Method, device, storage medium and electronic device for determining residual magnetism value of transformer

Abstract

The present application discloses a method, device, storage medium and electronic device for determining the residual magnetism value of a transformer. The method includes: obtaining a first equivalent inductance of the iron core in the transformer at a target frequency, and a second equivalent inductance of the excitation winding in the transformer under a waveform signal; performing curve fitting on the first equivalent inductance to obtain a first curve, and performing curve fitting on the second equivalent inductance to obtain a second curve; comparing the first curve and the second curve to obtain a comparison result; in response to the comparison result being within an error range, determining an offset of the second curve; and determining the residual magnetism value of the transformer based on the offset. The present application solves the technical problem of high complexity in determining the residual magnetism value of a transformer.

Description

Technical Field

[0001] The present application relates to the field of power equipment detection and maintenance, and in particular to a method, device, storage medium and electronic device for determining the residual magnetism value of a transformer. Background Art

[0002] After the direct resistance measurement and no-load closing operation, residual magnetism will remain in the iron core of the transformer due to the hysteresis characteristics of the ferromagnetic material. The existence of residual magnetism makes the iron core saturated. When the transformer is closed at no-load, a large excitation inrush current may be generated. Excessive excitation inrush current will cause the circuit breaker to trip, causing the transformer's protection device to malfunction, resulting in closing failure, which seriously affects the reliable operation of the transformer.

[0003] At present, the residual magnetism of the transformer core is detected by measuring the second harmonic in the transformer excitation inrush current, so as to determine whether there is residual magnetic flux in the transformer core. However, this method is complicated to operate, so there is a technical problem that the complexity of determining the residual magnetism value of the transformer is high.

[0004] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0005] The embodiments of the present application provide a method, device, storage medium and electronic device for determining the residual magnetism value of a transformer, so as to at least solve the technical problem of high complexity in determining the residual magnetism value of the transformer.

[0006] According to one aspect of an embodiment of the present application, a method for determining the residual magnetism value of a transformer is provided. The method may include: obtaining a first equivalent inductance of an iron core in a transformer at a target frequency, and a second equivalent inductance of an excitation winding in a transformer under a waveform signal; performing curve fitting on the first equivalent inductance to obtain a first curve, and performing curve fitting on the second equivalent inductance to obtain a second curve; comparing the first curve and the second curve to obtain a comparison result; in response to the comparison result being within an error range, determining an offset of the second curve; and determining the residual magnetism value of the transformer based on the offset.

[0007] Optionally, obtaining the first equivalent inductance of the iron core in the transformer at the target frequency includes: obtaining the hysteresis loop of the iron core in the transformer at the target frequency; performing scatter point processing on the hysteresis loop to obtain magnetic induction intensity and magnetic field intensity; determining the relative magnetic permeability based on the magnetic induction intensity and the magnetic field intensity; and determining the first equivalent inductance based on the relative magnetic permeability.

[0008] Optionally, determining the first equivalent inductance based on the relative magnetic permeability includes: determining the first equivalent inductance based on the relative magnetic permeability when the relative magnetic permeability and the first equivalent inductance are in direct proportion.

[0009] Optionally, obtaining the second equivalent inductance of the excitation winding in the transformer under the waveform signal includes: adjusting the waveform signal on the excitation winding in the transformer; using the adjusted waveform signal to measure the excitation current of the excitation winding to obtain a target time and a target current when the excitation current reaches stability; based on the target time and target current, determining the second equivalent inductance of the excitation winding in the transformer under the waveform signal.

[0010] Optionally, curve fitting is performed on the first equivalent inductance to obtain the first curve, including: curve fitting is performed on the first equivalent inductance to obtain a first initial curve; and first fitting parameters of the first initial curve are corrected to obtain the first curve, wherein the first fitting parameters are used to represent the longitudinal scaling of the first initial curve.

[0011] Optionally, the method also includes: in response to the comparison result being not within the error range, correcting the second fitting parameter and the third fitting parameter of the first curve to obtain a corrected first curve, wherein the second fitting parameter is used to represent the lateral offset of the first curve, and the third fitting parameter is used to represent the longitudinal offset of the first curve.

[0012] Optionally, performing curve fitting on the second equivalent inductance to obtain the second curve includes: performing curve fitting on the second equivalent inductance to obtain a second initial curve; and correcting an offset of the second initial curve to obtain the second curve.

