Arc resistance simulation verification method for de-excitation switch structure and operating characteristics and related device

Abstract

The invention discloses an arc resistance simulation verification method for a field suppression switch structure and operating characteristics, an arc resistance simulation verification device for the field suppression switch structure and operating characteristics, arc resistance simulation verification equipment and a computer readable storage medium. The method comprises the following steps: firstly, establishing a three-dimensional geometric model comprising an arc extinguish chamber, a contact system and an operating mechanism; then, constructing a mechanical structure dynamic simulation model to obtain the motion characteristics of the moving contact, and finally, establishing a multi-physical field coupling mathematical model based on a fluid dynamic equation, an electromagnetic field equation and a heat transfer equation to realize numerical simulation of the arc breaking process of the field suppression switch. According to the method, the flowing, electromagnetic and heat transfer characteristics of the arc are comprehensively considered, the whole process from generation to extinguishing of the arc can be completely simulated, and an effective simulation analysis means is provided for design optimization, performance evaluation and breaking capacity verification of the field suppression switch.

Description

Technical Field

[0001] This invention belongs to the field of arc simulation of magnetic field circuit breakers, and more specifically, relates to an arc resistance simulation verification method for the structure and operating characteristics of a demagnetizing switch, an arc resistance simulation verification device for the structure and operating characteristics of a demagnetizing switch, an arc resistance simulation verification equipment, and a computer-readable storage medium. Background Technology

[0002] The demagnetizing switch in the synchronous condenser excitation system is the last line of defense against internal unit faults. When a fault occurs in the stator, main transformer, or excitation system, the demagnetizing switch must trip quickly to cut off the rotor current and dissipate the rotor's magnetic energy. During the process of interrupting DC current, the demagnetizing switch generates a DC arc. The arc's motion characteristics, voltage rise process, and post-arc dielectric recovery are all critical factors determining the success of the interruption. Failure to control the arc can lead to severe destructive consequences. Therefore, accurately simulating the generation, development, and extinction of the DC arc during the demagnetizing switch's interruption process is of great significance for verifying the switch's breaking capacity and guiding product performance improvements.

[0003] In related technologies, DC arc modeling mainly relies on approximate models for simulation studies, such as the Mayr arc model and the Schwarz arc model. These models make relatively coarse assumptions, failing to fully consider the actual structural characteristics of the demagnetizing switch and the dynamic characteristics of the operating mechanism. They also fail to accurately describe the complex physical processes involving the interaction of magnetic, electric, airflow, and thermal fields in the arc-extinguishing chamber, resulting in low simulation accuracy and difficulty in effectively guiding the design optimization and breaking capacity verification of the demagnetizing switch.

[0004] Therefore, how to provide an arc resistance model based on the structure and operating characteristics of the demagnetizing switch and its simulation verification method, and how to establish a simulation model that considers the geometry of the demagnetizing switch, the dynamic characteristics of the operating mechanism and the multi-physics coupling of the arc-extinguishing chamber, to accurately simulate the transient process of the DC arc, thereby obtaining key parameters such as the maximum arcing time and the maximum breaking time, and providing technical support for the reliability verification of the DC breaking capacity of the demagnetizing switch, is a key issue of concern to those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a method, device, and computer-readable storage medium for simulating and verifying the arc resistance of a demagnetizing switch structure and operating characteristics. By establishing a simulation model that considers the geometry of the demagnetizing switch, the dynamic characteristics of the operating mechanism, and the multi-physics coupling of the arc-extinguishing chamber, the transient process of the DC arc can be accurately simulated, thereby obtaining key parameters such as the maximum arcing time and the maximum opening time, providing technical support for the reliability verification of the DC breaking capacity of the demagnetizing switch.

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for simulating and verifying the arc resistance of a demagnetizing switch structure and operating characteristics, comprising: S1. Construct a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; wherein, the three-dimensional geometric model includes: arc-extinguishing chamber, contact system, operating mechanism, and opening / closing control module; wherein, the contact system includes main contacts and arc contacts; S2, construct a mechanical structure dynamics simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein, the mechanical structure dynamics simulation model describes the motion characteristics of the moving contact under electromagnetic repulsion. S3, construct a finite element simulation model of the arc-extinguishing chamber based on the arc-extinguishing principle and arc-blowing principle of the arc-extinguishing switch to be modeled; wherein, the finite element simulation model includes the geometric structure and material properties of the arc-extinguishing grid and the arc-extinguishing cover; S4. Based on the assumptions of local thermodynamic equilibrium and turbulence, a multi-physics coupled mathematical model is constructed for the generation, development, and extinction of electric arcs; wherein, the multi-physics coupled mathematical model includes fluid dynamics control equations, electromagnetic field equations, and heat transfer equations; S5. Import the three-dimensional geometric model, the mechanical structure dynamics simulation model, the finite element simulation model, and the multiphysics coupling mathematical model into the simulation software, set the boundary conditions and material parameters, and then perform simulation to obtain the maximum arcing time and the maximum circuit breaker tripping time.

