Method, device and apparatus for manufacturing on-load tap changer

Abstract

The application provides a preparation method, device and equipment of an on-load tap changer, and relates to the technical field of power equipment optimization. The method comprises the following steps: obtaining electromechanical parameters of an on-load tap changer to be designed; wherein the electromechanical parameters comprise basic parameters and adjustable parameters; performing electromechanical bidirectional coupling operation on the electromechanical parameters according to a pre-constructed mechanical dynamics model and a circuit simulation model to obtain performance indexes; wherein the performance indexes comprise arc energy, mechanical impact force, contact ablation amount and steady-state loss of switching contacts of the on-load tap changer; taking the adjustable parameters as variables, taking the minimum performance indexes as a target to construct a target function, taking operation conditions and structure limitation conditions as constraint conditions to construct a multi-objective optimization model, and performing iterative optimization to obtain an optimal solution; determining a preparation scheme by using the optimal solution, and preparing the on-load tap changer according to the preparation scheme. The application can improve the service life of the on-load tap changer.

Description

Technical Field

[0001] This invention relates to the field of power equipment optimization technology, and in particular to a method, apparatus and equipment for manufacturing an on-load tap changer. Background Technology

[0002] As power systems develop towards larger capacity and higher voltage, on-load tap changers, as core equipment for transformer voltage regulation, directly affect the overall reliability of power grid voltage regulation. During frequent tap changes, the contacts of on-load tap changers are continuously subjected to mechanical impacts, arc erosion, and other effects, leading the industry to impose stringent requirements on the overall electromechanical performance of the switch.

[0003] Currently, the design mode in which mechanical structure and electrical performance are independent is generally adopted. Optimization work is carried out only for a single dimension, and the design process relies heavily on experience to obtain values, making it difficult to accurately reproduce the actual operating conditions of the equipment.

[0004] This type of discrete design approach severs the interrelationship between mechanical and electrical characteristics. Not only does it fail to take into account multiple performance indicators, but it also easily leads to situations where the design margin is blindly too large, parameters are redundant and wasted, or some structural and electrical points have performance shortcomings, resulting in inconsistent overall performance. Ultimately, this leads to poor overall operation of the switch and a significantly shortened service life. Summary of the Invention

[0005] This invention provides a method, apparatus, and equipment for manufacturing an on-load tap changer, which solves the problem that existing on-load tap changers, where the mechanical structure and electrical performance are designed separately, are prone to having excessive design margins or poor local performance, thus affecting the lifespan of the switch.

[0006] In a first aspect, embodiments of the present invention provide a method for fabricating an on-load tap changer, comprising: obtaining electromechanical parameters of the on-load tap changer to be designed; wherein the electromechanical parameters include basic parameters and adjustable parameters, and the adjustable parameters include adjustable structural parameters and electrical parameters; performing electromechanical bidirectional coupling calculations on the electromechanical parameters according to a pre-constructed mechanical dynamics model and circuit simulation model to obtain performance indicators; wherein the performance indicators include the arc energy, mechanical impact force, contact ablation amount, and steady-state loss of the switching contacts of the on-load tap changer; constructing an objective function with the adjustable parameters as variables and the minimum performance indicators as the objective, constructing a multi-objective optimization model with operating conditions and structural constraints as constraints, and performing iterative optimization to obtain the optimal solution; determining the fabrication scheme using the optimal solution, and fabricating the on-load tap changer according to the fabrication scheme.

[0007] In one possible implementation, the switching contacts of the on-load tap changer include main contacts, main on / off contacts, and transition contacts. Before obtaining performance indicators, the implementation further includes: equipping the main contacts under steady-state current-carrying conditions as a contact resistance and switch series branch; equipping the main on / off contacts during the current transfer stage as a contact resistance and switch series branch, and equipping the main on / off contacts during the arcing stage as an arc resistance, a minimum arc inductance, and switch series branch; equipping the transition contacts as a contact branch and an arcing branch, where the contact branch includes a series current-limiting resistor and a contact resistor, and the arcing branch includes a series current-limiting resistor, an arc resistance, and a minimum arc inductance; constructing a single-sided equivalent circuit based on the equivalent branches of the main contacts, main on / off contacts, and transition contacts; and constructing a circuit simulation model based on the single-sided equivalent circuit and the number of tap changer positions.

[0008] In one possible implementation, based on a pre-built mechanical dynamics model and circuit simulation model, electromechanical parameters are subjected to bidirectional electromechanical coupling calculations to obtain performance indicators. This includes: performing mechanical dynamics simulation on the electromechanical parameters based on the mechanical dynamics model to obtain mechanical state parameters, including contact velocity, contact force, and contact gap distance; calculating circuit simulation parameters based on the mechanical state parameters, including arc resistance and contact resistance; performing circuit and arc simulation on the electromechanical parameters based on the mechanical state parameters, circuit simulation parameters, and circuit simulation model to obtain electrical arc state parameters, including operating circuit current, actual arc voltage, and arc duration; and performing bidirectional interactive calculations based on the mechanical state parameters and electrical arc state parameters to calculate arc energy, contact mechanical impact force, contact ablation, and steady-state loss.

[0009] In one possible implementation, circuit simulation parameters are calculated based on mechanical state parameters, including: determining the reference arc voltage based on the sum of the cathode and anode voltage drops, the arc electric field strength coefficient, and the contact gap distance; calculating the arc heat dissipation power based on the static heat dissipation power, the velocity heat dissipation coefficient, and the contact movement speed; calculating the arc resistance based on the reference arc voltage, the rated circuit current, the arc time constant, and the arc heat dissipation power; and calculating the contact resistance based on the contact material resistivity, the contact material hardness, and the contact contact force.

[0010] In one possible implementation, bidirectional interactive calculations are performed based on mechanical state parameters and electrical arc state parameters, including: calculating arc energy based on the actual arc voltage, operating circuit current, and arc duration; calculating contact mechanical impact force based on contact movement speed, contact elastic modulus, and contact mass; calculating contact ablation based on the actual arc voltage, operating circuit current, arc duration, energy utilization coefficient, contact material density, and latent heat of vaporization; and calculating steady-state losses based on contact resistance and operating circuit current.

[0011] In one possible implementation, constructing the objective function with the goal of minimizing the performance indicators includes: normalizing the arc energy, contact mechanical impact force, contact ablation, and steady-state loss to obtain normalized performance indicators; performing a weighted summation based on the normalized performance indicators and their corresponding weight coefficients, and minimizing the function obtained by the weighted summation to obtain the objective function.

[0012] In one possible implementation, the operating conditions include the allowable temperature rise range of the transition resistance and the rated switching time limit specified in the standard; the structural constraints include insulation distance requirements, mechanism size requirements, and component mechanical load-bearing strength requirements; after obtaining the performance indicators, the following are also included: calculating the allowable temperature rise range of the transition resistance based on the operating circuit current, transition resistance value, transition resistance mass, and transition resistance specific heat capacity; calculating the insulation distance requirement based on the insulation distance, mechanical movement margin, and manufacturing tolerances; and constructing constraint conditions based on the allowable temperature rise range of the transition resistance, the rated switching time limit, the insulation distance requirement, the mechanism size requirement, and the component mechanical load-bearing strength requirements.

