Transformer winding deformation prediction method under short circuit impact and related device

Abstract

The invention belongs to the technical field of power equipment short circuit dynamic characteristic analysis, and discloses a transformer winding deformation prediction method under short circuit impact and a related device, and the method comprises the steps: calculating radial electromagnetic force and circumferential electromagnetic force borne by a winding wire cake according to the short circuit impact current borne by a transformer; establishing an equivalent dynamic model of the winding wire cake according to the material characteristics of the transformer and the partitioning result of the winding wire cake; according to the radial electromagnetic force and the circumferential electromagnetic force borne by the winding wire cake and in combination with the equivalent dynamic model of the winding wire cake, a preset deformation index of the winding wire cake is solved, and a winding deformation prediction result of the transformer under the short-circuit impact is obtained; wherein the preset deformation indexes of the winding wire cake comprise radial deformation, radial displacement, circumferential deformation and circumferential displacement of the winding wire cake; according to the method, the calculation efficiency of winding deformation and displacement is improved, more accurate winding displacement and deformation data after short-circuit impact can be obtained, and the method has important significance for accurately diagnosing the state of the transformer winding.

Description

Technical Field

[0001] The present invention belongs to the technical field of short-circuit dynamic characteristic analysis of electric power equipment, and in particular relates to a method for predicting winding deformation of a transformer under a short-circuit impact and a related device. Background Art

[0002] Transformers are core equipment for voltage conversion and energy transmission in power systems. The safe and stable operation of transformers is closely related to daily production and life. During normal operation, the electromagnetic force acting on the windings is relatively small and insufficient to cause faults. However, under extreme conditions such as short-circuit shocks, the short-circuit current flowing through the windings is much higher than the rated value, and the leakage magnetic field increases sharply. Under the combined action of the short-circuit current and the leakage magnetic field, a huge electromagnetic force will be generated, causing the windings to shift and deform. In severe cases, it may cause inter-turn insulation breakage, partial discharge, and even winding collapse.

[0003] With the continuous improvement of the scientific nature of transformer design and manufacturing methods, the mechanical strength, stability and impact resistance of transformer windings have also been greatly improved; the transformer will not be completely destroyed by a single short-circuit impact, but after a short-circuit impact occurs, due to the covering of the oil tank and insulating medium, the specific displacement and deformation of the winding cannot be directly observed, and thus the transformer status cannot be accurately assessed; in addition, due to the high cost of transformers, the short-circuit impact test has high requirements for test conditions and is a destructive test, making the research on the mechanical characteristics of transformer windings based on short-circuit impact tests expensive and difficult to carry out. There are few samples of the transformer winding status after short-circuit impact, and it is impossible to intuitively summarize the laws of winding displacement and deformation.

[0004] Currently, most studies on winding stress and deformation use the finite element method. However, existing finite element methods generally have problems such as large computational workload and complex calculation process. In particular, when calculating for each winding coil, the computational workload increases dramatically, seriously affecting the calculation efficiency of winding deformation and displacement. Summary of the Invention

[0005] In response to the technical problems existing in the prior art, the present invention provides a method and related device for predicting the winding deformation of a transformer under a short-circuit impact, so as to solve the technical problems of the existing finite element method, such as large amount of calculation and complex calculation process.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a method for predicting transformer winding deformation under short-circuit impact, comprising: According to the short-circuit impulse current of the transformer, the radial electromagnetic force and circumferential electromagnetic force acting on the winding coil are calculated; Based on the material properties of the transformer and the partition results of the winding coil, an equivalent dynamic model of the winding coil is established; Based on the radial and circumferential electromagnetic forces acting on the winding coil and combined with the equivalent dynamic model of the winding coil, the preset deformation indicators of the winding coil are solved to obtain the prediction results of the transformer winding deformation under short-circuit impact. Among them, the preset deformation indicators of the winding coil include the radial deformation, radial displacement, circumferential deformation and circumferential displacement of the winding coil.

[0007] Furthermore, the process of calculating the radial electromagnetic force and the circumferential electromagnetic force on the winding coil according to the short-circuit impulse current received by the transformer includes: According to the structural parameters and electrical parameters of the transformer, a three-dimensional equivalent model of the transformer is established; The short-circuit impulse current applied to the transformer is used as an excitation and applied to the three-dimensional equivalent model of the transformer to obtain the three-dimensional equivalent model of the transformer with the applied excitation; Perform transient calculations on the three-dimensional equivalent model of the transformer with applied excitation to obtain the transient electromagnetic forces acting on the winding coils. The radial electromagnetic force and circumferential electromagnetic force acting on the winding coil are extracted from the transient electromagnetic force acting on the winding coil.

[0008] Furthermore, the equivalent dynamic model of the winding coil is a mass-spring-damper system model in a polar coordinate system.