[0007] Optionally, in S1, the number of breaks in the demagnetizing switch is single or double, the surface of the main contact is coated with composite silver material, the arc contact is made of copper material, and the arc contact is connected to the connecting strip by a braided soft strip.

[0008] Optionally, in S2, the mechanical structure dynamics simulation model includes a disc spring holding device model and an electromagnetic repulsion driving model; wherein, the disc spring holding device model is used to describe the holding state of the moving contact in the opening and closing positions, and the electromagnetic repulsion driving model is used to describe the rapid separation movement of the moving contact when the short-circuit current rises.

[0009] Optionally, the mechanical structure dynamics simulation model also includes an action timing model of the interlocking device. The interlocking device includes a slow interlocking device for normal tripping and a fast latch for short-circuit or overload tripping. The slow interlocking device responds to the trigger signal of the shunt trip unit or the undervoltage trip unit, and the fast latch responds to the trigger signal of the overcurrent trip unit.

[0010] Optionally, in S3, the arc extinguishing principle includes arc extinguishing by an insulating arc extinguishing grid or arc extinguishing by a metal arc extinguishing grid, and the arc blowing principle includes electromagnetic arc blowing or a combination of air blowing and electromagnetic arc blowing. The material of the arc extinguishing cover is an arc-resistant material and it integrates an arc extinguishing plate. The arc extinguishing plate is used to cut the electric arc into multiple short arcs connected in series to increase the arc voltage.

[0011] Optionally, in S4, the fluid dynamics governing equations include mass conservation equations, momentum conservation equations, and energy conservation equations, used to describe the spatiotemporal distribution of density, velocity, and temperature of the arc plasma; the electromagnetic field equations use Maxwell's equations to solve for the electric and magnetic field strengths in the arc region; and the heat transfer equations include a thermal radiation model based on the Stefan-Boltzmann law and a heat conduction model based on Fourier's law.

[0012] Optionally, S5 further includes performing thermodynamic simulation analysis on the arc extinguishing cover to verify whether the highest temperature of the arc extinguishing cover exceeds the temperature resistance limit of its material, so as to verify the thermal stability and arc energy absorption capacity of the arc extinguishing cover.

[0013] This application also provides an arc resistance simulation verification device for the structure and operating characteristics of a demagnetizing switch, comprising: A geometric model construction module is used to construct a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; wherein, the three-dimensional geometric model includes: an arc-extinguishing chamber, a contact system, an operating mechanism, and a switching control module; wherein, the contact system includes main contacts and arc contacts; The dynamic model construction module is used to construct a mechanical structure dynamic simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein, the mechanical structure dynamic simulation model describes the motion characteristics of the moving contact under electromagnetic repulsion. The arc-extinguishing chamber model construction module is used to construct a finite element simulation model of the arc-extinguishing chamber based on the arc-extinguishing principle and arc-blowing principle of the demagnetizing switch to be modeled; wherein, the finite element simulation model includes the geometric structure and material properties of the arc-extinguishing grid and the arc-extinguishing cover; The mathematical model construction module is used to construct a multi-physics coupled mathematical model of the arc generation, development, and extinction process based on the assumptions of local thermodynamic equilibrium and turbulence; wherein, the multi-physics coupled mathematical model includes fluid dynamics control equations, electromagnetic field equations, and heat transfer equations; The simulation solution module is used to import the three-dimensional geometric model, the mechanical structure dynamics simulation model, the finite element simulation model, and the multiphysics coupling mathematical model into the simulation software, set boundary conditions and material parameters, and then perform simulation solution to obtain the maximum arcing time and the maximum tripping time.

[0014] This application also provides an arc resistance simulation and verification device, including: Memory, used to store computer programs; A processor is used to execute the computer program to implement the steps of the arc resistance simulation verification method as described above.

[0015] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the arc resistance simulation verification method described above.

[0016] This application provides a method for simulating and verifying the arc resistance of a demagnetizing switch structure and operating characteristics, comprising: S1, constructing a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; wherein the three-dimensional geometric model includes: an arc-extinguishing chamber, a contact system, an operating mechanism, and a switching control module; wherein the contact system includes a main contact and an arc contact; S2, constructing a mechanical structure dynamics simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein the mechanical structure dynamics simulation model describes the motion characteristics of the moving contact under electromagnetic repulsion; S3, constructing an arc-extinguishing mechanism based on the arc-extinguishing principle and arc-blowing principle of the demagnetizing switch to be modeled. The finite element simulation model of the arc-extinguishing chamber is constructed, including the geometric structure and material properties of the arc-extinguishing grid and arc-extinguishing shield. S4, Based on the assumptions of local thermodynamic equilibrium and turbulence, a multi-physics coupled mathematical model of the arc generation, development, and extinction process is constructed. This multi-physics coupled mathematical model includes fluid dynamics control equations, electromagnetic field equations, and heat transfer equations. S5, The three-dimensional geometric model, the mechanical structure dynamics simulation model, the finite element simulation model, and the multi-physics coupled mathematical model are imported into simulation software. Boundary conditions and material parameters are set, and simulation is performed to obtain the maximum arcing time and the maximum circuit breaker tripping time.

