Method and device for evaluating anti-short-circuit capability of transformer

Abstract

The invention relates to a method and device for evaluating the anti-short-circuit capability of a transformer. The method comprises the steps of obtaining a first electrodynamic force and a second electrodynamic force under the condition that the transformer has a short-circuit fault, determining a first deformation quantity and a second deformation quantity of a winding wire according to electrical parameters of the transformer, the first electrodynamic force and the second electrodynamic force, and evaluating the short-circuit resistance of the transformer according to the first deformation quantity and the second deformation quantity. By adopting the method, the anti-short-circuit capability of the transformer can be evaluated by acquiring the first deformation quantity and the second deformation quantity of the winding wire under the condition that the transformer has a short-circuit fault, the relationship between wire deformation and short-circuit failure is directly reflected, and the evaluation accuracy is improved.

Description

Technical Field

[0001] The present application relates to the technical field of transformers, and in particular to a method and device for evaluating the short-circuit resistance capability of a transformer. Background Art

[0002] During the operation of the transformer, a short circuit fault may occur in the power grid. The current of the short circuit fault is often huge. When the fault current passes through the transformer winding, a huge electric force is generated under the action of leakage magnetic field and short-circuit current. Under the action of the electric force, the winding wires in the transformer are deformed by force. If the transformer's short-circuit resistance is insufficient, it will cause damage to the transformer winding. It is necessary to evaluate the transformer's short-circuit resistance for subsequent reasonable planning.

[0003] However, currently, the short-circuit resistance of the transformer is often evaluated by the radial bending stress and axial bending stress of the winding wire in the transformer under a short-circuit fault. This fails to directly reflect the relationship between the wire deformation and the short-circuit failure, and there is a problem of low evaluation accuracy. Summary of the invention

[0004] Based on this, it is necessary to provide a method and device for evaluating the short-circuit resistance capability of a transformer, which can improve the accuracy of the short-circuit resistance capability evaluation of the transformer, in order to address the above technical problems.

[0005] In a first aspect, the present application provides a method for evaluating the short-circuit resistance of a transformer, wherein a plurality of inner support bars are arranged in a winding conductor of the transformer, and the distance between any two adjacent inner support bars is equal; a plurality of pads are arranged on the outer surface of the winding conductor, and the distance between any two adjacent pads is equal; the method comprises:

[0006] In the event of a short-circuit fault in the transformer, a first electromotive force and a second electromotive force are obtained, wherein the first electromotive force is used to characterize the radial electromotive force received by the winding conductor under the action of the maximum short-circuit current, and the second electromotive force is used to characterize the axial electromotive force received by the winding conductor under the action of the maximum short-circuit current;

[0007] Based on the electrical parameters of the transformer, the first electric force and the second electric force, the first deformation amount and the second deformation amount of the winding wire are determined, wherein the first deformation amount is used to characterize the maximum radial bending amount of the winding wire between any two adjacent inner support bars under the influence of the first electric force, and the second deformation amount is used to characterize the maximum axial bending amount of the winding wire between any two adjacent spacers under the influence of the second electric force; the electrical parameters include the distance between any two adjacent inner support bars, the distance between any two adjacent spacers, the elastic modulus of the winding wire and the moment of inertia of the winding wire;

[0008] The short-circuit resistance of the transformer is evaluated according to the first deformation amount and the second deformation amount.

[0009] In one embodiment, determining a first deformation amount and a second deformation amount of a winding conductor based on an electrical parameter of the transformer, a first electromotive force, and a second electromotive force comprises:

[0010] Obtaining a first distance, the first distance being used to characterize the distance from the midpoint of the winding wire between any two adjacent inner support bars to the inner support bar closest to each other; obtaining a first deformation amount according to the first distance, the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force;

[0011] Obtain a second distance, which is used to characterize the distance from the midpoint of the winding wire between any two adjacent pads to the pad closest to each other; obtain a second deformation amount based on the second distance, the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electromotive force.

[0012] In one embodiment, the first deformation amount y1 is obtained based on the following formula:

[0013]

[0014] Wherein, q1 is the first electromotive force; E is the elastic modulus; I is the moment of inertia; x1 is the first distance; l1 is the distance between any two adjacent inner stays;

[0015] The second deformation variable y2 is obtained based on the following formula:

[0016]

[0017] Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; x2 is the second distance; l2 is the distance between any two adjacent pads.

[0018] In one embodiment, determining a first deformation amount and a second deformation amount of a winding conductor based on an electrical parameter of the transformer, a first electromotive force, and a second electromotive force comprises:

[0019] Obtaining a first deformation amount according to the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force;

[0020] The second deformation amount is obtained according to the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electromotive force.

[0021] In one embodiment, the first deformation amount y1 is obtained based on the following formula:

[0022]

[0023] Where, q1 is the first electromotive force; E is the elastic modulus; I is the moment of inertia; l1 is the distance between any two adjacent inner struts;

[0024] The second deformation variable y2 is obtained based on the following formula:

[0025]

[0026] Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; l2 is the distance between any two adjacent pads.