[0013] In one possible implementation, a multi-objective optimization model is constructed with operating conditions and structural constraints as constraints, and iterative optimization is performed to obtain the optimal solution. This includes: initializing the variables to generate an initial parameter population containing multiple sets of electromechanical parameters; performing bidirectional electromechanical coupling operations on the electromechanical parameters based on a pre-constructed mechanical dynamics model and circuit simulation model to update performance indicators; recalculating the objective function based on the updated performance indicators, sorting the population individuals according to the objective function, and selecting superior solutions; using the NSGA-II multi-objective optimization algorithm to sequentially perform selection, crossover, and mutation on the superior solutions to obtain new variables, and removing new variables that do not meet the constraints; cyclically performing coupling operations, updating indicators, and selecting superior solutions until the preset number of iterations is reached or the convergence accuracy of the optimal solution meets the requirements; terminating the iteration process, determining the optimal solution based on the optimal solution set, and using the adjustable parameters corresponding to the optimal solution as the optimal solution.

[0014] Secondly, embodiments of the present invention provide a fabrication apparatus for an on-load tap changer, comprising: a communication module for acquiring electromechanical parameters of the on-load tap changer to be designed; wherein the electromechanical parameters include basic parameters and adjustable parameters, and the adjustable parameters include adjustable structural parameters and electrical parameters; a processing module for performing electromechanical bidirectional coupling calculations on the electromechanical parameters according to a pre-constructed mechanical dynamics model and a circuit simulation model to obtain performance indicators; wherein the performance indicators include the arc energy, mechanical impact force, contact ablation amount, and steady-state loss of the switching contacts of the on-load tap changer; constructing an objective function with adjustable parameters as variables and minimizing performance indicators as the objective, constructing a multi-objective optimization model with operating conditions and structural constraints as constraints, and performing iterative optimization to obtain the optimal solution; determining a fabrication scheme using the optimal solution, and fabricating the on-load tap changer according to the fabrication scheme.

[0015] Thirdly, embodiments of the present invention provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in the first aspect or any possible implementation thereof.

[0016] This invention provides a method, apparatus, and device for manufacturing an on-load tap changer. First, electromechanical bidirectional coupling calculations are performed based on a mechanical dynamics model and a circuit simulation model, overcoming the limitations of traditional independent mechanical and electrical simulations. This accurately reproduces the electromechanical linkage characteristics of the switch under actual operating conditions, obtaining accurate performance indicators. Then, a multi-objective optimization model is constructed and iteratively optimized. On one hand, reasonable parameter value ranges are defined based on switch operation and structural constraints, selecting the optimal parameter combination to reduce excessive design margins and eliminate parameter redundancy. On the other hand, all performance indicators are considered, and local performance defects are specifically optimized to solve the problem of performance imbalance in traditional designs. Finally, the product design is completed based on the optimal parameters, ensuring the switch's electromechanical parameters reach optimal matching, reducing contact arc erosion, mechanical impact, and steady-state losses, effectively improving the overall operational stability and service life of the equipment. Attached Figure Description

[0017] Figure 1 This is a circuit model diagram of the on-load tap changer fabrication method provided in the embodiments of the present invention; Figure 2 This is a flowchart illustrating the implementation of the on-load tap changer manufacturing method provided in this embodiment of the invention. Figure 3a This is a first-view schematic diagram of the multibody dynamics model of the on-load tap changer switching core provided in an embodiment of the present invention; Figure 3b This is a second-view schematic diagram of the multibody dynamics model of the on-load tap changer switching core provided in an embodiment of the present invention; Figure 3cThis is a third-view schematic diagram of the multibody dynamics model of the on-load tap changer switching core provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the fabrication apparatus for an on-load tap changer provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0018] The on-load tap changer (OLTC) is a key component for voltage regulation in a transformer and the only part that operates frequently. Its performance directly affects the transformer's reliability, lifespan, and grid stability. During operation, the OLTC is subjected to the direct effects of multiple physical fields, including electrical, high-temperature, and impact stresses. Its design must consider various factors, including electrical, mechanical, and material aspects. Traditional design methods rely heavily on empirical formulas and static checks, making it difficult to comprehensively consider the coupling effects between mechanical dynamics, arc characteristics, electrical transients, and structural parameters. This can lead to excessive design margins or insufficient local performance. Problems such as contact erosion and contact bounce remain unresolved, requiring a comprehensive consideration of reliability and service life. Currently, a systematic OLTC design method that combines mechanical-electrical co-simulation and multi-objective optimization decision-making is lacking.

[0019] To address the technical shortcomings of traditional designs, this invention first begins with low-level modeling of the electrical circuit, constructing a single-phase equivalent circuit that closely reflects actual voltage regulation conditions. It clarifies the electrical interaction logic of various contacts and voltage regulating windings, using this as the electrical foundation for subsequent co-simulation. The embodiments of this invention will now be described in detail with reference to the accompanying drawings.

[0020] Figure 1 This is a circuit model diagram of the method for fabricating an on-load tap changer provided in an embodiment of the present invention. Figure 1 As shown, this includes the electrical connection relationships of the primary transformer main winding, tap winding, three types of contacts (main contacts, main on / off contacts, and transition contacts), transition current limiting element, multi-position tap circuit, and grounding neutral point.

[0021] Among them, the transformer main winding is the main voltage regulating winding of the transformer body, which is the main power supply input terminal of the entire voltage regulating circuit and the main branch of the power input.

[0022] The tap winding is marked with a separate dashed box, and its equivalent series transition resistance R is... w Minimum arc inductance L w The corresponding current-limiting and parasitic inductance equivalent elements of the transition contact branch simulate the current-limiting effect and small parasitic inductance of the transition circuit during gear switching, and also represent the independent voltage regulating winding unit for each gear; the ellipsis in the figure represents the extended arrangement of multiple sets of repeating gear branches.

[0023] The main contact branch consists of only the equivalent contact resistance R1 connected in series, with an ideal open / close switch below. During the steady-state current-carrying phase, the switch is closed, and only the contact resistance exists, with no arc branch. This matches the modeling rule that the main contact is equivalent to the contact resistance and the switch in series under steady-state current-carrying conditions.

[0024] The main on / off contact branch includes two parallel branches, R2 and R3, with an inductor L1 attached to each branch. It can switch between two working states in a time-division manner: in the current transfer stage, only the contact resistance branch is connected, and there is no arc; in the arc breaking stage, the contacts separate and the arc is started, and the arc resistance and inductor branches are automatically switched in; thus, the main on / off contact can be fully realized in terms of different working conditions.

[0025] The transition contact branch includes a double parallel branch of R4 and R5, with matching inductor L2, naturally separating the contact branch and the arcing branch: when closing the transition, it runs through the contact resistance branch, relying on the resistor to limit current and suppress circulating current; after the contacts separate and arc is started, it switches to the arcing branch, connecting the arc resistance and parasitic inductance in series.

[0026] Multi-stage expansion and end neutral point: The multiple ellipses in the middle represent the continuous and repeated arrangement of multi-stage voltage regulation stages of the tap changer. The basic branch topology can be copied in batches according to the actual number of voltage regulation stages, and the modeling of tap changers with different stage specifications can be adapted.

[0027] All branches at the far right converge to the neutral point grounding terminal, forming a complete single-phase closed electrical circuit, which meets the standard wiring form for transformer neutral point voltage regulation.

[0028] Based on the above circuit topology, the tap changer has two typical operating modes: steady-state operation and dynamic tap switching. The contact switching logic and loop current path are significantly different between the two modes. The specific operating logic is as follows: In steady-state operation, the main contacts corresponding to the current position are reliably closed, and the current flows steadily through the main contacts and main winding. The transition contacts and main on / off contacts are disconnected, and no electric arc is generated. The circuit only has contact resistance heating loss.

