A fault diagnosis method, device and storage medium of an oil-immersed power equipment
By constructing a three-dimensional geometric model of oil-immersed power equipment and simulating the diffusion behavior of fault gases, the problem of identifying the location of internal discharge defects in oil-immersed power equipment was solved, enabling accurate location and timely handling of defects and ensuring equipment safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING UNIV
- Filing Date
- 2026-03-10
- Publication Date
- 2026-06-09
AI Technical Summary
Existing technologies cannot accurately identify the location of internal discharge defects in oil-immersed power equipment, nor can they grasp the gas diffusion process from a macroscopic perspective, resulting in the inability to locate defects in a timely manner.
A three-dimensional geometric model of an oil-immersed power equipment is constructed. Based on measured data and boundary conditions, the diffusion behavior of fault gases is simulated. The fault location is determined by the spatiotemporal distribution characteristics of multiple sampling points, and a fault diagnosis image library is constructed.
It enables accurate location of internal discharge defects in oil-immersed power equipment, timely detection and handling of defects, and ensures safe operation of the equipment.
Smart Images
Figure CN122174738A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power grid equipment technology, and in particular to a fault diagnosis method, apparatus and storage medium for oil-immersed power equipment. Background Technology
[0002] Oil-immersed power equipment (oil-immersed power transformers, oil-immersed reactors, oil-immersed instrument transformers, and oil-immersed power capacitors) is a core component of the power grid. Early detection of internal discharge defects in power equipment is crucial for ensuring its safe operation and maintaining grid stability. When insulation discharge defects occur in power equipment, the internal insulating oil undergoes a decomposition reaction under the high temperature and strong electric field energy generated by the defect, producing fault-specific gases. As the discharge continues, these fault gases dissolve in the insulating oil, forming dissolved gases that diffuse and eventually distribute evenly within the power equipment.
[0003] Current research on the diffusion behavior of dissolved gases in oil mainly focuses on experimental methods, lacking a comprehensive understanding of the gas diffusion process when a discharge defect occurs in the power equipment. This lack of research covers the gas generation from the cracking of insulating oil under discharge defects, the dissolution of fault gases into the oil, and the complex diffusion of dissolved gases within the power equipment. Consequently, it is impossible to grasp the gas diffusion process when a discharge defect occurs within the power equipment from a macroscopic perspective, making it impossible to accurately locate the defect.
[0004] It is evident that accurately identifying the location of defects is a problem that needs to be solved by those skilled in the art. Summary of the Invention
[0005] The purpose of this application is to provide a fault diagnosis method, apparatus, and storage medium for oil-immersed power equipment, which can accurately identify the location of defects.
[0006] This application provides a fault diagnosis method for oil-immersed power equipment, including: Based on the structural parameters of oil-immersed power equipment, a three-dimensional geometric model of a transformer including discharge defects is constructed. Based on measured data and the material parameters and set boundary conditions of the transformer's three-dimensional geometric model, the constructed fault gas diffusion behavior is assigned values; among them, the fault gas diffusion behavior includes the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution-spatiotemporal diffusion and disorder process. The three-dimensional geometric model of the transformer is meshed and divided into gas and liquid phases. The three-dimensional geometric model of the transformer is then used to simulate the diffusion behavior of the fault gas after assignment, so as to obtain the spatiotemporal distribution characteristics of the dissolved gas. The fault location was determined based on the spatiotemporal distribution characteristics of multiple sampling points.
[0007] On the one hand, regarding the construction process of fault gas diffusion behavior, the methods also include: Based on the linear relationship between the gas production volume and the cumulative energy of discharge, a discharge gas production equation is constructed; Based on the pressure difference between the characteristic gas in the gas phase and the gas film, the driving force equation for the mass transfer process on the gas phase side is determined. Based on the concentration difference of the characteristic gas between the liquid phase and the liquid film, the driving force equation for the mass transfer process on the liquid phase side is determined. A fluid volume model is constructed based on the spatiotemporal diffusion characteristics of dissolved gases within power equipment.
[0008] On the one hand, based on measured data and the material parameters and set boundary conditions of the transformer's three-dimensional geometric model, values are assigned to the constructed fault gas diffusion behavior, including: The measured data, including discharge breakdown time, breakdown voltage, and breakdown current amplitude, are assigned to the discharge gas production equation to determine the gas production volume. The partial pressure of the characteristic gas in the gas phase included in the measured data is assigned to the driving force equation of the mass transfer process on the gas phase side, and the molar concentration of the characteristic gas in the liquid phase included in the measured data is assigned to the driving force equation of the mass transfer process on the liquid phase side. Based on Henry's law of the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film included in the boundary conditions, the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film are determined. The fluid volume model is assigned values based on the material parameters and boundary parameter values included in the boundary conditions of the three-dimensional geometric model of the transformer, so as to determine the governing equations of the fluid volume model after assignment; among them, the governing equations of the fluid volume model include the mass transfer equation, the kinetic energy transfer equation and the energy transfer equation.
[0009] On the one hand, based on the material parameters and boundary parameter values included in the boundary conditions of the transformer's three-dimensional geometric model, values are assigned to the fluid volume model to determine the governing equations of the assigned fluid volume model, including: The density of the gas phase and the density of the liquid phase inside the power equipment, which are included in the material parameters, as well as the volume fraction of the gas phase, the volume fraction of the liquid phase, the velocity vector of the gas phase, and the velocity vector of the liquid phase inside the power equipment, which are included in the boundary conditions, are assigned to the continuity equation to obtain the continuity equation after assignment. The material parameters, including the density of the gas phase, the density of the liquid phase, the dynamic viscosity of the gas phase, and the dynamic viscosity of the liquid phase within the power equipment, as well as the boundary conditions, including the pressure, the volume fraction of the gas phase, the volume fraction of the liquid phase, the velocity vector of the gas phase, and the velocity vector of the liquid phase, are assigned to the momentum equation to obtain the assigned momentum equation. The material parameters, including the density of the gas phase and the density of the liquid phase within the power equipment, the diffusion coefficient of the characteristic gas in the gas phase and the diffusion coefficient of the characteristic gas in the liquid phase, as well as the boundary conditions, including the pressure, the mass fraction of the characteristic gas in the gas phase, the mass fraction of the characteristic gas in the liquid phase, the volume fraction of the gas phase within the power equipment, and the volume fraction of the liquid phase within the power equipment, are assigned to the mass transfer equation to obtain the assigned mass transfer equation.
