Optimization design method and device for heat engine performance of transformer

Abstract

The invention provides a transformer heat engine performance optimization design method and device, and relates to the technical field of transformer optimization design. The method comprises the following steps: establishing a three-dimensional winding finite element model, and determining a hot-spot temperature of a target transformer under each group of transformer winding structure parameters according to the three-dimensional winding finite element model; calculating a winding anti-short-circuit safety coefficient of the target transformer under each group of transformer winding structure parameters by utilizing each group of transformer winding structure parameters of the target transformer; and determining an optimal solution set of the target transformer on the Pareto leading edge surface based on the hot-spot temperature and the winding anti-short-circuit safety coefficient of the target transformer under each group of transformer winding structure parameters, and determining a transformer winding structure parameter design scheme of the target transformer based on the optimal solution set. The optimal solution set is a plurality of groups of optimal transformer winding structure parameters. The safety and the heat engine performance of the transformer can be improved, and the stability of a power system is improved.

Description

Technical Field

[0001] This application relates to the technical field of transformer optimal design, and particularly relates to a method and device for optimizing the thermal-mechanical performance of a transformer. Background Art

[0002] Power transformers are expensive and important hub devices in the power grid. Their operating reliability is directly related to the safety and stability of the entire power system. When a winding short-circuits, the electromagnetic force generated is even thousands of times that during the steady-state operation of the transformer, causing the winding to deform. In severe cases, it can lead to insulation failures of the transformer. Therefore, researching and exploring a method to improve the short-circuit resistance of power transformers will be an effective measure to avoid damage to power transformers caused by short-circuit faults.

[0003] When designing for improving short-circuit resistance, such as increasing the number of spacers between winding disks, it will lead to a decrease in the heat dissipation capacity of the winding and an increase in the hot spot temperature. The temperature reached in the hottest area of the winding is considered the main cause of transformer insulation aging and faults, which will accelerate the decomposition of insulating oil and insulating paper, increase the content of dissolved gases and furfural in the oil, increase the overall aging rate of the winding insulation, increase the probability of transformer failures, and endanger the safe and stable operation of the power system. Moreover, during the existing transformer production process, the number of spacers, the width of spacers, the winding radius, etc. are mostly based on design experience. At the same time, when designing the winding, the correlation between the hot spot temperature of the winding and the short-circuit resistance is not considered simultaneously, but only designed separately, which in turn leads to problems such as excessive margin selection, high equipment cost, and large load loss. Therefore, the optimal design of transformers is a non-linear optimization problem with multiple variables and multiple constraints. How to efficiently and conveniently optimize the design of transformers and improve the thermal-mechanical performance of transformers is crucial for the stability of the power system. Summary of the Invention

[0004] This application provides a method and device for optimizing the thermal-mechanical performance of a transformer to solve the problem of reduced stability of the low-power system caused by poor thermal-mechanical performance of the transformer in the prior art.

[0005] In a first aspect, this application provides a method for optimizing the thermal-mechanical performance of a transformer, including:

[0006] Establish a three-dimensional winding finite element model, and determine the hot spot temperature of the target transformer under each set of transformer winding structure parameters, where the transformer winding structure parameters include the number of spacers, the width of spacers, and the winding radius;

[0007] Using each set of transformer winding structure parameters of the target transformer, calculate the winding short-circuit safety factor of the target transformer under each set of transformer winding structure parameters;

[0008] Based on the hot spot temperature and the short - circuit withstand safety factor of the target transformer under each set of transformer winding structure parameters, determine the optimal solution set of the target transformer on the Pareto front, and based on the optimal solution set, determine the design scheme of the transformer winding structure parameters of the target transformer. The optimal solution set is multiple sets of optimal transformer winding structure parameters.

[0009] In a second aspect, the present application provides a transformer thermal - mechanical performance optimization design device, including:

[0010] A hot spot temperature determination module, configured to establish a three - dimensional winding finite element model, and based on the three - dimensional winding finite element model, determine the hot spot temperature of the target transformer under each set of transformer winding structure parameters. The transformer winding structure parameters include the number of spacers, the width of the spacers, and the winding radius;

[0011] A safety factor determination module, configured to use each set of transformer winding structure parameters of the target transformer to calculate the short - circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters;

[0012] A design scheme determination module, configured to based on the hot spot temperature and the short - circuit withstand safety factor of the target transformer under each set of transformer winding structure parameters, determine the optimal solution set of the target transformer on the Pareto front, and based on the optimal solution set, determine the design scheme of the transformer winding structure parameters of the target transformer. The optimal solution set is multiple sets of optimal transformer winding structure parameters.