[0017] It has the following beneficial effects: By constructing a three-dimensional geometric model including the arc-extinguishing chamber, contact system, and operating mechanism, the actual structural characteristics of the demagnetizing switch are fully considered, overcoming the problem of insufficient simulation accuracy caused by the coarse assumptions of traditional arc models. By establishing a dynamic simulation model of the mechanical structure, the motion characteristics of the moving contact can be accurately described, providing reliable boundary conditions for arc simulation. Based on a multi-physics coupled mathematical model of fluid dynamics, electromagnetic field, and heat transfer, the complete process of arc generation, development, and extinction can be accurately simulated. Compared with traditional empirical models, it has higher simulation accuracy and stronger applicability, effectively guiding the design optimization and breaking capacity verification of the demagnetizing switch. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 A flowchart illustrating an arc resistance simulation verification method for the structure and operating characteristics of a demagnetizing switch provided in this application embodiment; Figure 2 This is a schematic diagram of an arc resistance simulation verification device for the structure and operating characteristics of a demagnetizing switch provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of the arc resistance simulation verification device provided in the embodiments of this application. Detailed Implementation

[0020] The purpose of this application is to provide a method, device, and computer-readable storage medium for simulating and verifying the arc resistance of a demagnetizing switch structure and operating characteristics. By establishing a simulation model that considers the geometry of the demagnetizing switch, the dynamic characteristics of the operating mechanism, and the multi-physics coupling of the arc-extinguishing chamber, the transient process of the DC arc can be accurately simulated, thereby obtaining key parameters such as the maximum arcing time and the maximum opening time, providing technical support for the reliability verification of the DC breaking capacity of the demagnetizing switch.

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] The following embodiment illustrates the arc resistance simulation verification method for the structure and operating characteristics of a demagnetizing switch provided in this application.

[0023] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a method for simulating and verifying the arc resistance of a demagnetizing switch structure and operating characteristics, as provided in an embodiment of this application.

[0024] In this embodiment, the method may include: S1. Construct a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; the three-dimensional geometric model includes: arc-extinguishing chamber, contact system, operating mechanism, and opening / closing control module; the contact system includes main contacts and arc contacts; First, obtain the structural parameters and design drawings of the demagnetizing switch to be modeled, and then establish a simplified three-dimensional geometric model based on the main structure of the demagnetizing switch. This three-dimensional geometric model mainly retains the core components such as the arc-extinguishing chamber, contact system, operating mechanism, and opening and closing control module, while auxiliary structures that do not affect the accuracy of arc simulation can be appropriately simplified.

[0025] The contact system is a core component of the 3D geometric model, comprising main contacts and arc contacts. The main contacts conduct current under normal operating conditions; their surface is coated with a composite silver material to reduce contact resistance and improve conductivity. The arc contacts withstand arc erosion during the breaking process; they are made of copper, exhibiting excellent arc erosion resistance and are easily replaceable. The arc contacts are connected to the connecting strip via a braided flexible strip. This strip employs a very tight weave structure, ensuring both good conductivity and sufficient flexibility to accommodate contact movement.

[0026] The number of contacts on a demagnetizing switch can be configured as a single-contact or double-contact structure depending on its rated voltage and breaking current capacity. The single-contact structure is simple and low-cost, and is suitable for medium breaking capacity applications; the double-contact structure can effectively distribute arc energy and is suitable for higher breaking capacity applications.

[0027] S2, construct a mechanical structure dynamics simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein, the mechanical structure dynamics simulation model describes the motion characteristics of the moving contact under electromagnetic repulsion. The operating mechanism of a demagnetizing switch typically employs a rapid repulsion mechanism. This step establishes a mechanical structure dynamics simulation model based on the dynamic characteristics of the operating mechanism. This mechanical structure dynamics simulation model is used to describe the motion characteristics of the moving contact under electromagnetic repulsion, providing key parameters such as contact separation speed and displacement for subsequent arc simulation.

[0028] The mechanical structure dynamics simulation model includes two sub-models: a disc spring retaining device model and an electromagnetic repulsion drive model. The disc spring retaining device model describes the holding state of the moving contact in the open / closed position. The rapid repulsion mechanism uses a disc spring retaining device, which avoids the misalignment and damage problems caused by traditional mechanical locking devices. The electromagnetic repulsion drive model describes the rapid separation movement of the moving contact when the short-circuit current rises. When the short-circuit current rises sharply, the electromagnetic repulsion force rapidly pushes the moving contact to move. Because electromagnetic repulsion drive is used instead of mechanical transmission, friction between components is avoided, improving the opening speed and reliability.