[0010] On the one hand, the governing equations of the fluid volume model also include the turbulent kinetic energy equation; Based on the material parameters and boundary parameter values included in the boundary conditions of the transformer's three-dimensional geometric model, values are assigned to the fluid volume model to determine the governing equations of the assigned fluid volume model, including: The turbulent kinetic energy, velocity, and specific heat loss contained in the boundary conditions are assigned to the turbulent kinetic energy equation to obtain the assigned turbulent kinetic energy equation.
[0011] On the one hand, the diffusion behavior of the fault gas after assignment is simulated using the partitioned three-dimensional geometric model of the transformer to obtain the spatiotemporal distribution characteristics of the dissolved gas, including: The control equations of the assigned fluid volume model were simulated using the divided three-dimensional geometric model of the transformer to determine the operating behavior of the dissolved gas diffusion process. The behavior of dissolved gas diffusion process is disturbed based on the turbulent kinetic energy equation and the specific heat dissipation equation contained in the boundary conditions, so as to obtain the spatiotemporal distribution characteristics of dissolved gas.
[0012] On the one hand, based on the spatiotemporal distribution characteristics corresponding to multiple sampling points, the fault location is determined to include: Based on the spatiotemporal distribution characteristics of multiple sampling points, distribution maps of multiple sampling points at different times are constructed; among them, the distribution maps include distribution maps of free gas clouds and distribution maps of dissolved gases; The location of the fault is determined by analyzing the gas position changes in the distribution maps of multiple sampling points at the same time.
[0013] On the one hand, it also includes: Based on the distribution maps of different fault locations at different times, a fault diagnosis image library is constructed. Once the spatiotemporal distribution characteristics corresponding to the new sampling points are obtained, a new distribution map is constructed based on these characteristics. If a target distribution map that matches the new distribution map exists in the fault diagnosis image library, the fault location corresponding to the target distribution map is taken as the fault location corresponding to the new distribution map.
[0014] This application also provides a fault diagnosis device for oil-immersed power equipment, including a construction unit, an assignment unit, a simulation unit, and a determination unit; The building unit is used to construct a three-dimensional geometric model of a transformer, including discharge defects, based on the structural parameters of oil-immersed power equipment. The assignment unit is used to assign values to the constructed fault gas diffusion behavior based on measured data, material parameters of the transformer's three-dimensional geometric model, and set boundary conditions. The fault gas diffusion behavior includes the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process. The simulation unit is used to mesh the three-dimensional geometric model of the transformer and divide it into gas and liquid phases. It then uses the meshed three-dimensional geometric model of the transformer to simulate the diffusion behavior of the fault gas after assignment, so as to obtain the spatiotemporal distribution characteristics of the dissolved gas. The determination unit is used to determine the fault location based on the spatiotemporal distribution characteristics corresponding to multiple sampling points.
[0015] This application also provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, it implements the steps of any of the above-described fault diagnosis methods for oil-immersed power equipment.
[0016] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of any of the above-described fault diagnosis methods for oil-immersed power equipment.
[0017] As can be seen from the above technical solution, a three-dimensional geometric model of a transformer incorporating discharge defects is constructed based on the structural parameters of the oil-immersed power equipment. Based on measured data and the material parameters and set boundary conditions of the transformer's three-dimensional geometric model, values are assigned to the constructed fault gas diffusion behavior. This fault gas diffusion behavior can include the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process. The transformer's three-dimensional geometric model is meshed, and the gas and liquid phases are divided. The assigned fault gas diffusion behavior is then simulated using the meshed transformer three-dimensional geometric model to obtain the spatiotemporal distribution characteristics of the dissolved gas. Based on the spatiotemporal distribution characteristics corresponding to multiple sampling points, the fault location is determined. In this technical solution, by jointly analyzing the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process, the entire process of gas generation, dissolution, and diffusion under discharge defects inside the oil-immersed power equipment is simulated and calculated. This allows for a macroscopic understanding of the spatiotemporal distribution characteristics of dissolved gas in the oil, thereby enabling accurate prediction of the fault location. Attached Figure Description
[0018] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 A flowchart illustrating a fault diagnosis method for oil-immersed power equipment provided in this application embodiment; Figure 2 A schematic diagram of a three-dimensional geometric model of a transformer containing discharge defects, provided for an embodiment of this application; Figure 3 A schematic diagram of a three-dimensional geometric model of a transformer after mesh generation, provided as an embodiment of this application; Figure 4 A distribution diagram of a gas generation, dissolution, and diffusion process at a first moment, provided as an embodiment of this application; Figure 5 A distribution diagram of gas generation, dissolution and diffusion processes at a second time point is provided as an embodiment of this application; Figure 6 A distribution diagram of gas generation, dissolution and diffusion processes at a third time point is provided as an embodiment of this application; Figure 7 This is a schematic diagram illustrating the gas generation, dissolution, and diffusion process under internal discharge defects in power equipment, provided as an embodiment of this application. Figure 8 This is a schematic diagram of the structure of a fault diagnosis device for oil-immersed power equipment provided in an embodiment of this application. Detailed Implementation
[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.
[0021] The terms "comprising" and "having," and any variations thereof, in the specification and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may include steps or units not listed.
[0022] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0023] Oil-immersed power equipment is a core component of the power grid. Early detection of discharge defects within the equipment is crucial for ensuring its safe operation and maintaining grid stability.
[0024] Current methods for simulating the diffusion of dissolved gases in oil employ diffusion simulation test platforms consisting of an oil-filled cylinder and a gas vacuum pump. The injection of gas into the cylinder via the vacuum pump simulates the gas generation scenario during a power equipment fault, allowing for the study of the spatiotemporal distribution characteristics of gases within the power equipment. Alternatively, diffusion test platforms can be used, comprising a transformer tank with a built-in fault model, temperature sensors, and dissolved gas sampling devices in the oil, to study the diffusion patterns of dissolved gases in the oil within power equipment during a fault. Another approach integrates transformer devices, a fault-generating gas module, and a real-time dissolved gas analysis module to realistically simulate the gas generation and diffusion phenomena during a power equipment fault.