[0027] In one embodiment, the method further comprises:

[0028] When the transformer clears the short-circuit fault, a first residual deformation amount and a second residual deformation amount are obtained, wherein the first residual deformation amount is used to characterize the radial bending amount of the winding wire between any two adjacent inner support bars, and the second residual deformation amount is used to characterize the axial bending amount of the winding wire between any two adjacent spacers;

[0029] The short-circuit resistance of the transformer is evaluated according to the electrical parameters, the first residual deformation amount and the second residual deformation amount.

[0030] In one embodiment, the electrical parameters include structural parameters of the winding conductor; and evaluating the short-circuit resistance of the transformer according to the electrical parameters, the first residual deformation amount, and the second residual deformation amount comprises:

[0031] The structural parameters of the winding conductor are compared with the first residual deformation amount and the second residual deformation amount respectively, and the short-circuit resistance of the transformer is evaluated according to the comparison results.

[0032] In a second aspect, the present application further provides a short-circuit resistance evaluation device for a transformer, wherein a plurality of inner support bars are arranged in a winding conductor of the transformer, and the distance between any two adjacent inner support bars is equal; a plurality of pads are arranged on the outer surface of the winding conductor, and the distance between any two adjacent pads is equal; the device comprises:

[0033] An acquisition module, used for acquiring a first electric force and a second electric force when a short circuit fault occurs in the transformer, wherein the first electric force is used for characterizing the radial electric force to which the winding conductor is subjected under the action of the maximum short circuit current, and the second electric force is used for characterizing the axial electric force to which the winding conductor is subjected under the action of the maximum short circuit current;

[0034] A determination module, for determining a first deformation amount and a second deformation amount of a winding conductor based on electrical parameters of the transformer, a first electromotive force and a second electromotive force, wherein the first deformation amount is used to characterize a maximum radial bending amount of the winding conductor between any two adjacent inner support bars under the influence of the first electromotive force, and the second deformation amount is used to characterize a maximum axial bending amount of the winding conductor between any two adjacent pads under the influence of the second electromotive force; the electrical parameters include a distance between any two adjacent inner support bars, a distance between any two adjacent pads, an elastic modulus of the winding conductor, and a moment of inertia of the winding conductor;

[0035] The evaluation module is used to evaluate the short-circuit resistance of the transformer according to the first deformation amount and the second deformation amount.

[0036] In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0037] In a fourth aspect, the present application also provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when the computer program is executed by a processor.

[0038] The above-mentioned method and device for evaluating the short-circuit resistance of the transformer obtain the first electric force and the second electric force when a short-circuit fault occurs in the transformer, and determine the first deformation amount and the second deformation amount of the winding conductor based on the electrical parameters of the transformer, the first electric force and the second electric force, and evaluate the short-circuit resistance of the transformer based on the first deformation amount and the second deformation amount; the present application obtains the first deformation amount and the second deformation amount of the winding conductor when a short-circuit fault occurs in the transformer, thereby evaluating the short-circuit resistance of the transformer, directly reflecting the relationship between the conductor deformation and the short-circuit failure, and improving the accuracy of the evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0040] FIG1 is a schematic diagram of radial bending of winding wires in a transformer in one embodiment;

[0041] FIG2 is a schematic diagram of axial bending of winding wires in a transformer in one embodiment;

[0042] FIG3 is a schematic flow chart of a method for evaluating the short-circuit resistance capability of a transformer in one embodiment;

[0043] FIG4 is a schematic diagram of a short-circuit current waveform of a transformer having a short-circuit fault in one embodiment;

[0044] FIG5 is a schematic diagram of magnetic leakage of a transformer with a short circuit fault in one embodiment;

[0045] FIG6 is a schematic structural diagram of a simply supported beam model in one embodiment;

[0046] FIG7 is a schematic flow chart of a method for evaluating the short-circuit resistance capability of a transformer in another embodiment;

[0047] FIG8 is a structural block diagram of a device for evaluating the short-circuit resistance capability of a transformer in one embodiment;

[0048] FIG. 9 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0049] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0051] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first adapter board may be referred to as a second adapter board, and similarly, a second adapter board may be referred to as a first adapter board. Both the first adapter board and the second adapter board are adapter boards, but they are not the same adapter board.

[0052] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0053] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0054] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0055] At present, when a short circuit occurs in the power grid, the fault current passes through the transformer winding, generating huge electric force under the action of magnetic leakage and short-circuit current. Under the action of the electric force, the winding wires in the transformer are deformed by force. The greater the deformation, the greater the probability of short circuit failure of the transformer winding.

[0056] It should be noted that the bending deformation caused by the electromotive force on the winding wire is mainly divided into radial bending and axial bending. The radial bending, as shown in Figure 1, refers to the radial electromotive force F on the winding wire. x , supported by the inner support bars of the coil, the winding wire is bent and deformed inward between two adjacent inner support bars, and the deformation amount in the middle is usually the largest; 1 in FIG. 1 is a top view of the winding wire, wherein a plurality of inner support bars are arranged in the winding wire of the transformer (the number of inner support bars can be set according to actual conditions, and 6 inner support bars are used as an example for explanation in the embodiment of the present application), and the distance between any two adjacent inner support bars (set according to actual conditions) is equal; 2 in FIG. 1 is an inner support bar of the winding coil, hereinafter referred to as an inner support bar; 3 in FIG. 1 represents the initial position of the winding wire when it is not subjected to radial electromotive force; 4 in FIG. 1 represents the maximum deformation amount of the winding wire caused by the radial electromotive force between two adjacent inner support bars, which is located in the middle of the winding wire section, that is, the maximum radial bending amount; 5 in FIG. 1 is the line width of the winding wire, which can be set according to actual conditions and is not limited in the embodiment of the present application; F in FIG. 1 x The winding wires are subjected to inward radial electromotive force.