[0009] Furthermore, based on the material properties of the transformer and the partitioning results of the winding coils, the process of establishing an equivalent dynamic model of the winding coils includes: Partitioning the winding coil according to the structural parameters of the winding coil to obtain a partition result of the winding coil; wherein the structural parameters of the winding coil include the number of parallel conductors and the number of struts in the winding coil; Based on the structural parameters of the winding coil, several mass units, several elastic elements and several damping elements are created; Based on the partitioning results of the winding coil, several mass units, several elastic elements, and several damping elements are arranged in a fan-shaped manner in the pre-constructed polar coordinates until a circular ring form is formed. According to the Young's modulus of the copper wire and the Young's modulus of the strut in the winding coil, and the damping coefficient of the transformer oil, the parameters of the several elastic elements and the damping elements are set to obtain the mass-spring-damper system model in the polar coordinate system as the equivalent dynamic model of the winding coil.

[0010] Furthermore, the process of partitioning the winding coil according to the structural parameters of the winding coil to obtain the partitioning result of the winding coil includes: The winding coil is partitioned radially and circumferentially according to the number of parallel conductors and the number of struts in the winding coil, respectively, to obtain the partitioning results of the winding coil. When the winding coil is partitioned radially, the winding coil is divided into regions along the radial direction according to multiples or factors of the number of parallel conductors in the winding coil; when the winding coil is partitioned circumferentially, the winding coil is divided into regions along the circumferential direction according to multiples of the number of struts in the winding coil.

[0011] Furthermore, based on the radial electromagnetic force and circumferential electromagnetic force acting on the winding coil and in combination with the equivalent dynamic model of the winding coil, a preset deformation index of the winding coil is solved to obtain the winding deformation prediction result of the transformer under the short-circuit impact, which includes: According to the attenuation characteristics of the short-circuit impulse current received by the transformer and the predetermined winding deformation prediction accuracy, the total iterative solution time and the iterative solution step size are determined; The radial electromagnetic force and circumferential electromagnetic force acting on the winding coil are substituted into the equivalent dynamic model of the winding coil. Based on the total iterative solution time and iterative solution step size, the preset deformation index of the winding coil is iteratively solved to obtain the prediction result of the winding deformation of the transformer under short-circuit impact.

[0012] The present invention also provides a system for predicting transformer winding deformation under short-circuit impact, comprising: The electromagnetic force calculation module is used to calculate the radial electromagnetic force and circumferential electromagnetic force on the winding coil according to the short-circuit impact current of the transformer; Modeling module, used to establish an equivalent dynamic model of the winding coil based on the material properties of the transformer and the partition results of the winding coil; The deformation solution module is used to solve the preset deformation indicators of the winding coil based on the radial electromagnetic force and circumferential electromagnetic force on the winding coil, combined with the equivalent dynamic model of the winding coil, to obtain the winding deformation prediction result of the transformer under short-circuit impact; among which, the preset deformation indicators of the winding coil include the radial deformation, radial displacement, circumferential deformation and circumferential displacement of the winding coil.

[0013] The present invention also provides an electronic device, comprising: a processor suitable for executing a computer program; A computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the method for predicting transformer winding deformation under short-circuit impact is executed.

[0014] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the method for predicting transformer winding deformation under short-circuit impact is implemented.

[0015] The present invention also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the method for predicting the winding deformation of a transformer under a short-circuit impact.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for predicting transformer winding deformation under short-circuit impact. The method calculates the electromagnetic force on the winding coil according to the short-circuit impact current, establishes an equivalent dynamic model based on the material properties and the partitioning results, and then solves the preset deformation index to predict the winding deformation. Compared with the existing finite element method, the method can comprehensively consider multiple factors such as the transformer winding material and structure, and can be modeled without significant simplification. It avoids the problems of large calculation amount and complex process of the finite element method, improves the calculation efficiency of the winding deformation and displacement, and can obtain more accurate winding displacement and deformation data after short-circuit impact. It has important practical significance for accurately diagnosing the winding status of the power transformer and scientifically evaluating its life. It effectively solves the problems of being unable to intuitively observe the winding displacement and deformation, the high cost of the short-circuit impact test and the small number of samples, and the difficulty in studying the winding status law.

[0017] The system, electronic device, computer-readable storage medium and computer program product for predicting transformer winding deformation under short-circuit impact provided by the present invention have all the advantages of the above-mentioned method for predicting transformer winding deformation under short-circuit impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 A flow chart of the method for predicting transformer winding deformation under short-circuit impact provided in Example 1; Figure 2 A top view of the winding structure of the double-winding transformer in Example 1; Figure 3 Schematic diagram of the equivalent dynamic model of the winding coil in Example 1; Figure 4 A structural block diagram of a system for predicting transformer winding deformation under short-circuit impact provided in Example 2; Figure 5 This is a structural block diagram of the electronic device provided in Example 3.

[0020] Among them, there are 1 support bar, 100 mass units, 200 elastic elements, and 300 damping elements. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions, and beneficial effects solved by this application more clearly understood, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application; it is obvious that the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of this application.

[0022] The present invention provides a method for predicting transformer winding deformation under short-circuit impact, comprising the following steps: Step 100: Calculate the radial electromagnetic force and the circumferential electromagnetic force on the winding coil according to the short-circuit impulse current received by the transformer.

[0023] Step 200: Establish an equivalent dynamic model of the winding coil according to the material properties of the transformer and the partitioning result of the winding coil.

[0024] Step 300: Based on the radial electromagnetic force and circumferential electromagnetic force acting on the winding coil and in combination with the equivalent dynamic model of the winding coil, a preset deformation index of the winding coil is solved to obtain a prediction result of the winding deformation of the transformer under the short-circuit impact; wherein the preset deformation index of the winding coil includes the radial deformation, radial displacement, circumferential deformation, and circumferential displacement of the winding coil.