[0029] The mechanical structure dynamics simulation model also includes an action sequence model of the interlocking devices. The mechanism achieves mechanical interlocking in the closed position, and is equipped with two interlocking devices. The slow-speed interlocking device is used for opening under normal conditions, responding to the trigger signal of the shunt trip or undervoltage trip. The fast latch is used to separate the main contact arm from the mechanism, responding to the trigger signal of the overcurrent trip device; it can separate the contacts in a very short time. This interlocking device is used during short circuits or overloads. By establishing the action sequence model of the interlocking devices, the opening action process under different operating conditions can be accurately simulated.

[0030] The closing of the magnetic field circuit breaker is achieved through a high-power electromagnetic drive, while overload tripping is achieved directly through an overcurrent tripping device, or alternatively through an electric coil. Indirect remote tripping can be achieved through a shunt tripping device or an undervoltage tripping device.

[0031] S3. Construct a finite element simulation model of the arc-extinguishing chamber based on the arc-extinguishing principle and arc-blowing principle of the demagnetizing switch to be modeled; the finite element simulation model includes the geometric structure and material properties of the arc-extinguishing grid and the arc-extinguishing cover. A finite element simulation model of the arc-extinguishing chamber is established based on the arc-extinguishing and arc-blowing principles of the demagnetizing switch to be modeled. This finite element simulation model includes the geometry and material properties of the arc-extinguishing grid and the arc-extinguishing shield.

[0032] Arc extinguishing principles include two types: insulated arc-extinguishing grids and metal arc-extinguishing grids. Insulated arc-extinguishing grids primarily cool and elongate the arc through insulating materials, suitable for breaking small to medium currents. Metal arc-extinguishing grids use metal plates to cut and cool the arc, suitable for breaking large currents. Arc blowing principles include electromagnetic arc blowing or a combination of air blowing and electromagnetic arc blowing. Electromagnetic arc blowing utilizes the magnetic blowing force generated by the combined action of the current within the conductor and the arc itself to drive the arc's movement. The combination of air blowing and electromagnetic arc blowing utilizes both airflow driving force and magnetic blowing force, achieving a stronger arc extinguishing capability.

[0033] The arc-extinguishing chamber is made of arc-resistant material, possessing extremely high durability and heat resistance. An arc-extinguishing plate is integrated within the chamber, used to cut the electric arc into multiple short arcs connected in series to increase the arc voltage. During the interruption process, the DC arc, driven by magnetic blowing force and airflow, moves upward along the arc-starting ring and enters the arc-extinguishing chamber. Under the action of the arc-extinguishing grid, it is rapidly elongated and divided into several short arcs connected in series. Each short arc has a cathode and an anode voltage drop, forming a series of voltage drops on the metal surface, causing the total arc voltage to increase exponentially. Simultaneously, due to the high heat absorption capacity of the arc-extinguishing plate and the chamber wall, a large amount of arc energy can be absorbed, thereby transferring arc energy and extinguishing the arc.

[0034] S4. Based on the assumptions of local thermodynamic equilibrium and turbulence, a multi-physics coupled mathematical model is constructed for the generation, development and extinction of electric arcs. The multi-physics coupled mathematical model includes the fluid dynamics control equations, electromagnetic field equations and heat transfer equations. The motion of arc plasma in the arc-extinguishing chamber is a complex process involving the interaction of magnetic, electric, airflow, and thermal fields. To simplify the mathematical model for arc simulation, the following assumptions are made when simulating the arc interruption by the demagnetizing switch: First, local thermodynamic equilibrium is satisfied, meaning the electron temperature and heavy particle temperature in the arc plasma are equal; second, the arc flow is turbulent, and a turbulence model is used to describe the flow characteristics of the arc.

[0035] Based on the above simplifying assumptions, a multi-physics coupled mathematical model of the arc generation, development, and extinction process is constructed. This multi-physics coupled mathematical model consists of three parts: fluid dynamics governing equations, electromagnetic field equations, and heat transfer equations.

[0036] The governing equations of hydrodynamics include the mass conservation equation, momentum conservation equation, and energy conservation equation, which describe the spatiotemporal distribution of density, velocity, and temperature of the arc plasma. The mass conservation equation describes the variation of arc plasma density with time and space. The momentum conservation equation describes the motion of the arc plasma under the influence of electromagnetic forces, pressure gradients, and viscous forces. The energy conservation equation describes the energy input, output, and conversion processes of the arc plasma.

[0037] The mass equation is: In the formula, ρ represents the density of the electric arc plasma, with units of kg / m3; t represents time. Let i be the components of the fluid velocity in each direction (x, y, z) in a Cartesian coordinate system, in m / s.