[0029] Gear switching process: (1) First close the transition contact branch and connect the current limiting resistor to limit the circulating current of the voltage regulating winding; (2) Disconnect the original gear main on / off contact, the contact separates and arcs, and automatically switches to the arc path resistor and inductor arcing branch; (3) Connect the next gear main contact to complete the current transfer; (4) Disconnect the transition contact, the switching process ends, and enters the new gear steady-state operation. During the entire switching process, the three types of contacts open and close at different times, the branch is automatically switched, and the actual action sequence of the on-load tap changer and the entire process of arc generation and extinction are completely reproduced.

[0030] To achieve coordinated design of mechanical and electrical parameters, this invention relies on circuit models and mechanical dynamics models to establish a complete fabrication and implementation process. (See attached document.) Figure 2The document illustrates a flowchart of the fabrication method for an on-load tap changer provided in an embodiment of the present invention, which is described in detail below: Step 201: Obtain the electromechanical parameters of the on-load tap changer to be designed; wherein, the electromechanical parameters include basic parameters and adjustable parameters, and the adjustable parameters include adjustable structural parameters and electrical parameters.

[0031] In some embodiments, the basic parameters are inherent fixed parameters of the device. For example, basic parameters include the resistivity of the contact material, the characteristics of the arc-extinguishing medium, the electrode voltage drop, the component mass, the specific heat capacity, the preset rated current, and the arc time constant, which remain unchanged during the optimization process. Adjustable parameters are optimization variables. For example, structural parameters include spring stiffness, cam profile control point coordinates, mass block mass, and contact speed. Electrical parameters include the contact resistance R. con Current limiting resistor R e (This parameter is determined during the design phase), Arc resistance R arc The switching time of each branch circuit, along with other parameters, primarily affect the contact heating and ablation levels, and ultimately their electrical life.

[0032] In this embodiment, a clear distinction is made between fixed basic parameters and optimizable variables, and the optimization boundary is defined to avoid iteration without target parameters.

[0033] Step 202: Based on the pre-constructed mechanical dynamics model and circuit simulation model, perform electromechanical bidirectional coupling calculations on the electromechanical parameters to obtain performance indicators; among which, the performance indicators include the arc energy, mechanical impact force, contact ablation amount, and steady-state loss of the switching contacts of the on-load tap changer.

[0034] In some embodiments, the mechanical dynamics model establishes the motion equations of the tap changer operating mechanism, solves the dynamic behavior of the contact movement throughout the entire process, and outputs the contact movement speed, contact pressure, and contact gap distance to provide mechanical boundary conditions for arc simulation. The circuit simulation model is an equivalent circuit model built according to the equivalent branches of the main contact, main on / off contact, and transition contact under different operating conditions. It can solve for electrical quantities such as real-time circuit current, arc voltage, and arc duration. The electromechanical bidirectional coupling operation includes forward coupling and reverse coupling. In the forward process, the mechanical model outputs the contact movement gap and contact force, solves for the arc resistance and contact resistance, and sends them to the circuit model for arc simulation. In the reverse process, the circuit simulation obtains the arc energy, Joule heat, and ablation amount, which are substituted back into the mechanical model to check the contact strength and impact load, realizing the mutual transfer of data between the mechanical and electrical systems. The arc energy is the cumulative energy of the arc throughout the entire arc process; the greater the energy, the more severe the contact ablation. The mechanical impact force is the instantaneous force of the contact closing / breaking impact; a large impact can cause mechanical fatigue and contact bounce. Contact erosion is the amount of material loss in the contact area caused by arc erosion; the greater the loss, the shorter the lifespan of the switch. Steady-state loss is the power loss caused by the continuous heating of the contact resistance and current-limiting resistor when current is flowing; the greater the loss, the greater the temperature rise.

[0035] In this embodiment, the traditional fragmented design of mechanical and electrical components is broken, and the motion of the mechanism and the characteristics of the electric arc are no longer checked separately. Instead, a two-way coupled simulation is achieved, in which the mechanical motion characteristics directly affect the electrical characteristics of the electric arc, and the electric arc heating and electrical erosion inversely affect the life of the mechanical structure. The calculated electric arc energy, impact load, ablation amount, and power loss are more in line with the actual operating conditions of the switch, thus improving the simulation accuracy. All key evaluation indicators are output simultaneously at one time, eliminating the need for multiple step-by-step simulations and improving computational efficiency.

[0036] Step 203: Construct an objective function with adjustable parameters as variables and minimum performance index as the goal, construct a multi-objective optimization model with operating conditions and structural constraints as constraints, and perform iterative optimization to obtain the optimal solution.

[0037] In this embodiment, multiple mutually restrictive indicators such as low arc erosion, low impact, and low heat loss are simultaneously optimized to avoid the serious degradation of other performance due to single-objective optimization. Engineering constraints such as temperature rise, switching time, insulation, and structural strength are added. The optimized parameters are not purely theoretical optimal solutions, but engineering feasible solutions that meet the boundaries of actual equipment operation, assembly, and manufacturing processes. Intelligent algorithms are used to automatically iterate and optimize, replacing manual trial and error of parameters, which greatly shortens the design iteration cycle and reduces the rework cost of prototype production.

[0038] Step 204: Determine the preparation scheme using the optimal solution, and prepare the on-load tap changer according to the preparation scheme.

[0039] In some embodiments, based on the optimal structural dimensions, part selection, electrical component parameters, and assembly tolerances, machining drawings, assembly processes, and component selection lists are generated; based on the scheme, machining, assembly, and testing are performed to physically produce the on-load tap changer.

[0040] In this embodiment, the theoretically optimal parameters optimized by simulation are directly translated into a physical manufacturing process document that can be processed and assembled. The resulting on-load tap changer has multiple advantages, including less contact erosion, less mechanical impact, and lower heat loss during operation. It also has a longer electrical life, higher mechanical reliability, and lower operating temperature rise, resulting in a comprehensive improvement in the overall performance of the product.

[0041] This invention provides a method for manufacturing an on-load tap changer. First, electromechanical bidirectional coupling calculations are performed based on a mechanical dynamics model and a circuit simulation model, overcoming the limitations of traditional independent mechanical and electrical simulations. This accurately reproduces the electromechanical linkage characteristics of the switch under actual operating conditions, obtaining accurate performance indicators. Then, a multi-objective optimization model is constructed and iteratively optimized. On one hand, reasonable parameter value ranges are defined based on switch operation and structural constraints, selecting the optimal parameter combination to reduce excessive design margins and eliminate parameter redundancy. On the other hand, all performance indicators are considered, and local performance defects are specifically optimized to solve the problem of performance imbalance in traditional designs. Finally, the product design is completed based on the optimal parameters, ensuring the switch's electromechanical parameters reach optimal matching, reducing contact arc erosion, mechanical impact, and steady-state losses, effectively improving the overall operational stability and service life of the equipment.

[0042] This invention proposes a method for fabricating an on-load tap changer. This method constructs a bidirectional mechanical-electrical coupling simulation framework for the tap changer, establishing a multi-body dynamics model of the switching core and circuit and arc models, and utilizing a co-simulation interface to achieve real-time data interaction. Using contact displacement, velocity, mechanical impact force, and contact pressure as mechanical-side output variables, and current and arc characteristics as electrical-side feedback variables, a coupling relationship is established to achieve high-precision co-simulation of the tap changer switching process, ultimately realizing the synergistic optimization of the electrical and mechanical performance of the on-load tap changer.

[0043] To clarify the details of building the circuit simulation model, the following section provides a detailed explanation of the contact differentiation equivalent modeling method.

