion during operation, if the heat is not dissipated in time, the high temperature caused by a large amount of heat can accelerate the aging of the transformer's insulating material, shorten its service life, and even cause transformer failures. Therefore, 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 air convection or forced air is relied on for heat dissipation, etc.

[0004] To optimize the heat dissipation design of the transformer, it is necessary to closely monitor and understand the temperature distribution of the transformer winding. Summary of the Invention

[0005] In view of the above problems, this 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 solutions are as follows:

[0006] The first aspect of this application provides a method for obtaining the temperature field of a transformer winding. The temperature simulation method of the transformer winding includes:

[0007] Calculating the current fluid velocity in the three-dimensional simulation model 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 the fluid between the transformer winding model and the radiator model. The three-dimensional simulation model is divided into multiple grids, and each grid has multiple grid nodes;

[0008] Determining the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid velocity;

[0009] 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;

[0010] 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;

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

[0012] If the temperature difference between at least one pair of grid nodes at the same position in the updated current temperature field and the current temperature field is not less than the set threshold, then use the updated current temperature field as the current temperature field, and return to execute the step of calculating the current fluid velocity of the fluid in the three-dimensional simulation models of the transformer and the radiator according to the current temperature field of the three-dimensional simulation model;

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

[0014] In a possible implementation, it further includes:

[0015] Obtain the temperature distribution characteristics and variation rules of the transformer winding model according to the temperature fields within multiple time steps.

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

[0017] Substitute the temperatures of the grid nodes in the three-dimensional simulation model that are in contact with the fluid into the flow momentum equation of the fluid to calculate the current fluid velocity of the fluid affected by temperature.

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

[0019] Use the current fluid velocity, dynamic viscosity, turbulent viscosity, and average velocity gradient as input parameters and input them 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, where 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, 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 includes:

[0021] Obtain the convective heat transfer coefficient, and take the product of the convective heat transfer coefficient and the temperature difference as the current heat flux density between the fluid and the transformer winding model.

[0022] In a possible implementation, it 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 convective heat transfer coefficient and the boundary fluid temperature.

[0025] The second aspect of this application provides a temperature field acquisition system for a transformer winding. The temperature simulation system of the transformer winding includes:

[0026] A flow velocity calculation unit, configured to calculate the current fluid flow velocity affected by temperature in the three-dimensional simulation model 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 the fluid between the transformer winding model and the radiator model. The three-dimensional simulation model is divided into multiple grids, and each grid has multiple 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 velocity;

[0028] A temperature calculation unit, configured to determine the current temperature of the fluid according to the current kinetic energy and kinetic energy dissipation rate of the fluid, and determine the current temperature of the 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 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 amount of the fluid according to the current heat flux density;

[0030] A temperature update unit, configured to update the current temperature field according to the current heat dissipation amount of the fluid;

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

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

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

[0034] In a possible implementation, it further includes a temperature analysis unit:

[0035] The temperature analysis unit is configured to obtain the temperature distribution characteristics and variation rules of the transformer winding model based on the temperature fields within multiple time steps.

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

[0037] The memory is used to store a computer program;

[0038] The processor is configured to execute the computer program so that the electronic device can implement the temperature field acquisition method of the transformer winding in the above first aspect or any implementation manner of the first aspect.

[0039] A fourth aspect of the present application provides a computer program product, including computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement the temperature field acquisition method of the transformer winding in the above first aspect or any implementation manner of the first aspect.

[0040] With the above technical solution, the present application provides a method for obtaining the temperature field of a transformer winding and related equipment. The method for obtaining the temperature field of the transformer winding first calculates the current fluid velocity of the fluid affected by temperature through the temperature field of the three-dimensional simulation model of the transformer winding and the radiator. According to the current fluid velocity of the fluid, the current kinetic energy and the kinetic energy dissipation rate of the fluid can be determined. Thus, the current temperature of the fluid can be determined. Since there is a contact part between the fluid and the transformer winding model, therefore, the current temperature of the transformer winding model can be determined according to the current temperature of the fluid. According to the temperature difference between the fluid and the transformer winding model, the current heat flux density of the transformer winding model can be determined. According to the current heat flux density, the current heat dissipation of the fluid can be determined. Then, the current temperature field is updated according to the heat dissipation. Taking the node temperature difference of the temperature field as the iteration condition, continuous updates are made between the velocity field of the fluid and the temperature field of the transformer winding until the temperature difference between the updated current temperature field and the grid nodes at the same positions in the current temperature field is less than the set threshold, then the iteration is stopped, and the 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 fluid velocity, kinetic energy, and kinetic energy dissipation rate 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 is considered, and the influence of the temperature on the fluid velocity is also considered. The velocity field of the fluid is used to continuously iterate the temperature field, and the temperature difference is used as the stop condition, indicating that the temperature field within the current time step has tended to be stable under the influence of the heat dissipation capacity of the fluid. Therefore, this method can obtain a temperature field of the transformer winding with relatively high accuracy under the influence of the heat dissipation fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In combination with the accompanying drawings and with reference to the following specific embodiments, the above and other features, advantages, and aspects of the various embodiments of the present disclosure will become more apparent. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic, and the original components and elements are not necessarily drawn to scale.