[0013] The present application provides a transformer thermal - mechanical performance optimization design method and device. By establishing a three - dimensional winding finite element model, and based on the three - dimensional winding finite element model, determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters. The transformer winding structure parameters include the number of spacers, the width of the spacers, and the winding radius; using each set of transformer winding structure parameters of the target transformer to calculate the short - circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters; based on the hot spot temperature and the short - circuit withstand safety factor of the target transformer under each set of transformer winding structure parameters, determining the optimal solution set of the target transformer on the Pareto front, and based on the optimal solution set, determining the design scheme of the transformer winding structure parameters of the target transformer. The optimal solution set is multiple sets of optimal transformer winding structure parameters. The present application determines the optimal solution set of the target transformer on the Pareto front by simultaneously using the hot spot temperature and the short - circuit withstand safety factor of the transformer, providing users with the optimal transformer winding structure parameters suitable for the target transformer, not only improving the safety of the transformer, but also improving the thermal - mechanical performance of the transformer, thereby improving the stability of the power system. Description of the Drawings

[0014] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 is the implementation flowchart of the transformer thermal-mechanical performance optimization design method provided by the embodiments of the present application;

[0016] Figure 2 is the structural schematic diagram of the three-dimensional winding finite element model provided by the embodiments of the present application;

[0017] Figure 3 is the implementation flowchart block diagram of the transformer thermal-mechanical performance optimization design method provided by the embodiments of the present application;

[0018] Figure 4 is the structural schematic diagram of the transformer thermal-mechanical performance optimization design device provided by the embodiments of the present application. Specific Embodiments

[0019] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0020] To make the objectives, technical solutions, and advantages of the present application clearer, the following will be described through specific embodiments in conjunction with the drawings.

[0021] During the production process of existing transformers, the number of spacers, the width of spacers, the winding radius, etc. are mostly designed based on design experience. At the same time, when designing the winding, the relationship between the hot spot temperature of the winding and the short-circuit resistance ability is not considered simultaneously, but only designed separately, which leads to problems such as excessive margin selection, high equipment cost, and large load loss.

[0022] The embodiments of the present application provide a transformer thermal-mechanical performance optimization design method. First, the hot spot temperature is calculated through multi-physical simulation, the relationship between the hot spot temperature and the number of spacers, the width of spacers, and the winding radius is fitted, and at the same time, the functional formula of the short-circuit resistance ability of the winding and the structural parameters is given. Then, based on the non-dominated sorting genetic algorithm (NSGA-II), a response surface between the short-circuit resistance ability of the winding, the hot spot temperature, and the structural parameters of the transformer winding is established, and a multi-objective optimization design of the winding against the short-circuit resistance ability and the hot spot temperature is carried out.

[0023] Figure 1 The implementation flowchart of the transformer thermal performance optimization design method provided by the embodiments of the present application is described in detail as follows:

[0024] In step 101, a three-dimensional winding finite element model is established, and based on the three-dimensional winding finite element model, the hot spot temperature of the target transformer under each set of transformer winding structure parameters is determined. The transformer winding structure parameters include the number of spacers, the width of the spacers, and the winding radius.

[0025] In the embodiments of the present application, first, a simulated three-dimensional winding finite element model is established according to the structure and application scenario of the target transformer, where the three-dimensional winding finite element model is accurate to the high- and low-voltage winding disks and the insulation spacers between the disks. For the structural schematic diagram of the specific three-dimensional winding finite element model, refer to Figure 2 .

[0026] Then, using the three-dimensional winding finite element model, the hot spot temperature of the target transformer under different transformer winding structure parameters is calculated. Among them, the transformer winding structure parameters may include the number of spacers, the width of the spacers, and the winding radius.

[0027] In a possible implementation manner, establishing a three-dimensional winding finite element model may include:

[0028] Using finite element analysis to simulate the target transformer to establish a three-dimensional winding finite element model.

[0029] Among them, finite element analysis (FEA) uses a mathematical approximation method to simulate a real physical system (geometry and load conditions). By using simple and interacting elements (i.e., units), a real system with an infinite number of unknowns can be approximated with a finite number of unknowns.

[0030] Optionally, in this embodiment, finite element analysis is used to simulate the target transformer, including the winding structure and winding structure parameters of the target transformer, to establish a three-dimensional winding finite element model.

[0031] In a possible implementation manner, before determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters according to the three-dimensional winding finite element model, the method may further include:

[0032] Obtain the rated current of the target transformer and output the rated current into the three-dimensional winding finite element model to obtain the winding eddy current loss and DC resistance loss of the target transformer under each set of transformer winding structure parameters;

[0033] Calculate the sum of the winding eddy current loss and DC resistance loss of the target transformer under each set of transformer winding structure parameters as the corresponding winding loss;

[0034] Correspondingly, according to the three-dimensional winding finite element model, determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters may include:

[0035] Determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters according to the three-dimensional winding finite element model and the winding losses of the target transformer under each set of transformer winding structure parameters.