[0025] The method for predicting transformer winding deformation under short-circuit impact described in the present invention adopts numerical modeling and comprehensively considers factors such as transformer winding material and structure. Compared with the finite element method, the calculation process is greatly simplified and the amount of calculation is reduced. It can more efficiently solve the preset deformation index of the winding coil and obtain more accurate winding deformation prediction results. It solves the problem of difficulty in accurately evaluating the transformer state due to the inability to intuitively observe the winding displacement deformation after a short-circuit impact, and provides a strong basis for diagnosing the state of the power transformer winding and evaluating its life. In the present invention, there is no need to over-simplify the winding structure, and the material properties and structural factors can be comprehensively considered, thereby improving the calculation accuracy and reducing the amount of calculation. It can be used for state diagnosis and life assessment of power transformers, etc., and provides a reliable basis for safety analysis of transformer windings under short-circuit impact.

[0026] The following further explains the method for predicting transformer winding deformation under short-circuit impact provided by the present invention with some specific embodiments: Example 1 As attached Figure 1 As shown, this embodiment 1 provides a method for predicting winding deformation of a transformer under a short-circuit impact, comprising the following steps: Step 1: Calculate the radial electromagnetic force and circumferential electromagnetic force on the winding coil according to the short-circuit impulse current of the transformer. Specifically, the steps are as follows: Step 11: Establish a three-dimensional equivalent model of the transformer based on the structural parameters and electrical parameters of the transformer. The structural parameters of the transformer include the core size, number of winding turns, winding wire diameter, number of winding layers, insulation distance between windings, and oil tank size of the transformer. The electrical parameters of the transformer include rated voltage, rated current, short-circuit impedance, no-load loss, load loss, and excitation current.

[0027] Step 12: For different short-circuit conditions, the impact current under the corresponding short-circuit condition is calculated in the form of a circuit to obtain the short-circuit impact current received by the transformer.

[0028] Step 13: Use the short-circuit impulse current received by the transformer as excitation and apply it to the three-dimensional equivalent model of the transformer to obtain the three-dimensional equivalent model of the transformer with applied excitation.

[0029] Step 14: Using predetermined finite element analysis software or predetermined computational analysis software, perform transient calculations on the three-dimensional equivalent model of the transformer to which excitation is applied, to obtain the transient electromagnetic force acting on the winding coils; wherein the predetermined finite element analysis software may be, for example, COMSOL or ANSYS, and the predetermined computational analysis software may be, for example, pre-programmed software that uses the edge finite element method for calculations.

[0030] Step 15: Extract the radial electromagnetic force and the circumferential electromagnetic force on the winding coil from the transient electromagnetic force on the winding coil.

[0031] Step 2: Based on the material properties of the transformer and the partitioning results of the winding coil, an equivalent dynamic model of the winding coil is established. The equivalent dynamic model of the winding coil is a mass-spring-damper system model in a polar coordinate system.

[0032] Specifically, the process of establishing the equivalent dynamic model of the winding coil is as follows: Step 21: partition the winding coil according to the structural parameters of the winding coil to obtain the partition results of the winding coil; wherein the structural parameters of the winding coil include the number of parallel conductors and the number of struts in the winding coil.

[0033] Specifically, the process of partitioning the winding coil includes: partitioning the winding coil radially and circumferentially according to the number of parallel conductors and the number of struts in the winding coil, respectively, to obtain the partitioning results of the winding coil; wherein, when the winding coil is partitioned radially, the winding coil is divided into regions along the radial direction according to multiples or factors of the number of parallel conductors in the winding coil; when the winding coil is partitioned circumferentially, the winding coil is divided into regions along the circumferential direction according to multiples of the number of struts in the winding coil.

[0034] Step 22: Based on the structural parameters of the winding bobbin, create a number of mass units, a number of elastic elements, and a number of damping elements.

[0035] Step 23: Based on the partitioning result of the winding coil, a plurality of mass units, a plurality of elastic elements, and a plurality of damping elements are arranged in a fan-shaped manner in a pre-constructed polar coordinate system until a circular ring shape is formed; parameters of the plurality of elastic elements and the plurality of damping elements are set according to the Young's modulus of the copper wire in the winding coil, the Young's modulus of the strut, and the damping coefficient of the transformer oil, to obtain a mass-spring-damper system model in the polar coordinate system as an equivalent dynamic model of the winding coil.

[0036] Taking a two-winding transformer as an example, the construction process of the equivalent dynamic model of the winding coil is explained as follows: As attached Figure 2 As shown, attached Figure 2 The top view of the winding structure of the double-winding transformer is given in the following; Figure 2 In the figure, a rectangular block is used to represent the strut 1.