[0057] Axial bending, as shown in Figure 2, refers to the axial electromotive force F on the winding wire. y, supported by the pads inside the coil, the winding wire is axially bent and deformed between two adjacent pads, and the deformation amount in the middle is usually the largest; 1 in FIG2 is a front view of the winding wire, wherein a plurality of pads are provided on the outer surface of the winding wire (the number of pads can be set according to actual conditions, and is not limited in the embodiments of the present application), and the distance between any two adjacent pads (set according to actual conditions) is equal; 2 in FIG2 is a pad inside the coil, hereinafter referred to as a pad; 3 in FIG2 represents the maximum deformation amount of the wire between two adjacent pads due to the axial electromotive force, which is located in the middle of the section of the winding wire, that is, the maximum axial bending amount; 4 in FIG2 is the diameter of the winding wire; F in FIG2 y The winding wire is subjected to downward axial electromotive force.

[0058] The short-circuit resistance evaluation method of the transformer provided in the embodiment of the present application can be applied to computer equipment. The computer equipment obtains the radial electromotive force (first electromotive force) and the axial electromotive force (second electromotive force) of the winding wire under the maximum short-circuit current when a short-circuit fault occurs in the transformer, and determines the maximum radial bending amount (first deformation amount) of the winding wire between any two adjacent inner support bars under the influence of the first electromotive force and the maximum axial bending amount (second deformation amount) of the winding wire between any two adjacent pads under the influence of the second electromotive force based on the electrical parameters of the transformer, the first electromotive force and the second electromotive force. Finally, the short-circuit resistance of the transformer is evaluated based on the first deformation amount and the second deformation amount, which can directly reflect the relationship between the deformation of the wire and the short-circuit failure, and improve the accuracy of the evaluation.

[0059] Exemplarily, the type of transformer can be set according to actual conditions. In the embodiment of the present application, the transformer is taken as an example of a power transformer.

[0060] In an exemplary embodiment, as shown in FIG3 , a method for evaluating the short-circuit resistance capability of a transformer is provided, the method comprising:

[0061] S302, when a short circuit fault occurs in the transformer, obtain a first electric force and a second electric force, wherein the first electric force is used to characterize the radial electric force to which the winding conductor is subjected under the action of the maximum short-circuit current, and the second electric force is used to characterize the axial electric force to which the winding conductor is subjected under the action of the maximum short-circuit current.

[0062] Specifically, when a short-circuit fault occurs in the transformer, a short-circuit current as shown in FIG4 will be generated in the winding. The short-circuit current includes a steady-state component (i.e., a sinusoidal current with a constant amplitude) and a free component (a DC component that decays according to an exponential law). The waveform of the short-circuit current can be shown in the following formula (1):

[0063] (1)

[0064] Where, i(t) is the short-circuit current; i s (t) is the steady-state component; i k (t) is the free component; I is the peak value of the sinusoidal current, that is, the initial value of the DC component; ω is the frequency of the sinusoidal current; Φ is the initial phase of the sinusoidal current, that is, the phase of the current waveform before short circuit; τ is the free component attenuation coefficient, which is related to the inductance L and resistance R of the coil.

[0065] For example, the frequency ω of the sinusoidal current may be expressed as follows (2) and (3):

[0066] ω = 2πf(2)

[0067] f = 50 Hz (3)

[0068] The free component attenuation coefficient τ can be expressed as follows (4):

[0069] (4)

[0070] Among them, L is the inductance of the coil; R is the resistance of the coil.

[0071] As shown in Figure 4, the maximum short-circuit current corresponding to the short-circuit current peak moment is I SCm This application only considers the maximum deformation caused by the short-circuit electromotive force on the winding conductor at the peak moment of the short-circuit current, and ignores the dynamic process of the conductor being subjected to the short-circuit dynamic force. This is because: the short-circuit electromotive force is positively correlated with the square of the short-circuit current. At the peak moment of the short-circuit current, the short-circuit electromotive force reaches the maximum value, and the winding conductor produces the maximum deformation, wherein the short-circuit electromotive force includes radial electromotive force and axial electromotive force.

[0072] When the computer equipment detects that a short circuit fault occurs in the transformer, the maximum short circuit current I SCm The radial electromotive force (first electromotive force) received by the winding conductor under the action of the maximum short-circuit current I SCm The axial electromotive force (second electromotive force) is applied to the shaft.

[0073] It should be noted that the method for obtaining short-circuit electric power can be set according to actual conditions and is not limited in the embodiments of the present application.