[0025] Current research on the diffusion behavior of dissolved gases in oil mainly focuses on experimental methods, lacking a comprehensive understanding of the gas diffusion process when a discharge defect occurs in a power equipment. This includes the process of gas generation from the cracking of insulating oil under discharge defects, the dissolution of fault gases into the oil, and the complex diffusion of dissolved gases in the oil within the power equipment under the influence of factors such as temperature, energy impact, and gas mass movement. As a result, it is impossible to gain a macroscopic understanding of the gas diffusion process when a discharge defect occurs within a power equipment.
[0026] Therefore, this application provides a fault diagnosis method, device, and storage medium for oil-immersed power equipment, forming a complete simulation of the diffusion process of dissolved gas in oil caused by internal discharge defects in oil-immersed power equipment. Based on the generation, dissolution, and diffusion laws of gas under internal discharge defects in power equipment, the spatiotemporal distribution characteristics of dissolved gas in oil are grasped from a macroscopic perspective, thereby predicting the type and location of defects, realizing timely resolution of discharge defects in the initial stage, and ensuring the safe operation of power equipment.
[0027] Next, a fault diagnosis method for oil-immersed power equipment provided in the embodiments of this application will be described in detail. Figure 1 A flowchart of a fault diagnosis method for oil-immersed power equipment provided in this application embodiment, the method including: S101: Based on the structural parameters of oil-immersed power equipment, construct a three-dimensional geometric model of a transformer that includes discharge defects.
[0028] Taking the structural and material parameters of the S20-M-100 / 10 ternary hybrid oil transformer as an example of power equipment, Figure 2 This application provides a schematic diagram of a three-dimensional geometric model of a transformer with discharge defects, including a casing, windings, core clamps, and a core. Figure 2The lower right corner of the rear side of the middle housing represents the location of the discharge defect. In practical applications, the transformer can be set to a length of 747mm, a width of 377mm, and a height of 650mm.
[0029] Material parameters, including density, specific heat capacity, and thermal conductivity, are defined. Insulating paper is selected for the winding material, steel is selected for the transformer housing and core clamps, and silicon steel is selected for the core material. A ternary composite insulating oil is selected as the insulating oil material, and its performance parameters are shown in Table 1.
[0030] Table 1
[0031] Table 1 lists the specific values of different performance parameters for ternary hybrid insulating oils.
[0032] S102: Assign values to the constructed fault gas diffusion behavior based on measured data, material parameters of the transformer's three-dimensional geometric model, and set boundary conditions.
[0033] The measured data can be obtained through preliminary experimental testing.
[0034] Among them, the diffusion behavior of fault gas includes the gas generation process under the action of discharge energy, the two-phase mass transfer process of fault gas and insulating oil, and the spatiotemporal diffusion and disorder process of gas dissolution.
[0035] In this embodiment, the process of constructing the fault gas diffusion behavior may include constructing a discharge gas generation equation based on the linear relationship between the gas generation volume and the cumulative discharge energy. The driving force equation for the mass transfer process on the gas phase side is determined based on the pressure difference between the characteristic gas in the gas phase and the gas film. The driving force equation for the mass transfer process on the liquid phase side is determined based on the concentration difference between the characteristic gas in the liquid phase and the liquid film. A fluid volume model is constructed based on the spatiotemporal diffusion characteristics of dissolved gases within the power equipment.
[0036] For the gas generation process under the action of discharge energy, the discharge breakdown time, breakdown voltage and breakdown current amplitude are required to determine the gas generation volume. Therefore, the discharge breakdown time, breakdown voltage and breakdown current amplitude contained in the measured data can be assigned to the discharge gas generation equation to determine the gas generation volume.
[0037] For the two-phase mass transfer process of fault gas insulating oil, the diffusion rate of the characteristic gas in the oil during the mass transfer process on the gas phase side and the diffusion rate of the characteristic gas in the oil during the mass transfer process on the liquid phase side can be calculated separately. Combined with Henry's law, the partial pressure of the characteristic gas at the gas film and the molecular concentration of the characteristic gas at the liquid film can be calculated, thereby assessing how much gas dissolves into the liquid.
[0038] Therefore, in practical implementation, the partial pressure of the characteristic gas in the gas phase contained in the measured data can be assigned to the driving force equation of the mass transfer process on the gas phase side, and the molar concentration of the characteristic gas in the liquid phase contained in the measured data can be assigned to the driving force equation of the mass transfer process on the liquid phase side. Based on Henry's law, which includes the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film contained in the boundary conditions, the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film can be determined.
[0039] For the spatiotemporal diffusion and chaotic process of gas dissolution, the fluid volume model can be assigned values based on the material parameters of the transformer's three-dimensional geometric model and the boundary parameter values included in the boundary conditions, so as to determine the governing equations of the fluid volume model after assignment; among them, the governing equations of the fluid volume model can include mass transfer equations, kinetic energy transfer equations and energy transfer equations.
[0040] For the continuity equation, the density of the gas phase and the density of the liquid phase inside the power equipment, which are included in the material parameters, as well as the volume fraction of the gas phase, the volume fraction of the liquid phase, the velocity vector of the gas phase, and the velocity vector of the liquid phase inside the power equipment, which are included in the boundary conditions, can be assigned to the continuity equation to obtain the continuity equation after assignment.
[0041] For the momentum equation, the material parameters, including the density of the gas phase, the density of the liquid phase, the dynamic viscosity of the gas phase, and the dynamic viscosity of the liquid phase within the power equipment, as well as the boundary conditions, including the pressure, the volume fraction of the gas phase, the volume fraction of the liquid phase, the velocity vector of the gas phase, and the velocity vector of the liquid phase, can be assigned to the momentum equation to obtain the assigned momentum equation.
[0042] For the mass equation, the density of the gas phase inside the power equipment, the density of the liquid phase inside the power equipment, the diffusion coefficient of the characteristic gas in the gas phase and the diffusion coefficient of the characteristic gas in the liquid phase, as well as the pressure, mass fraction of the characteristic gas in the gas phase, mass fraction of the characteristic gas in the liquid phase, volume fraction of the gas phase inside the power equipment, and volume fraction of the liquid phase inside the power equipment included in the boundary conditions can be assigned to the mass transfer equation to obtain the assigned mass transfer equation.
[0043] In this embodiment of the application, in order to increase the complexity of liquid flow and make the behavior of dissolved gas diffusion and chaotic processes more in line with the actual situation, a turbulent kinetic energy equation can be added to the control equation of the fluid volume model.