[0038] The electromagnetic field equations are solved using Maxwell's equations to determine the electric and magnetic field strengths in the arc region. By solving for the electromagnetic field distribution, the electromagnetic force acting on the arc plasma can be obtained. This electromagnetic force is a crucial driving force propelling the arc towards the arc-extinguishing chamber.

[0039] The heat transfer equations include a thermal radiation model based on the Stefan-Boltzmann law and a thermal conduction model based on Fourier's law. The thermal radiation model describes the radiative heat transfer process between the electric arc and its surrounding environment; the higher the temperature of the object itself, the stronger the radiative energy produced. The thermal conduction model describes the heat conduction process between the electric arc and solid components such as contacts and arc-extinguishing grids; heat energy is always transferred from the high-temperature object to the low-temperature object.

[0040] The formula for radiative heat transfer between objects is: Where ε is the Stefan-Boltzmann constant, which is the absorption coefficient; T1 is the surface temperature of the object, and T2 is the ambient temperature.

[0041] Fourier's law, also known as the fundamental law of heat conduction, is generally expressed as: Where λ is the thermal conductivity, t is the absolute temperature, and x is the unit length in the tangential direction of heat transfer. Since heat energy always flows from the hotter object to the colder object during heat conduction, a negative sign is required.

[0042] S5 imports the three-dimensional geometric model, mechanical structure dynamics simulation model, finite element simulation model, and multiphysics coupling mathematical model into the simulation software, sets boundary conditions and material parameters, and then performs simulation to obtain the maximum arcing time and the maximum tripping time.

[0043] The three-dimensional geometric model, the mechanical structure dynamics simulation model, the finite element simulation model, and the multiphysics coupled mathematical model are imported into the simulation software. In this embodiment, COMSOL Multiphysics software is used as the simulation platform.

[0044] Set appropriate boundary conditions and material parameters in the simulation software. Boundary conditions include current input boundaries, voltage output boundaries, temperature boundaries, and fluid boundaries. Material parameters include the electrical conductivity, thermal conductivity, and specific heat capacity of the contact material, the thermophysical properties of the arc-extinguishing grid material, and the physical properties of air and arc plasma.

[0045] After setting the boundary conditions and material parameters, simulations were performed to obtain key parameters such as the maximum arcing time and maximum opening time during the opening process of the demagnetizing switch. The maximum arcing time reflects the time required for the arc to extinguish completely from its inception, and is an important indicator for evaluating the arc-extinguishing capability of the demagnetizing switch. The maximum opening time reflects the time required for the contacts to fully disconnect from the initial separation, and is an important indicator for evaluating the operating speed of the demagnetizing switch.

[0046] This step also includes performing thermodynamic simulation analysis on the arc-extinguishing shroud to verify whether its maximum temperature exceeds the temperature resistance limit of its material, thus validating the shroud's thermal stability and arc energy absorption capacity. The arc-extinguishing shroud needs to absorb a large amount of arc energy during the interruption process; if its temperature exceeds the material's temperature resistance limit, it will lead to a decline in material performance or even damage, affecting the reliability and service life of the demagnetizing switch.

[0047] In summary, this embodiment constructs a three-dimensional geometric model including the arc-extinguishing chamber, contact system, and operating mechanism, fully considering the actual structural characteristics of the demagnetizing switch and overcoming the problem of insufficient simulation accuracy caused by the coarse assumptions of traditional arc models. By establishing a mechanical structure dynamics simulation model, the motion characteristics of the moving contact can be accurately described, providing reliable boundary conditions for arc simulation. Based on a multi-physics coupled mathematical model of fluid dynamics, electromagnetic field, and heat transfer, the complete process of arc generation, development, and extinction can be accurately simulated. Compared with traditional empirical models, it has higher simulation accuracy and stronger applicability, and can effectively guide the design optimization and breaking capacity verification of the demagnetizing switch.

[0048] Specifically, another embodiment is provided below to further illustrate the arc resistance simulation verification method for the structure and operating characteristics of a demagnetizing switch provided in this application.

[0049] This embodiment uses a synchronous condenser demagnetizing switch manufactured by a foreign manufacturer as the object to conduct simulation modeling and verify the effectiveness of its breaking capacity. The main technical parameters of this demagnetizing switch are: rated voltage 3000V, rated current 4200A, maximum breaking current 40kA, and it adopts a single-break structure with an arc-extinguishing shroud.

[0050] Step 1: Constructing the 3D geometric model.

[0051] A simplified three-dimensional geometric model was created based on the structural drawings of the demagnetizing switch. This switch employs a single-break structure, with the contact system consisting of main contacts and arc contacts. The main contacts are coated with a composite silver material, resulting in low contact resistance and good conductivity. The arc contacts are made of copper and are easily replaceable via a braided flexible strip connected to a connecting strip. The three-dimensional geometric model retains core components such as the arc-extinguishing chamber, contact system, operating mechanism, and opening / closing control module.