[0074] S304, based on the electrical parameters of the transformer, the first electric force and the second electric force, determine the first deformation amount and the second deformation amount of the winding wire, wherein the first deformation amount is used to characterize the maximum radial bending amount of the winding wire between any two adjacent inner support bars under the influence of the first electric force, and the second deformation amount is used to characterize the maximum axial bending amount of the winding wire between any two adjacent spacers under the influence of the second electric force; the electrical parameters include the distance between any two adjacent inner support bars, the distance between any two adjacent spacers, the elastic modulus of the winding wire and the moment of inertia of the winding wire.

[0075] Specifically, the computer device may store the electrical parameters of the transformer, and based on the electrical parameters, the first electric force and the second electric force, the computer device obtains the maximum radial bending amount (first deformation amount) of the winding wire between any two adjacent inner support bars under the influence of the first electric force, and the maximum axial bending amount (second deformation amount) of the winding wire between any two adjacent pads under the influence of the second electric force.

[0076] S306, evaluating the short-circuit resistance of the transformer according to the first deformation amount and the second deformation amount.

[0077] Specifically, the first deformation amount and the second deformation amount are both used to characterize the maximum deformation amount of the winding wire caused by the short-circuit electromotive force. The computer device can compare the first deformation amount and the second deformation amount respectively by setting preset parameters, and determine the short-circuit resistance capability of the winding wire, that is, the short-circuit resistance capability of the transformer according to the comparison result; wherein the preset parameters can be set according to actual conditions and are not limited in the embodiments of the present application.

[0078] The above-mentioned method for evaluating the short-circuit resistance capability of the transformer obtains the first electric force and the second electric force when a short-circuit fault occurs in the transformer, and determines the first deformation amount and the second deformation amount of the winding conductor based on the electrical parameters of the transformer, the first electric force and the second electric force. The short-circuit resistance capability of the transformer is evaluated based on the first deformation amount and the second deformation amount, which can directly reflect the relationship between the deformation of the conductor and the short-circuit failure, thereby improving the accuracy of the evaluation.

[0079] In one embodiment, determining a first deformation amount and a second deformation amount of a winding conductor based on an electrical parameter of the transformer, a first electromotive force, and a second electromotive force comprises:

[0080] Obtaining a first distance, the first distance being used to characterize the distance from the midpoint of the winding wire between any two adjacent inner support bars to the inner support bar closest to each other; obtaining a first deformation amount according to the first distance, the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force;

[0081] Obtain a second distance, which is used to characterize the distance from the midpoint of the winding wire between any two adjacent pads to the pad closest to each other; obtain a second deformation amount based on the second distance, the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electromotive force.

[0082] It should be noted that the elastic modulus includes the axial elastic modulus and the radial elastic modulus. The radial elastic modulus indicates the ability of the winding conductor between the two inner support bars to resist deformation when subjected to force, and is only related to parameters such as the conductor material. The axial elastic modulus indicates the ability of the winding conductor between the two inner pads to resist deformation when subjected to force, and is only related to parameters such as the conductor material. The moment of inertia is related to the cross-sectional shape and size of the conductor.

[0083] Specifically, FIG5 exemplarily shows a schematic diagram of magnetic leakage of a power transformer (front view). As shown in FIG5 , due to the magnetic leakage at the end of the winding wire bending, the middle part basically maintains the axial magnetic flux. According to the left-hand rule, the axial magnetic flux generates radial electromotive force, so the radial bending of the winding wire is usually the most serious in the middle part, that is, the radial bending at the midpoint of the winding wire between any two adjacent inner support bars is the most serious. The computer device obtains the distance (first distance) from the midpoint of the winding wire between any two adjacent inner support bars to the inner support bar closest to each other, and calculates the first deformation amount according to the first distance, the distance between any two adjacent inner support bars, the elastic modulus (radial elastic modulus), the moment of inertia and the first electromotive force.

[0084] As shown in FIG5 , due to the bending of the leakage magnetic flux at the end of the winding wire, the radial component of the magnetic flux at the end of the winding wire is the largest. According to the left-hand rule, the radial magnetic flux generates an axial electromotive force, so the axial electromotive force received by the coil at the end of the winding wire is the largest, and the axial bending generated is the most serious, that is, the axial bending at the midpoint of the winding wire between two adjacent pads is the most serious. The computer device obtains the distance (the second distance) from the midpoint of the winding wire between any two adjacent pads to the nearest pad, and calculates the second deformation according to the second distance, the distance between any two adjacent pads, the elastic modulus (axial elastic modulus), the moment of inertia and the second electromotive force.

[0085] In an embodiment of the present application, by respectively obtaining the first distance and the second distance, in combination with the distance between any two adjacent inner support bars, the distance between any two adjacent pads, the elastic modulus, the moment of inertia, the first electric force and the second electric force, the first deformation amount and the second deformation amount are respectively obtained, which facilitates the subsequent evaluation of the short-circuit resistance of the transformer, and realizes direct evaluation of the transformer winding's ability to withstand short circuits by deformation amount, thereby improving the accuracy of the evaluation.