[0036] Optionally, in the established three-dimensional winding finite element model, select an actual magnetic field module, input the rated current of the target transformer into the three-dimensional winding finite element model, and automatically calculate the winding eddy current loss and DC resistance loss of the target transformer under each set of transformer winding structure parameters. And take the sum of the winding eddy current loss and DC resistance loss under each set of transformer winding structure parameters as the winding loss of the corresponding group.

[0037] Correspondingly, using the three-dimensional winding finite element model and the winding losses under each set of transformer winding structure parameters, determine the hot spot temperature of the target winding transformer under each set of transformer winding structure parameters.

[0038] In a possible implementation, the three-dimensional winding finite element model may include a laminar flow module and a solid-liquid heat transfer module.

[0039] In this embodiment, when performing thermal field analysis and using finite element software for fluid-solid coupling analysis, the laminar flow module and the solid-liquid heat transfer module in the three-dimensional winding finite element model can be selected for coupled calculation, and then the hot spot temperature can be calculated.

[0040] Among them, the three-dimensional diagram of the winding thermal field is used to intuitively display the temperature changes at different positions of the transformer winding. Since the temperatures at different positions of the transformer are definitely different, the hot spot temperature in this embodiment is the highest temperature selected in the winding thermal field.

[0041] In a possible implementation, according to the three-dimensional winding finite element model, determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters may include:

[0042] Perform coupled calculation on the laminar flow module and the solid-liquid heat transfer module;

[0043] Perform transient calculation on the winding losses of the target transformer under each set of transformer winding structure parameters and the laminar flow module and the solid-liquid heat transfer module after coupled calculation to obtain the hot spot temperature of the target transformer under this set of transformer winding structure parameters.

[0044] In this embodiment, considering that it is difficult for the finite element model of the three-dimensional winding to converge in the calculation of the steady-state thermal field (i.e., the winding thermal field), transient calculation is adopted. After the hot-spot temperature of the winding basically does not change with time, this temperature is considered the steady-state temperature. The basic principle of transient calculation is to discretize the fluid flow equation into a finite volume or from its original form, and use numerical methods to solve these discretized equations.

[0045] The specific calculation process is as follows: Taking the winding loss as the heat source of the winding, first perform a coupled calculation on the laminar flow module and the solid-liquid heat transfer module, and then perform a transient calculation on the winding loss of the target transformer under each set of transformer winding structure parameters and the laminar flow module and the solid-liquid heat transfer module after the coupled calculation to obtain the hot-spot temperature of the target transformer under each set of transformer winding structure parameters.

[0046] In a possible implementation, after obtaining the hot-spot temperature of the target transformer under this set of transformer winding structure parameters, the method may further include:

[0047] Taking each set of transformer winding structure parameters of the target transformer as inputs and the corresponding hot-spot temperatures as outputs, and jointly constructing a fitting function of the non-linear relationship between the transformer winding structure parameters and the hot-spot temperature;

[0048] The fitting function of the non-linear relationship between the transformer winding structure parameters and the hot-spot temperature is:

[0049] T = a1n 2 + a2R 2 + a3w 2 + a4nw + a5nR + a6Rw + a7n + a8R + a9w + a0

[0050] where T is the hot-spot temperature, n is the number of spacers, R is the winding radius, w is the spacer width, and a1, a2, a3, a4, a5, a6, a7, a8, a9, and a0 are all parameters to be fitted.

[0051] Optionally, using the established three-dimensional winding finite element model, by changing the number of spacers n, the winding radius R, and the spacer width w, the hot-spot temperatures corresponding to different structural parameters can be obtained. Then, based on this, regression modeling is performed, and the non-linear relationship between the winding structure parameters and the hot-spot temperature is fitted by a function to obtain the fitting function of the non-linear relationship between the transformer winding structure parameters and the hot-spot temperature, that is:

[0052] T = a1n 2 + a2R 2 + a3w 2 + a4nw + a5nR + a6Rw + a7n + a8R + a9w + a0

[0053] Wherein, T is the hot spot temperature, n is the number of spacers, R is the winding radius, w is the width of the spacer, and a1, a2, a3, a4, a5, a6, a7, a8, a9, and a0 are all fitting parameters to be determined.

