Transformer internal defect simulation method and device

Abstract

The invention relates to a transformer internal defect simulation method and device, and belongs to the technical field of transformers, and the method comprises the steps: determining the movement speed of impurity particles based on the dielectrophoretic force, fluid drag force and coulomb force borne by the impurity particles when the impurity particles move in insulating oil; based on the corresponding relation between the movement speed and the particle concentration of the impurity particles, determining the total conductivity and the total dielectric constant of the mixture; simulating a motion path of impurity particles in the converter transformer based on the total conductivity and the total dielectric constant; the motion path is used for determining internal defects of the converter transformer. According to the transformer internal defect simulation method provided by the invention, the movement and aggregation behaviors of impurity particles in the converter transformer under actual working conditions can be effectively simulated, and the position of the defect can be deduced by analyzing the particle track and the aggregation trend thereof. And a theoretical basis is provided for design and maintenance of the transformer, so that theoretical support is provided for improving the operation stability and safety of the converter transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular to a method and device for simulating internal defects of a transformer. Background Art

[0002] As one of the most critical equipment in the high-voltage direct current transmission system, the converter transformer is mainly used for voltage conversion and isolation under AC and DC conditions. As a key part of the insulation system of the power transformer, the oil-paper insulation material undertakes the dual functions of insulation and cooling. Its quality is directly related to the efficiency of the oil-paper insulation. About one-third of the transformer damage is caused by insulation failure. In the process of production, installation, commissioning, operation and maintenance of the transformer, solid impurities including particles such as metal, fiber and carbon impurities will inevitably be introduced. Among them, fiber particles account for a very high proportion of the impurity particles in the oil. Actual detection shows that fiber impurities account for more than 90% of the total impurities. Some impurity particles move to the connection position of different components with the oil flow, and the other part of the particles gather in the area with slower flow rate, forming a path between the connecting conductors, which is easy to induce partial discharge or dielectric breakdown, thus posing a great threat to the insulation performance.

[0003] Particle defects inside converter transformers usually refer to solid particles mixed into the transformer's internal medium (such as insulating oil). These particles may come from the aging and wear of insulating materials and other internal structures during manufacturing, installation or long-term operation. Particle defects mainly include fiber particles, metal particles and other impurities. Under the combined action of electric field and oil flow, they may cause a series of problems, such as increased local electric field strength and enhanced local discharge, thereby affecting the insulation performance and safety of the transformer. Particles will move in the electric field and tend to high field strength areas, which will cause particles to accumulate in the electrode gap and weak insulation, affecting the electric field distribution and increasing the risk of local discharge. Metal particles have high conductivity and may cause discharge once they come into contact with electrodes; fiber particles have high polarity and are easily polarized in the electric field and cause disturbances to the electric field distribution.

[0004] At present, although many studies have been conducted on the movement mechanism of particles inside transformers, there is still a lack of an effective method to simulate internal defects of transformers, which can systematically analyze the movement and aggregation process of impurity particles under different working conditions and provide a reference for improving transformer design. Summary of the invention

[0005] In view of this, it is necessary to provide a method and device for simulating internal defects of a transformer, so as to effectively simulate the movement and aggregation behavior of impurity particles inside the transformer under actual working conditions.

[0006] In order to achieve the above object, the present invention provides a method for simulating internal defects of a transformer, comprising: Determining the movement speed of the impurity particles based on the dielectrophoretic force, fluid drag force and Coulomb force to which the impurity particles are subjected when moving in the insulating oil; Based on the corresponding relationship between the movement speed and the particle concentration of the impurity particles, determining the total conductivity and the total dielectric constant of the mixture; the mixture is composed of the impurity particles and the insulating oil; Based on the total conductivity and the total dielectric constant, a movement path of the impurity particles inside the converter transformer is simulated; the movement path is used to determine internal defects of the converter transformer.

[0007] In a possible implementation manner, simulating the movement path of the impurity particles inside the converter transformer based on the total conductivity and the total dielectric constant includes: Establishing an internal model of a converter transformer; the internal model includes an oil flow channel and insulating oil; Determining the flow characteristics of the insulating oil under different working conditions based on the operating parameters of the converter transformer; Based on the flow characteristics, the total conductivity, the total dielectric constant and the internal model, a movement path of the foreign particles inside the converter transformer is simulated.