[0037] First, according to the number of parallel conductors and braces in the winding coil, and combined with the predetermined winding deformation prediction accuracy, the winding coil is evenly divided into The winding coil is evenly divided into radial sub-areas along the circumference. circumferential sub-regions; specifically, when the winding coil is divided radially, the winding coil is divided into regions along the radial direction according to the multiples or factors of the number of parallel conductors in the winding coil; when the winding coil is divided circumferentially, the winding coil is divided into regions along the circumferential direction according to the multiples of the number of struts in the winding coil; that is, the number of radial sub-regions is The value of is set according to the multiple or factor of the number of parallel conductors in the winding coil, and the number of circumferential sub-areas is The value is set as a multiple of the number of stays in the winding coil.

[0038] It should be noted that, in order to clearly demonstrate the mass-spring-damper system model in the polar coordinate system, in this embodiment 1, the number of circumferential sub-regions is The value of is set according to twice the number of struts in the winding coil, and the strut 1 is set to a fixed constraint or fixed displacement according to the actual situation of the transformer.

[0039] Next, based on the structural parameters of the winding bobbin, a number of mass units 100 , a number of elastic elements 200 and a number of damping elements 300 are created.

[0040] Next, according to the partitioning results of the winding coil, a number of mass units 100, a number of elastic elements 200 and a number of damping elements 300 are arranged in a fan-shaped manner in the pre-constructed polar coordinates until a circular ring form is formed; wherein the center of the winding coil is used as the origin of the pre-constructed polar coordinates; a mass unit 100 is arranged in the intersection area of ​​the circumferential sub-area and the radial sub-area, and an elastic element 200 and a damping element 300 are sequentially set between two adjacent mass units 100; it is worth noting that each mass unit 100 serves as a mass point in the corresponding area.

[0041] Finally, according to the Young's modulus of the copper wire in the winding coil, the Young's modulus of the stay and the damping coefficient of the transformer oil, the parameters of several elastic elements and several damping elements are set to obtain the mass-spring-damper system model in the polar coordinate system as the equivalent dynamic model of the winding coil, as shown in the attached figure. Figure 3 shown.

[0042] In the attached Figure 3 In the figure, according to the different partition positions where the mass unit 100 is located, it is divided into an inner area mass unit, a support area mass unit and a free area mass unit; wherein, the inner area mass unit is a mass unit located in the inner area away from the strut; the support area mass unit is a mass unit located in the area directly contacting the strut on both sides of the winding, and the support area mass unit includes the outer support area mass unit of the winding and the inner support area mass unit of the winding; the free area mass unit is a mass unit located on both sides of the winding, without strut support and without spring elements and damping elements connected to the outside, and the free area mass unit includes the free mass unit of the outer part of the winding and the free mass unit of the inner part of the winding.

[0043] The spring element and the damping element between two adjacent mass units form a set of connection pairs, and the unit vector on the connection pair is:

[0044] in, For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to The unit vector of the upper adjacent mass unit; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to The vector difference between adjacent mass units; For direction, take 、 、 or .

[0045] Since the forces on the mass units in different partitions are different, the dynamic equation of the mass unit 100 is specifically expressed as follows: (1) The radial motion formula of the inner mass unit is as follows:

[0046]

[0047]

[0048]

[0049] in, For the radial sub-regions and the The mass of the mass unit at the intersection of the circumferential sub-regions, , ; is the total number of radial sub-partitions; is the total number of circumferential sub-partitions; For the radial sub-regions and the The linear displacement of the mass unit in the radial direction at the intersection of the circumferential sub-regions; For the The stiffness of the elastic elements connected to the inner sides of the mass units arranged radially in the sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the radial direction is equal to the length of the elastic element in the adjacent radial direction at a certain moment. is the average distance between two adjacent mass units along the radial direction, which is equivalent to the original length of the radial elastic element. Due to the uniform partitioning, the lengths of all radial elastic elements are considered to be the same; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to the unit vector of the adjacent mass unit in the radial outward direction; The polar coordinate system with the winding center as the origin points to the first radial sub-regions and the The unit vector of the mass unit at the intersection of the circumferential sub-regions; To follow the The radial damping coefficient inside the mass unit arranged in the radial sub-region; To follow the The stiffness of the radial elastic elements connected to the inner sides of the mass units arranged in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the radial direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to the unit vector of the adjacent unit in the radial direction; To follow the The radial damping coefficient inside the mass unit arranged in radial sub-regions; To follow the The stiffness of the elastic elements arranged circumferentially in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the counterclockwise direction of the circumference; To follow the The average distance between two adjacent mass units in the radial sub-region is equivalent to the The original length of the elastic element in each radial sub-region; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent unit in the circumferential direction, that is, in the counterclockwise direction; To follow the Circumferential damping coefficient of the mass units arranged in radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The radial component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions; is the outer radius of the winding; is the inner radius of the winding; To follow the The distance from the mass unit of each radial sub-region to the center of the winding circle.

[0050] (2) The circumferential motion formula of the inner mass unit is as follows:

[0051] in, For the radial sub-regions and the The linear displacement of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; is the polar coordinate system with the winding center as the origin. radial sub-regions and the The unit vector of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; For the radial sub-regions and the The circumferential component of the short-circuit electromotive force acting on the mass unit at the intersection of the circumferential sub-regions.

[0052] It should be noted that in the inner area mass unit, the subscript , subscript In the above formulas for radial motion of the inner mass unit and circumferential motion of the inner unit, the subscript represents the position of the circumferential sub-region; since or It only represents the adjacent mass units in the counterclockwise or clockwise direction, which changes periodically; therefore, if or If it exceeds the defined range, or operation.