[0052] Step 2: Construction of the dynamic simulation model of the mechanical structure.

[0053] The demagnetizing switch uses a rapid repulsion mechanism as its operating mechanism. The established mechanical structure dynamics simulation model includes a disc spring retaining device model, an electromagnetic repulsion drive model, and a locking device action timing model.

[0054] The disc spring retaining device model describes the holding state of the moving contact in the open / closed position. When the short-circuit current reaches 40kA, the electromagnetic repulsion force can overcome the disc spring retaining force and quickly push the moving contact apart. The electromagnetic repulsion driving model calculates the time-varying characteristics of the electromagnetic repulsion force based on the parameters of the repulsion coil and the magnitude of the short-circuit current, and then solves for the movement speed and displacement of the moving contact.

[0055] The interlocking device includes a slow interlocking device and a fast latch. Under normal tripping conditions, the shunt trip unit or undervoltage trip unit triggers the slow interlocking device to operate; under 40kA short-circuit current interruption conditions, the overcurrent trip unit triggers the fast latch to operate, achieving rapid contact separation.

[0056] Step 3: Constructing the finite element simulation model of the arc extinguishing chamber.

[0057] This demagnetizing switch employs both the metal arc-extinguishing grid principle and the electromagnetic arc-blowing principle. A finite element simulation model was established based on the structure of the arc-extinguishing chamber, including the geometry and material properties of the arc-extinguishing grid. The arc-extinguishing cover is made of flame-retardant material and integrates multiple metal arc-extinguishing plates internally.

[0058] During the interruption of a 40kA short-circuit current, the operating mechanism first drives the contacts to separate, generating a DC arc between the contacts, which is then elongated by the gap between the main contacts. Simultaneously, under the combined action of the current within the conductor and the arc itself, the DC arc is further elongated and moves upward along the arc-initiating ring into the arc-extinguishing chamber. Under the action of the arc-extinguishing grid, the DC arc is rapidly elongated and divided into several short arcs connected in series, resulting in a significant increase in the total arc voltage. The DC arc extinguishes as the arc voltage rises sharply.

[0059] Step 4: Construction of a multiphysics coupling mathematical model.

[0060] Based on the assumptions of local thermodynamic equilibrium and turbulence, a multi-physics field coupled mathematical model is established for the generation, development and extinction of electric arc under a 40kA interrupting current.

[0061] In the governing equations of fluid dynamics, the initial density of the arc plasma is taken as the air density, and the initial temperature is taken as the ambient temperature. The momentum conservation equation considers the effects of electromagnetic force, pressure gradient, and viscous force. The energy conservation equation considers Joule heat input, thermal radiation loss, and thermal conduction loss.

[0062] The electromagnetic field equations are used to solve for the electric and magnetic field distributions in the arc region by setting current input boundary conditions based on a breaking current of 40kA.

[0063] In the heat transfer equation, the Stefan-Boltzmann law is used for the thermal radiation model, and Fourier's law is used for the thermal conduction model. The ambient temperature is set to room temperature.

[0064] Step 5: Simulation solution and result analysis.

[0065] The above models were imported into COMSOL Multiphysics software, and simulations were performed after setting boundary conditions and material parameters. The simulation results show that when the demagnetizing switch interrupts a 40kA short-circuit current, the maximum arcing time and the maximum tripping time are both within the design allowable range, verifying that its breaking capacity meets the design requirements.

[0066] Thermodynamic simulation analysis of the arc extinguishing shroud showed that the highest temperature of the shroud did not exceed the temperature resistance limit of its material, verifying that the arc extinguishing shroud has sufficient thermal stability and arc energy absorption capacity.

[0067] The following describes an arc resistance simulation verification device for the structure and operating characteristics of a demagnetizing switch provided in an embodiment of this application. The arc resistance simulation verification device for the structure and operating characteristics of a demagnetizing switch described below and the arc resistance simulation verification method for the structure and operating characteristics of a demagnetizing switch can be referred to each other.

[0068] Please refer to Figure 2 , Figure 2 This is a schematic diagram of an arc resistance simulation verification device for the structure and operating characteristics of a demagnetizing switch provided in an embodiment of this application.