[0044] In practical implementation, the turbulent kinetic energy, velocity, and specific heat dissipation contained in the boundary conditions can be assigned to the turbulent kinetic energy equation to obtain the assigned turbulent kinetic energy equation.
[0045] S103: Mesh the three-dimensional geometric model of the transformer and divide it into gas and liquid phases. Then, use the divided three-dimensional geometric model of the transformer to simulate the diffusion behavior of the fault gas after assignment, so as to obtain the spatiotemporal distribution characteristics of the dissolved gas.
[0046] Figure 3 This is a schematic diagram of a three-dimensional geometric model of a transformer after meshing, provided in an embodiment of this application. After setting the material parameters of the three-dimensional geometric model of the transformer, the three-dimensional geometric model of the transformer can be meshed to facilitate subsequent simulation.
[0047] Since this application simulates the spatiotemporal evolution of fault gas between the gas and liquid phases, it is necessary to divide the three-dimensional geometric model of the transformer after meshing into gas and liquid phases. By simulating the governing equations of the assigned fluid volume model using the divided three-dimensional geometric model of the transformer, the operating behavior of the dissolved gas diffusion process can be determined. The operating behavior of the dissolved gas diffusion process is then disturbed based on the turbulent kinetic energy equation and the specific heat dissipation equation included in the boundary conditions to obtain the spatiotemporal distribution characteristics of the dissolved gas.
[0048] The model is initialized based on the set boundary conditions. After setting the transient calculation time and step size of the transformer's three-dimensional geometric model, the simulation calculation begins to obtain the gas generation, dissolution, and diffusion processes under internal discharge defects in the transformer.
[0049] S104: Determine the fault location based on the spatiotemporal distribution characteristics of multiple sampling points.
[0050] The gas distribution pattern is different at different sampling points. Based on the gas distribution pattern at different sampling points, it is possible to determine which sampling point is closest to the fault location, and thus that sampling point can be used as the fault location.
[0051] In this embodiment, distribution maps of multiple sampling points at different times can be constructed based on their spatiotemporal distribution characteristics. These distribution maps include distribution maps of free gas clouds and dissolved gases. The fault location is determined based on the gas position changes in the distribution maps of the multiple sampling points at each same time.
[0052] In this application, the gas generation, dissolution, and diffusion processes can be obtained through simulation. Figure 4 This is the distribution diagram at the first moment, where t = 3 seconds. Figure 4 The left image shows the distribution of free gas clusters generated at the first moment, and the right image shows the distribution of dissolved gases in the oil at the first moment. Figure 4As shown in the left figure, when a defect discharges, a fault gas cloud is generated from the defect location. This gas cloud is distributed in the oil area near the defect and on the top oil surface of the transformer. Some of the gas cloud dissolves in the oil, forming dissolved gases in the oil, such as... Figure 4 As shown in the right figure.
[0053] As time progresses, the gas masses along the rising path dissolve first in the insulating oil, forming dissolved gases in the oil. Simultaneously, the gases on the top oil surface also slowly dissolve into the oil. Figure 5 As shown. Figure 5 This is the distribution diagram at the second time point, which can be t=3600 seconds. Figure 5 The left image shows the distribution of free gas plumes generated at the second time point, and the right image shows the distribution of dissolved gases in the oil at the second time point. Figure 4 As shown in Figures 5 to 6, the volume fraction of dissolved gases in the oil continues to diffuse from the faulty oil area to the surrounding low-concentration areas and downwards from the top oil surface, until the overall dissolved gas concentration in the transformer oil reaches equilibrium after 22 hours. Figure 6 As shown. Figure 6 This is the distribution diagram at the third time point. The first time point can be t=79200 seconds. Figure 6 The left image shows the distribution of free gas clusters generated at the third time point, and the right image shows the distribution of dissolved gases in the oil at the third time point.
[0054] based on Figures 4 to 6 Simulation results show that this scheme can simulate the gas generation process of discharge defects from a macroscopic perspective, the process of fault gas dissolving in insulating oil to form dissolved gas in the oil, and the complex diffusion process of dissolved gas in the oil in the transformer under the influence of factors such as temperature, energy impact, and gas mass floating. This enables the prediction of defect location, allowing for early detection and timely handling of discharge defects, thus ensuring the safe operation of the transformer.
[0055] As can be seen from the above technical solution, a three-dimensional geometric model of a transformer incorporating discharge defects is constructed based on the structural parameters of the oil-immersed power equipment. Based on measured data and the material parameters and set boundary conditions of the transformer's three-dimensional geometric model, values are assigned to the constructed fault gas diffusion behavior. This fault gas diffusion behavior can include the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process. The transformer's three-dimensional geometric model is meshed, and the gas and liquid phases are divided. The assigned fault gas diffusion behavior is then simulated using the meshed transformer three-dimensional geometric model to obtain the spatiotemporal distribution characteristics of the dissolved gas. Based on the spatiotemporal distribution characteristics corresponding to multiple sampling points, the fault location is determined. In this technical solution, by jointly analyzing the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process, the entire process of gas generation, dissolution, and diffusion under discharge defects inside the oil-immersed power equipment is simulated and calculated. This allows for a macroscopic understanding of the spatiotemporal distribution characteristics of dissolved gas in the oil, thereby enabling accurate prediction of the fault location.
[0056] The above content introduces the governing equations for the gas generation process, the two-phase mass transfer process of fault gas and insulating oil, and the spatiotemporal diffusion and disorder process of gas dissolution under the action of discharge energy. The specific forms of the governing equations for different stages will be introduced next.
[0057] In oil-immersed power equipment, the insulating oil inside continuously deteriorates under the combined stress of electricity, heat, and machinery. This causes insulation discharge defects to gradually develop from the initial stage to a severe stage, eventually resulting in high-energy discharge. Consequently, the insulating oil decomposes during discharge, producing fault-characteristic gases. For ease of description, this process is introduced using a "gas-generating module under the action of discharge energy," and its governing equations are shown below.
[0058] The gas production volume has a good linear relationship with the cumulative discharge energy, and the discharge gas production formula is shown in (1): (1); in, V This represents the gas production volume, in cm³. 3 ; k This is the gas production coefficient, in cm³. 3 / kJ, since ternary mixed insulating oil produces more characteristic gases than mineral oil, k is taken as 90; W is the cumulative discharge energy, in kJ.