[0053] (3) The radial motion formula of the mass unit in the outer support area of ​​the winding is as follows:

[0054] in, For the radial sub-regions and the The mass of the mass unit at the intersection of the circumferential sub-regions, ; For the radial sub-regions and the The linear displacement of the mass unit in the radial direction at the intersection of the circumferential sub-regions; is the stiffness of the radially arranged elastic elements outside the mass unit of the support area; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit on the outside in the radial direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to the unit vector of the adjacent mass unit outside in the radial direction; The polar coordinate system with the winding center as the origin points to the first radial sub-regions and the The unit vector of the mass unit at the intersection of the circumferential sub-regions; is the damping coefficient of the radially arranged damping elements outside the support area mass unit; To follow the The stiffness of the radially arranged elastic elements connected to the inner sides of the mass units arranged in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the radial direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to the unit vector of the adjacent unit in the radial direction; To follow the The radial damping coefficient inside the mass unit arranged in radial sub-regions; To follow the The stiffness of the circumferentially arranged elastic elements of the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the counterclockwise direction of the circumference; To follow the The average distance between two adjacent mass units arranged in the radial sub-region is equivalent to the The original length of the elastic elements arranged in radial sub-regions; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent unit in the counterclockwise direction of the circumference; To follow the Circumferential damping coefficient of the mass units arranged in radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent unit in the circumferential clockwise direction; For the radial sub-regions and the The radial component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is .

[0055] (4) The formula for the circumferential motion of the mass unit in the outer support area of ​​the winding is as follows:

[0056] in, For the radial sub-regions and the The linear displacement of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; is the polar coordinate system with the winding center as the origin. radial sub-regions and the The unit vector of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; For the radial sub-regions and the The circumferential component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is: .

[0057] (5) The radial motion formula of the mass unit in the inner support area of ​​the winding is as follows:

[0058] in, For the radial sub-regions and the The mass of the mass unit at the intersection of the circumferential sub-regions, ; For the radial sub-regions and the The linear displacement of the mass unit in the radial direction at the intersection of the circumferential sub-regions; To follow the The stiffness of the radially arranged elastic elements connected to the inner sides of the mass units arranged in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit on the outside in the radial direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to the unit vector of the adjacent unit outside in the radial direction; The polar coordinate system with the winding center as the origin points to the first radial sub-regions and the The unit vector of the mass unit at the intersection of the circumferential sub-regions; To follow the The damping coefficient of the radially arranged damping element inside the mass unit arranged in the radial sub-region; is the stiffness of the radially arranged elastic elements inside the support mass unit; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the radial direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to the unit vector of the adjacent unit in the radial direction; is the damping coefficient of the radially arranged damping elements inside the support area mass unit; To follow the The spring stiffness of the circumferential arrangement of the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the counterclockwise direction of the circumference; To follow the The average distance between two connected mass units in the radial sub-region is equivalent to the The original length of the elastic elements arranged in radial sub-regions; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent mass unit in the circumferential counterclockwise direction; To follow the Circumferential damping coefficient of the mass units arranged in radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The radial component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is .

[0059] (6) The formula for the circumferential motion of the mass unit in the inner support area of ​​the winding is as follows:

[0060] in, For the radial sub-regions and the The linear displacement of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; is the polar coordinate system with the winding center as the origin. radial sub-regions and the The unit vector of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; For the radial sub-regions and the The circumferential component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is: .

[0061] It should be noted that in the support area mass unit, the subscript ; At this time, when calculating the vector difference When and situation, and and It has no specific physical meaning, it only means that the position of the strut is connected; if the strut is assumed to be fixed, its position remains unchanged.

[0062] It should also be noted that for The stiffness of the radially arranged elastic elements inside the mass unit of the radial sub-region ,when Taking into account the influence of external bracing on stiffness, The influence of the inner brace on the stiffness is considered; The radial damping coefficient of the mass unit inside the radial sub-region is The influence of the external support is taken into account. The influence of the internal brace is considered; if the nonlinear characteristics of the brace material need to be considered, Further corrections such as using nonlinear stiffness Or use the plastic stress-strain relationship such as , to reflect the nonlinearity of the material.

[0063] (7) The radial motion formula of the free mass unit outside the winding is as follows:

[0064] in, For the radial sub-regions and the The mass of the mass unit at the intersection of the circumferential sub-regions, ; For the radial sub-regions and the The linear displacement of the mass unit in the radial direction at the intersection of the circumferential sub-regions; To follow the The stiffness of the radially arranged elastic elements connected to the inner sides of the mass units arranged in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the radial direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-regions points to the unit vector of the adjacent unit in the radial direction; The polar coordinate system with the winding center as the origin points to the first radial sub-regions and the The unit vector of the mass unit at the intersection of the circumferential sub-regions; To follow the The damping coefficient of the radially arranged damping element inside the mass unit arranged in the radial sub-region; To follow the The stiffness of the elastic elements arranged circumferentially in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the counterclockwise direction of the circumference; To follow the The average distance between two adjacent mass units in the radial sub-region is equivalent to the The original length of the elastic elements arranged in radial sub-regions; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent unit in the counterclockwise direction of the circumference; To follow the Circumferential damping coefficient of the mass units arranged in radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent unit in the circumferential clockwise direction; For the radial sub-regions and the The radial component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is: .