[0008] In a possible implementation, simulating the movement path of the impurity particles inside the converter transformer based on the flow characteristics, the total conductivity, the total dielectric constant and the internal model includes: Simulating an electric field inside the transformer based on the total conductivity and the total dielectric constant; Based on the NS equation, the oil flow field inside the transformer is simulated; The internal model is simulated based on the flow characteristics, the electric field, and the oil flow field to obtain the movement path of the impurity particles inside the converter transformer.

[0009] In a possible implementation, the expression of the movement speed is as follows:

[0010] in, Indicates the speed of movement, represents the radius of the impurity particle, represents the dielectric constant of insulating oil, represents the conductivity of the impurity particles, Indicates the conductivity of insulating oil, Indicates the kinematic viscosity of insulating oil, represents the gradient electric field strength.

[0011] In a possible implementation, the expression of the total conductivity is as follows:

[0012] in, is the total conductivity, represents the conductivity of the impurity particles, Indicates the conductivity of insulating oil, Indicates the particle concentration.

[0013] In a possible implementation, the expression of the total dielectric constant includes any one of the following:

[0014]

[0015]

[0016] in, represents the total dielectric constant, , , are three constants, represents the dielectric constant of the impurity particles, represents the dielectric constant of insulating oil, Indicates the particle concentration.

[0017] In a possible implementation, the operating parameters of the converter transformer include: Electric field type, electric field strength, electrode type, plate spacing, dielectric barrier and oil flow velocity.

[0018] The present invention also provides a transformer internal defect simulation device, comprising: A first determination module is used to determine the movement speed of the impurity particles based on the dielectrophoretic force, fluid drag force and Coulomb force exerted on the impurity particles when they move in the insulating oil; A second determination module is used to determine the total conductivity and the total dielectric constant of the mixture based on the corresponding relationship between the movement speed and the particle concentration of the impurity particles; the mixture is composed of the impurity particles and the insulating oil; A simulation module is used to simulate the movement path of the impurity particles inside the converter transformer based on the total conductivity and the total dielectric constant; the movement path is used to determine the internal defects of the converter transformer.

[0019] On the other hand, the present invention also provides an electronic device, including a memory and a processor, wherein: The memory is used to store programs; The processor is coupled to the memory and is used to execute the program stored in the memory to implement the transformer internal defect simulation method described in any of the above implementations.

[0020] On the other hand, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for simulating internal defects of a transformer described in any of the above implementations is implemented.

[0021] The beneficial effects of the present invention are as follows: the transformer internal defect simulation method and device provided by the present invention can obtain the movement speed of the impurity particles by analyzing the dielectrophoretic force, fluid drag force and Coulomb force to which the impurity particles are subjected when moving in the insulating oil. When the particle concentration of the aggregated particles reaches a certain value, the particle movement speed will drop to 0, so the corresponding relationship between the movement speed and the particle concentration of the impurity particles can be obtained, thereby obtaining the total conductivity and total dielectric constant of the mixture composed of the impurity particles and the insulating oil according to the corresponding relationship, and calculating the electric field of the mixture according to the total conductivity and total dielectric constant, and simulating the movement path of the impurity particles inside the converter transformer by combining the electric field distribution and fluid dynamics characteristics of the converter transformer, and effectively simulating the movement and aggregation behavior of the impurity particles inside the converter transformer under actual working conditions by combining fluid mechanics, electric field analysis and particle dynamics, and inferring the location of the defect by analyzing the particle trajectory and its aggregation trend. For example, particles aggregate in certain high electric field areas, which usually indicates that the electric field strength in these areas is high, which is a weak point of the insulation system and is prone to discharge. At the same time, the trajectory changes of particles under the action of oil flow and electric field are analyzed, and the location where the particles are concentrated is obtained by simulation, that is, pointing to the defect area. This provides a theoretical basis for the design and maintenance of transformers, helps researchers to deeply understand the impact of impurity particles on the insulation performance of transformers, and thus provides theoretical support for improving the operating stability and safety of converter transformers. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 One of the method flow charts of an embodiment of the transformer internal defect simulation method provided by the present invention; Figure 2 A schematic diagram of a model for simulating different electric fields in a converter transformer provided by the present invention; Figure 3A second method flow chart of an embodiment of the transformer internal defect simulation method provided by the present invention; Figure 4 A schematic diagram of the simulation of particle movement and aggregation under a slightly non-uniform electric field provided by the present invention; Figure 5 A schematic diagram of the particle movement and aggregation under a simulated uniform electric field provided by the present invention; Figure 6 A schematic diagram of the simulation of particle movement and aggregation under an extremely non-uniform electric field provided by the present invention; Figure 7 A schematic structural diagram of an embodiment of a transformer internal defect simulation device provided by the present invention; Figure 8 A schematic structural diagram of an embodiment of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0025] In the description of the embodiments of the present invention, unless otherwise specified, "multiple" means two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone.