[0013] Optionally, in response to the comparison result being within the error range, determining the offset of the second curve includes: in response to the comparison result being within the error range, establishing a fitting relationship between the offset of the second initial curve and a third fitting parameter of the first initial curve; and determining the offset of the second curve based on the fitting relationship.

[0014] Optionally, after determining the residual magnetism value of the transformer, the method further includes: determining a target area of ​​the residual magnetism point based on the residual magnetism value; determining a demagnetization strategy for demagnetizing the residual magnetism point based on the target area; and demagnetizing the residual magnetism point based on the demagnetization strategy.

[0015] According to another aspect of the embodiment of the present application, a device for determining the residual magnetism value of a transformer is also provided. The device may include: an acquisition unit, for acquiring a first equivalent inductance of the iron core in the transformer at a target frequency, and a second equivalent inductance of the excitation winding in the transformer under a waveform signal; a fitting unit, for performing curve fitting on the first equivalent inductance to obtain a first curve, and performing curve fitting on the second equivalent inductance to obtain a second curve; a comparison unit, for comparing the first curve and the second curve to obtain a comparison result; a first determination unit, for determining an offset of the second curve in response to the comparison result being within an error range; and a second determination unit, for determining the residual magnetism value of the transformer based on the offset.

[0016] According to another aspect of an embodiment of the present application, a non-volatile storage medium is also provided, including: the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute any method for determining the residual magnetism value of a transformer.

[0017] According to another aspect of an embodiment of the present application, there is also provided an electronic device, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is configured to execute instructions to implement a method for determining a residual magnetism value of any transformer.

[0018] According to another aspect of the embodiment of the present application, a computer program product is further provided. The computer program product may include a computer program, wherein the computer program is configured to execute any of the above-mentioned methods for determining the residual magnetism value of a transformer when running.

[0019] According to another aspect of the embodiment of the present application, a computer program product is also provided. The computer program product may include a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and the computer program is configured to execute any of the above-mentioned methods for determining the residual magnetism value of a transformer when running.

[0020] According to another aspect of the embodiment of the present application, a computer program is further provided, wherein the computer program is configured to execute any of the above-mentioned methods for determining the residual magnetism value of a transformer when running.

[0021] In an embodiment of the present application, a first equivalent inductance of the iron core of the transformer at a target frequency and a second equivalent inductance of the excitation winding of the transformer under a waveform signal are obtained; a curve fitting is performed on the first equivalent inductance to obtain a first curve, and a curve fitting is performed on the second equivalent inductance to obtain a second curve; the first curve and the second curve are compared to obtain a comparison result; in response to the comparison result being within an error range, an offset of the second curve is determined; based on the offset, the residual magnetism value of the transformer is determined. That is, the present application performs a curve fitting on the first equivalent inductance of the iron core of the transformer at a target frequency to obtain a first curve, and performs a curve fitting on the second equivalent inductance of the excitation winding of the transformer under a waveform signal to obtain a second curve, and further performs an error analysis on the obtained first curve and the second curve, and when the error analysis result is within the error range, the offset of the second curve is determined, and the residual magnetism value of the transformer is determined based on the determined offset of the second curve, thereby achieving a technical effect of reducing the complexity of determining the residual magnetism value of the transformer, thereby solving the high technical problem of the complexity of determining the residual magnetism value of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0023] Figure 1 is a flow chart of a method for determining a residual magnetism value of a transformer according to an embodiment of the present application;

[0024] Figure 2 It is a schematic diagram of a process of equivalent inductance calibration under a square wave signal according to an embodiment of the present application;

[0025] Figure 3 is a schematic diagram of a hysteresis loop of a silicon steel sheet under an industrial frequency according to an embodiment of the present application;

[0026] Figure 4 is a schematic diagram of a change law of relative magnetic permeability according to an embodiment of the present application;

[0027] Figure 5 is a schematic diagram of a change rule of excitation inductance according to an embodiment of the present application;

[0028] Figure 6 is a schematic diagram of a square wave signal according to an embodiment of the present application;

[0029] Figure 7 is a schematic diagram of an excitation current waveform under square wave excitation according to an embodiment of the present application;

[0030] Figure 8 is a schematic diagram of an equivalent inductance of a power frequency transformer and an equivalent inductance under square wave excitation according to an embodiment of the present application;