[0086] In one embodiment, the first deformation amount y1 is obtained based on the following equation (5):

[0087] (5)

[0088] Wherein, q1 is the first electromotive force; E is the elastic modulus; I is the moment of inertia; x1 is the first distance; l1 is the distance between any two adjacent inner stays;

[0089] The second deformation amount y2 is obtained based on the following equation (6):

[0090] (6)

[0091] Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; x2 is the second distance; l2 is the distance between any two adjacent pads.

[0092] Specifically, the radial direction of the winding is usually composed of multiple current-carrying wires. Due to the mutual support of the inner and outer wires, the multiple radial wires are regarded as a whole. The present application is calculated according to the overall radial force. The cross-sectional area is the cross-sectional area of ​​the multiple current-carrying wires. Combined with Figure 1, the adjacent inner support bars of the inner diameter are used as fulcrums to form a simply supported beam calculation model, as shown in Figure 6. The triangles at both ends of Figure 6 represent two adjacent inner support bars on the middle coil (wire) of the winding, and the rectangle represents a section of the coil between the two adjacent inner support bars on the middle coil of the winding. The arrow represents the load q (also the first electric force q1) on the section of the coil, corresponding to F in Figure 1. x .

[0093] Based on the simply supported beam model, the bending amount at any position of the conductor can be calculated using formula (5), that is, by replacing x1 with the distance between any position of the conductor and the nearest support (inner support bar), the radial bending amount at any position of the conductor can be calculated according to formula (5). From the above, it can be obtained that the radial bending at the midpoint of the winding conductor between any two adjacent inner support bars is the most serious. The maximum radial bending amount (first deformation amount) y1 of the winding conductor can be obtained by formula (5).

[0094] The radial direction of the winding usually consists of multiple current-carrying wires, and when subjected to axial force, the multiple wires in the radial direction have no supporting effect on each other. Therefore, the present application performs calculations based on the wire subjected to the maximum axial electromotive force. Combined with FIG2 , two adjacent pads are used as fulcrums to form a simply supported beam calculation model, as shown in FIG6 . The triangles at both ends of FIG6 represent two adjacent inner pads on the coil at the end of the winding, and the rectangle represents a section of the coil between the two adjacent inner pads on the coil at the end of the winding. The arrow represents the load q (also the second electromotive force q2) on the section of the coil, corresponding to F in FIG2 y .

[0095] Based on the simply supported beam model, the bending amount at any position of the conductor can be calculated using formula (6), that is, by replacing x2 with the distance between any position of the conductor and the nearest support (pad), the axial bending amount at any position of the conductor can be calculated according to formula (6). From the above, it can be obtained that the axial bending at the midpoint of the winding conductor between any two adjacent pads is the most serious. The maximum axial bending amount (second deformation amount) y2 of the winding conductor can be obtained by formula (6).

[0096] It should be noted that when the simply supported beam model is used to calculate the first deformation, q in Figure 6 represents the first electric force, x in Figure 6 represents the first distance, A and B in Figure 6 represent any two adjacent inner supports, and l in Figure 6 represents the distance between any two adjacent inner supports; when the simply supported beam model is used to calculate the second deformation, q in Figure 6 represents the second electric force, x in Figure 6 represents the second distance, A and B in Figure 6 represent any two adjacent pads, and l in Figure 6 represents the distance between any two adjacent pads.

[0097] In one embodiment, determining a first deformation amount and a second deformation amount of a winding conductor based on an electrical parameter of the transformer, a first electromotive force, and a second electromotive force comprises:

[0098] Obtaining a first deformation amount according to the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force;

[0099] The second deformation amount is obtained according to the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electromotive force.

[0100] It should be noted that the elastic modulus includes the axial elastic modulus and the radial elastic modulus. The radial elastic modulus indicates the ability of the winding conductor between the two inner support bars to resist deformation when subjected to force, and is only related to parameters such as the conductor material. The axial elastic modulus indicates the ability of the winding conductor between the two inner pads to resist deformation when subjected to force, and is only related to parameters such as the conductor material. The moment of inertia is related to the cross-sectional shape and size of the conductor.

[0101] Specifically, the computer device obtains the first deformation amount based on the distance between any two adjacent inner supports, the radial elastic modulus, the moment of inertia and the first electric force; the computer device obtains the second deformation amount based on the distance between any two adjacent pads, the axial elastic modulus, the moment of inertia and the second electric force.

[0102] Exemplarily, the first deformation amount can be a first deflection, which reflects the linear displacement of the conductor between two adjacent inner supports in a direction perpendicular to the axial line, corresponding to the maximum radial bending amount in Figure 1; the second deformation amount can be a second deflection, which reflects the maximum displacement of the conductor between two adjacent pads in a direction perpendicular to the conductor, corresponding to the maximum axial bending amount in Figure 2.

[0103] In an embodiment of the present application, by obtaining the first deformation amount and the second deformation amount respectively based on the distance between any two adjacent inner support bars, the distance between any two adjacent pads, the elastic modulus, the moment of inertia, the first electric force and the second electric force, it is convenient for the subsequent evaluation of the short-circuit resistance of the transformer, and the ability of the transformer winding to withstand short circuit can be directly evaluated by the deformation amount, thereby improving the accuracy of the evaluation.