[0044] In one possible implementation, the switching contacts of the on-load tap changer include main contacts, main on / off contacts, and transition contacts. Before obtaining performance indicators, the implementation further includes: equipping the main contacts under steady-state current-carrying conditions as a contact resistance and switch series branch; equipping the main on / off contacts during the current transfer stage as a contact resistance and switch series branch, and equipping the main on / off contacts during the arcing stage as an arc resistance, a minimum arc inductance, and switch series branch; equipping the transition contacts as a contact branch and an arcing branch, where the contact branch includes a series current-limiting resistor and a contact resistor, and the arcing branch includes a series current-limiting resistor, an arc resistance, and a minimum arc inductance; constructing a single-sided equivalent circuit based on the equivalent branches of the main contacts, main on / off contacts, and transition contacts; and constructing a circuit simulation model based on the single-sided equivalent circuit and the number of tap changer positions.

[0045] In some embodiments, the switching contact is a core contact assembly for a on-load tap changer to implement gear position switching, load current transfer, and arc extinction. There are three types of contacts: main contacts, main on-off contacts and transition contacts, which have different divisions of labor and staggered operating timings. The equivalent branch is a combination of standard circuit elements such as ideal switches, resistors and inductors, which equivalently replaces the electrical conduction characteristics of real contacts under different working conditions, and is used for circuit simulation modeling. The steady-state current-carrying condition is the stable working condition after the gear switching is completed, the dynamic and static contacts are completely closed without arc, and continuously carry the rated load current for a long term. Contact resistance is the equivalent resistance generated by the contraction of current flowing through the contact surface due to the limited actual contact area of the metal surfaces of dynamic and static contacts; the smaller the pressing force and the higher the material hardness, the greater the contact resistance. The switch series branch is an ideal electrical switching element used to characterize the two on-off states of the contact, that is, the closed branch is conducted and the opened branch is disconnected. The current transfer phase is a transition process in which current is gradually transferred from the original contact to the new contact during the gear switching process, and no arc is generated yet. The arcing phase is the dynamic process in which after the contacts are separated, the inter-electrode voltage breaks down the air / arc extinguishing medium to form a plasma arc, and the arc continues to burn. Arc path resistance is the equivalent resistance corresponding to the conductive channel of the arc plasma. The longer the arc length and the lower the arc temperature, the greater the arc path resistance, which is a core parameter of arc simulation. The minimum arc path inductance is a weak parasitic inductance existing in the arc channel. The inductance value is extremely small, which will not change the calculation results of circuit voltage and current, and is only added for the stability of numerical simulation solution, with no actual electrical function. The transition contact is a special contact with a transition current-limiting resistor. During the switching process, the current-limiting resistor is connected first to limit the circulating current, and then the current transfer is completed to prevent the winding short-circuit circulating current from being too large. The contact branch is a conduction branch when the transition contact is reliably closed without arc, and carries the transfer current by means of the current-limiting resistor and the contact resistance. The arcing branch is a conduction branch after the transition contact is separated and arcing is initiated, which is connected in series with the current-limiting resistor, the arc path resistance and the tiny arc path inductance to simulate the electrical characteristics of arcing. The current-limiting resistor is a series resistor matched with the transition contact, which suppresses the instantaneous circulating current during gear switching and limits the amplitude of arc current, so as to protect the contact from being quickly burned by large current. The unilateral equivalent circuit is an equivalent topological circuit that only constructs the contact group on one side of a single phase of the tap changer, and does not include the symmetrical structure on the other side, so the model is simple and has a small amount of calculation. The number of tap positions of the tap changer is the total number of voltage regulating positions of the transformer. The number of positions determines the number of repeated stages and the number of nodes of the circuit branch topology, which is used to completely expand the simulation model of the whole machine circuit.

[0046] In the specific implementation process, the main contact undertakes the current-carrying task when the on-load tap changer is not switching, and is characterized by small contact resistance, so it can be equivalent to a contact resistance R1 connected in series with a switch.

[0047] When the on-load tap changer switches, the main contact switches to the main on / off contact first. At this time, the main on / off contact can be equivalent to the contact resistance R2 connected in series with a switch. When the main on / off contact switches to the transition contact, an arc will be generated when the main on / off contact separates. At this time, the main on / off contact can be equivalent to the arc resistance R3, the arc inductance L1 (which can be ignored and assigned a minimum value), and a switch connected in series.

[0048] The transition contact is similar to the main on / off contact, except that the transition contact branch includes a current-limiting resistor. Therefore, R4 includes a current-limiting resistor and a contact resistance (which can be ignored), R5 includes a current-limiting resistor and an arc resistance, and L2 is the arc inductance (which can be ignored and assigned a very small value).

[0049] R w L w These are the tap winding resistance and inductance, respectively, which are inherent parameters of the transformer. Since the two sides of the switching switch are symmetrical, the equivalent method on the right side is the same as on the left side; this constitutes one unit of the on-load tap changer circuit model. The circuit model contains several units, the specific number depending on the number of tap positions of the on-load tap changer (commonly 15, 17, or 19).

[0050] As can be seen from the circuit model, the main electrical parameters of an adjustable on-load tap changer include: contact resistance R. con Current limiting resistor R e (This parameter is determined during the design phase), Arc resistance R arc The switching time of each branch circuit, along with other parameters, primarily affect the contact heating and ablation levels, and ultimately their electrical life.

[0051] Among these electrical parameters, the contact resistance R is... con The arc parameter R is determined by the contact force of the contacts. arc The switching time of each branch is determined by the mechanical structure and is related to the contact opening and closing speed and contact displacement. These parameters need to be obtained by multibody dynamics simulation.

[0052] In this embodiment, different functional contacts are classified and defined, clarifying the action sequence and division of labor of each contact. Subsequent working conditions can be separately analyzed for each type of contact, avoiding modeling confusion and ensuring clear modeling boundaries. The model accurately simulates the steady-state electrical characteristics of the contacts during the stationary operation phase, where only contact resistance exists and there is no arc. The model can accurately calculate the contact heat loss under steady-state current flow, providing accurate electrical boundaries for steady-state temperature rise and long-term current flow verification. It achieves refined modeling of the same contact under multiple working conditions in a time-sharing manner. During the transition phase, there is no arc, and only contact loss is considered; during the arcing phase, the equivalent impedance of the arc is fully considered. The model distinguishes between the two key transient processes of pre-arc breaking and arcing, allowing the simulation to reproduce the current and voltage mutation processes throughout the entire process of contact breaking and arc initiation, significantly improving the accuracy of arc energy calculation. A minimal arc path inductance is added to avoid the divergence problem in the numerical solution of rigid circuit equations, resulting in stronger simulation stability. The simulation closely replicates the actual operating logic of the transition contact, which closes first to limit current and then separates to initiate arcing. The two branches automatically switch based on the contact's opening and closing state. It fully reproduces the protective function of the current-limiting resistor in suppressing circulating current and limiting arc current, without losing the key design feature of the transition resistor's current-limiting capability, ensuring the simulation results closely match engineering realities. The dispersed individual contact branches are integrated into a complete single-sided topology circuit, achieving interconnection of electrical nodes in each branch. This allows for simultaneous calculation of current and voltage distribution relationships among multiple contacts, eliminating the need for isolated calculations of individual contact electrical quantities. The model is lightweight, with short calculation times for single-sided circuits, making it suitable for subsequent iterative optimization and repeated use. The single-sided basic topology is expanded in batches according to the actual tap position levels, resulting in a complete simulation model adapted to the tap changer's complete voltage regulation circuit. The model can be directly connected to subsequent electromechanical coupling calculations without secondary modifications to the topology, enabling one-time modeling and repeated use throughout the entire process.