[0065] (8) The circumferential motion formula of the free mass unit on the outer side of the winding is as follows:

[0066] in, For the radial sub-regions and the The linear displacement of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; is the polar coordinate system with the winding center as the origin. radial sub-regions and the The unit vector of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; For the radial sub-regions and the The circumferential component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is: .

[0067] (9) The radial motion formula of the free mass unit inside the winding is as follows:

[0068] in, For the radial sub-regions and the The mass of the mass unit at the intersection of the circumferential sub-regions, ; For the radial sub-regions and the The linear displacement of the mass unit in the radial direction at the intersection of the circumferential sub-regions; To follow the The stiffness of the radially arranged elastic elements connected to the inner sides of the mass units arranged in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit on the outside in the radial direction; The polar coordinate system with the winding center as the origin points to the first radial sub-regions and the The unit vector of the mass unit at the intersection of the circumferential sub-regions; To follow the The damping coefficient of the radially arranged damping element inside the mass unit arranged in the radial sub-region; To follow the The stiffness of the continuation elements arranged circumferentially in the radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the counterclockwise direction of the circumference; To follow the The average distance between two adjacent mass units in the radial sub-region is equivalent to the The original length of the elastic elements arranged in radial sub-regions; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent mass unit in the circumferential counterclockwise direction; To follow the Circumferential damping coefficient of the mass units arranged in radial sub-regions; For the radial sub-regions and the The vector difference between the mass unit at the intersection of the circumferential sub-regions and the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The mass unit at the intersection of the circumferential sub-areas points to the unit vector of the adjacent mass unit in the circumferential clockwise direction; For the radial sub-regions and the The radial component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is .

[0069] (10) The formula for the radial motion of the free mass unit inside the winding is as follows:

[0070] in, For the radial sub-regions and the The linear displacement of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; is the polar coordinate system with the winding center as the origin. radial sub-regions and the The unit vector of the mass unit in the circumferential direction at the intersection of the circumferential sub-regions; For the radial sub-regions and the The circumferential component of the short-circuit electromotive force on the mass unit at the intersection of the circumferential sub-regions is: .

[0071] Step 3: Based on the radial electromagnetic force and circumferential electromagnetic force acting on the winding coil and in combination with the equivalent dynamic model of the winding coil, the preset deformation index of the winding coil is solved to obtain the winding deformation prediction result of the transformer under the short-circuit impact; wherein the preset deformation index of the winding coil includes the radial deformation, radial displacement, circumferential deformation and circumferential displacement of the winding coil.

[0072] Specifically, the steps are as follows: Step 31. Determine the total iterative solution time and iterative solution step size based on the attenuation characteristics of the short-circuit impact current received by the transformer and the predetermined winding deformation prediction accuracy. It should be noted that different transformers have different attenuation time constants of short-circuit current when a short circuit occurs. The peak value and variation of the short-circuit current are also different under different short-circuit conditions. The short-circuit reclosing time is different, and different researchers need to analyze different lengths of time.

[0073] When performing the analysis, the time accuracy required for obtaining the winding deformation and displacement results is determined; preferably, in the transformer generally used at an industrial frequency of 50 Hz, the iterative solution step size is 0.0001 s.

[0074] Step 32: Substitute the radial electromagnetic force and circumferential electromagnetic force on the winding coil into the equivalent dynamic model of the winding coil. Based on the total iterative solution time and the iterative solution step size, iteratively solve the preset deformation index of the winding coil to obtain the winding deformation prediction result of the transformer under short-circuit impact.

[0075] The method for predicting the winding deformation of a transformer under a short-circuit impact described in Example 1 first establishes a three-dimensional equivalent model of the transformer, and calculates the transformer leakage magnetic field and the radial electromagnetic force and circumferential electromagnetic force acting on the winding for different short-circuit conditions; comprehensively considers the material and structural characteristics of the transformer windings and gaskets, and uniformly partitions the windings in the radial and circumferential directions according to accuracy requirements to establish an equivalent dynamic model of the winding coil; by selecting the total iterative solution time and the iterative solution step size and performing iterative calculations, the radial deformation, radial displacement, circumferential deformation, and circumferential displacement of the transformer winding are obtained as the prediction results of the transformer winding deformation under a short-circuit impact; in the present invention, a number of influencing factors are comprehensively considered and a transformer winding dynamic model is constructed, and its mechanical response during a short circuit is analyzed, so that the specific impact of the short circuit on the winding can be understood within a short period of time after the short circuit occurs, which is of great significance for diagnosing the state of the power transformer winding and evaluating its life.

[0076] In the present invention, a numerical method is used to model the winding coil, which can comprehensively consider the transformer winding material and structural factors. Compared with the finite element calculation that requires significant simplification to be convenient, more accurate displacement and deformation data of the winding after the short-circuit impact can be obtained, which is of great significance for diagnosing the status of the power transformer winding and evaluating its life. Among them, by calculating the radial electromagnetic force and circumferential electromagnetic force exerted on the winding coil, and combining the equivalent dynamic model to solve the preset deformation index, the winding deformation prediction result can be obtained, thereby intuitively evaluating the status of the transformer winding after the short-circuit impact, providing an important basis for the maintenance and inspection of the transformer.