[0059] The formula for calculating the cumulative discharge energy W is shown in equation (2): (2); In the formula, t The breakdown time of the discharge defect is expressed in milliseconds (ms).u This is the breakdown voltage, expressed in kV. i This represents the breakdown current amplitude, measured in amperes (A).
[0060] The generated characteristic gases dissolve in the oil to form dissolved gases, which is a gas-liquid two-phase mass transfer process. A "fault gas-insulating oil two-phase mass transfer module" is added, setting the material composition of the gas and liquid phases. The gas phase uses characteristic gases such as hydrogen, carbon monoxide, carbon dioxide, acetylene, ethane, ethylene, and methane, while the liquid phase uses a ternary mixed insulating oil. The physical properties of the two-phase components, including density, specific heat capacity, thermal conductivity, and viscosity, are defined to describe the mass transfer process between the gas and liquid phases over time and space. The control equations for the component transport module are shown below.
[0061] The driving force of the gas-phase mass transfer process mainly comes from the pressure difference between the characteristic gas in the gas phase and the gas film. The gas-phase mass transfer process can be represented by equation (3): (3); in, N d The diffusion rate of the characteristic gas in oil is expressed in mol / (m). 2 s); K g This is the mass transfer coefficient of the gas film, with units of kmol / m³. 2 / s / kPa; P d This represents the partial pressure of the characteristic gas in the gas phase, expressed in kPa. P d， i This represents the partial pressure of the characteristic gas at the gas film, expressed in kPa.
[0062] The driving force for the liquid-phase mass transfer process mainly comes from the concentration difference of the characteristic gas between the liquid phase and the liquid film, which can be expressed by equation (4): (4); in, K l is the mass transfer coefficient of the liquid film, with units of m / s; C d，i The molecular concentration of the characteristic gas in the liquid film, expressed in kmol / m³. 3 ; C d The molar concentration of the characteristic gas in the liquid phase, in kmol / m³. 3 .
[0063] When the diffusion rate of the characteristic gas through the thin film layer no longer changes with time, it indicates that the mass transfer process has reached a steady state, which can be expressed by Herry's law, as shown in equation (5): (5); in, H The Henry's law is the characteristic gas's coefficient in oil, expressed in Pa / (mol). L).
[0064] N d The diffusion rate of the characteristic gas in oil is given by formula (3), which is the calculation method for the diffusion rate of the characteristic gas in oil during the gas-phase mass transfer process, and formula (4), which is the calculation method for the diffusion rate of the characteristic gas in oil during the liquid-phase mass transfer process. In actual calculations, the following can be obtained from formulas (3) and (4): Combining formula (5), the solution can be obtained. and The value of .
[0065] During the dissolution and diffusion of characteristic gases in insulating oil, mass, momentum, and energy transfer also occur simultaneously between the gas and liquid phases, resulting in a complex spatiotemporal diffusion pattern for dissolved gases within electrical equipment. To accurately describe the diffusion location and process of dissolved gases in the oil within electrical equipment, a "Dissolved Gas Diffusion Module" is added. The material composition of the gas and liquid phases is set. The gas phase uses characteristic gases such as hydrogen, carbon monoxide, carbon dioxide, acetylene, ethane, ethylene, and methane, while the liquid phase uses a ternary mixed insulating oil. The physical properties of the two phase components, including density, specific heat capacity, thermal conductivity, and viscosity, as well as the surface tension coefficient and mass transfer coefficient of the model, are defined. The basic governing equations of the fluid volume model are shown below.
[0066] The continuity equations are shown in equations (6)-(7): (6); (7); in, t Time, in seconds; The density of the gas phase inside the power equipment. This refers to the density of the liquid phase inside the electrical equipment, expressed in kg / m³. 3 ; This represents the volume fraction of the gas phase within the electrical equipment. This refers to the volume fraction of the liquid phase within the electrical equipment. u g The velocity vector of the gas phase inside the power equipment. u l This is the velocity vector of the liquid phase inside the power equipment, with units of m / s; S g For the mass source term in the gas-phase continuity equation, S l This is the mass source term in the liquid phase continuity equation, with units of kg / m³.3 / s.
[0067] The momentum equations are shown in equations (8)-(9): (8); (9); in, g This is the acceleration due to gravity, measured in m / s². 2 p represents pressure, measured in kPa. The dynamic viscosity of the gas phase inside the power equipment. The dynamic viscosity of the liquid phase inside the power equipment; F g This is the force source term in the gas phase momentum equation. F l This is the force source term in the liquid phase momentum equation, with units of N / m. 3 .
[0068] The mass transfer equations are shown in equations (10)-(11): (10); (11); in, C d，g This represents the mass fraction of the characteristic gas in the gas phase. C d，l This represents the mass fraction of the characteristic gas in the liquid phase. S d，g This is the source term for the equation representing the mass fraction of characteristic gases in the gas phase. S d，l This is the source term of the equation for the mass fraction of characteristic gas in the liquid phase, in units of kg / m³. 2 / s; D d，g The diffusion coefficient of the characteristic gas in the gas phase. D d，l These are the diffusion coefficients of the characteristic gas in the liquid phase, in m. 2 / s.
[0069] To further describe the chaotic motion behavior during the diffusion of dissolved gases in oil, a "dissolved gas diffusion optimization module" is added, and its control equation is shown below.
[0070] The turbulent kinetic energy equation is shown in equation (12): (12); in, This refers to the mixed-phase density, expressed in kg / m³. 3 ; K k Turbulent kinetic energy, unit is m2 / s 2 ; v Speed, unit: m / s; u m The viscosity of the mixed phase is expressed in Pa. s; u t Turbulent viscosity, in Pa. s; The Prandtl number corresponds to the turbulent kinetic energy. S k This is the turbulent kinetic energy generation term, with units of kg / (m³). s 3 ); These are the empirical constants of the turbulent kinetic energy equation; The specific dissipation rate is expressed in units of 1 / s.
[0071] The specific dissipation rate equation is shown in equation (13): (13); in, , , All of them are empirical constants in the specific dissipation rate equation; The specific dissipation rate corresponds to the Prandtl number of the turbulent flow. F 1 It is a mixed function.
[0072] The generation and diffusion process of discharge fault gases in oil-immersed power equipment includes the gas generation process under the action of discharge energy, the two-phase mass transfer process between fault gas and insulating oil, and the spatiotemporal diffusion and disorder process of gas dissolution. Corresponding functional modules can be set for each process. By adding these functional modules to the simulation model and assigning values to them, the gas generation, dissolution, and diffusion processes under discharge defects inside the transformer can be simulated and calculated.