[0104] In one embodiment, the first deformation amount y1 is obtained based on the following equation (7):

[0105] (7)

[0106] Where, q1 is the first electromotive force; E is the elastic modulus; I is the moment of inertia; l1 is the distance between any two adjacent inner struts;

[0107] The second deformation amount y2 is obtained based on the following equation (8):

[0108] (8)

[0109] Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; l2 is the distance between any two adjacent pads.

[0110] Specifically, the computer device obtains the first deformation amount and the second deformation amount through the above equations (7) and (8).

[0111] It should be noted that, in the present application, the bending amount (including the first deformation amount and the second deformation amount) at any position of the wire can be obtained by using equations (5) and (6), and the first deformation amount and the second deformation amount can also be obtained by using equations (7) and (8). The specific selection can be set according to the actual situation and will not be described in detail in the embodiments of the present application.

[0112] In one embodiment, the method further comprises:

[0113] When the transformer clears the short-circuit fault, a first residual deformation amount and a second residual deformation amount are obtained, wherein the first residual deformation amount is used to characterize the radial bending amount of the winding wire between any two adjacent inner support bars, and the second residual deformation amount is used to characterize the axial bending amount of the winding wire between any two adjacent spacers;

[0114] The short-circuit resistance of the transformer is evaluated according to the electrical parameters, the first residual deformation amount and the second residual deformation amount.

[0115] Specifically, after the short circuit fault is removed, since the winding wire is a plastic material, it will gradually return to its position before deformation, and the deformation of the winding wire needs to be remeasured to obtain the first residual deformation and the second residual deformation. The method for obtaining the first residual deformation and the second residual deformation can be set according to actual conditions and is not limited in the embodiments of the present application.

[0116] The computer device can compare the structural parameters of the wire winding that have not been deformed in the electrical parameters with the first residual deformation amount and the second residual deformation amount respectively, so as to complete the evaluation of the short-circuit resistance of the transformer.

[0117] In the embodiment of the present application, by obtaining the first residual deformation and the second residual deformation after the short-circuit fault is removed, the subsequent evaluation of the short-circuit resistance of the transformer is facilitated, and the ability of the transformer winding to withstand short circuit is directly evaluated by the deformation, thereby improving the accuracy of the evaluation.

[0118] In one embodiment, the electrical parameters include structural parameters of the winding conductor; and evaluating the short-circuit resistance of the transformer according to the electrical parameters, the first residual deformation amount, and the second residual deformation amount comprises:

[0119] The structural parameters of the winding conductor are compared with the first residual deformation amount and the second residual deformation amount respectively, and the short-circuit resistance of the transformer is evaluated according to the comparison results.

[0120] Specifically, the structural parameters of the winding wire include the wire width d of the winding wire. x and the diameter d of the winding wire y According to the standard, the permanent residual plastic deformation value is generally 0.2% of the original length, that is, the maximum deformation of the wire after short-circuiting in the radial direction does not exceed 0.2%d x ; The maximum deformation of the conductor axis after short circuit removal shall not exceed 0.2%d y ; The first residual deformation and 0.2%d x Compare the second residual deformation with 0.2%d y Compare, if the result of the comparison is that the first residual deformation does not exceed 0.2%d x And the second residual deformation does not exceed 0.2%d y, indicating that the winding wire has not undergone irreversible deformation, and it also means that the maximum axial bending and maximum radial bending calculated above do not exceed the short-circuit resistance of the transformer winding, and the short-circuit resistance is strong; otherwise, it is confirmed that the winding wire has undergone irreversible deformation, that is, the maximum axial bending and maximum radial bending exceed the short-circuit resistance of the transformer winding, and the short-circuit resistance is weak.

[0121] In an embodiment of the present application, by comparing the structural parameters of the winding conductor with the first residual deformation and the second residual deformation respectively, it is determined whether the first residual deformation and the second residual deformation exceed 0.2% of the original length, and the short-circuit resistance of the transformer winding in the event of a short-circuit fault is evaluated, thereby more comprehensively evaluating the short-circuit resistance of the transformer and improving the accuracy of the evaluation.

[0122] In order to facilitate the understanding of those skilled in the art, the short-circuit protection capability evaluation method of the transformer is described below with reference to a specific example, as shown in FIG7 :

[0123] The computer equipment determines whether a short-circuit fault occurs in the transformer. When a short-circuit fault occurs in the transformer, the short-circuit current and waveform are obtained by recording data, and the short-circuit current peak value is obtained. The computer equipment obtains the axial leakage magnetic component and radial electromotive force (first electromotive force) of the middle winding, and obtains the radial leakage magnetic component and axial electromotive force (second electromotive force) of the end winding through simulation, experiments and other means.

[0124] The computer equipment calculates the maximum radial bending amount (first deformation amount) of the middle winding and the maximum axial bending amount (second deformation amount) of the end winding through the simply supported beam model.

[0125] After the fault is removed, the radial residual deformation of the middle winding (the first residual deformation) and the axial residual deformation of the end winding (the second residual deformation) are tested. According to the 0.2% criterion, it is judged whether the short circuit causes irreversible deformation of the conductor. Based on the judgment result, it is evaluated whether the maximum bending amount during the short circuit exceeds the short-circuit resistance of the transformer winding.