[0026] The descriptions of "first", "second", etc. involved in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the technical features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0027] Figure 1 A method flow chart of an embodiment of the transformer internal defect simulation method provided by the present invention is as follows Figure 1 As shown in FIG. 1 , the transformer internal defect simulation method includes: S101, determining the movement speed of the impurity particles based on the dielectrophoretic force, fluid drag force and Coulomb force exerted on the impurity particles when they move in the insulating oil; S102, determining a total conductivity and a total dielectric constant of a mixture based on a corresponding relationship between the movement speed and the particle concentration of the impurity particles; the mixture is composed of the impurity particles and the insulating oil; S103. Based on the total conductivity and the total dielectric constant, simulate the movement path of the impurity particles inside the converter transformer; the movement path is used to determine the internal defects of the converter transformer.

[0028] Compared with the prior art, the transformer internal defect simulation method provided by the embodiment of the present invention can obtain the movement speed of the impurity particles by analyzing the dielectrophoretic force, fluid drag force and Coulomb force to which the impurity particles are subjected when moving in the insulating oil. When the particle concentration of the aggregated particles reaches a certain value, the particle movement speed will drop to 0, so the corresponding relationship between the movement speed and the particle concentration of the impurity particles can be obtained, and the total conductivity and total dielectric constant of the mixture composed of the impurity particles and the insulating oil can be obtained according to the corresponding relationship. The electric field of the mixture can be calculated according to the total conductivity and the total dielectric constant. Combined with the electric field distribution and fluid dynamics characteristics of the converter transformer, the movement path of the impurity particles inside the converter transformer is simulated. By combining fluid mechanics, electric field analysis and particle dynamics, the movement and aggregation behavior of the impurity particles inside the converter transformer under actual working conditions can be effectively simulated. By analyzing the particle trajectory and its aggregation trend, the location of the defect can be inferred. For example, particles aggregate in certain high electric field areas, which usually indicates that the electric field strength in these areas is high, which is a weak point of the insulation system and is prone to discharge. At the same time, the trajectory changes of particles under the action of oil flow and electric field are analyzed, and the location where the particles are concentrated is obtained by simulation, that is, pointing to the defect area. This provides a theoretical basis for the design and maintenance of transformers, helps researchers to deeply understand the impact of impurity particles on the insulation performance of transformers, and thus provides theoretical support for improving the operating stability and safety of converter transformers.

[0029] The movement characteristics under the action of oil flow, by analyzing the particle trajectory and its aggregation trend, infer the location of the defect. If particles aggregate in certain high electric field areas, it usually indicates that the electric field strength in these areas is high, which may be the weak point of the insulation system and easily cause discharge. At the same time, the trajectory changes of particles under the action of oil flow and electric field are analyzed, and the location where the particles are concentrated is simulated, which may point to the defect area.

[0030] In some embodiments of the present invention, the expression of the movement speed is as follows:

[0031] in, Indicates the speed of movement, represents the radius of the impurity particle, represents the dielectric constant of insulating oil, represents the conductivity of the impurity particles, Indicates the conductivity of insulating oil, Indicates the kinematic viscosity of insulating oil, represents the gradient electric field strength.

[0032] In some embodiments of the present invention, the expression of the total conductivity is as follows:

[0033] in, is the total conductivity, represents the conductivity of the impurity particles, Indicates the conductivity of insulating oil, Indicates the particle concentration.

[0034] In some embodiments of the present invention, the expression of the total dielectric constant includes any one of the following:

[0035]

[0036]

[0037] in, represents the total dielectric constant, , , are three constants, represents the dielectric constant of the impurity particles, represents the dielectric constant of insulating oil, Indicates the particle concentration.

[0038] For example, the movement and aggregation model of impurity particles inside the converter transformer can be simulated, and the modeling process is as follows: The particles suspended in the flowing insulating oil are mainly affected by the dielectrophoretic force in the horizontal direction during the movement. F DEP ), fluid drag ( F drag ), the interaction force between particles ( F i ) and Coulomb force ( F c ), since the interaction force between particles is smaller than the electrostatic force, it can be ignored.