[0054] In the embodiment of the present application, the non-linear relationship fitting function between the above-mentioned transformer winding structure parameters and the hot spot temperature can be used to calculate the hot spot temperature under different winding structure parameters, providing a convenient calculation basis for subsequent calculation of the hot spot temperature, and can improve the calculation speed and accuracy of the hot spot temperature and the transformer winding structure parameters.

[0055] In step 102, using the transformer winding structure parameters of each group of the target transformer, calculate the short-circuit withstand safety factor of the winding of the target transformer under the transformer winding structure parameters of each group.

[0056] Since the coils in the transformer are subjected to the action of uniformly distributed radial loads, under normal circumstances, the spacers on the inner side of the low-voltage winding can provide effective support for the winding. Under the action of the radial compressive stress, when it exceeds its critical load, the winding will become unstable. In addition, the circular arc arches between the spacers meet the conditions of thin walls and large height-span ratios, and the inner spacers have sufficient support stiffness. The circular arcs between the spacers are regarded as fixed-end straight beams, and the winding is subjected to radial bending stress, manifested as the uniform inward depression of the wires between the spacers. Therefore, when checking, it is necessary to consider the action of the radial compressive stress and the radial bending stress respectively.

[0057] In the embodiment of the present application, using the transformer winding structure parameters of each group of the target transformer, calculate the radial compressive stress and the radial bending stress respectively, and obtain the short-circuit withstand safety factor of the winding of the target transformer under the transformer winding structure parameters of each group.

[0058] In a possible implementation manner, the short-circuit withstand safety factor of the winding may include the radial stability safety factor of the winding. Using the transformer winding structure parameters of each group of the target transformer to calculate the short-circuit withstand safety factor of the winding of the target transformer under the transformer winding structure parameters of each group may include:

[0059] Input the transformer winding structure parameters of each group into the first formula to obtain the corresponding radial stability safety factor of the winding. The first formula is:

[0060]

[0061] Wherein, K1 is the radial stability safety factor of the winding, F is the actual compressive stress value, C is the critical load of winding instability, F rad is the radial load of the winding, R is the winding radius, E is the elastic modulus of the winding, I is the moment of inertia of the winding cross-section, n is the number of spacers, b is the height of the winding, and t is the thickness of the winding.

[0062] Optionally, the radial stability safety factor of the winding is calculated by taking the ratio of the actual compressive stress value of the transformer to the critical load of winding instability, that is, through the first formula The radial stability safety factor of the winding is calculated, where the calculation formula for the actual compressive stress value is F = F rad ·R, and the calculation formula for the critical load of winding instability is

[0063] In a possible implementation, the short-circuit resistance safety factor of the winding may include the radial bending stress safety factor of the winding. Using the structural parameters of each transformer winding of the target transformer, calculating the short-circuit resistance safety factor of the target transformer under the structural parameters of each transformer winding may include:

[0064] Inputting the structural parameters of each transformer winding into the second formula to obtain the corresponding radial bending stress safety factor of the winding. The second formula is:

[0065]

[0066] where K2 is the radial bending stress safety factor of the winding, R p0.2 is the non-proportional extension constant of the winding, σ r is the bending stress of the winding, F rad is the radial load of the winding, l is the length of the winding between pads, n is the number of pads, w is the width of the pads, R is the radius of the winding, and t is the thickness of the winding.

[0067] Optionally, the radial bending stress safety factor of the winding is calculated by taking the ratio of the non-proportional extension constant of the winding to the bending stress of the winding, that is, through the second formula The radial bending stress safety factor of the winding is calculated, where the non-proportional extension constant of the winding is a standard constant, and the calculation formula for the bending stress of the winding is

[0068] It can be seen from the above first formula and second formula that both the radial stability safety factor K1 of the winding and the radial bending stress safety factor K2 of the winding are related to the number of pads, the radius of the winding, and the width of the pads.

[0069] In step 103, based on the hot spot temperature and the short-circuit resistance safety factor of the winding of the target transformer under the structural parameters of each transformer winding, an optimal solution set of the target transformer on the Pareto front is determined, and a design scheme of the transformer winding structure parameters of the target transformer is determined based on the optimal solution set. The optimal solution set is multiple groups of optimal transformer winding structure parameters.

[0070] Among them, in a multi-objective optimization problem, there is usually no single optimal solution because different objectives may conflict with each other. The solutions on the Pareto front are considered non-dominated, that is, it is impossible to improve one objective without sacrificing other objectives. The purpose of calculating the Pareto front is to display all possible trade-off options as much as possible, enabling decision-makers to comprehensively understand the potential trade relationships between different objectives and providing diverse solutions. Generally speaking, in multi-objective optimization, the solutions on the Pareto front are already the optimal solution sets, and there is no situation where changing one variable can improve the performance of two or more objectives to be optimized on the Pareto front.