[0073] Figure 7 This is a schematic diagram illustrating the gas generation, dissolution, and diffusion process under internal discharge defects in power equipment, provided in an embodiment of this application. Figure 7 The three columns of modules contained in the upper dashed box correspond to the calculation and analysis of the gas generation process under the action of discharge energy, the calculation and analysis of the fault gas-insulating oil two-phase mass transfer process, and the calculation and analysis of the gas dissolution, spatiotemporal diffusion, and disorder process. The calculation and analysis of the gas generation process under the action of discharge energy: Based on the discharge gas generation formula and the discharge cumulative energy calculation formula, this describes the process by which insulating oil in power equipment decomposes under the high temperature and strong electric field energy of discharge defects to generate fault gas.
[0074] Calculation and analysis of the two-phase mass transfer process of fault gas and insulating oil: Based on the driving force formulas for the mass transfer process on the gas phase side, the driving force formulas for the mass transfer process on the liquid phase side, and Herry's law, this paper describes the gas-oil two-phase mass transfer process in which fault gas dissolves in the oil after being generated, forming dissolved gas in the oil.
[0075] Computational Analysis of Spatiotemporal Diffusion and Chaotic Processes of Gas Dissolution: Based on the continuity equation, momentum equation, and mass transfer equation, this study describes the mass, momentum, and energy transfer processes between the gas and liquid phases as the characteristic gas dissolves and diffuses in insulating oil. Furthermore, based on the turbulent kinetic energy equation and specific dissipation rate equation, the study further optimizes the description of the chaotic motion process of dissolved gas in oil diffusing within electrical equipment.
[0076] Figure 7 The lower middle section shows a schematic diagram of the simulation process. Calculation and analysis of the gas movement behavior during discharge faults in oil-immersed power equipment: Based on the properties of the insulating oil and the gases produced by its decomposition, the material composition of the gas and liquid phases is set, and the physical properties of the two phase components, the surface tension coefficient, and the mass transfer coefficient of the model are defined. A three-dimensional geometric model is created based on the structural parameters of the power equipment. Based on the material parameters of the actual power equipment and its internal insulating oil, the material parameters of the power equipment and the model used in the simulation are set. The three-dimensional geometric model of the power equipment is meshed, and the gas and liquid phases are separated in the fluid domain of the power equipment model; the boundary conditions of the simulation model are set, and the model is initialized. The transient calculation time and step size of the simulation model are set, and the simulation calculation begins to obtain the generation and diffusion process of discharge fault gases in oil-immersed power equipment.
[0077] This application employs computational fluid dynamics simulation technology to jointly analyze the gas generation process under the influence of discharge energy, the two-phase mass transfer process between fault gas and insulating oil, the spatiotemporal diffusion and chaotic process of gas dissolution, and the movement behavior of fault gas in oil-immersed power equipment. Simulation calculations are performed to simulate the complex diffusion process of dissolved gas in oil within the power equipment under the influence of factors such as temperature, energy impact, and gas mass floating. This helps to theoretically reveal the spatiotemporal distribution characteristics of dissolved gas in oil within power equipment, providing guidance for fault diagnosis and prediction of power equipment based on dissolved gas analysis.
[0078] In this embodiment of the application, in order to improve the efficiency of fault analysis, a fault diagnosis image library can be constructed based on the distribution maps of different fault locations at different times. When the spatiotemporal distribution features corresponding to new sampling points are obtained, a new distribution map is constructed based on these features. If a target distribution map matching the new distribution map exists in the fault diagnosis image library, the fault location corresponding to the target distribution map is used as the fault location corresponding to the new distribution map.
[0079] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method.
[0080] Figure 8 A schematic diagram of the structure of a fault diagnosis device for oil-immersed power equipment provided in this application embodiment includes a construction unit 81, an assignment unit 82, a simulation unit 83, and a determination unit 84; Building unit 81 is used to construct a three-dimensional geometric model of a transformer containing discharge defects based on the structural parameters of oil-immersed power equipment. The assignment unit 82 is used to assign values to the constructed fault gas diffusion behavior based on the measured data, the material parameters of the transformer's three-dimensional geometric model, and the set boundary conditions. The fault gas diffusion behavior includes the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process. Simulation unit 83 is used to mesh the three-dimensional geometric model of the transformer and divide it into gas and liquid phases. It also uses the meshed three-dimensional geometric model of the transformer to simulate the diffusion behavior of the fault gas after assignment, so as to obtain the spatiotemporal distribution characteristics of the dissolved gas. The determination unit 84 is used to determine the fault location based on the spatiotemporal distribution characteristics corresponding to multiple sampling points.
[0081] In some embodiments, for the construction process of fault gas diffusion behavior, the apparatus further includes a first construction unit, a first driving force determination unit, a second driving force determination unit, and a second construction unit; The first building unit is used to construct the discharge gas generation equation based on the linear relationship between the gas generation volume and the cumulative discharge energy. The first driving force determination unit is used to determine the driving force equation of the mass transfer process on the gas phase side based on the pressure difference between the characteristic gas in the gas phase and the gas film. The second driving force determination unit is used to determine the driving force equation of the mass transfer process on the liquid side based on the concentration difference of the characteristic gas between the liquid phase and the liquid film. The second building block is used to construct a fluid volume model based on the spatiotemporal diffusion patterns of dissolved gases within electrical equipment.
[0082] In some embodiments, the assignment unit includes a first determining subunit, a second determining subunit, and a third determining subunit; The first determining subunit is used to assign the discharge breakdown time, breakdown voltage and breakdown current amplitude contained in the measured data to the discharge gas production equation in order to determine the gas production volume. The second determining subunit is used to assign the partial pressure of the characteristic gas in the gas phase contained in the measured data to the driving force equation of the mass transfer process on the gas phase side, and to assign the molar concentration of the characteristic gas in the liquid phase contained in the measured data to the driving force equation of the mass transfer process on the liquid phase side. Based on Henry's law of the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film contained in the boundary conditions, the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film are determined. The third determining sub-unit is used to assign values to the fluid volume model based on the material parameters of the transformer's three-dimensional geometric model and the boundary parameter values included in the boundary conditions, so as to determine the governing equations of the fluid volume model after assignment; among which, the governing equations of the fluid volume model include the mass transfer equation, the kinetic energy transfer equation, and the energy transfer equation.