[0039] The dielectrophoretic force on the suspended particles is shown in formula (1): (1) in, represents the radius of the impurity particle, represents the dielectric constant of insulating oil, represents the conductivity of the impurity particles, Indicates the conductivity of insulating oil. represents the gradient electric field strength.

[0040] When solid particles are suspended in flowing insulating oil, drag affects the motion characteristics of the particles in the fluid. Drag is caused by the friction and resistance exerted by insulating oil molecules on the particle surface, and it presents complex characteristics related to the particle motion state and insulating oil characteristics.

[0041] The fluid drag force on the suspended particles is shown in formula (2): (2) in, Indicates the kinematic viscosity of insulating oil, Indicates the movement speed of impurity particles, Represents the correction factor.

[0042] Due to the nonlinearity of fluid drag, a correction factor C related to the Reynolds coefficient Re is used d Correction is performed as shown in formula (3): (3) Among them, the Reynolds coefficient As shown in formula (4): (4) in, Indicates the density of insulating oil.

[0043] When the radius is When the spherical particles collide with the electrode, they will acquire a certain amount of charge. , the Coulomb force on the particle is expressed as shown in formula (5): (5) in, Indicates the electric field strength.

[0044] According to the dielectrophoretic force, fluid drag force and Coulomb force on the impurity particles when they move in the insulating oil, the moving speed of the impurity particles can be obtained according to equations (1) to (5): for: (6) When the particle concentration of the particles reaches a certain value c crit When the particle velocity drops to 0, a large number of particles are bound by the accumulation of bridges.

[0045] Therefore, the speed of the impurity particles v p With particle concentration There is a certain corresponding relationship between them, as shown in the following formula (7): (7) According to the corresponding relationship shown in formula (7), the particle concentration of the particle aggregation can be determined according to the movement speed of the impurity particles.

[0046] Furthermore, the Laplace equation can be used to solve the potential distribution, and the current conservation equation can be used to solve the current distribution, as shown in equations (8) and (9): (8) (9) in, is the total current density, represents the external current density, Represents the total conductivity.

[0047] It is the total conductivity of a mixture of impurity particles and insulating oil derived from the Looyenga formula. That is, according to the corresponding relationship between the movement speed and the particle concentration of the impurity particles, the particle concentration can be determined based on the movement speed, thereby obtaining the total conductivity of the mixture.

[0048] In some embodiments of the present invention, simulating the movement path of the impurity particles inside the converter transformer based on the total conductivity and the total dielectric constant includes: Establishing an internal model of a converter transformer; the internal model includes an oil flow channel and insulating oil; Determining the flow characteristics of the insulating oil under different working conditions based on the operating parameters of the converter transformer; Based on the flow characteristics, the total conductivity, the total dielectric constant and the internal model, a movement path of the foreign particles inside the converter transformer is simulated.

[0049] In some embodiments of the present invention, simulating the movement path of the impurity particles inside the converter transformer based on the flow characteristics, the total conductivity, the total dielectric constant and the internal model includes: Simulating an electric field inside the transformer based on the total conductivity and the total dielectric constant; Based on the NS equation, the oil flow field inside the transformer is simulated; The internal model is simulated based on the flow characteristics, the electric field, and the oil flow field to obtain the movement path of the impurity particles inside the converter transformer.

[0050] In some embodiments of the present invention, the operating parameters of the converter transformer include: Electric field type, electric field strength, electrode type, plate spacing, dielectric barrier and oil flow velocity.

[0051] For example, the size of different electrodes can be set according to actual parameters to model. Figure 2 This is a schematic diagram of a model for simulating different electric fields in a converter transformer provided by the present invention. Figure 2 (a) is the ball-ball electrode model, (b) is the plate-plate electrode model, and (c) is the needle-plate electrode model.

[0052] based on Figure 2 The model shown in the figure adds physical fields and boundary condition settings, setting the flowing insulating oil to flow in from the left boundary of the model and out from the right boundary, and the lower plate of the electrode is grounded. The physical fields include the electric field and the oil flow field.

[0053] According to the laws of Maxwell's equations, the finite element equation in the electric field is: (10) (11) (12) Among them, formula (10) is the current divergence, that is, the change in the amount of charge; formula (11) is that the current is equal to the sum of the conduction current, displacement current and external current; formula (12) is that the electric field strength is equal to the negative gradient of the potential.