[0031] Fig. 9 is a schematic diagram of an equivalent inductance of a power frequency transformer and an equivalent inductance under square wave excitation during a calibration process according to an embodiment of the present application;

[0032] Fig.10 is a schematic diagram of an equivalent inductance of an industrial frequency transformer after a bias correction and an equivalent inductance under square wave excitation according to an embodiment of the present application;

[0033] Fig.11 is a schematic flow chart of a demagnetization method according to an embodiment of the present application;

[0034] Fig.12 is a schematic diagram of a residual magnetic point area division according to an embodiment of the present application;

[0035] Fig.13 is a schematic diagram of a square wave excitation change of a residual magnetic point corresponding to a second region according to an embodiment of the present application;

[0036] Fig.14 is a schematic diagram of a square wave excitation change corresponding to a residual magnetic point in a third region according to an embodiment of the present application;

[0037] Fig.15 is a schematic diagram of a square wave excitation change corresponding to a residual magnetic point in a fourth region according to an embodiment of the present application;

[0038] Fig.16 is a structural schematic diagram of a device for determining a residual magnetism value of a transformer according to an embodiment of the present application;

[0039] Fig.17 A schematic block diagram of an example electronic device 1700 that can be used to implement embodiments of the present application is shown. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0041] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] According to an embodiment of the present application, a method embodiment of a method for determining a residual magnetism value of a transformer is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0043] Figure 1 is a flow chart of a method for determining a residual magnetism value of a transformer according to an embodiment of the present application, such as Figure 1 As shown, the method may include the following steps:

[0044] Step S102, obtaining a first equivalent inductance of the iron core in the transformer at a target frequency, and a second equivalent inductance of the excitation winding in the transformer under a waveform signal.

[0045] In the above step S102, the first equivalent inductance of the transformer core at the target frequency and the second equivalent inductance of the transformer excitation winding under the waveform signal can be obtained. The target frequency can be the power frequency, for example, 50 Hz. This is only an example and does not limit the value of the target frequency. The first equivalent inductance can be the equivalent inductance of the transformer at the power frequency, which can be expressed as L AC The waveform signal may be a square wave signal, which is only an example here and does not specifically limit the type of the waveform signal. The second equivalent inductance may be the equivalent inductance of the transformer under square wave excitation, which may be represented by L DC To express.

[0046] Step S104: performing curve fitting on the first equivalent inductance to obtain a first curve, and performing curve fitting on the second equivalent inductance to obtain a second curve.

[0047] In the above step S104, after obtaining the first equivalent inductance, curve fitting can be performed on the first equivalent inductance to obtain a first curve. After obtaining the second equivalent inductance, curve fitting can be performed on the second equivalent inductance to obtain a second curve.

[0048] Optionally, after obtaining the first equivalent inductance L AC After that, the first equivalent inductance L can be obtained AC The first curve is obtained by curve fitting. DC Then, the second equivalent inductance L can be obtained DC The numerical value is used for curve fitting to obtain the second curve.

[0049] Step S106: compare the first curve and the second curve to obtain a comparison result.

[0050] In the above step S106, after curve fitting is performed on the first equivalent inductance to obtain a first curve, and curve fitting is performed on the second equivalent inductance to obtain a second curve, the obtained first curve and the second curve may be compared to obtain a comparison result.

[0051] Optionally, after obtaining the first curve and the second curve, an error analysis may be performed on the obtained first curve and the second curve using the following formula:

[0052]

[0053] Among them, aLAC Can be used to represent the first curve. L DC It can be used to represent the second curve, and RSS can be used to represent the error analysis result, that is, the comparison result.

[0054] Step S108 , in response to the comparison result being within the error range, determining an offset of the second curve.

[0055] In the above step S108, after the first curve and the second curve are compared and a comparison result is obtained, when the comparison result is within the error range, in response to the comparison result being within the error range, the offset of the second curve can be determined. The error range can be an error value pre-set according to actual conditions, for example, it can be 0.1, which is only for example description and does not specifically limit the value of the error range.

[0056] For example, the error range is set to 0.1, and after comparing the first curve and the second curve to obtain the comparison result RSS, when RSS<0.1, that is, the comparison result RSS is within the error range 0.1, the offset of the second curve can be further determined.

[0057] Step S110, determining the residual magnetism value of the transformer based on the offset.