[0053] After completing the circuit and mechanical dynamics model, the following details the four-layer coupling operation steps and clarifies the timing sequence of bidirectional interaction between mechanical and electrical data.

[0054] In one possible implementation, based on a pre-built mechanical dynamics model and circuit simulation model, electromechanical parameters are subjected to bidirectional electromechanical coupling calculations to obtain performance indicators. This includes: performing mechanical dynamics simulation on the electromechanical parameters based on the mechanical dynamics model to obtain mechanical state parameters, including contact velocity, contact force, and contact gap distance; calculating circuit simulation parameters based on the mechanical state parameters, including arc resistance and contact resistance; performing circuit and arc simulation on the electromechanical parameters based on the mechanical state parameters, circuit simulation parameters, and circuit simulation model to obtain electrical arc state parameters, including operating circuit current, actual arc voltage, and arc duration; and performing bidirectional interactive calculations based on the mechanical state parameters and electrical arc state parameters to calculate arc energy, contact mechanical impact force, contact ablation, and steady-state loss.

[0055] In some embodiments, the contact movement speed is the instantaneous moving rate of the moving and stationary contacts during opening and closing, directly determining the arc ignition moment and the arc length extension speed; the contact contact force is the clamping force after the contacts close; the greater the clamping force, the larger the contact area and the smaller the contact resistance; the contact gap distance is the inter-electrode distance after the moving and stationary contacts separate, determining whether the arc can break through the medium, the arc length, and the arc resistance. The operating circuit current is the instantaneous actual current of the circuit during the switching process; the actual arc voltage is the real voltage drop across the arc during the arcing stage; the arc duration is the complete arcing time from contact separation and arc ignition to complete arc extinguishing.

[0056] In the specific implementation process, parameters such as contact displacement x(t) (i.e., contact gap distance), contact velocity v(t), and contact pressure F (i.e., contact force) obtained from multibody dynamics simulation are input into the circuit model. Among them, contact displacement x(t) is used to determine the contact opening and closing state and determine the arc parameters; contact velocity affects the arc duration and arc resistance; contact pressure is transmitted to the electrical model to correct the contact resistance Rc(F).

[0057] The arc energy Warc calculated in the circuit model is fed back to the multibody dynamics model, affecting the contact state of the contacts. Contact erosion leads to a decrease in contact area and an increase in contact resistance Rc(F).

[0058] It should be noted that the time scales of mechanical and circuit simulations are mismatched, and direct synchronous calculation would waste computing power. Therefore, time step adaptation is required: bidirectional strong coupling is achieved through time step iteration. Since circuit simulation is at the μs level and mechanical simulation is at the ms level, an intermediate interpolation / extrapolation method is used to achieve adaptive step size synchronous calculation in order to reduce the amount of computation.

[0059] After completing the electromechanical coupling simulation and outputting all performance indicators, the optimization modeling stage can begin: construct a multi-objective optimization model with arc energy, contact mechanical impact force, and ablation as optimization objectives. Under the constraints of insulation distance, temperature rise, and mechanical strength, an optimization method based on a non-dominated sorting genetic algorithm is used to solve the problem.

[0060] The optimization problem is uniformly expressed as a multi-objective optimization model: , In the formula, Let x1, x2...xn be a set of variables, representing spring stiffness, mass of mass block, transition resistance, and other variables to be optimized, respectively. f 1, f 2... f m represents the objective functions for minimum arc energy, minimum contact erosion, and minimum steady-state loss, respectively.

[0061] In this embodiment, instead of artificially providing a fixed contact motion curve, the driving characteristics of the real mechanism are reproduced through dynamic simulation. The output speed, pressure, and opening distance closely match the actual action process. The resulting set of mechanical quantities serves as the direct input for subsequent calculations of contact resistance and arc resistance, enabling quantitative transfer of mechanical quantities to the electrical simulation stage and establishing a seamless data interface between the mechanical and electrical systems. The contact impact velocity is obtained in advance, providing raw dynamic data for subsequent mechanical impact force calculations. A quantitative correlation is established between mechanical quantities and electrical parameters: the contact force determines the contact resistance, and the contact gap distance determines the arc resistance, achieving dynamic parameter linkage rather than using fixed resistance values. The core resistance parameters of the circuit model are dynamically updated, allowing the circuit simulation to change synchronously with the real-time contact motion state, giving the simulation model time-varying characteristics. The intermediate parameters necessary for electrical simulation are centrally generated, and the calculation process is modularly broken down, facilitating batch parameter updates during subsequent iterative optimizations. Simultaneously, by introducing the mechanism's motion boundary and time-varying resistance parameters, the transient electrical changes throughout the entire process of contact opening and closing, arc initiation, arc burning, and arc extinction are fully reproduced. Three key electrical results—real-time circuit current, arc voltage, and arc burning duration—are solved in one go, providing a complete electrical data source for the quantitative calculation of four performance indicators. The system automatically solves based on a pre-built standardized circuit model, eliminating the need for repeated topology construction and adapting to the massive iterative calculation scenarios of optimization algorithms. It truly achieves bidirectional electromechanical coupling, with mechanical parameters used to calculate impact loads and electrical arc parameters used to calculate arc energy, contact ablation, and heat loss. These two types of parameters mutually support the calculation of complete indicators. All four optimization target indicators are output simultaneously in one go, eliminating the need for multiple independent calculations of mechanical and electrical indicators, significantly reducing the overall simulation calculation time. The output quantitative indicators can be directly integrated into subsequent objective function construction and multi-objective optimization stages, achieving seamless connection between simulation calculation and optimization iteration, fully supporting the entire optimization preparation process.

[0062] To quantify the circuit parameter solution process, the following section refines the parameter calculations by combining classical arc theory and contact resistance theory.

[0063] In one possible implementation, circuit simulation parameters are calculated based on mechanical state parameters, including: determining the reference arc voltage based on the sum of the cathode and anode voltage drops, the arc electric field strength coefficient, and the contact gap distance; calculating the arc heat dissipation power based on the static heat dissipation power, the velocity heat dissipation coefficient, and the contact movement speed; calculating the arc resistance based on the reference arc voltage, the rated circuit current, the arc time constant, and the arc heat dissipation power; and calculating the contact resistance based on the contact material resistivity, the contact material hardness, and the contact contact force.

[0064] In some embodiments, the sum of the cathode and anode voltage drops represents the fixed potential drop of each of the arc cathode and anode metal electrodes. The sum of these two drops is the inherent total voltage drop in the near-electrode region of the arc, determined by the contact material and the arc-extinguishing medium, and is a fixed input parameter. The arc electric field strength coefficient is a characteristic coefficient of the arc voltage increment per unit arc length, determined by the type, pressure, and temperature of the arc-extinguishing gas, and is used to convert arc length to arc voltage. The reference arc voltage is the arc reference voltage calculated based on electrode voltage drop, electric field strength, and arc length. It serves only as an intermediate input for solving the arc resistance and is not the real-time arc voltage obtained from simulation. Static heat dissipation power is the power continuously lost by the arc to the surrounding arc-extinguishing medium and contact metal parts during the arcing process. The faster the contact is pulled apart, the faster the arc is stretched, and the heat dissipation power changes accordingly. The velocity heat dissipation coefficient is a fitting coefficient that establishes the correspondence between contact movement speed and arc heat dissipation power, determined by experiments or an arc calibration model. The contact movement speed is the contact opening and closing movement rate output from the mechanical dynamics simulation, directly affecting the arc stretching rate and heat dissipation speed. The rated circuit current is a fixed preset current value given under the rated operating conditions of the switch; it is a boundary parameter given in the design and not a dynamic solution quantity in the simulation. The arc time constant is the inherent inertial time constant of the arc plasma energy establishment and dissipation; it is an inherent characteristic constant of the arc model and remains constant. The arc heat dissipation power is the power lost in the outward transfer of arc energy and participates in the iterative solution of the arc resistance.