[0042] Figure 1 It is a schematic flowchart of a method for obtaining the temperature field of a transformer winding provided by an embodiment of the present application;

[0043] Figure 2 It is a schematic structural diagram of a three-dimensional simulation model provided by an embodiment of the present application;

[0044] Figure 3 It is a schematic diagram of the fluid velocity in a three-dimensional simulation model provided by an embodiment of the present application;

[0045] Figure 4 It is a schematic diagram of the internal transient temperature distribution provided by an embodiment of the present application;

[0046] Figure 5 It is a schematic structural diagram of a temperature field acquisition system for a transformer winding provided by an embodiment of the present application;

[0047] Figure 6 It is a hardware structure block diagram of an electronic device provided by the present application. Specific embodiments

[0048] The following describes the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. The terms used in the embodiment part of the present application are only used to explain the specific embodiments of the present application, rather than aiming to limit the present application.

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

[0050] The terms "first", "second", etc. in the specification of the present application and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances, which is only a way of distinguishing when describing objects with the same attributes in the embodiments of the present application. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, so that a process, method, system, product or device comprising a series of units does not have to be limited to those units, but may include other units not clearly listed or inherent to these processes, methods, products or devices.

[0051] With the rapid development of the power system, as a core device in the power system, the temperature rise problem of the transformer winding can directly affect the operation performance and service life of the transformer. Specifically, it can be manifested as: high temperature can accelerate the aging of the transformer insulation material, thus shortening the service life of the transformer and even causing the transformer to malfunction. Therefore, in order to ensure the normal operation of the transformer and extend its service life, transformers generally have radiators for dissipating heat from the transformer during operation. The radiator can use transformer oil as a cooling medium for heat dissipation, or rely on natural air convection or forced air for heat dissipation, etc.

[0052] In order to optimize the heat dissipation design of the transformer and improve the operation efficiency and safety of the transformer, it is necessary to closely monitor and understand the temperature distribution of the transformer winding, determine the hot spot temperature and its location in the temperature distribution, especially in terms of reducing the hot spot temperature through the winding structure. Among them, a hot spot refers to a point or area with an 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 limited to a specific spatial range.

[0053] Since the heat dissipation of the transformer affects the temperature distribution of the transformer winding, it is difficult to obtain a highly accurate temperature distribution. Moreover, the internal structure of the transformer winding is complex, and the installation positions of temperature sensors are limited, making it difficult to install temperature sensors at key internal positions of 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 local high-load positions, making it difficult to comprehensively capture the temperature distribution of the transformer winding.

[0054] To solve the above problems, the embodiments of the present application provide a method for obtaining the temperature field of a transformer winding. This solution uses numerical simulation methods and computer simulation technology to study the temperature field of the transformer winding, avoiding the use of temperature sensors 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 parameters representing the fluid velocity field to update the temperature field. Considering that the temperature also affects the fluid, the updated temperature field is used to update the velocity field in reverse, and the updated velocity field is used to update the temperature field again, and so on, iterating the temperature field multiple times until the temperature difference between each grid node of the current temperature field and the previous temperature field is less than a preset threshold, indicating that at this time, the current temperature field has stabilized under the influence of the heat dissipation capacity of the fluid. Then, a temperature field of the transformer winding with relatively high accuracy under the influence of the heat dissipation fluid can be obtained. A temperature field with relatively high accuracy is also conducive to analyzing the hot spot temperature and its position. The following will introduce in detail the method for obtaining the temperature field of the transformer winding in the embodiments of the present application with reference to the accompanying drawings.