[0126] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0127] Based on the same inventive concept, the embodiment of the present application also provides a transformer short-circuit capability assessment device for implementing the transformer short-circuit capability assessment method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of one or more transformer short-circuit capability assessment devices provided below can refer to the limitations of the transformer short-circuit capability assessment method above, and will not be repeated here.

[0128] In an exemplary embodiment, as shown in FIG8 , a short-circuit protection capability evaluation device 800 of a transformer is provided. A plurality of inner support bars are arranged in a winding conductor of the transformer, and the distance between any two adjacent inner support bars is equal. A plurality of pads are arranged on the outer surface of the winding conductor, and the distance between any two adjacent pads is equal. The device 800 includes:

[0129] The acquisition module 801 is used to acquire a first electric force and a second electric force when a short circuit fault occurs in the transformer, wherein the first electric force is used to characterize the radial electric force received by the winding wire under the action of the maximum short circuit current, and the second electric force is used to characterize the axial electric force received by the winding wire under the action of the maximum short circuit current;

[0130] The determination module 802 is used to determine the first deformation amount and the second deformation amount of the winding wire based on the electrical parameters of the transformer, the first electromotive force and the second electromotive force, wherein the first deformation amount is used to characterize the maximum radial bending amount of the winding wire between any two adjacent inner support bars under the influence of the first electromotive force, and the second deformation amount is used to characterize the maximum axial bending amount of the winding wire between any two adjacent pads under the influence of the second electromotive force; the electrical parameters include the distance between any two adjacent inner support bars, the distance between any two adjacent pads, the elastic modulus of the winding wire and the moment of inertia of the winding wire;

[0131] The evaluation module 803 is used to evaluate the short-circuit resistance capability of the transformer according to the first deformation amount and the second deformation amount.

[0132] In one embodiment, the determination module 802 is further used to obtain a first distance, the first distance is used to characterize the distance from the midpoint of the winding wire between any two adjacent inner support bars to the inner support bar closest to each other; according to the first distance, the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force, the first deformation amount is obtained;

[0133] Obtain a second distance, which is used to characterize the distance from the midpoint of the winding wire between any two adjacent pads to the pad closest to each other; obtain a second deformation amount based on the second distance, the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electromotive force.

[0134] In one embodiment, the first deformation amount y1 is obtained based on the following formula:

[0135]

[0136] Wherein, q1 is the first electromotive force; E is the elastic modulus; I is the moment of inertia; x1 is the first distance; l1 is the distance between any two adjacent inner stays;

[0137] The second deformation variable y2 is obtained based on the following formula:

[0138]

[0139] Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; x2 is the second distance; l2 is the distance between any two adjacent pads.

[0140] In one embodiment, the determination module 802 is further used to obtain the first deformation amount according to the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force;

[0141] The second deformation amount is obtained according to the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electromotive force.

[0142] In one embodiment, the first deformation amount y1 is obtained based on the following formula:

[0143]

[0144] Where, q1 is the first electromotive force; E is the elastic modulus; I is the moment of inertia; l1 is the distance between any two adjacent inner struts;

[0145] The second deformation variable y2 is obtained based on the following formula:

[0146]

[0147] Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; l2 is the distance between any two adjacent pads.

[0148] In one embodiment, the device 800 further includes a comparison module, which is used to obtain a first residual deformation amount and a second residual deformation amount when the transformer removes a short-circuit fault, wherein the first residual deformation amount is used to characterize the radial bending amount of the winding wire between any two adjacent inner support bars, and the second residual deformation amount is used to characterize the axial bending amount of the winding wire between any two adjacent spacers;

[0149] The short-circuit resistance of the transformer is evaluated according to the electrical parameters, the first residual deformation amount and the second residual deformation amount.

[0150] In one embodiment, the electrical parameters include structural parameters of the winding conductor; the comparison module is further used to compare the structural parameters of the winding conductor with the first residual deformation amount and the second residual deformation amount respectively, and evaluate the short-circuit resistance of the transformer according to the comparison result.

[0151] Each module in the above-mentioned transformer short-circuit resistance evaluation device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0152] In an exemplary embodiment, a computer device is provided, which may be a server or a terminal. In the embodiment of the present application, the computer device is taken as an example for explanation as a server, and its internal structure diagram may be shown in FIG9. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store electrical parameters. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for evaluating the short-circuit resistance of a transformer is implemented.

[0153] Those skilled in the art will understand that the structure shown in FIG. 9 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0154] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the above-mentioned method for evaluating the short-circuit resistance capability of a transformer when executing the computer program.

[0155] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method for evaluating the short-circuit resistance capability of a transformer is implemented.

[0156] In one embodiment, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the method for evaluating the short-circuit resistance capability of a transformer is implemented.