[0054] The internal oil channel structure of large oil-immersed transformers is complex, and the flow of insulating oil in them is generally turbulent. Fluid mechanics theory research shows that any fluid flow and heat transfer follow the three conservation laws of mass, momentum and energy. If it is a turbulent flow, the time-averaged Reynolds average compressibility is obtained by Reynolds averaging the various physical quantities in the flow field in the time domain. NS System of equations: (13) in, is the average density of the fluid; is the Reynolds stress; is laminar heat flow; Turbulent heat flow.

[0055] Since the total conductivity and total dielectric constant of the mixture of insulating oil and fiber impurity particles depend on the conductivity and dielectric constant of the insulating oil and solid fiber impurity particles, in the mixture, the electric field is calculated based on the dielectric constant and conductivity of the mixture of insulating oil and solid fiber impurity particles.

[0056] The uneven distribution of solid fiber impurity particles in the insulating oil means that the conductivity and dielectric constant of the mixture will also be uneven, so the concentration of solid fiber impurity particles needs to be considered and depends on where the particles are concentrated.

[0057] Three different formulas are derived from the Looyenga formula, among which the total dielectric constant of the mixture of insulating oil and fiber impurity particles is expressed as follows: (14) (15) (16) in, , , are three constants, c is the concentration of solid fiber impurity particles.

[0058] Therefore, according to the simulation needs, different parameters can be set, such as electric field type, electric field strength, electrode type, plate spacing, dielectric barrier, oil flow velocity, etc., to simulate the movement and aggregation of impurity particles in oil flow under different conditions. And use visualization tools to generate particle movement trajectory diagrams, aggregation distribution diagrams, electric field distribution diagrams, etc.

[0059] The transformer internal defect simulation method provided in the embodiment of the present invention can effectively simulate the movement and aggregation behavior of impurity particles inside the transformer under actual working conditions by combining fluid mechanics, electric field analysis and particle dynamics, thereby providing a theoretical basis for the design and maintenance of the transformer.

[0060] Figure 3 The second method flow chart of an embodiment of the transformer internal defect simulation method provided by the present invention is as follows: Figure 3 As shown in FIG. 1 , the transformer internal defect simulation method includes: A model of the movement and aggregation of impurity particles inside the converter transformer is established, including key components such as oil flow channels and insulating materials.

[0061] The oil flow channel is divided in the model and the inlet and outlet positions of the oil flow are defined to simulate the flow path of the transformer oil.

[0062] Simulate the oil flow field inside the transformer and input the operating parameters of the insulating oil including oil flow velocity, temperature and viscosity.

[0063] Based on the flow characteristics of oil flow under different working conditions, the oil flow velocity distribution and turbulence characteristics in the oil channel are analyzed.

[0064] Different types of particles are selected according to the types of impurities that may exist inside the transformer, such as metal particles, fiber impurities, carbide particles, etc.

[0065] In the model, impurity particles of different types and sizes are simulated and their physical properties are defined, including density, charge, surface characteristics, etc.

[0066] By controlling the initial distribution position and quantity of the particles, the state of the particles in the early stage of transformer operation is simulated to ensure the repeatability and statistical significance of the simulation.

[0067] Based on the actual operating parameters of the transformer, such as oil flow velocity, electric field strength, dielectric barrier, etc., fluid mechanics analysis is performed to calculate the flow characteristics of the oil flow under different working conditions.

[0068] Furthermore, the electric field distribution inside the transformer was simulated by finite element analysis (FEA), and the movement trajectory of particles under the action of oil flow and electric field was analyzed in combination with the fluid flow model.

[0069] The oil flow field and electric field distribution are coupled to analyze their combined effects on the movement of impurity particles.

[0070] Based on the above analysis results, the particle dynamics model is used to simulate the movement path of impurity particles inside the transformer, taking into account the interaction between particles and the collision behavior with the inner wall of the transformer and other structures. The distribution of particles inside the transformer is monitored in real time to identify the areas and conditions where particles accumulate.

[0071] Furthermore, the movement and aggregation trajectories of particles in different areas under different conditions are analyzed as needed. Combined with the simulation results of particle aggregation, its impact on the insulation performance of the transformer is analyzed, especially in areas with high electric field strength, where aggregation may cause partial discharge or electrical breakdown. Possible preventive measures or design optimization suggestions are proposed to reduce the adverse effects of particle aggregation on transformer performance.