[0058] In the above step S110, after determining the offset of the second curve, the residual magnetism value of the transformer can be determined based on the determined offset, wherein the residual magnetism value can be the magnetic flux remaining in the iron core of the transformer, which can also be called the residual magnetism size.

[0059] In an embodiment of the present application, a first equivalent inductance of the iron core of the transformer at a target frequency and a second equivalent inductance of the excitation winding of the transformer under a waveform signal are obtained; a curve fitting is performed on the first equivalent inductance to obtain a first curve, and a curve fitting is performed on the second equivalent inductance to obtain a second curve; the first curve and the second curve are compared to obtain a comparison result; in response to the comparison result being within an error range, an offset of the second curve is determined; based on the offset, the residual magnetism value of the transformer is determined. That is, the present application performs a curve fitting on the first equivalent inductance of the iron core of the transformer at a target frequency to obtain a first curve, and performs a curve fitting on the second equivalent inductance of the excitation winding of the transformer under a waveform signal to obtain a second curve, and further performs an error analysis on the obtained first curve and the second curve, and when the error analysis result is within the error range, the offset of the second curve is determined, and the residual magnetism value of the transformer is determined based on the determined offset of the second curve, thereby achieving a technical effect of reducing the complexity of determining the residual magnetism value of the transformer, thereby solving the high technical problem of the complexity of determining the residual magnetism value of the transformer.

[0060] The above embodiments of the present application are further described below.

[0061] In some embodiments of the present application, step S102, obtaining the first equivalent inductance of the iron core in the transformer at the target frequency, includes: obtaining the hysteresis loop of the iron core in the transformer at the target frequency; performing scatter point processing on the hysteresis loop to obtain magnetic induction intensity and magnetic field intensity; determining the relative magnetic permeability based on the magnetic induction intensity and the magnetic field intensity; determining the first equivalent inductance based on the relative magnetic permeability.

[0062] In this embodiment, the hysteresis loop of the iron core in the transformer at the target frequency can be obtained. After obtaining the hysteresis loop, the hysteresis loop can be subjected to scatter processing to obtain the magnetic induction intensity and the magnetic field intensity. Based on the obtained magnetic induction intensity and the magnetic field intensity, the relative magnetic permeability can be determined. Further based on the determined relative magnetic permeability, the first equivalent inductance can be determined. Among them, the hysteresis loop can be a curve of the change of the internal magnetization intensity of the iron core material in the transformer when the intensity of the magnetic field changes. The magnetic induction intensity can be the magnetic flux passing through a unit area, which can be represented by B. The magnetic field intensity can be the force or torque between unit magnetic poles, which can be represented by H. The relative magnetic permeability can be the ratio of the magnetization ability under the action of an external magnetic field to the magnetization ability under the action of a magnetic field in a vacuum, which can be represented by μ r To express.

[0063] Optionally, the hysteresis loop of the transformer core at the power frequency is obtained, and the obtained hysteresis loop is subjected to scatter point processing to obtain the magnetic induction intensity and the magnetic field intensity. Based on the obtained magnetic induction intensity and magnetic field intensity, the relative magnetic permeability can be calculated by the following formula:

[0064]

[0065] Among them, ΔB can be used to represent the differential of magnetic induction intensity B, and ΔH can be used to represent the differential of magnetic field intensity H. Further based on the obtained relative magnetic permeability, the first equivalent inductance L can be determined: AC .

[0066] In some embodiments of the present application, determining the first equivalent inductance based on the relative magnetic permeability includes: determining the first equivalent inductance based on the relative magnetic permeability when the relative magnetic permeability and the first equivalent inductance are in direct proportion.

[0067] In this embodiment, after the relative magnetic permeability is obtained, in the case where the relative magnetic permeability and the first equivalent inductance are in a proportional relationship, the first equivalent inductance can be determined based on the obtained relative magnetic permeability.