[0065] In the specific implementation process, the contact resistance R of the contactor con Using the Holm contact resistance model, the calculation formula is as follows: In the formula, ρ The resistivity of the contact material; H The hardness of the contact material is approximately equal to its yield strength. F The contact force is obtained from multibody dynamics simulation.

[0066] The arc resistance Rarc is closely related to the mechanical motion parameters of the contacts and the circuit parameters, and follows the improved Mayr arc model. The calculation formula is as follows: In the formula, u ( t ), i ( t These represent the low voltage of the electric arc (V) and the current of the electric arc (A), respectively. τ ( t ) represents the arc time constant (s). P ( t ) represents the arc heat dissipation power (W).

[0067] Arc voltage u (t Distance between contacts d ( t The relationship between the fixed contact and the moving contact (i.e., the distance between them, obtained from multibody dynamics simulation) can be expressed as: In the formula, u 0 represents the sum of the voltage drops at the cathode and anode (V). E 0 represents the electric field strength coefficient of the electric arc (V / m).

[0068] Arc heat dissipation power P ( t ) speed of contact movement v ( t The influence (obtained from multibody dynamics simulation) can be expressed as: In the formula, P 0 represents static heat dissipation power (W). kv The velocity heat dissipation coefficient is (W·s / m).

[0069] In this embodiment, a complete set of quantitative conversions from mechanical state parameters to intermediate electrical parameters in circuit simulation is fully realized. The three mechanical quantities output by dynamic simulation—speed, pressure, and gap—are all converted into the two core time-varying resistances required by the circuit model: arc resistance and contact resistance. The quantitative link of electromechanical coupling is completely closed-loop. All parameter calculations are based on classical arc theory and contact resistance theory, with complete physical mechanisms and high reliability of the simulation model, avoiding design errors caused by purely empirical fixed parameters. The resistances of the two key branches are calculated modularly and centrally. The calculation units are independent and can be called individually or updated in batches during optimization iterations, adapting to massive iterative simulation scenarios.

[0070] After solving for the two types of circuit parameters, arc resistance and contact resistance, the final four performance indicators can be quantitatively calculated by combining the electrical parameters output from the circuit simulation.

[0071] In one possible implementation, bidirectional interactive calculations are performed based on mechanical state parameters and electrical arc state parameters, including: calculating arc energy based on the actual arc voltage, operating circuit current, and arc duration; calculating contact mechanical impact force based on contact movement speed, contact elastic modulus, and contact mass; calculating contact ablation based on the actual arc voltage, operating circuit current, arc duration, energy utilization coefficient, contact material density, and latent heat of vaporization; and calculating steady-state losses based on contact resistance and operating circuit current.

[0072] In some embodiments, the actual arc voltage is the real voltage value measured in real time across the arc plasma during the contact arcing stage, and is a dynamic electrical quantity directly output by the circuit arc simulation. The contact mechanical impact force is the instantaneous impact force generated at the moment of contact closing; excessive impact can cause contact bounce, mechanical fatigue damage, and secondary arc initiation. The energy utilization coefficient is the proportion of the total arc energy actually used to erode and melt the contact metal material; the remaining energy is dissipated in the form of heat dissipation and radiation, and serves as the calibration coefficient for the arc ablation model.

[0073] In the specific implementation process, the arc energy W arc It can be represented as: In the formula, u ( t) , i ( t These are the low voltage of the electric arc (V) and the current of the operating circuit (A), respectively. t arc The duration of the arc is the time interval between the separation of the contacts and the nearest current zero-crossing point (obtained through circuit simulation).

[0074] To accurately calculate the mechanical impact force of the contacts, a multibody dynamics model of the on-load tap changer switching core needs to be established, such as... Figure 3a , 3b As shown in Figure 3c, the model includes an energy storage mechanism, springs, cams, drive shafts, dampers, gear pairs, and contact systems. The motion equations of the mechanism are solved as follows: In the formula, M For the quality matrix, C Here is the damping matrix. K Here is the stiffness matrix. q For generalized coordinate vectors, Fext As an external driving force, Fc This refers to the contact force between the contacts.

[0075] The specific calculation of the mechanical impact force on the contact is as follows: In the formula, v 0 represents the impact velocity at the moment of contact. k The contact's elastic modulus. m For contact quality.

[0076] The formula for calculating the contact ablation volume ΔV is as follows: In the formula, u arc、 i These are the arc voltage and current, respectively. tarc For the duration of the electric arc, The energy utilization coefficient (values ​​range from 0.2 to 0.4). ρ Density of the contact material H Material latent heat of vaporization. For common Cu-W contacts, approximately 5-10 mg of erosion occurs per 1 kJ of arc energy. The erosion amount can be calculated using the formula above, and the contact parameters can be adjusted in the multibody dynamics model.

[0077] Steady-state loss refers to the loss when the tap changer is not operating. The power loss can be expressed as: In the formula, R 1 and Rcon All of these are contact resistances of the contacts.

[0078] In this embodiment, the mechanical state parameters and electrical arc state parameters output by the electromechanical coupling simulation above are fully inherited, and all four optimized performance indicators are solved at once. The indicator calculation link is complete and closed-loop, without parameter gaps. The four indicators correspond to the four core design problems of arc erosion, mechanical impact, electrical life, and steady-state heating, respectively, and cover both electrical reliability and mechanical reliability, providing a comprehensive design evaluation dimension.

[0079] The four performance indicators have vastly different dimensions and numerical magnitudes, making them unsuitable for direct weighted optimization. Therefore, normalization is needed to eliminate these dimensional differences and construct a unified comprehensive objective function.

[0080] In one possible implementation, constructing the objective function with the goal of minimizing the performance indicators includes: normalizing the arc energy, contact mechanical impact force, contact ablation, and steady-state loss to obtain normalized performance indicators; performing a weighted summation based on the normalized performance indicators and their corresponding weight coefficients, and minimizing the function obtained by the weighted summation to obtain the objective function.

[0081] In this embodiment, the mathematical fusion of multiple performance indicators is completed, and a data interface is established between the simulation performance results and the intelligent optimization algorithm, realizing a seamless connection between simulation calculation indicators, indicator fusion, and algorithm optimization. The construction method of normalization and weighted combination combines customer objectivity and design flexibility, which will not cause dimensional imbalance and can adapt to the differentiated design needs of different customers and different working conditions. The optimization direction of minimization is clearly locked, the optimization logic is a complete closed loop, and there is a clear basis for subsequent algorithm iteration.

[0082] The objective function only defines the performance optimization goal. Without engineering boundary constraints, the optimized solution may suffer from practical defects such as insufficient insulation, excessive temperature rise, and dimensional overruns. Therefore, it is necessary to simultaneously supplement both electrical and structural constraints to improve the boundary of the optimization model.

[0083] In one possible implementation, the operating conditions include the allowable temperature rise range of the transition resistance and the rated switching time limit specified in the standard; the structural constraints include insulation distance requirements, mechanism size requirements, and component mechanical load-bearing strength requirements; after obtaining the performance indicators, the following are also included: calculating the allowable temperature rise range of the transition resistance based on the operating circuit current, transition resistance value, transition resistance mass, and transition resistance specific heat capacity; calculating the insulation distance requirement based on the insulation distance, mechanical movement margin, and manufacturing tolerances; and constructing constraint conditions based on the allowable temperature rise range of the transition resistance, the rated switching time limit, the insulation distance requirement, the mechanism size requirement, and the component mechanical load-bearing strength requirements.