[0077] Specifically, numerical methods are used to model and calculate the winding coils, without the need for actual short-circuit impact tests, which greatly reduces research costs and makes the study of the mechanical characteristics of transformer windings more feasible and economical; in the process of establishing the equivalent dynamic model of the winding coils, the material and structural characteristics of the transformer windings and gaskets are comprehensively considered, the windings are uniformly partitioned in the radial and circumferential directions, and an equivalent mass-spring-damper system based on polar coordinates is established; by selecting the total solution time and solution step size and performing iterative calculations, the radial and circumferential deformation and displacement of the transformer windings are obtained; in summary, by establishing mathematical models and performing numerical calculations, the deformation of the transformer windings under different short-circuit conditions can be simulated, thereby providing more data support for summarizing the laws of winding displacement and deformation, and helping to deeply understand the mechanical behavior of the transformer windings under short-circuit impact.

[0078] Example 2 As attached Figure 4 As shown, this embodiment 2 provides a system for predicting transformer winding deformation under short-circuit impact, including an electromagnetic force calculation module, a modeling module and a deformation solution module.

[0079] The electromagnetic force calculation module is used to calculate the radial electromagnetic force and circumferential electromagnetic force acting on the winding coil according to the short-circuit impact current of the transformer; the modeling module is used to establish an equivalent dynamic model of the winding coil based on the material properties of the transformer and the partitioning results of the winding coil; the deformation solution module is used to solve the preset deformation index of the winding coil according to the radial electromagnetic force and circumferential electromagnetic force acting on the winding coil, combined with the equivalent dynamic model of the winding coil, to obtain the winding deformation prediction result of the transformer under short-circuit impact; among which, the preset deformation index of the winding coil includes the radial deformation, radial displacement, circumferential deformation and circumferential displacement of the winding coil.

[0080] Example 3 As attached Figure 5As shown, this embodiment 3 provides an electronic device, including: a memory for storing a computer program; a processor for implementing the steps of a method for predicting winding deformation of a transformer under a short-circuit impact when executing the computer program; or, when the processor executes the computer program, implementing the functions of each module in the above-mentioned system for predicting winding deformation of a transformer under a short-circuit impact.

[0081] Exemplarily, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing preset functions, and the instruction segments are used to describe the execution process of the computer program in the electronic device.

[0082] The electronic device may be a computing device such as a desktop computer, laptop, PDA, or cloud server. The electronic device may include, but is not limited to, a processor and memory. Those skilled in the art will appreciate that the above are examples of electronic devices and do not constitute a limitation on electronic devices. The electronic device may include more components than those described above, or a combination of certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[0083] The processor may be a central processing unit, or other general-purpose processor, a digital signal processor, an application-specific integrated circuit, an off-the-shelf programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. A general-purpose processor may be a microprocessor or any conventional processor. The processor is the control center of the electronic device, connecting various parts of the entire electronic device using various interfaces and lines.

[0084] The memory may be used to store the computer programs and / or modules, and the processor implements various functions of the electronic device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory.

[0085] The memory may primarily include a program storage area and a data storage area. The program storage area may store an operating system and at least one application required for a function (such as a sound playback function or an image playback function); the data storage area may store data generated based on the use of the mobile phone (such as audio data, a phone book, etc.). Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as a hard disk, internal memory, a plug-in hard disk, a smart memory card, a secure digital card, a flash memory card, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage device.

[0086] Example 4 This embodiment 4 also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the method for predicting winding deformation of a transformer under a short-circuit impact are implemented.

[0087] If the integrated modules / units of the transformer winding deformation prediction system under short-circuit impact are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0088] Based on this understanding, the present invention implements all or part of the process of the above-mentioned method for predicting transformer winding deformation under short-circuit impact, and can also be completed by using a computer program to instruct related hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above-mentioned method for predicting transformer winding deformation under short-circuit impact. The computer program includes computer program code, which can be in source code form, object code form, executable file, or preset intermediate form.

[0089] The computer-readable storage medium may include: any entity or device that can carry the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0090] Example 5 This embodiment 5 provides a computer product, which includes a computer program product, and the computer program is stored in a computer-readable storage medium; the processor of the electronic device reads the computer program from the computer-readable storage medium, and the processor executes the computer program, so that the electronic device can perform the winding deformation prediction of the transformer under the short-circuit impact described in embodiment 1, which will not be repeated here.

[0091] It should be noted that a person skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0092] The winding deformation prediction method described in the present invention greatly reduces the amount of calculation by using an equivalent dynamic model of the winding coil and a mathematical model. It can grasp the specific impact of the short circuit on the transformer winding within a short time after the short circuit occurs, which is of great significance for diagnosing the status of the power transformer winding and evaluating its life.

[0093] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention.