[0055] Refer to Figure 1 , Figure 1 which is a schematic flow chart of a method for obtaining the temperature field of a transformer winding provided by the embodiments of the present application. As Figure 1 shown, a data processing method provided by the embodiments of the present application may include steps S10 to S16, and the following will describe these steps in detail respectively.

[0056] S10. Calculate the current fluid flow velocity of the fluid in the three-dimensional simulation model 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 a fluid between the transformer winding model and the radiator model, the three-dimensional simulation model is divided into multiple grids, and each grid has multiple grid nodes;

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

[0058] Among them, the fluid in this embodiment may refer to insulating oil used for heat dissipation. The three-dimensional simulation model is a virtual environment generated by computer simulation technology. Data such as the geometric shape and physical properties of a real object are obtained through a data acquisition device, and a three-dimensional model is established based on the collected data. Then, the three-dimensional model is dynamically simulated and rendered through a physics engine and simulation algorithms. As Figure 2 shown, in this embodiment, a three-dimensional simulation model of a transformer and its radiator with a 1:1 equivalence is established, and a fluid is provided between the transformer winding model and the radiator model. The three-dimensional simulation model in this embodiment is a complex three-dimensional structure composed of multiple interconnected meshes. Among them, a mesh is usually composed of triangles, quadrilaterals or other simple polygons, and each mesh may have multiple mesh nodes, and the mesh nodes are located at the intersection points or endpoints of the mesh.

[0059] After obtaining the three-dimensional simulation model, the three-dimensional simulation model can be imported into simulation software, the mesh information is initialized and loaded, and the solver, which is the core component of the simulation software, is set as a steady-state solver. Relevant parameters such as material properties and boundary conditions are set in the steady-state solver. Among them, the solver is an algorithm or technology used to find the optimal solution or approximate solution that satisfies preset constraint conditions. The steady-state solver is a solver specifically used to solve problems where the dependent variables of the physical field do not change with time, and 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 solving 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, in this embodiment, the three-dimensional simulation model is imported into ANSYS software, and the solver is set as a steady-state pressure-based solver. The Meshing software is used to re-perform step-by-step mesh division on the structural area and fluid area of the transformer winding model. The mesh selected in this embodiment is a tetrahedral mesh with good distribution control ability. 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 a flow composed of vortices with rotating structures of various different scales superimposed on each other. 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, which is a model used to predict the flow characteristics of the fluid between the transformer winding model and the radiator model, and its representation form can be as follows:

[0062]

[0063]

[0064] Among them, can represent the average velocity gradient; can represent the kinetic energy of the fluid; can represent the flow velocity (flow rate) component of the fluid along the direction; can represent the dissipation rate of the fluid kinetic energy; can represent the influence of pulsating expansion on the dissipation rate in compressible turbulence; can represent the turbulent kinetic energy generated by buoyancy; can represent the turbulent kinetic energy generated by the average velocity gradient; and can represent Cartesian coordinates; can represent the dynamic viscosity of the fluid; can represent the turbulent viscosity of the fluid; , and are all coefficients, The value of can be 1.44; The value of can be 1.0; The value of can be 1.3; can represent the buoyancy effect; can represent the 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, 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.

[0066] The first boundary condition is used to define the boundary temperature, and its representation form can be as follows:

[0067]

[0068] Among them, can represent the object boundary, which can represent the boundary of the transformer winding model here; can represent the known surface temperature of the transformer winding model; can represent the surface temperature function of the transformer winding model.

[0069] The second boundary condition is used to define the boundary heat flux density, and its representation form can be as follows:

[0070]

[0071] Among them, It can represent the boundary of an object, here representing the boundary of the radiator model; It can represent a constant, and its value can be 1.92; Represents the surface temperature function of the radiator model.

[0072] The third boundary condition is used to define the boundary convective heat transfer coefficient and the boundary fluid temperature, and its representation form can be as follows:

[0073]

[0074] Among them, It can represent the boundary of an object, here representing 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, and its value can be 1.44; It can represent a constant, and its value can be 1.92.