[0083] In some embodiments, the third determining subunit is used to assign the density of the gas phase and the density of the liquid phase inside the power equipment, which are included in the material parameters, as well as the volume fraction of the gas phase inside the power equipment, the volume fraction of the liquid phase inside the power equipment, the velocity vector of the gas phase inside the power equipment, and the velocity vector of the liquid phase inside the power equipment, which are included in the boundary conditions, to the continuity equation to obtain the assigned continuity equation. The material parameters, including the density of the gas phase, the density of the liquid phase, the dynamic viscosity of the gas phase, and the dynamic viscosity of the liquid phase within the power equipment, as well as the boundary conditions, including the pressure, the volume fraction of the gas phase, the volume fraction of the liquid phase, the velocity vector of the gas phase, and the velocity vector of the liquid phase, are assigned to the momentum equation to obtain the assigned momentum equation. The material parameters, including the density of the gas phase and the density of the liquid phase within the power equipment, the diffusion coefficient of the characteristic gas in the gas phase and the diffusion coefficient of the characteristic gas in the liquid phase, as well as the boundary conditions, including the pressure, the mass fraction of the characteristic gas in the gas phase, the mass fraction of the characteristic gas in the liquid phase, the volume fraction of the gas phase within the power equipment, and the volume fraction of the liquid phase within the power equipment, are assigned to the mass transfer equation to obtain the assigned mass transfer equation.
[0084] In some embodiments, the governing equations of the fluid volume model further include turbulent kinetic energy equations; The third determining sub-unit is also used to assign the turbulent kinetic energy, velocity, and specific heat dissipation contained in the boundary conditions to the turbulent kinetic energy equation, so as to obtain the assigned turbulent kinetic energy equation.
[0085] In some embodiments, the simulation unit is used to simulate the control equations of the assigned fluid volume model using the divided three-dimensional geometric model of the transformer to determine the operating behavior of the dissolved gas diffusion process; and to interfere with the operating behavior of the dissolved gas diffusion process according to the turbulent kinetic energy equation and the specific heat dissipation equation contained in the boundary conditions to obtain the spatiotemporal distribution characteristics of the dissolved gas.
[0086] In some embodiments, the determining unit is configured to construct a distribution map of multiple sampling points at different times based on the spatiotemporal distribution characteristics corresponding to multiple sampling points; wherein the distribution map includes a distribution map of free gas clouds and a distribution map of dissolved gases; and determine the fault location based on the gas position changes in the distribution maps of multiple sampling points at each same time.
[0087] In some embodiments, the system further includes a library construction unit, a distribution map construction unit, and a data collection unit; The image library construction unit is used to build a fault diagnosis image library based on the distribution maps of different fault locations at different times; The distribution map construction unit is used to construct a new distribution map based on the spatiotemporal distribution characteristics corresponding to the new sampling points, once the spatiotemporal distribution characteristics of the new sampling points are obtained. As a unit, it is used to take the fault location corresponding to the target distribution map as the fault location corresponding to the new distribution map when there is a target distribution map in the fault diagnosis image library that matches the new distribution map.
[0088] Figure 8 For a description of the features in the corresponding embodiments, please refer to Figure 1 The relevant descriptions of the corresponding embodiments will not be repeated here.
[0089] As can be seen from the above technical solution, a three-dimensional geometric model of a transformer incorporating discharge defects is constructed based on the structural parameters of the oil-immersed power equipment. Based on measured data and the material parameters and set boundary conditions of the transformer's three-dimensional geometric model, values are assigned to the constructed fault gas diffusion behavior. This fault gas diffusion behavior can include the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process. The transformer's three-dimensional geometric model is meshed, and the gas and liquid phases are divided. The assigned fault gas diffusion behavior is then simulated using the meshed transformer three-dimensional geometric model to obtain the spatiotemporal distribution characteristics of the dissolved gas. Based on the spatiotemporal distribution characteristics corresponding to multiple sampling points, the fault location is determined. In this technical solution, by jointly analyzing the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution, spatiotemporal diffusion, and disorder process, the entire process of gas generation, dissolution, and diffusion under discharge defects inside the oil-immersed power equipment is simulated and calculated. This allows for a macroscopic understanding of the spatiotemporal distribution characteristics of dissolved gas in the oil, thereby enabling accurate prediction of the fault location.
[0090] Embodiments of this application also provide a computer-readable storage medium storing a computer program, wherein the computer program is configured to execute the steps in any of the above embodiments of the fault diagnosis method for oil-immersed power equipment when it is run.
[0091] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard disk, magnetic disk, or optical disk.
[0092] The embodiments of this application also provide a computer program product, which includes a computer program that, when executed by a processor, implements the steps in any of the above embodiments of the fault diagnosis method for oil-immersed power equipment.
[0093] Embodiments of this application also provide another computer program product, including a non-volatile computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps in any of the above embodiments of the fault diagnosis method for oil-immersed power equipment.
[0094] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0095] The foregoing has provided a detailed description of a fault diagnosis method, apparatus, computer-readable storage medium, and computer program product for oil-immersed power equipment provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only intended to aid in understanding the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of this application.
Claims
1. A fault diagnosis method for oil-immersed power equipment, characterized in that, include: Based on the structural parameters of oil-immersed power equipment, a three-dimensional geometric model of a transformer including discharge defects is constructed. Based on the measured data and the material parameters and set boundary conditions of the three-dimensional geometric model of the transformer, the constructed fault gas diffusion behavior is assigned values; wherein, the fault gas diffusion behavior includes the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, the gas dissolution-spatiotemporal diffusion and disorder process; The three-dimensional geometric model of the transformer is meshed and divided into gas and liquid phases. The three-dimensional geometric model of the transformer is then used to simulate the diffusion behavior of the fault gas after assignment, so as to obtain the spatiotemporal distribution characteristics of the dissolved gas. The fault location was determined based on the spatiotemporal distribution characteristics of multiple sampling points.