Claims

1. A method for predicting transformer winding deformation under short-circuit impact, characterized in that: include: According to the short-circuit impulse current of the transformer, the radial electromagnetic force and circumferential electromagnetic force acting on the winding coil are calculated; Based on the material properties of the transformer and the partition results of the winding coil, an equivalent dynamic model of the winding coil is established; Based on the radial and circumferential electromagnetic forces acting on the winding coil and combined with the equivalent dynamic model of the winding coil, the preset deformation indicators of the winding coil are solved to obtain the prediction results of the transformer winding deformation under short-circuit impact. Among them, the preset deformation indicators of the winding coil include the radial deformation, radial displacement, circumferential deformation and circumferential displacement of the winding coil.

2. The method for predicting transformer winding deformation under short-circuit impact according to claim 1, characterized in that: The process of calculating the radial electromagnetic force and circumferential electromagnetic force on the winding coil based on the short-circuit impulse current applied to the transformer includes: According to the structural parameters and electrical parameters of the transformer, a three-dimensional equivalent model of the transformer is established; The short-circuit impulse current applied to the transformer is used as an excitation and applied to the three-dimensional equivalent model of the transformer to obtain the three-dimensional equivalent model of the transformer with the applied excitation; Perform transient calculations on the three-dimensional equivalent model of the transformer with applied excitation to obtain the transient electromagnetic forces acting on the winding coils. The radial electromagnetic force and circumferential electromagnetic force acting on the winding coil are extracted from the transient electromagnetic force acting on the winding coil.

3. The method for predicting transformer winding deformation under short-circuit impact according to claim 1, characterized in that: The equivalent dynamic model of the winding coil is a mass-spring-damper system model in a polar coordinate system.

4. The method for predicting transformer winding deformation under short-circuit impact according to claim 3, characterized in that: Based on the material properties of the transformer and the partitioning results of the winding coils, the process of establishing the equivalent dynamic model of the winding coils includes: Partitioning the winding coil according to the structural parameters of the winding coil to obtain a partition result of the winding coil; wherein the structural parameters of the winding coil include the number of parallel conductors and the number of struts in the winding coil; Based on the structural parameters of the winding coil, several mass units, several elastic elements and several damping elements are created; Based on the partitioning results of the winding coil, several mass units, several elastic elements, and several damping elements are arranged in a fan-shaped manner in the pre-constructed polar coordinates until a circular ring form is formed. According to the Young's modulus of the copper wire and the Young's modulus of the strut in the winding coil, and the damping coefficient of the transformer oil, the parameters of the several elastic elements and the damping elements are set to obtain the mass-spring-damper system model in the polar coordinate system as the equivalent dynamic model of the winding coil.

5. The method for predicting transformer winding deformation under short-circuit impact according to claim 4, characterized in that: The process of partitioning the winding coil according to the structural parameters of the winding coil and obtaining the partitioning result of the winding coil includes: The winding coil is partitioned radially and circumferentially according to the number of parallel conductors and the number of struts in the winding coil, respectively, to obtain the partitioning results of the winding coil. When the winding coil is partitioned radially, the winding coil is divided into regions along the radial direction according to multiples or factors of the number of parallel conductors in the winding coil; when the winding coil is partitioned circumferentially, the winding coil is divided into regions along the circumferential direction according to multiples of the number of struts in the winding coil.

6. The method for predicting transformer winding deformation under short-circuit impact according to claim 1, characterized in that: The process of solving the preset deformation index of the winding coil based on the radial electromagnetic force and circumferential electromagnetic force on the winding coil and combining the equivalent dynamic model of the winding coil to obtain the winding deformation prediction result of the transformer under short-circuit impact includes: According to the attenuation characteristics of the short-circuit impulse current received by the transformer and the predetermined winding deformation prediction accuracy, the total iterative solution time and the iterative solution step size are determined; The radial electromagnetic force and circumferential electromagnetic force acting on the winding coil are substituted into the equivalent dynamic model of the winding coil. Based on the total iterative solution time and iterative solution step size, the preset deformation index of the winding coil is iteratively solved to obtain the prediction result of the winding deformation of the transformer under short-circuit impact.

7. A system for predicting transformer winding deformation under short-circuit impact, characterized in that: include: The electromagnetic force calculation module is used to calculate the radial electromagnetic force and circumferential electromagnetic force on the winding coil according to the short-circuit impact current of the transformer; Modeling module, used to establish an equivalent dynamic model of the winding coil based on the material properties of the transformer and the partition results of the winding coil; The deformation solution module is used to solve the preset deformation indicators of the winding coil based on the radial electromagnetic force and circumferential electromagnetic force on the winding coil, combined with the equivalent dynamic model of the winding coil, to obtain the winding deformation prediction result of the transformer under short-circuit impact; among which, the preset deformation indicators of the winding coil include the radial deformation, radial displacement, circumferential deformation and circumferential displacement of the winding coil.

8. An electronic device, characterized in that: include: a processor suitable for executing a computer program; A computer-readable storage medium having a computer program stored therein, wherein when the computer program is executed by the processor, the method for predicting winding deformation of a transformer under a short-circuit impact according to any one of claims 1 to 6 is executed.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for predicting winding deformation of a transformer under a short-circuit impact according to any one of claims 1 to 6 is implemented.

10. A computer program product, characterized in that The computer program product includes a computer program, and when the computer program is executed by a processor, the method for predicting winding deformation of a transformer under a short-circuit impact according to any one of claims 1 to 6 is implemented.

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