[0069] In this embodiment, the device may include: The geometric model construction module 100 is used to construct a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; wherein, the three-dimensional geometric model includes: arc-extinguishing chamber, contact system, operating mechanism, and opening and closing control module; wherein, the contact system includes main contacts and arc contacts; The dynamic model construction module 200 is used to construct a mechanical structure dynamic simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein, the mechanical structure dynamic simulation model describes the motion characteristics of the moving contact under the drive of electromagnetic repulsion. The arc-extinguishing chamber model construction module 300 is used to construct a finite element simulation model of the arc-extinguishing chamber based on the arc-extinguishing principle and arc-blowing principle of the demagnetizing switch to be modeled; the finite element simulation model includes the geometric structure and material properties of the arc-extinguishing grid and the arc-extinguishing cover; The mathematical model construction module 400 is used to construct a multi-physics coupled mathematical model of the arc generation, development, and extinction process based on the assumptions of local thermodynamic equilibrium and turbulence. The multi-physics coupled mathematical model includes fluid dynamics control equations, electromagnetic field equations, and heat transfer equations. The simulation solution module 500 is used to import three-dimensional geometric models, mechanical structure dynamics simulation models, finite element simulation models, and multiphysics coupling mathematical models into the simulation software, set boundary conditions and material parameters, and then perform simulation solutions to obtain the maximum arcing time and the maximum tripping time.

[0070] This application also provides an arc resistance simulation and verification device; please refer to it. Figure 3 , Figure 3 This is a schematic diagram of the arc resistance simulation and verification device provided in the embodiments of this application. The arc resistance simulation and verification device may include: Memory, used to store computer programs; The processor, used to execute computer programs, can implement the steps of an arc resistance simulation verification method for any of the above-described demagnetizing switch structures and operating characteristics.

[0071] like Figure 3 The diagram shows the structural composition of an arc resistance simulation and verification device. The device may include a processor 10, a memory 11, a communication interface 12, and a communication bus 13. The processor 10, memory 11, and communication interface 12 all communicate with each other via the communication bus 13.

[0072] In this embodiment, the processor 10 may be a central processing unit (CPU), an application-specific integrated circuit, a digital signal processor, a field-programmable gate array, or other programmable logic devices.

[0073] The processor 10 can call the program stored in the memory 11. Specifically, the processor 10 can execute the operations in the embodiment of the abnormal IP identification method.

[0074] The memory 11 is used to store one or more programs. The programs may include program code, which includes computer operation instructions. In this embodiment, the memory 11 stores at least a program for implementing the following functions: S1. Construct a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; the three-dimensional geometric model includes: arc-extinguishing chamber, contact system, operating mechanism, and opening / closing control module; the contact system includes main contacts and arc contacts; S2, construct a mechanical structure dynamics simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein, the mechanical structure dynamics simulation model describes the motion characteristics of the moving contact under electromagnetic repulsion. S3. Construct a finite element simulation model of the arc-extinguishing chamber based on the arc-extinguishing principle and arc-blowing principle of the demagnetizing switch to be modeled; the finite element simulation model includes the geometric structure and material properties of the arc-extinguishing grid and the arc-extinguishing cover. S4. Based on the assumptions of local thermodynamic equilibrium and turbulence, a multi-physics coupled mathematical model is constructed for the generation, development and extinction of electric arcs. The multi-physics coupled mathematical model includes the fluid dynamics control equations, electromagnetic field equations and heat transfer equations. S5 imports the three-dimensional geometric model, mechanical structure dynamics simulation model, finite element simulation model, and multiphysics coupling mathematical model into the simulation software, sets boundary conditions and material parameters, and then performs simulation to obtain the maximum arcing time and the maximum tripping time.

[0075] In one possible implementation, the memory 11 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and applications required for at least one function; and the data storage area may store data created during use.

[0076] In addition, memory 11 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device or other volatile solid-state storage device.

[0077] Communication interface 12 can be an interface for the communication module, used to connect with other devices or systems.

[0078] Of course, it should be noted that, Figure 3 The structure shown does not constitute a limitation on the arc resistance simulation verification device in the embodiments of this application. In practical applications, the arc resistance simulation verification device may include more than Figure 3 More or fewer components as shown, or combinations of certain components.

[0079] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the steps of the arc resistance simulation verification method for any of the above-described demagnetizing switch structures and operating characteristics.

[0080] The computer-readable storage medium may include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0081] For a description of the computer-readable storage medium provided in this application, please refer to the above method embodiments; further details will not be repeated here.

[0082] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0083] 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.

[0084] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0085] The above provides a detailed description of the arc resistance simulation verification method, device, equipment, and computer-readable storage medium for the structure and operating characteristics of a demagnetizing switch 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 merely for the purpose of helping to understand the method and its core ideas. 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 the claims of this application.