[0071] In the embodiment of the present application, based on the hot spot temperature of the target transformer under each set of transformer winding structure parameters calculated in step 101 and the corresponding winding short-circuit withstand safety factor calculated in step 102, the optimal solution set of the target transformer on the Pareto front is determined, where the optimal solution set includes multiple sets of optimal transformer winding structure parameters. Then, a transformer winding structure parameter design scheme suitable for the requirements of the target transformer is selected from the optimal solution set.

[0072] In a possible implementation manner, based on the hot spot temperature of the target transformer under each set of transformer winding structure parameters and the winding short-circuit withstand safety factor, determining the optimal solution set of the target transformer on the Pareto front may include:

[0073] Using the non-dominated sorting genetic algorithm, the convergence of each set of objective function values composed of the hot spot temperature and the winding short-circuit withstand safety factor is determined by iteration, and multiple sets of optimal solutions on the Pareto front are generated.

[0074] Among them, the non-dominated sorting genetic algorithm (NSGA-II) is a genetic algorithm based on the concept of Pareto optimality. Its main feature is to perform stratification according to the dominance relationship between individuals before the selection operator is executed. In this embodiment, multi-objective optimization is performed on the number of spacers, the width of spacers, and the winding radius based on the NSGA-II algorithm.

[0075] In the embodiment of the present application, the hot spot temperature and the winding short-circuit withstand safety factor conflict with each other. Therefore, the hot spot temperature of the target transformer under each set of transformer winding structure parameters and the winding short-circuit withstand safety factor are used as the objective function values of the corresponding group, and under the constraint of the objective function values, the non-dominated sorting genetic algorithm is used to determine the convergence by iteration, generating multiple sets of optimal solutions on the Pareto front, that is, multiple sets of optimal transformer winding structure parameters on the Pareto front.

[0076] The process of optimizing using the non-dominated sorting genetic algorithm is as follows:

[0077] (1) Set the range of the number of spacers, the width of spacers, and the winding radius, and initialize the population within this range.

[0078] (2) Select mutation and crossover operations to generate a new population.

[0079] (3) Merge the paternal population and the filial population to generate a new population.

[0080] (4) Perform fast non-dominated sorting. Based on the objective function values (hot spot temperature, radial stability safety factor of the winding, radial bending stress safety factor of the winding), determine the population sorting. Through sorting, the individuals in the population can be divided into different fronts.

[0081] (5) Calculate the distance between an individual in a certain front and other individuals in the same front to characterize the degree of crowding among individuals. Prioritize selecting individuals with a large crowding distance to enter the next round of screening, so as to comprehensively explore various possibilities. Iterate repeatedly to obtain the optimal Pareto front.

[0082] The specific implementation flowchart of the embodiments of this application is referred to Figure 3 , and the implementation process is as follows:

[0083] Step 1: Establish a three-dimensional winding finite element model, calculate the winding loss, then perform a thermal field analysis, perform a coupled calculation on the laminar flow module and the solid-liquid heat transfer module, and finally use the nonlinear relationship fitting function between the transformer winding structure parameters and the hot spot temperature to calculate the hot spot temperature under different transformer winding structure parameters. Among them, the transformer winding structure parameters include the number of spacers, the width of spacers, and the winding radius.

[0084] Step 2: Use the winding electromagnetic force, calculate the radial stability safety factor of the winding using the radial compression stress and the critical load of stability, and calculate the radial bending stress safety factor of the winding using the radial bending stress and the winding yield limit. Among them, both the radial stability safety factor of the winding and the radial bending stress safety factor of the winding are related to the number of spacers, the width of spacers, and the winding radius.

[0085] Step 3: Perform multi-objective optimization using the non-dominated sorting genetic algorithm:

[0086] 1) Population initialization;

[0087] 2) Non-dominated sorting crowding degree calculation;

[0088] 3) Selection, crossover, mutation, and population merging;

[0089] 4) Non-dominated sorting crowding degree calculation;

[0090] 5) Generate a new population;

[0091] 6) Determine whether the genetic algebra Gen of the population is less than the set value. If it is greater, end and output the new population. If it is less, then Gen = Gen + 1, and return to step 2) to continue execution.