[0084] In some embodiments, the allowable temperature rise range of the transition resistor is the temperature at which the transition current-limiting resistor heats up when energized, and the temperature must not exceed the material's heat resistance limit. This upper and lower temperature limit constitutes the allowable temperature rise range; exceeding the limit will cause the resistor to burn out and the insulation to age. The rated switching time limit is the maximum allowable switching time specified by industry standards and transformer specifications. Exceeding the switching time will cause the transformer circulating current to remain for too long, damaging the windings. The mechanical load-bearing strength requirements for components are that after contacts, springs, connecting rods, and other parts are subjected to impact forces, elastic forces, and operating forces, the stress and deformation must not exceed the material's yield strength to avoid fatigue fracture and permanent deformation. Manufacturing tolerances are the allowable dimensional deviations in machining and component assembly.

[0085] In the specific implementation process, when adjusting the mechanical parameters, in addition to the external transformer size limitations, it is also necessary to meet the insulation distance and mechanism size constraints, as shown in Table 1: Table 1 Insulation Distance and Mechanism Dimension Constraints Regarding insulation, the minimum electrical envelope principle should be met, meaning the minimum spacing between metal components must satisfy the following constraint formula: In the formula, di For insulation distance, sm For mechanical motion margin, tc To manufacture tolerances.

[0086] In addition, moving parts (shafts, connecting rods, contacts) must not enter dangerous electric field areas under extreme conditions such as maximum vibration and thermal expansion.

[0087] Upper limit of temperature rise of transition resistance T max , can be represented as: In the formula, i ( t ) represents current. RThis is the transition resistance value. m For the quality of the transition resistance, c This is the specific heat capacity of the transition resistor. For a typical transition resistor, the limiting temperature rise should not exceed 250K.

[0088] In this embodiment, the constraint system of the multi-objective optimization model is completed, which is different from unconstrained pure theoretical optimization and achieves the dual objectives of optimal performance and engineering feasibility. All constraint thresholds are quantitatively calculated by formulas rather than empirically assigned, so the constraint boundaries are accurate and quantifiable, and the optimization model has high credibility. The constraints fully cover the three major engineering dimensions of electrical operation safety, mechanical structure strength, and processing and assembly technology, and there are no theoretical solutions in the optimization solution set that cannot be implemented.

[0089] After all the objective functions and constraints are established, it is necessary to rely on mature multi-objective intelligent algorithms to complete automatic iterative optimization. The following section details the complete execution process of adapting the algorithm to this scheme.

[0090] In one possible implementation, a multi-objective optimization model is constructed with operating conditions and structural constraints as constraints, and iterative optimization is performed to obtain the optimal solution. This includes: initializing the variables to generate an initial parameter population containing multiple sets of electromechanical parameters; performing bidirectional electromechanical coupling operations on the electromechanical parameters based on a pre-constructed mechanical dynamics model and circuit simulation model to update performance indicators; recalculating the objective function based on the updated performance indicators, sorting the population individuals according to the objective function, and selecting superior solutions; using the second-generation non-dominated sorting genetic algorithm (NSGA-II) in multi-objective optimization algorithms to sequentially perform selection, crossover, and mutation on superior solutions to obtain new variables, and removing new variables that do not meet the constraints; cyclically coupling operations, updating indicators, and selecting superior solutions until the preset number of iterations is reached or the convergence accuracy of the optimal solution meets the requirements; terminating the iteration process, determining the optimal scheme based on the optimal solution set, and taking the adjustable parameters corresponding to the optimal scheme as the optimal solution.

[0091] In the specific implementation process, the iterative optimization steps include: First, generating the initial population within the design space using the Latin hypercube method: Each individual represents a design scheme (a set of mechanical parameters + electrical parameters: contact gap distance, contact movement speed, mechanical impact force, contact contact force, operating circuit current, arc characteristics, and the parameters needed to solve these variables).

[0092] The second step is to call the co-simulation model for each design scheme and calculate... .

[0093] The third step is to rank all the solutions according to their merits and select the best solution.

[0094] The fourth step involves using the NSGA-II optimization algorithm to select (preserve the best solution), cross (combine parameters), and mutate (introduce new solutions) the best solutions to obtain a new generation of design variables.

[0095] The fifth step is to eliminate solutions that do not meet the constraints.

[0096] Step 6: Repeat steps 2 to 5, continuously update the population, and gradually approach the optimal solution set. Stop the calculation when the number of iterations reaches the preset value or the accuracy meets the requirements.

[0097] The seventh step is to obtain a set of Pareto optimal solutions and select the final solution based on actual needs.

[0098] In this embodiment, the simulation modeling, index calculation, objective function, and constraints described above are all integrated into an automated iterative closed loop, enabling unmanned and automated execution of the entire process of simulation, evaluation, and optimization. This replaces the traditional design mode of repeatedly trial-and-error with manual parameters and multiple rounds of prototype testing and iteration, significantly shortening the development cycle of on-load tap changers and reducing the cost of multiple prototype testing versions. The optimization simultaneously considers multiple boundaries such as optimal performance, operational safety, structural assembly, and mechanical strength. The final optimal solution is a practical solution that balances theoretical performance and engineering feasibility, and there are no purely theoretical parameter combinations that are not feasible to implement. The complete closed-loop parameter acquisition, coupled simulation, iterative optimization, and physical fabrication of the entire invention support the complete industrialization of the entire method.

[0099] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0100] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0101] Figure 4 A schematic diagram of the fabrication apparatus for an on-load tap changer according to an embodiment of the present invention is shown. For ease of explanation, only the parts relevant to the embodiment of the present invention are shown, and are described in detail below: like Figure 4 As shown, the on-load tap changer manufacturing apparatus 4 includes: The communication module 41 is used to acquire the electromechanical parameters of the on-load tap changer to be designed; wherein, the electromechanical parameters include basic parameters and adjustable parameters, and the adjustable parameters include adjustable structural parameters and electrical parameters; The processing module 42 is used to perform electromechanical bidirectional coupling calculations on the electromechanical parameters based on the pre-constructed mechanical dynamics model and circuit simulation model to obtain performance indicators. Among them, the performance indicators include the arc energy, mechanical impact force, contact ablation amount and steady-state loss of the switching contacts of the on-load tap changer. An objective function is constructed with adjustable parameters as variables and the minimum performance indicators as the objective. A multi-objective optimization model is constructed with operating conditions and structural constraints as constraints, and the optimal solution is obtained through iterative optimization. The optimal solution is used to determine the manufacturing scheme, and the on-load tap changer is manufactured according to the manufacturing scheme.

[0102] Figure 5 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. For example... Figure 5 As shown, the electronic device 5 of this embodiment includes a processor 50 and a memory 51. The memory 51 stores a computer program 52. When the processor 50 executes the computer program 52, it implements the steps in the various method embodiments described above. Alternatively, when the processor 50 executes the computer program 52, it implements the functions of each module / unit in the various device embodiments described above.

[0103] For example, computer program 52 may be divided into one or more modules / units, which are stored in memory 51 and executed by processor 50 to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 52 in electronic device 5.

[0104] Electronic device 5 may include, but is not limited to, processor 50 and memory 51. Those skilled in the art will understand that... Figure 5 This is merely an example of electronic device 5 and does not constitute a limitation on electronic device 5. It may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device 5 may also include input / output devices, network access devices, buses, etc.