[0075] This embodiment can calculate the current fluid velocity of the fluid in the three-dimensional simulation model affected by temperature according to the current temperature field of the three-dimensional simulation model. Specifically, this embodiment substitutes the temperature of the grid nodes in the three-dimensional simulation model in contact with the fluid into the fluid flow momentum equation to calculate the current fluid velocity affected by temperature, as Figure 3 shown in the schematic diagram of the fluid velocity. From Figure 3 it can be seen that the insulating oil flows along the vertical oil ducts and the horizontal oil ducts as a whole. The high-velocity regions of the insulating oil are mainly concentrated at the positions near the oil outlets at both ends of the transformer winding, while the velocity in the middle region is relatively low. Among them, the fluid flow momentum equation is based on the Boussinesq hypothesis and finite pressure, and its specific representation form can be as follows:

[0076]

[0077] Among them, It can represent the fluid density; It can represent the component of the fluid velocity in the coordinate axis; It can represent the component of the fluid velocity in the coordinate axis; 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; It can represent the angle between the coordinate axis and the direction of the acceleration due to gravity; It can represent the coefficient of thermal expansion of the fluid.

[0078] After calculating the current fluid flow velocity affected by temperature in this embodiment, the current kinetic energy and kinetic energy dissipation rate of the fluid can be obtained according to the turbulence model. Specifically, in this embodiment, the current fluid flow velocity, dynamic viscosity, turbulent viscosity, and average velocity gradient are used as input parameters and input 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. 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 the fluid per unit mass in turbulence, that is, the rate at which the mechanical energy of isotropic small-scale vortices is converted into heat energy.

[0079] S12. Determine the current temperature of the fluid according to the current kinetic energy and kinetic energy dissipation rate of the fluid, and determine 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 obtaining the current kinetic energy and kinetic energy dissipation rate of the fluid output by the preset turbulence model in this embodiment, the current temperature of the fluid can be directly calculated, and using the principle of variable conservation at the interface between the fluid and the transformer winding, the boundary conditions at the interface between the fluid and the transformer winding should satisfy the equality or conservation of variables such as the displacement, heat flux, and temperature of the fluid and the transformer winding. Therefore, in this embodiment, the current temperature of the transformer winding model in contact with the fluid can be directly determined through the current temperature of the fluid. Among them, the representation form of the boundary conditions at the interface between the fluid and the transformer winding can be as follows:

[0082]

[0083] Among them, can represent the displacement of the fluid; can represent the displacement of the transformer winding; can represent the heat flux of the fluid; can represent the heat flux of the transformer winding; can represent the temperature of the fluid; can represent the temperature of the transformer winding; can represent the grid of the fluid; can represent the grid of the transformer winding.

[0084] Therefore, for each grid, after determining the current temperature of the fluid in this embodiment, the current temperature of the grid of the transformer winding in contact with the fluid grid can be calculated according to and thus the current temperature of the transformer winding model is obtained.

[0085] After determining the current temperature of the fluid and the current temperature of the transformer winding model in contact with the fluid in this embodiment, the heat flux density between the fluid and the transformer winding model can be calculated based on the temperature difference between the two. Heat flux density, also known as heat flux, is defined as: the amount of heat passing through a unit cross-sectional area of an object per unit time. Heat flux density can reflect the rate of heat transfer within an object or between objects.

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

[0087]

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

[0089] The value of the convective heat transfer coefficient can 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 calculated based on the current state between the fluid and the transformer winding model. The calculation formula for the convective heat transfer coefficient can be shown as follows:

[0090]

[0091] Among them, can represent a constant, and its value can be 1.92; can represent the characteristic length of convective heat transfer; can represent the Nusselt number.

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

[0093]

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

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

[0096]

[0097] Among them, can represent the current heat dissipation, can represent the heat taken away by the fluid due to the 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 the mass flow rate; can represent the specific enthalpy brought in when the fluid flows out of the transformer winding model; can represent the specific enthalpy brought in 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 the unit mass of a substance changes under constant pressure, and the mass flow rate reflects the mass of the 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, in this embodiment, the heat taken away by the fluid, that is, the current heat dissipation, can be determined according to 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 can be ignored in this embodiment, 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, according to different actual situations, the influence of heat radiation on the heat exchange amount can also be considered. Specifically, the calculation formula of the heat radiation heat exchange amount 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. This method first calculates the current fluid velocity of the fluid affected by temperature through the temperature field of the three-dimensional simulation model of the transformer winding and the radiator. According to the current fluid velocity of the fluid, the current kinetic energy and the kinetic energy dissipation rate of the fluid can be determined. From this, the current temperature of the fluid can be determined. Since the fluid and the transformer winding model have a contact part, therefore, the current temperature of the transformer winding model can be determined according to the current temperature of the fluid. According to the temperature difference between the fluid and the transformer winding model, the current heat flux density of the transformer winding model can be determined. According to the current heat flux density, the current heat dissipation of the fluid can be determined. Then, the current temperature field is updated according to the heat dissipation. Taking the node temperature difference of the temperature field as the iteration condition, continuous updates are performed between the velocity field of the fluid and the temperature field of the transformer winding until the temperature difference between the updated current temperature field and the grid nodes at the same positions in the current temperature field is less than the set threshold, then the iteration is stopped, and the 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 fluid velocity, kinetic energy, and kinetic energy dissipation rate 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 is considered, and the influence of the temperature on the fluid velocity is also considered. The velocity field of the fluid is used to continuously iterate the temperature field, and the temperature difference is used as the stop condition, indicating that at this time, the temperature field within the current time step has tended to be stable under the influence of the heat dissipation capacity of the fluid. Therefore, this method can obtain a temperature field of the transformer winding with higher accuracy under the influence of the heat dissipation fluid.