[0072] The data such as particle movement path, aggregation area and aggregation degree of each simulation are recorded to form a data set. The data should include simulation results under different working conditions to facilitate subsequent analysis.

[0073] Use visualization tools to generate particle motion trajectory maps, aggregation distribution maps, electric field distribution maps, etc. Analyze the main factors affecting particle movement and aggregation, such as oil flow velocity, electric field strength, particle properties, etc., and identify particle aggregation patterns under different working conditions.

[0074] According to the results of the spectrum signal analysis, a multi-source discharge fingerprint library of fiber impurity particles is constructed. Combined with the aggregation of impurity particles, the correlation between the different aggregation growth states of fiber impurity particles and the multi-source characteristic signals of PD is obtained, and the PRPD spectrum is drawn to show it. The key features are extracted and the relationship model between particle aggregation and transformer insulation performance is established.

[0075] Based on the simulation and analysis results, optimization suggestions for converter transformer design can be put forward. For example, the design of the oil flow channel can be optimized to reduce the possibility of particle aggregation. By adjusting the electric field distribution, the generation of local high electric field areas can be avoided. This provides a reference for engineering practice and improves the operating safety and stability of the transformer.

[0076] A transformer internal defect simulation method proposed in the present invention can effectively simulate the movement and aggregation behavior of impurity particles inside the converter transformer under actual working conditions, helping researchers to gain a deep understanding of the impact of impurity particles on the insulation performance of the transformer, thereby providing theoretical support for improving the operating stability and safety of the converter transformer.

[0077] Based on the above scheme, Figures 4 to 6 The present invention provides a schematic diagram of simulating the movement and aggregation of particles under different electric fields. The aggregation of impurity particles is different under different oil flow rates. Due to the effect of the oil flow rate, it can be observed that the phenomenon of impurity particles agglomerating into bridges is gradually shifting toward the direction of the oil flow. When the oil flow rate is relatively high, the impurity particles between the ball-ball and needle-plate electrodes are "blown away" by the oil flow, and the impurity particles basically do not aggregate between the electrodes, and cannot form "impurity bridges", but can still aggregate into bridges under the plate-plate electrodes. Therefore, under the same voltage, the oil flow has a greater impact on the movement of fiber impurity particles. Increasing the oil flow rate can reduce the number of collisions between particles and electrodes, effectively reducing the probability of particles transferring charges between electrodes and reducing the possibility of aggregation into bridges.

[0078] Figure 4 The schematic diagram of the present invention for simulating the movement and aggregation of particles under a slightly non-uniform electric field is as follows: Figure 4 As shown, Figure 4 The ball-ball electrode simulates a slightly non-uniform electric field. Since the electric field distribution between the ball-ball electrodes is more concentrated, the uniformity of the electric field is improved compared to the needle-plate electrode, but there is still a gradient, which can produce a higher electric field strength near the midpoint. The electric field strength is highest on the surface of the sphere and decreases rapidly with increasing distance. The accumulation of impurity particles in the central area is more obvious. The farther away from the center of the electrode, the slower the accumulation rate of impurity particles, resulting in less accumulation of impurity particles in the area far away from the electrode.

[0079] Figure 5 The schematic diagram of the particle movement and aggregation under the simulated uniform electric field provided by the present invention is as follows: Figure 5 As shown, Figure 5The plate-plate electrode simulates a uniform electric field, and the electric field between the plate-plate electrodes is relatively uniform, especially in the center area between the two plates. This uniform electric field provides a stable environment for the charging and migration of particles, which helps to gather impurity particles more evenly in the entire working area, so that the impurity particle bridges formed between the electrodes are relatively dense. In the plate-plate electrode, the particles migrate directly to the surface of the opposite electrode mainly through the electric field force. Due to the uniformity of the electric field, the forces exerted on the particles during the migration process are relatively consistent, resulting in a relatively uniform distribution of particle deposition. Compared with the ball-ball electrode and the needle-plate electrode, the impurity particles between the plate-plate electrodes are less affected by the oil flow velocity, and the phenomenon of aggregation into bridges is more obvious.