[0092] The present application provides a method for optimizing the thermal-mechanical performance design of a transformer. By establishing a three-dimensional winding finite element model and based on the three-dimensional winding finite element model, the hot spot temperature of the target transformer under each set of transformer winding structure parameters is determined. The transformer winding structure parameters include the number of spacers, the width of the spacers, and the winding radius. Using each set of transformer winding structure parameters of the target transformer, the short-circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters is calculated. Based on the hot spot temperature and the short-circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters, the optimal solution set of the target transformer on the Pareto front is determined, and based on the optimal solution set, the design scheme of the transformer winding structure parameters of the target transformer is determined. The optimal solution set is multiple sets of optimal transformer winding structure parameters. The present application determines the optimal solution set of the target transformer on the Pareto front by simultaneously using the hot spot temperature and the short-circuit withstand safety factor of the winding of the transformer, providing users with the option to select the optimal transformer winding structure parameters suitable for the target transformer, which not only improves the safety of the transformer but also improves the thermal-mechanical performance of the transformer, thus improving the stability of the power system.

[0093] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0094] The following is the device embodiment of the present application. For the details not described in detail herein, reference may be made to the corresponding method embodiment above.

[0095] Figure 4 The structural schematic diagram of the transformer thermal-mechanical performance optimization design device provided by the embodiment of the present application is shown. For the convenience of description, only the parts related to the embodiment of the present application are shown and are described in detail as follows:

[0096] As Figure 4 shown, the transformer thermal-mechanical performance optimization design device 4 includes:

[0097] A hot spot temperature determination module 41, configured to establish a three-dimensional winding finite element model and, based on the three-dimensional winding finite element model, determine the hot spot temperature of the target transformer under each set of transformer winding structure parameters, where the transformer winding structure parameters include the number of spacers, the width of the spacers, and the winding radius;

[0098] A safety factor determination module 42, configured to use each set of transformer winding structure parameters of the target transformer to calculate the short-circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters;

[0099] A design scheme determination module 43, configured to determine an optimal solution set of the target transformer on the Pareto front based on the hot spot temperature and the short-circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters, and determine a design scheme of the transformer winding structure parameters of the target transformer based on the optimal solution set, where the optimal solution set is multiple sets of optimal transformer winding structure parameters.

[0100] The present application provides a transformer thermal-mechanical performance optimization design device. By establishing a three-dimensional winding finite element model, and based on the three-dimensional winding finite element model, determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters, where the transformer winding structure parameters include the number of spacers, the width of the spacers, and the winding radius; using each set of transformer winding structure parameters of the target transformer to calculate the short-circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters; based on the hot spot temperature and the short-circuit withstand safety factor of the winding of the target transformer under each set of transformer winding structure parameters, determining an optimal solution set of the target transformer on the Pareto front, and determining a design scheme of the transformer winding structure parameters of the target transformer based on the optimal solution set, where the optimal solution set is multiple sets of optimal transformer winding structure parameters. The present application determines an optimal solution set of the target transformer on the Pareto front by simultaneously using the hot spot temperature and the short-circuit withstand safety factor of the transformer, for the user to select the optimal transformer winding structure parameters suitable for the target transformer, which not only improves the safety of the transformer, but also improves the thermal-mechanical performance of the transformer, thereby improving the stability of the power system.

[0101] In a possible implementation manner, the hot spot temperature determination module may be configured to:

[0102] Simulate the target transformer using finite element analysis to establish a three-dimensional winding finite element model.

[0103] In a possible implementation manner, the hot spot temperature determination module may also be configured to:

[0104] Obtain the rated current of the target transformer, and output the rated current into the three-dimensional winding finite element model to obtain the winding eddy current loss and the direct resistance loss of the target transformer under each set of transformer winding structure parameters;

[0105] Respectively calculate the sum of the winding eddy current loss and the direct resistance loss of the target transformer under each set of transformer winding structure parameters as the corresponding winding loss;

[0106] Correspondingly, the hot spot temperature determination module may be configured to:

[0107] Determine the hot spot temperature of the target transformer under each set of transformer winding structure parameters according to the three-dimensional winding finite element model and the winding loss of the target transformer under each set of transformer winding structure parameters.

[0108] In a possible implementation, the three-dimensional winding finite element model may include a laminar flow module and a solid-liquid heat transfer module.

[0109] In a possible implementation, the hot spot temperature determination module may also be used for:

[0110] Performing coupled calculations on the laminar flow module and the solid-liquid heat transfer module;

[0111] Performing transient calculations on the winding losses of the target transformer under each set of transformer winding structure parameters and the laminar flow module and the solid-liquid heat transfer module after coupled calculations to obtain the hot spot temperature of the target transformer under this set of transformer winding structure parameters.