[0114] The above introduces a method for obtaining the temperature field of a transformer winding provided by the embodiment of the present application. The following will introduce a system applying the above method for obtaining the temperature field of the transformer winding.

[0115] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of a system for obtaining the temperature field of a transformer winding provided by the embodiment of the present application. As Figure 5 shown, the system for obtaining the temperature field of the transformer winding includes:

[0116] A flow velocity calculation unit 100, configured to calculate the current fluid velocity of the fluid affected by temperature in the three-dimensional simulation model 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 multiple grids, and each grid has multiple grid nodes;

[0117] A kinetic energy calculation unit 110, configured to determine the current kinetic energy and the kinetic energy dissipation rate of the fluid according to the current fluid velocity;

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

[0119] A heat dissipation calculation unit 130, configured 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 update unit 140, configured to update the current temperature field according to the current heat dissipation of the fluid;

[0121] If the temperature difference between at least one pair of grid nodes at the same position in the updated current temperature field and the current temperature field is not less than the set threshold, then use the updated current temperature field as the current temperature field and return to trigger the flow velocity calculation unit 100;

[0122] If the temperature difference between each pair of grid nodes at the same position in the updated current temperature field and the current temperature field is less than the set threshold, then trigger the temperature output unit 150,

[0123] A temperature output unit 150, configured 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 configured to obtain the temperature distribution characteristics and variation laws of the transformer winding model according to the temperature fields within multiple time steps.

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

[0127] Substitute the temperatures of the grid nodes in contact with the fluid in the three-dimensional simulation model into the fluid flow momentum equation to calculate the current fluid flow velocity affected by the temperature.

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

[0129] Use the current fluid flow velocity, dynamic viscosity, turbulent viscosity, and average velocity gradient as input parameters and input them 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 used to predict 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, and can be specifically configured as follows:

[0131] Obtain the convective heat transfer coefficient, and use the product of the convective heat transfer coefficient and the temperature difference 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 can 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 convective heat transfer coefficient and the boundary fluid temperature.

[0135] An embodiment of the present application also provides an electronic device. Refer to Figure 6 As shown, it shows a schematic structural diagram of an electronic device suitable for implementing the electronic device in 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, laptop computers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), desktop computers, and the like. Figure 6 The electronic device shown is only an example and should not impose any limitations on the functions and usage scope of the embodiment of the present application.

[0136] As Figure 6 shown, the electronic device may include a processing device (such as a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 602 or the program loaded from the storage device 608 into the 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 through a bus 604. The input / output (I / O) interface 605 is also connected to the bus 604.

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

[0138] An embodiment of the present application also provides a computer program product including computer-readable instructions. When the computer-readable instructions run on an electronic device, the electronic device is enabled to implement any one of the temperature field acquisition methods of the transformer winding provided by the embodiments of the present application.

[0139] An embodiment of the present application also provides a computer-readable storage medium. 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 be enabled to implement any one of the temperature field acquisition methods of the transformer winding provided by the embodiments of the present application.

[0140] In addition, it should be noted that the system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the system embodiments provided by the present application, the connection relationships between the modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines.

[0141] Through the description of the above embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software plus necessary general hardware. Of course, it can also be implemented by dedicated hardware including application-specific integrated circuits, dedicated CPUs, dedicated memories, dedicated components, etc. Generally, functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structures for implementing the same function can also be various, such as analog circuits, digital circuits, or dedicated circuits, etc. However, for the present application, in more cases, software program implementation is a better embodiment. Based on such an understanding, the technical solution of the present application, in essence, or the part that makes a contribution to the prior art, can be embodied in the form of a software product. The computer software product is stored in a readable storage medium, such as a floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disc of a computer, etc., and includes several instructions for causing a computer device (which can be a personal computer, training device, or network device, etc.) to execute the methods described in various embodiments of the present application.