[0157] It should be noted that the data involved in this application (including but not limited to data used for analysis, stored data, displayed data, etc.) are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0158] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0159] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0160] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for evaluating the short-circuit resistance of a transformer. It is characterized in that The transformer winding wire is provided with a plurality of inner support bars, and the distance between any two adjacent inner support bars is equal; the outer surface of the winding wire is provided with a plurality of pads, and the distance between any two adjacent pads is equal; the method comprises: In the event of a short circuit fault in the transformer, a first electric force and a second electric force are obtained, wherein the first electric force is used to characterize the radial electric force to which the winding conductor is subjected under the action of the maximum short circuit current, and the second electric force is used to characterize the axial electric force to which the winding conductor is subjected under the action of the maximum short circuit current; Based on the electrical parameters of the transformer, the first electric force and the second electric force, the first deformation amount and the second deformation amount of the winding wire are determined, wherein the first deformation amount is used to characterize the maximum radial bending amount of the winding wire between any two adjacent inner support bars under the influence of the first electric force, and the second deformation amount is used to characterize the maximum axial bending amount of the winding wire between any two adjacent spacers under the influence of the second electric force; the electrical parameters include the distance between any two adjacent inner support bars, the distance between any two adjacent spacers, the elastic modulus of the winding wire and the moment of inertia of the winding wire; The short-circuit resistance capability of the transformer is evaluated according to the first deformation amount and the second deformation amount.

2. The method according to claim 1, It is characterized in that The determining of the first deformation amount and the second deformation amount of the winding conductor based on the electrical parameters of the transformer, the first electromotive force and the second electromotive force comprises: Obtaining a first distance, where the first distance is used to characterize the distance from the midpoint of the winding wire between any two adjacent inner support bars to the inner support bar closest to each other; obtaining the first deformation amount according to the first distance, the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force; Obtain a second distance, where the second distance is used to characterize the distance from the midpoint of the winding wire between any two adjacent pads to the nearest pad; obtain the second deformation amount based on the second distance, the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electric force.

3. The method according to claim 2, It is characterized in that The first deformation amount y1 is obtained based on the following formula: Wherein, q1 is the first electric force; E is the elastic modulus; I is the moment of inertia; x1 is the first distance; l1 is the distance between any two adjacent inner support bars; The second deformation amount y2 is obtained based on the following formula: Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; x2 is the second distance; and l2 is the distance between any two adjacent pads.

4. The method according to claim 1, It is characterized in that The determining of the first deformation amount and the second deformation amount of the winding conductor based on the electrical parameters of the transformer, the first electromotive force and the second electromotive force comprises: Obtaining the first deformation amount according to the distance between any two adjacent inner support bars, the elastic modulus, the moment of inertia and the first electromotive force; The second deformation amount is obtained according to the distance between any two adjacent pads, the elastic modulus, the moment of inertia and the second electromotive force.

5. The method according to claim 4, It is characterized in that The first deformation amount y1 is obtained based on the following formula: Wherein, q1 is the first electric force; E is the elastic modulus; I is the moment of inertia; l1 is the distance between any two adjacent inner support bars; The second deformation amount y2 is obtained based on the following formula: Among them, q2 is the second electric force; E is the elastic modulus; I is the moment of inertia; and l2 is the distance between any two adjacent pads.

6. The method according to claim 1, It is characterized in that The method further comprises: In the case where the transformer clears the short-circuit fault, a first residual deformation amount and a second residual deformation amount are obtained, wherein the first residual deformation amount is used to characterize the radial bending amount of the winding wire between any two adjacent inner support bars, and the second residual deformation amount is used to characterize the axial bending amount of the winding wire between any two adjacent spacers; The short-circuit resistance capability of the transformer is evaluated according to the electrical parameter, the first residual deformation amount, and the second residual deformation amount.

7. The method according to claim 6, It is characterized in that The electrical parameters include structural parameters of the winding conductors; and evaluating the short-circuit resistance of the transformer according to the electrical parameters, the first residual deformation amount, and the second residual deformation amount includes: The structural parameters of the winding conductor are compared with the first residual deformation amount and the second residual deformation amount respectively, and the short-circuit resistance capability of the transformer is evaluated according to the comparison result.

8. A transformer short-circuit resistance evaluation device, It is characterized in that The transformer winding wire is provided with a plurality of inner support bars, and the distance between any two adjacent inner support bars is equal; the outer surface of the winding wire is provided with a plurality of pads, and the distance between any two adjacent pads is equal; the device comprises: an acquisition module, configured to acquire a first electric force and a second electric force when a short circuit fault occurs in the transformer, wherein the first electric force is used to characterize the radial electric force to which the winding conductor is subjected under the action of the maximum short circuit current, and the second electric force is used to characterize the axial electric force to which the winding conductor is subjected under the action of the maximum short circuit current; A determination module, for determining a first deformation amount and a second deformation amount of the winding wire based on electrical parameters of the transformer, the first electric force and the second electric force, wherein the first deformation amount is used to characterize the maximum radial bending amount of the winding wire between any two adjacent inner support bars under the influence of the first electric force, and the second deformation amount is used to characterize the maximum axial bending amount of the winding wire between any two adjacent pads under the influence of the second electric force; the electrical parameters include the distance between any two adjacent inner support bars, the distance between any two adjacent pads, the elastic modulus of the winding wire and the moment of inertia of the winding wire; An evaluation module is used to evaluate the short-circuit resistance capability of the transformer according to the first deformation amount and the second deformation amount.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program. It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

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

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