[0068] Optionally, due to the presence of the transformer core, the magnetic flux and current are not always proportional. The inductance value is a function related to the magnetic flux in the input core. The relationship of the magnetic flux inside the core can be expressed by the following formula:

[0069] φ=B×S

[0070] B=μ×H

[0071] H×l=N×I

[0072] Among them, φ can be used to represent magnetic flux, S can be used to represent the cross-sectional area of ​​the core, μ can be used to represent magnetic permeability, l can be used to represent the average magnetic path length, N can be used to represent the number of turns, and I can be used to represent current. Furthermore, the definition of inductance can be expressed by the following formula:

[0073]

[0074] Among them, L can be used to represent inductance. From the above, it can be seen that for the transformer, the number of turns N, the core cross-sectional area S and the average magnetic path length l of the transformer are determined at the factory, that is, the nonlinear inductance of the coil is only related to the magnetic permeability μ of the core, and is proportional. When obtaining the relative magnetic permeability μ of the rising and falling curves of the hysteresis loop r After the relative magnetic permeability μ is obtained, r The numerical curve fitting is performed to obtain the regularity diagram of the relative magnetic permeability changing with the magnetic field strength H during the rising and falling processes. Further based on the regularity diagram of the relative magnetic permeability changing with the magnetic field strength H obtained, due to the first equivalent inductance L AC and relative magnetic permeability μ r is proportional to, therefore, the first equivalent inductance L AC The regularity diagram of the change with magnetic field strength H is consistent with the regularity diagram of the change with magnetic field strength H of relative magnetic permeability.

[0075] In some embodiments of the present application, step S102, obtaining the second equivalent inductance of the excitation winding in the transformer under the waveform signal, includes: adjusting the waveform signal on the excitation winding in the transformer; using the adjusted waveform signal, measuring the excitation current of the excitation winding to obtain the target time and target current when the excitation current reaches stability; based on the target time and target current, determining the second equivalent inductance of the excitation winding in the transformer under the waveform signal.

[0076] In this embodiment, the waveform signal on the excitation winding in the transformer can be adjusted, and the excitation current of the excitation winding can be further measured using the adjusted waveform signal to obtain the target time and target current when the excitation current reaches stability. Based on the obtained target time and target current, the second equivalent inductance of the excitation winding in the transformer under the waveform signal can be determined. Among them, the target time can be the time when the excitation current reaches stability, which can be represented by Δt. The target current can be the current when the excitation current reaches stability, which can be represented by ΔI.

[0077] Optionally, adjust the peak voltage applied to the excitation winding, measure the current waveform under k times the excitation current in sequence, and obtain the time Δt and current ΔI when the current reaches stability. After obtaining the time Δt and current ΔI when the current reaches stability, the equivalent inductance L in the square wave scenario can be calculated using the empirical formula u=L*ΔI / Δt. DC . Wherein, k is 0.1*i (i=1,…,20), and u can be used to represent voltage.

[0078] In some embodiments of the present application, step S104, performing curve fitting on the first equivalent inductance to obtain a first curve, includes: performing curve fitting on the first equivalent inductance to obtain a first initial curve; and correcting a first fitting parameter of the first initial curve to obtain the first curve, wherein the first fitting parameter is used to represent the longitudinal scaling of the first initial curve.

[0079] In this embodiment, after obtaining the first equivalent inductance, the obtained first equivalent inductance can be subjected to curve fitting to obtain a first initial curve. Further, the first fitting parameter of the obtained first initial curve can be corrected to obtain the first curve. The first fitting parameter can be used to represent the longitudinal scaling of the first initial curve, which can be represented by a.

[0080] Optionally, after obtaining the first equivalent inductance L AC After that, the first equivalent inductance L can be obtained AC Perform curve fitting to obtain the first initial curve as follows:

[0081]

[0082] Wherein, a can be used to represent the first fitting parameter, b can be used to represent the second fitting parameter, and c can be used to represent the third fitting parameter. The first fitting parameter a of the obtained first initial curve can be further corrected to obtain the first curve as follows:

[0083]

[0084] Wherein, a' can be used to represent the corrected first fitting parameter.

[0085] In some embodiments of the present application, the method also includes: in response to the comparison result being not within the error range, correcting the second fitting parameter and the third fitting parameter of the first curve to obtain a corrected first curve, wherein the second fitting parameter is used to represent the lateral offset of the first curve, and the third fitting parameter is used to represent the longitudinal offset of the first curve.

[0086] In this embodiment, after comparing the first curve and the second curve to obtain a comparison result, when the comparison result is not within the error range, in response to the comparison result not being within the error range, the second fitting parameter and the third fitting parameter of the first curve can be corrected to obtain a corrected first curve. The second fitting parameter can be used to represent the lateral offset of the first curve, which can be represented by b. The third fitting parameter can be used to represent the longitudinal offset of the first curve, which can be represented by c.