[0142] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part 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 processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices. The computer instructions can 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 can be transmitted from a website, computer, training device, or data center to another website, computer, training device, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or a wireless manner (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can store, or a data storage device such as a training device or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid-state disk (SSD)), etc.

[0144] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and reference can be made to the relevant parts of the method embodiments for the related content.

[0145] It can be understood that before using the technical solutions disclosed in the embodiments of the present disclosure, the types, usage scopes, 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 the embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within 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 includes: Calculating the current fluid velocity of the fluid in the three-dimensional simulation model affected by temperature according to the current temperature field of the three-dimensional simulation model, where the three-dimensional simulation model includes a transformer winding model and a radiator model, there is the fluid between the transformer winding model and the radiator model, the three-dimensional simulation model is divided into multiple grids, and each grid has multiple grid nodes; Determining the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid velocity; 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; 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, and determining the 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 at least one grid node at the same position in the updated current temperature field and the current temperature field is not less than the set threshold, then taking the updated current temperature field as the current temperature field, and returning to execute the step of calculating the current fluid velocity of the fluid in the three-dimensional simulation models of the transformer and the radiator according to the current temperature field of the three-dimensional simulation model; If the temperature difference between each grid node at the same position in the updated current temperature field and the current temperature field is less than the set threshold, then outputting the updated current temperature field as the temperature field within the current time step.

2. The method for obtaining the temperature field of the transformer winding according to claim 1, characterized in that It also includes: Obtaining the temperature distribution characteristics and variation laws of the transformer winding model according to the temperature fields within 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 velocity of the fluid in the three-dimensional simulation model affected by temperature according to the current temperature field of the three-dimensional simulation model includes: Substituting the temperatures of the grid nodes in the three-dimensional simulation model in contact with the fluid into the flow momentum equation of the fluid to calculate the current fluid velocity of the fluid affected by temperature.

4. The method for obtaining the temperature field of a transformer winding according to claim 1, wherein The step of determining the current kinetic energy and kinetic energy dissipation rate of the fluid according to the current fluid velocity includes: Taking the current fluid velocity, dynamic viscosity, turbulent viscosity, and average velocity gradient as input parameters and inputting them 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, where 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 step of 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: Obtaining the convective heat transfer coefficient, and taking the product of the convective heat transfer coefficient and the temperature difference as the current heat flux density between the fluid and the transformer winding model.

6. The method for obtaining the temperature field of the transformer winding according to claim 1, characterized in that, It 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 convective heat transfer coefficient and the boundary fluid temperature.

7. A temperature field acquisition system for a transformer winding, characterized in that The temperature simulation system of the transformer winding includes: A flow velocity calculation unit, configured to calculate the current fluid flow velocity affected by temperature in the three-dimensional simulation model 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, and there is the fluid between the transformer winding model and the radiator model. The three-dimensional simulation model is divided into multiple grids, and each grid has multiple 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 velocity; A temperature calculation unit, configured to determine the current temperature of the fluid according to the current kinetic energy and kinetic energy dissipation rate of the fluid, and determine the current temperature of the transformer winding model in contact with the fluid according to the current temperature of the fluid; A heat dissipation calculation unit, configured 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; A temperature update unit, configured to update the current temperature field according to the current heat dissipation of the fluid; If the temperature difference between at least one grid node at the same position in the updated current temperature field and the current temperature field is not less than the set threshold, then use the updated current temperature field as the current temperature field and return to trigger the flow velocity calculation unit; If the temperature difference between each grid node at the same position in the updated current temperature field and the current temperature field is less than the set threshold, then trigger the temperature output unit, The temperature output unit is configured to output the updated current temperature field as the temperature field within the current time step.

8. The temperature field acquisition system of the transformer winding according to claim 7, wherein, It further includes a temperature analysis unit: The temperature analysis unit is configured to obtain the temperature distribution characteristics and variation rules of the transformer winding model according to the temperature fields within multiple time steps.

9. An electronic device, characterized in that, It includes at least one processor and a memory connected to the processor, where: 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 obtaining 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 includes computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement the method for obtaining the temperature field of the transformer winding as described in any one of claims 1 to 6.

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