[0112] In a possible implementation, the device may further include a function fitting module, and the function fitting module may be used for:

[0113] Taking each set of transformer winding structure parameters of the target transformer as inputs and the corresponding hot spot temperatures as outputs, and jointly constructing a non-linear relationship fitting function between the transformer winding structure parameters and the hot spot temperatures;

[0114] The non-linear relationship fitting function between the transformer winding structure parameters and the hot spot temperatures is:

[0115] T = a1n 2 + a2R 2 + a3w 2 + a4nw + a5nR + a6Rw + a7n + a8R + a9w + a0

[0116] Wherein, T is the hot spot temperature, n is the number of spacers, R is the winding radius, w is the spacer width, and a1, a2, a3, a4, a5, a6, a7, a8, a9, and a0 are all parameters to be fitted.

[0117] In a possible implementation, the short-circuit resistance safety factor of the winding may include the radial stability safety factor of the winding, and the safety factor determination module may be used for:

[0118] Inputting each set of transformer winding structure parameters into the first formula to obtain the corresponding radial stability safety factor of the winding. The first formula is:

[0119]

[0120] Wherein, K1 is the radial stability safety factor of the winding, F is the actual compressive stress value, C is the critical load for winding instability, F rad is the radial load of the winding, R is the winding radius, E is the elastic modulus of the winding, I is the moment of inertia of the winding cross-section, n is the number of spacers, b is the winding height, and t is the winding thickness.

[0121] In a possible implementation, the short-circuit resistance safety factor of the winding may include the safety factor of the radial bending stress of the winding, and the safety factor determination module may be used for:

[0122] Input the structural parameters of each group of transformer windings into the second formula to obtain the corresponding safety factor of the radial bending stress of the winding. The second formula is:

[0123]

[0124] where K2 is the safety factor of the radial bending stress of the winding, R p0.2 is the non-proportional extension constant of the winding, σ r is the bending stress of the winding, F rad is the radial load of the winding, l is the length of the winding between the pads, n is the number of pads, w is the width of the pads, R is the radius of the winding, and t is the thickness of the winding.

[0125] In a possible implementation, the design scheme determination module may be used for:

[0126] Using the non-dominated sorting genetic algorithm, perform iterative convergence determination on each group of objective function values composed of the hot spot temperature and the short-circuit resistance safety factor of the winding, and generate multiple groups of optimal solutions on the Pareto front.

[0127] In the above embodiments, the descriptions of the various embodiments have their own emphases. For parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0128] Those of ordinary skill in the art can realize that, in combination with the templates, units, and algorithm steps of the examples described in the embodiments disclosed herein, they can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0129] If the module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described embodiments of the various transformer heat engine performance optimization design methods can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0130] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for optimizing the thermal performance of a transformer, characterized in that: include: Establishing a three-dimensional winding finite element model, and determining the hot spot temperature of the target transformer under each set of transformer winding structural parameters according to the three-dimensional winding finite element model, wherein the transformer winding structural parameters include the number of pads, pad width and winding radius; Calculating the winding short-circuit safety factor of the target transformer under each set of transformer winding structural parameters using each set of transformer winding structural parameters of the target transformer; Based on the hot spot temperature and the winding short-circuit safety factor of the target transformer under each set of transformer winding structure parameters, the optimal solution set of the target transformer on the Pareto front surface is determined, and the transformer winding structure parameter design scheme of the target transformer is determined based on the optimal solution set, and the optimal solution set is a plurality of sets of optimal transformer winding structure parameters.

2. The transformer thermal engine performance optimization design method according to claim 1 is characterized in that: The three-dimensional winding finite element model is established, comprising: The target transformer is simulated by using finite element analysis to establish the three-dimensional winding finite element model.

3. The transformer thermal engine performance optimization design method according to claim 1 is characterized in that: Before determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters according to the three-dimensional winding finite element model, the method further includes: Acquire the rated current of the target transformer, and output the rated current to the three-dimensional winding finite element model to obtain the winding eddy current loss and direct resistance loss of the target transformer under each set of transformer winding structure parameters; Respectively calculating the sum of the winding eddy current loss and the direct resistance loss of the target transformer under each set of transformer winding structure parameters as the corresponding winding loss; Accordingly, determining the hot spot temperature of the target transformer under each set of transformer winding structure parameters according to the three-dimensional winding finite element model includes: The hot spot temperature of the target transformer under each set of transformer winding structural parameters is determined according to the three-dimensional winding finite element model and the winding loss of the target transformer under each set of transformer winding structural parameters.

4. The transformer thermal engine performance optimization design method according to claim 3 is characterized in that: The three-dimensional winding finite element model includes a laminar flow module and a solid-liquid heat transfer module. The hot spot temperature of the target transformer under each set of transformer winding structure parameters is determined according to the three-dimensional winding finite element model, including: Performing coupling calculation on the laminar flow module and the solid-liquid heat transfer module; Transient calculation is performed on the laminar flow module and the solid-liquid heat transfer module after coupling calculation of the winding loss of the target transformer under each set of transformer winding structural parameters to obtain the hot spot temperature of the target transformer under the set of transformer winding structural parameters.