Claims

1. A method for simulating and verifying the arc resistance of a demagnetizing switch structure and operating characteristics, characterized in that, include: S1. Construct a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; wherein, the three-dimensional geometric model includes: arc-extinguishing chamber, contact system, operating mechanism, and opening / closing control module; wherein, the contact system includes main contacts and arc contacts; S2, construct a mechanical structure dynamics simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein, the mechanical structure dynamics simulation model describes the motion characteristics of the moving contact under electromagnetic repulsion. S3, construct a finite element simulation model of the arc-extinguishing chamber based on the arc-extinguishing principle and arc-blowing principle of the arc-extinguishing switch to be modeled; wherein, the finite element simulation model includes the geometric structure and material properties of the arc-extinguishing grid and the arc-extinguishing cover; S4. Based on the assumptions of local thermodynamic equilibrium and turbulence, a multi-physics coupled mathematical model is constructed for the generation, development, and extinction of electric arcs; wherein, the multi-physics coupled mathematical model includes fluid dynamics control equations, electromagnetic field equations, and heat transfer equations; S5. Import the three-dimensional geometric model, the mechanical structure dynamics simulation model, the finite element simulation model, and the multiphysics coupling mathematical model into the simulation software, set the boundary conditions and material parameters, and then perform simulation to obtain the maximum arcing time and the maximum circuit breaker tripping time.

2. The arc resistance simulation verification method according to claim 1, characterized in that, In S1, the number of breaks in the demagnetizing switch is single or double, the surface of the main contact is coated with composite silver material, the arc contact is made of copper material, and the arc contact is connected to the connecting strip by a braided soft strip.

3. The arc resistance simulation verification method according to claim 2, characterized in that, In S2, the mechanical structure dynamics simulation model includes a disc spring holding device model and an electromagnetic repulsion driving model; wherein, the disc spring holding device model is used to describe the holding state of the moving contact in the opening and closing positions, and the electromagnetic repulsion driving model is used to describe the rapid separation movement of the moving contact when the short-circuit current rises.

4. The arc resistance simulation verification method according to claim 3, characterized in that, The mechanical structure dynamics simulation model also includes an action timing model of the interlocking device. The interlocking device includes a slow interlocking device for normal tripping and a fast latch for short-circuit or overload tripping. The slow interlocking device responds to the trigger signal of the shunt trip or undervoltage trip, and the fast latch responds to the trigger signal of the overcurrent trip device.

5. The arc resistance simulation verification method according to claim 4, characterized in that, In S3, the arc extinguishing principle includes arc extinguishing by an insulating arc extinguishing grid or arc extinguishing by a metal arc extinguishing grid, and the arc blowing principle includes electromagnetic arc blowing or a combination of air blowing and electromagnetic arc blowing. The material of the arc extinguishing cover is an arc-resistant material and it integrates an arc extinguishing plate. The arc extinguishing plate is used to cut the electric arc into multiple short arcs connected in series to increase the arc voltage.

6. The arc resistance simulation verification method according to claim 5, characterized in that, In S4, the fluid dynamics governing equations include mass conservation equations, momentum conservation equations, and energy conservation equations, used to describe the spatiotemporal distribution of density, velocity, and temperature of the arc plasma; the electromagnetic field equations use Maxwell's equations to solve for the electric and magnetic field strengths in the arc region; and the heat transfer equations include a thermal radiation model based on the Stefan-Boltzmann law and a thermal conduction model based on Fourier's law.

7. The arc resistance simulation verification method according to claim 6, characterized in that, S5 further includes performing thermodynamic simulation analysis on the arc extinguishing cover to verify whether the highest temperature of the arc extinguishing cover exceeds the temperature resistance limit of its material, so as to verify the thermal stability and arc energy absorption capacity of the arc extinguishing cover.

8. An arc resistance simulation verification device for the structure and operating characteristics of a demagnetizing switch, characterized in that, include: A geometric model construction module is used to construct a three-dimensional geometric model based on the main structure of the demagnetizing switch to be modeled; wherein, the three-dimensional geometric model includes: an arc-extinguishing chamber, a contact system, an operating mechanism, and a switching control module; wherein, the contact system includes main contacts and arc contacts; The dynamic model construction module is used to construct a mechanical structure dynamic simulation model based on the dynamic characteristics of the operating mechanism of the demagnetizing switch to be modeled; wherein, the mechanical structure dynamic simulation model describes the motion characteristics of the moving contact under electromagnetic repulsion. The arc-extinguishing chamber model construction module is used to construct a finite element simulation model of the arc-extinguishing chamber based on the arc-extinguishing principle and arc-blowing principle of the demagnetizing switch to be modeled; wherein, the finite element simulation model includes the geometric structure and material properties of the arc-extinguishing grid and the arc-extinguishing cover; The mathematical model construction module is used to construct a multi-physics coupled mathematical model of the arc generation, development, and extinction process based on the assumptions of local thermodynamic equilibrium and turbulence; wherein, the multi-physics coupled mathematical model includes fluid dynamics control equations, electromagnetic field equations, and heat transfer equations; The simulation solution module is used to import the three-dimensional geometric model, the mechanical structure dynamics simulation model, the finite element simulation model, and the multiphysics coupling mathematical model into the simulation software, set boundary conditions and material parameters, and then perform simulation solution to obtain the maximum arcing time and the maximum tripping time.

9. An arc resistance simulation and verification device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the arc resistance simulation verification method as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the arc resistance simulation verification method as described in any one of claims 1 to 7.

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