2. The fault diagnosis method for oil-immersed power equipment according to claim 1, characterized in that, Regarding the construction process of the aforementioned fault gas diffusion behavior, the method further includes: Based on the linear relationship between the gas production volume and the cumulative energy of discharge, a discharge gas production equation is constructed; Based on the pressure difference between the characteristic gas in the gas phase and the gas film, the driving force equation for the mass transfer process on the gas phase side is determined. Based on the concentration difference of the characteristic gas between the liquid phase and the liquid film, the driving force equation for the mass transfer process on the liquid phase side is determined. A fluid volume model is constructed based on the spatiotemporal diffusion characteristics of dissolved gases within power equipment.
3. The fault diagnosis method for oil-immersed power equipment according to claim 2, characterized in that, The process of assigning values to the constructed fault gas diffusion behavior based on measured data, material parameters of the transformer's three-dimensional geometric model, and set boundary conditions includes: The measured data, including discharge breakdown time, breakdown voltage, and breakdown current amplitude, are assigned to the discharge gas production equation to determine the gas production volume. The partial pressure of the characteristic gas in the gas phase contained in the measured data is assigned to the driving force equation of the mass transfer process on the gas phase side, and the molar concentration of the characteristic gas in the liquid phase contained in the measured data is assigned to the driving force equation of the mass transfer process on the liquid phase side. Based on Henry's law of the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film contained in the boundary conditions, the partial pressure of the characteristic gas in the gas film and the molecular concentration of the characteristic gas in the liquid film are determined. The fluid volume model is assigned values based on the material parameters and boundary parameter values included in the boundary conditions of the three-dimensional geometric model of the transformer, so as to determine the governing equations of the fluid volume model after assignment; wherein, the governing equations of the fluid volume model include the mass transfer equation, the kinetic energy transfer equation and the energy transfer equation.
4. The fault diagnosis method for oil-immersed power equipment according to claim 3, characterized in that, The process of assigning values to the fluid volume model based on the material parameters and boundary parameter values included in the three-dimensional geometric model of the transformer, and determining the governing equations of the assigned fluid volume model, includes: The density of the gas phase and the density of the liquid phase inside the power equipment, which are included in the material parameters, as well as the volume fraction of the gas phase, the volume fraction of the liquid phase, the velocity vector of the gas phase, and the velocity vector of the liquid phase inside the power equipment, which are included in the boundary conditions, are assigned to the continuity equation to obtain the assigned continuity equation. The material parameters, including the density of the gas phase, the density of the liquid phase, the dynamic viscosity of the gas phase, and the dynamic viscosity of the liquid phase within the power equipment, as well as the boundary conditions, including the pressure, the volume fraction of the gas phase, the volume fraction of the liquid phase, the velocity vector of the gas phase, and the velocity vector of the liquid phase, are assigned to the momentum equation to obtain the assigned momentum equation. The material parameters, including the density of the gas phase and the density of the liquid phase within the power equipment, the diffusion coefficient of the characteristic gas in the gas phase and the diffusion coefficient of the characteristic gas in the liquid phase, as well as the boundary conditions, including the pressure, the mass fraction of the characteristic gas in the gas phase, the mass fraction of the characteristic gas in the liquid phase, the volume fraction of the gas phase within the power equipment, and the volume fraction of the liquid phase within the power equipment, are assigned to the mass transfer equation to obtain the assigned mass transfer equation.
5. The fault diagnosis method for oil-immersed power equipment according to claim 4, characterized in that, The governing equations of the fluid volume model also include the turbulent kinetic energy equation; The process of assigning values to the fluid volume model based on the material parameters and boundary parameter values included in the three-dimensional geometric model of the transformer, and determining the governing equations of the assigned fluid volume model, includes: The turbulent kinetic energy, velocity, and specific heat dissipation contained in the boundary conditions are assigned to the turbulent kinetic energy equation to obtain the assigned turbulent kinetic energy equation.
6. The fault diagnosis method for oil-immersed power equipment according to claim 1, characterized in that, The simulation of the fault gas diffusion behavior using the partitioned three-dimensional geometric model of the transformer to obtain the spatiotemporal distribution characteristics of the dissolved gas includes: The control equations of the assigned fluid volume model were simulated using the divided three-dimensional geometric model of the transformer to determine the operating behavior of the dissolved gas diffusion process. The behavior of dissolved gas diffusion process is disturbed based on the turbulent kinetic energy equation and the specific heat dissipation equation contained in the boundary conditions, so as to obtain the spatiotemporal distribution characteristics of dissolved gas.
7. The fault diagnosis method for oil-immersed power equipment according to claim 1, characterized in that, Based on the spatiotemporal distribution characteristics of multiple sampling points, the fault location was determined to include: Based on the spatiotemporal distribution characteristics of multiple sampling points, distribution maps of multiple sampling points at different times are constructed; wherein, the distribution maps include distribution maps of free gas clouds and distribution maps of dissolved gases; The location of the fault is determined by analyzing the gas position changes in the distribution maps of multiple sampling points at the same time.
8. The fault diagnosis method for oil-immersed power equipment according to claim 7, characterized in that, Also includes: Based on the distribution maps of different fault locations at different times, a fault diagnosis image library is constructed. Once the spatiotemporal distribution characteristics corresponding to the new sampling points are obtained, a new distribution map is constructed based on the spatiotemporal distribution characteristics corresponding to the new sampling points. If a target distribution map matching the new distribution map exists in the fault diagnosis image library, the fault location corresponding to the target distribution map is taken as the fault location corresponding to the new distribution map.
9. A fault diagnosis device for oil-immersed power equipment, characterized in that, It includes construction units, assignment units, simulation units, and determination units; The construction unit is used to construct a three-dimensional geometric model of a transformer containing discharge defects based on the structural parameters of the oil-immersed power equipment. The assignment unit is used to assign values to the constructed fault gas diffusion behavior based on measured data, material parameters of the three-dimensional geometric model of the transformer, and set boundary conditions; wherein, the fault gas diffusion behavior includes the gas generation process under the action of discharge energy, the fault gas-insulating oil two-phase mass transfer process, and the gas dissolution-spatiotemporal diffusion and disorder process. The simulation unit is used to perform mesh generation and gas phase and liquid phase division on the three-dimensional geometric model of the transformer, and to use the divided three-dimensional geometric model of the transformer to simulate the diffusion behavior of the assigned fault gas in order to obtain the spatiotemporal distribution characteristics of the dissolved gas. The determining unit is used to determine the fault location based on the spatiotemporal distribution characteristics corresponding to multiple sampling points.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, it implements the steps of the fault diagnosis method for oil-immersed power equipment as claimed in any one of claims 1 to 8.