[0080] Figure 6 The schematic diagram of the present invention for simulating the movement and aggregation of particles under an extremely non-uniform electric field is as follows: Figure 6 As shown, Figure 6 The needle-plate electrode simulates an extremely non-uniform electric field. The electric field strength near the needle tip is much greater than that near the plate electrode, which is conducive to the generation of corona discharge near the needle tip. Corona discharge can improve the charging efficiency of small particles. Due to the small radius of curvature of the needle tip, the charge tends to accumulate in the tip area. The high electric field strength near the needle tip promotes the aggregation of particles. As the oil flow rate increases, the concentration of impurity particles between the two plates drops significantly to the point where no "impurity particle bridge" is generated.

[0081] The transformer internal defect simulation method provided by the present invention can effectively simulate the movement and aggregation behavior of impurity particles inside the converter transformer under actual working conditions, helping researchers to gain an in-depth understanding of the impact of impurity particles on the insulation performance of the transformer, thereby providing theoretical support for improving the operating stability and safety of the converter transformer.

[0082] In order to better implement the transformer internal defect simulation method in the embodiment of the present invention, based on the transformer internal defect simulation method, the embodiment of the present invention also provides a transformer internal defect simulation device. Figure 7 A schematic diagram of the structure of an embodiment of a transformer internal defect simulation device provided by the present invention is shown in FIG. Figure 7 As shown, the transformer internal defect simulation device 700 includes: A first determination module 710, configured to determine the movement speed of the impurity particles based on the dielectrophoretic force, fluid drag force and Coulomb force exerted on the impurity particles when they move in the insulating oil; A second determination module 720 is used to determine the total conductivity and the total dielectric constant of the mixture based on the corresponding relationship between the movement speed and the particle concentration of the impurity particles; the mixture is composed of the impurity particles and the insulating oil; The simulation module 730 is used to simulate the movement path of the impurity particles inside the converter transformer based on the total conductivity and the total dielectric constant; the movement path is used to determine the internal defects of the converter transformer.

[0083] The transformer internal defect simulation device 700 provided in the above embodiment can implement the technical solution described in the above transformer internal defect simulation method embodiment. The specific implementation principles of the above modules or units can refer to the corresponding contents in the transformer internal defect simulation method embodiment, which will not be repeated here.

[0084] like Figure 8 As shown, the present invention also provides an electronic device 800. The electronic device 800 includes a processor 801, a memory 802 and a display 803. Figure 8 Only some components of the electronic device 800 are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0085] In some embodiments, the processor 801 may be a central processing unit (CPU), a microprocessor or other data processing chip, and is used to run program codes or process data stored in the memory 802, such as the transformer internal defect simulation method of the present invention.

[0086] In some embodiments, the processor 801 may be a single server or a server group. The server group may be centralized or distributed. In some embodiments, the processor 801 may be local or remote. In some embodiments, the processor 801 may be implemented in a cloud platform. In some embodiments, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an internal cloud, a multi-cloud, etc., or any combination thereof.

[0087] In some embodiments, the memory 802 may be an internal storage unit of the electronic device 800, such as a hard disk or memory of the electronic device 800. In other embodiments, the memory 802 may also be an external storage device of the electronic device 800, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the electronic device 800.

[0088] Furthermore, the memory 802 may include both an internal storage unit of the electronic device 800 and an external storage device. The memory 802 is used to store application software installed in the electronic device 800 and various data.

[0089] In some embodiments, the display 803 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an organic light-emitting diode (OLED) touch device, etc. The display 803 is used to display information on the electronic device 800 and to display a visual user interface. The components 801-803 of the electronic device 800 communicate with each other via a system bus.

[0090] In one embodiment, when the processor 801 executes the transformer internal defect simulation program in the memory 802, the following steps may be implemented: Determining the movement speed of the impurity particles based on the dielectrophoretic force, fluid drag force and Coulomb force to which the impurity particles are subjected when moving in the insulating oil; Based on the corresponding relationship between the movement speed and the particle concentration of the impurity particles, determining the total conductivity and the total dielectric constant of the mixture; the mixture is composed of the impurity particles and the insulating oil; Based on the total conductivity and the total dielectric constant, a movement path of the impurity particles inside the converter transformer is simulated; the movement path is used to determine internal defects of the converter transformer.

[0091] It should be understood that: when the processor 801 executes the transformer internal defect simulation program in the memory 802, in addition to the above functions, other functions may also be implemented. For details, please refer to the description of the corresponding method embodiment above.