5. The transformer thermal engine performance optimization design method according to claim 4 is characterized in that: After obtaining the hot spot temperature of the target transformer under the group of transformer winding structure parameters, the method further includes: Each set of transformer winding structural parameters of the target transformer is taken as input, and the corresponding hot spot temperature is taken as output, and a nonlinear relationship fitting function between the transformer winding structural parameters and the hot spot temperature is jointly constructed; The nonlinear relationship fitting function between the transformer winding structure parameters and the hot spot temperature is: T=a1n 2 +a2R 2 +a3w 2 +a4nw+a5nR+a6Rw+a7n+a8R+a9w+a0 Among them, T is the hot spot temperature, n is the number of the pads, R is the winding radius, w is the pad width, and a1, a2, a3, a4, a5, a6, a7, a8, a9 and a0 are all parameters to be fitted.

6. The transformer thermal engine performance optimization design method according to claim 1 is characterized in that: The winding short-circuit safety factor includes a winding amplitude stability safety factor. The calculation of the winding short-circuit safety factor of the target transformer under each set of transformer winding structure parameters using each set of transformer winding structure parameters includes: Input the structural parameters of each set of transformer windings into the first formula to obtain the corresponding winding amplitude stability safety factor, and the first formula is: Wherein, K1 is the radial stability safety factor of the winding, F is the actual compressive stress value, C is the critical load of winding instability, and F rad is the radial load of the winding, R is the winding radius, E is the winding elastic modulus, I is the winding section inertia moment, n is the number of pads, b is the winding height, and t is the winding thickness.

7. The transformer thermal engine performance optimization design method according to claim 1 is characterized in that: The winding short-circuit safety factor includes a winding radial bending stress safety factor. The calculation of the winding short-circuit safety factor of the target transformer under each set of transformer winding structural parameters using each set of transformer winding structural parameters includes: Input the structural parameters of each set of transformer windings into the second formula to obtain the corresponding winding radial bending stress safety factor. The second formula is: Wherein, K2 is the safety factor of the winding radial bending stress, R p0.2 is the non-proportional extension constant of the winding, σ r is the winding bending stress, F rad is the radial load of the winding, l is the winding length between the pads, n is the number of the pads, w is the pad width, R is the winding radius, and t is the winding thickness.

8. The transformer thermal engine performance optimization design method according to claim 1 is characterized in that: The step of determining the optimal solution set of the target transformer on the Pareto front surface based on the hot spot temperature and the winding short-circuit safety factor of the target transformer under each set of transformer winding structure parameters includes: A non-dominated sorting genetic algorithm is used to iteratively determine the convergence of each group of objective function values ​​consisting of the hot spot temperature and the winding short-circuit safety factor, and generate multiple groups of optimal solutions on the Pareto front surface.

9. A transformer thermal engine performance optimization design device, characterized in that: include: A hot spot temperature determination module, used to establish a three-dimensional winding finite element model, and determine the hot spot temperature of the target transformer under each set of transformer winding structure parameters according to the three-dimensional winding finite element model, wherein the transformer winding structure parameters include the number of pads, the pad width and the winding radius; A safety factor determination module, used to calculate the winding short-circuit safety factor of the target transformer under each set of transformer winding structure parameters by using each set of transformer winding structure parameters of the target transformer; A design scheme determination module is used to determine the optimal solution set of the target transformer on the Pareto front surface based on the hot spot temperature and the winding short-circuit safety factor of the target transformer under each set of transformer winding structure parameters, and determine the transformer winding structure parameter design scheme of the target transformer based on the optimal solution set, wherein the optimal solution set is a plurality of sets of optimal transformer winding structure parameters.

10. The transformer thermal engine performance optimization design device according to claim 9, characterized in that: The device further comprises a fitting function determining module, wherein the fitting function determining module is used for: Each set of transformer winding structural parameters of the target transformer is taken as input, and the corresponding hot spot temperature is taken as output, and a nonlinear relationship fitting function between the transformer winding structural parameters and the hot spot temperature is jointly constructed; The nonlinear relationship fitting function between the transformer winding structure parameters and the hot spot temperature is: T=a1n 2 +a2R 2 +a3w 2 +a4nw+a5nR+a6Rw+a7n+a8R+a9w+a0 Among them, T is the hot spot temperature, n is the number of the pads, R is the winding radius, w is the pad width, and a1, a2, a3, a4, a5, a6, a7, a8, a9 and a0 are all parameters to be fitted.

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