[0105] For the sake of simplicity and clarity, only the above-described functional modules / units are used as examples. In practical applications, the functions described above can be assigned to different functional modules / units as needed. These modules / units can be implemented in hardware, software, or a combination of both.

[0106] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0107] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for manufacturing an on-load tap changer, characterized in that, include: Obtain the electromechanical parameters of the on-load tap changer to be designed; wherein, the electromechanical parameters include basic parameters and adjustable parameters, and the adjustable parameters include adjustable structural parameters and electrical parameters; Based on the pre-constructed mechanical dynamics model and circuit simulation model, the electromechanical parameters are subjected to bidirectional electromechanical coupling calculations to obtain performance indicators; wherein, the performance indicators include the arc energy, mechanical impact force, contact ablation amount and steady-state loss of the switching contacts of the on-load tap changer. Using the adjustable parameters as variables and the minimum performance index as the objective, a multi-objective optimization model is constructed. The operating conditions and structural constraints are used as constraints to construct the model and the optimal solution is obtained through iterative optimization. The optimal solution is used to determine the preparation scheme, and an on-load tap changer is prepared according to the preparation scheme.

2. The method for manufacturing an on-load tap changer according to claim 1, characterized in that, The switching contacts of the on-load tap changer include main contacts, main on / off contacts, and transition contacts; Before obtaining performance metrics, the following is also included: The main contact under steady-state current-carrying conditions is equivalent to a contact resistance and a switch connected in series. The main on / off contact during the current transfer stage is equivalent to a contact resistance and a switch series branch, and the main on / off contact during the arc burning stage is equivalent to an arc resistance, a minimum arc inductance and a switch series branch. The transition contact is equivalent to a contact branch and an arcing branch. The contact branch includes a current-limiting resistor and a contact resistor connected in series, and the arcing branch includes a current-limiting resistor, an arc resistance, and a minimum arc inductance connected in series. Construct a single-sided equivalent circuit based on the equivalent branches of the main contact, the main on / off contact, and the transition contact; Based on the single-sided equivalent circuit and the number of tap positions, a circuit simulation model is constructed.

3. The method for manufacturing an on-load tap changer according to claim 1, characterized in that, The process involves performing bidirectional electromechanical coupling calculations on the electromechanical parameters based on a pre-constructed mechanical dynamics model and circuit simulation model to obtain performance indicators, including: Based on the aforementioned mechanical dynamics model, the electromechanical parameters are simulated using mechanical dynamics to obtain the mechanical state parameters; wherein, the mechanical state parameters include the contact movement speed, the contact force, and the contact gap distance; Based on the mechanical state parameters, the circuit simulation parameters are calculated; wherein, the circuit simulation parameters include arc resistance and contact resistance. Based on the mechanical state parameters, the circuit simulation parameters, and the circuit simulation model, the electromechanical parameters are simulated using circuit and arc simulation to obtain the electrical arc state parameters; wherein, the electrical arc state parameters include the operating circuit current, the actual arc voltage, and the arc duration; Based on the mechanical state parameters and the electrical arc state parameters, bidirectional interactive calculations are performed to obtain the arc energy, contact mechanical impact force, contact ablation amount, and steady-state loss.

4. The method for manufacturing an on-load tap changer according to claim 3, characterized in that, The calculation of circuit simulation parameters based on the mechanical state parameters includes: The reference arc voltage is determined based on the sum of the cathode and anode voltage drops, the arc electric field strength coefficient, and the contact gap distance. Calculate the arc heat dissipation power based on the static heat dissipation power, the velocity heat dissipation coefficient, and the contact movement speed; The arc resistance is calculated based on the reference arc voltage, rated circuit current, arc time constant, and arc heat dissipation power. The contact resistance of the contact is calculated based on the resistivity of the contact material, the hardness of the contact material, and the contact force.

5. The method for manufacturing an on-load tap changer according to claim 3, characterized in that, The bidirectional interactive calculation based on the mechanical state parameters and the electrical arc state parameters includes: The arc energy is calculated based on the actual arc voltage, the operating circuit current, and the arc duration. The mechanical impact force of the contact is calculated based on the contact movement speed, contact elastic modulus, and contact mass. The contact ablation amount is calculated based on the actual arc voltage, the operating circuit current, the arc duration, the energy utilization coefficient, the contact material density, and the latent heat of vaporization of the material. The steady-state loss is calculated based on the contact resistance of the contact and the operating circuit current.

6. The method for manufacturing an on-load tap changer according to claim 1, characterized in that, The objective function, which aims to minimize the performance index, includes: The arc energy, contact mechanical impact force, contact ablation amount and steady-state loss are normalized respectively to obtain normalized performance indicators. The objective function is obtained by weighting and summing the normalized performance indicators and their corresponding weight coefficients, and then minimizing the weighted summation function.

7. The method for manufacturing an on-load tap changer according to any one of claims 1-6, characterized in that, The operating conditions include the allowable temperature rise range of the transition resistance and the rated switching time limit specified in the standard; the structural constraints include insulation distance requirements, mechanism size requirements, and component mechanical load-bearing strength requirements. After obtaining the performance metrics, the following is also included: The allowable temperature rise range of the transition resistor is calculated based on the operating circuit current, transition resistance value, transition resistance mass, and transition resistance specific heat capacity. The insulation distance requirement is calculated based on the insulation distance, mechanical movement margin, and manufacturing tolerances; The constraints are constructed based on the allowable temperature rise range of the transition resistance, the rated switching time limit, the insulation distance requirement, the mechanism size requirement, and the mechanical load-bearing strength requirement of the components.

8. The method for manufacturing an on-load tap changer according to claim 1, characterized in that, The process of constructing a multi-objective optimization model with operational and structural constraints as constraints, and iteratively searching for the optimal solution, includes: Population initialization is performed on the variables to generate an initial parameter population containing multiple sets of electromechanical parameters; Based on the pre-constructed mechanical dynamics model and circuit simulation model, the electromechanical parameters are subjected to bidirectional electromechanical coupling calculations to update the performance indicators; The objective function is recalculated based on the updated performance metrics, and the individuals in the population are ranked and selected based on the objective function. The NSGA-II multi-objective optimization algorithm is used to sequentially perform selection, crossover, and mutation on the excellent solution to obtain new variables, and new variables that do not meet the constraints are removed. The process involves cyclic coupling operations, index updates, and selection of superior solutions until the preset number of iterations or the convergence accuracy of the optimal solution meets the requirements. The iteration process is terminated, the optimal solution is determined based on the optimal solution set, and the adjustable parameters corresponding to the optimal solution are taken as the optimal solution.

9. An apparatus for preparing an on-load tap changer, characterized in that, include: A communication module is used to acquire the electromechanical parameters of the on-load tap changer to be designed; wherein, the electromechanical parameters include basic parameters and adjustable parameters, and the adjustable parameters include adjustable structural parameters and electrical parameters; The processing module is used to perform bidirectional electromechanical coupling calculations on the electromechanical parameters based on a pre-constructed mechanical dynamics model and circuit simulation model to obtain performance indicators. These performance indicators include the arc energy, mechanical impact force, contact ablation, and steady-state loss of the switching contacts of the on-load tap changer. An objective function is constructed using the adjustable parameters as variables and minimizing the performance indicators as the objective. A multi-objective optimization model is constructed using operating conditions and structural constraints as constraints, and iterative optimization is performed to obtain the optimal solution. The optimal solution is used to determine the fabrication scheme, and the on-load tap changer is fabricated according to the fabrication scheme.

10. An electronic device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method as described in any one of claims 1 to 8.

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