[0092] Furthermore, the embodiment of the present invention does not specifically limit the type of the electronic device 800 mentioned, and the electronic device 800 may be a portable electronic device such as a mobile phone, a tablet computer, a personal digital assistant (PDA), a wearable device, a laptop computer, etc. Exemplary embodiments of portable electronic devices include but are not limited to portable electronic devices equipped with IOS, Android, Microsoft or other operating systems. The above-mentioned portable electronic devices may also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present invention, the electronic device 800 may not be a portable electronic device, but a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0093] Correspondingly, an embodiment of the present invention also provides a computer-readable storage medium, which is used to store computer-readable programs or instructions. When the program or instructions are executed by a processor, the steps or functions in the transformer internal defect simulation method provided in the above-mentioned method embodiments can be implemented.

[0094] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0095] The transformer internal defect simulation method and device provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for simulating internal defects of a transformer, characterized in that: include: Determining the movement speed of the impurity particles based on the dielectrophoretic force, fluid drag force and Coulomb force to which the impurity particles are subjected when moving in the insulating oil; Based on the corresponding relationship between the movement speed and the particle concentration of the impurity particles, determining the total conductivity and the total dielectric constant of the mixture; the mixture is composed of the impurity particles and the insulating oil; Based on the total conductivity and the total dielectric constant, a movement path of the impurity particles inside the converter transformer is simulated; the movement path is used to determine internal defects of the converter transformer.

2. The transformer internal defect simulation method according to claim 1, characterized in that: The simulating the movement path of the impurity particles inside the converter transformer based on the total conductivity and the total dielectric constant includes: Establishing an internal model of a converter transformer; the internal model includes an oil flow channel and insulating oil; Determining the flow characteristics of the insulating oil under different working conditions based on the operating parameters of the converter transformer; Based on the flow characteristics, the total conductivity, the total dielectric constant and the internal model, a movement path of the foreign particles inside the converter transformer is simulated.

3. The transformer internal defect simulation method according to claim 2, characterized in that: The simulating the movement path of the impurity particles inside the converter transformer based on the flow characteristics, the total conductivity, the total dielectric constant and the internal model includes: Simulating an electric field inside the transformer based on the total conductivity and the total dielectric constant; Based on the NS equation, the oil flow field inside the transformer is simulated; The internal model is simulated based on the flow characteristics, the electric field, and the oil flow field to obtain the movement path of the impurity particles inside the converter transformer.

4. The transformer internal defect simulation method according to claim 1, characterized in that: The expression of the movement speed is as follows: in, Indicates the speed of movement, represents the radius of the impurity particle, represents the dielectric constant of insulating oil, represents the conductivity of the impurity particles, Indicates the conductivity of insulating oil, Indicates the kinematic viscosity of insulating oil, represents the gradient electric field strength.

5. The transformer internal defect simulation method according to claim 1, characterized in that: The expression of the total conductivity is as follows: in, is the total conductivity, represents the conductivity of the impurity particles, Indicates the conductivity of insulating oil, Indicates the particle concentration.

6. The transformer internal defect simulation method according to claim 1, characterized in that: The expression of the total dielectric constant includes any of the following: in, represents the total dielectric constant, , , are three constants, represents the dielectric constant of the impurity particles, represents the dielectric constant of insulating oil, Indicates the particle concentration.

7. The transformer internal defect simulation method according to claim 2, characterized in that: The operating parameters of the converter transformer include: Electric field type, electric field strength, electrode type, plate spacing, dielectric barrier and oil flow velocity.

8. A transformer internal defect simulation device, characterized in that: include: A first determination module is used to determine the movement speed of the impurity particles based on the dielectrophoretic force, fluid drag force and Coulomb force exerted on the impurity particles when they move in the insulating oil; A second determination module is used to determine the total conductivity and the total dielectric constant of the mixture based on the corresponding relationship between the movement speed and the particle concentration of the impurity particles; the mixture is composed of the impurity particles and the insulating oil; A simulation module is used to simulate the movement path of the impurity particles inside the converter transformer based on the total conductivity and the total dielectric constant; the movement path is used to determine the internal defects of the converter transformer.

9. An electronic device, characterized in that: comprising a memory and a processor, wherein: The memory is used to store programs; The processor is coupled to the memory, and is used to execute the program stored in the memory to implement the transformer internal defect simulation method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the transformer internal defect simulation method according to any one of claims 1 to 7 is implemented.

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