[0087] Optionally, when the comparison result is not within the error range, the first curve aL may be AC The second fitting parameter b and the third fitting parameter c are corrected to obtain the new aL under square wave drive AC As follows:

[0088]

[0089] Among them, b' can be used to represent the modified second fitting parameter, and c' can be used to represent the modified third fitting parameter.

[0090] In some embodiments of the present application, step S104, performing curve fitting on the second equivalent inductance to obtain a second curve, includes: performing curve fitting on the second equivalent inductance to obtain a second initial curve; and correcting an offset of the second initial curve to obtain the second curve.

[0091] In this embodiment, after the second equivalent inductance is obtained, the second equivalent inductance may be curve-fitted to obtain a second initial curve, and the offset of the obtained second initial curve may be further corrected to obtain a second curve.

[0092] Optionally, after obtaining the second equivalent inductance L DC Then, the second equivalent inductance L can be obtained DC Perform curve fitting to obtain the second initial curve as follows:

[0093]

[0094] Among them, m, n and p can be used to represent the fitting parameters of the second initial curve. Further, the offset of the second initial curve can be corrected to obtain the second curve.

[0095] In some embodiments of the present application, step S108, in response to the comparison result being within the error range, determining the offset of the second curve, includes: in response to the comparison result being within the error range, establishing a fitting relationship between the offset of the second initial curve and the third fitting parameter of the first initial curve; based on the fitting relationship, determining the offset of the second curve.

[0096] In this embodiment, after comparing the first curve and the second curve to obtain a comparison result, when the comparison result is within the error range, in response to the comparison result being within the error range, a fitting relationship between the offset of the second initial curve and the third fitting parameter of the first initial curve can be established. Further based on the established fitting relationship, the offset of the second curve can be determined.

[0097] Optionally, since the offset ΔH has different characteristics under different working conditions, according to the non-biased L DC and with bias L AC The curve equation below is used to perform linear fitting on the offset ΔH and the third fitting parameter c, and the following mathematical relationship is established:

[0098] c(ΔH)=mΔH+n

[0099] The inductance curve under different bias values ​​ΔH can be expressed by the following formula:

[0100]

[0101] Further, the first square wave (for example, 0.2-0.4 times the excitation current) is applied to the transformer excitation winding, and the equivalent inductance L is calculated by the empirical formula u=L*ΔI / Δt, and L DC When L and L DC When the error between is greater than 20%, it is determined that there is residual magnetism. The magnetic field intensity H can be determined by the excitation current, and the offset ΔH can be determined by the above fitting equation. Among them, ΔH can be used to represent the offset, and c′ can be used to represent the correction coefficient under the offset ΔH.

[0102] Optionally, the residual magnetism can be determined based on the determined offset ΔH. DC The direction of residual magnetism can be determined by numerical comparison. DC At this time, the residual magnetism value is small, and the applied square wave signal has a demagnetizing effect, and the curve changes towards zero. <L DC When , the residual magnetization deviates from the center position, and the square wave signal has a magnetizing effect, and the curve changes toward the saturation magnetization direction.

[0103] In some embodiments of the present application, after determining the residual magnetism value of the transformer, the method further includes: determining a target area of ​​the residual magnetism point based on the residual magnetism value; determining a demagnetization strategy for demagnetizing the residual magnetism point based on the target area; and demagnetizing the residual magnetism point based on the demagnetization strategy.

[0104] In this embodiment, after determining the residual magnetism value of the transformer, based on the determined magnetic value, the target area of ​​the residual magnetism point can be determined. Further based on the determined target area of ​​the residual magnetism point, a demagnetization strategy for demagnetizing the residual magnetism point can be determined. Based on the determined demagnetization strategy, the residual magnetism point can be demagnetized. Among them, the target area can include at least a first area, a second area, a third area and a fourth area. The demagnetization strategy can be different demagnetization methods taken for the target area where the residual magnetism point is located.

[0105] For example, when L and L DC When the error between L and L is less than 20%, it is determined that the residual magnetization point is in the first area. At this time, there is no residual magnetism and demagnetization is not required. DC When the residual magnetism point is in the second area, the residual magnetism value is small, and 0.3 times the excitation current is started to demagnetize. When L<0.5*L DC When the residual magnetism point is determined to be in the third area, the residual magnetism value is very large at this time, the excitation current direction should be changed immediately, and 1 times the excitation current should be applied to demagnetize. DC When the residual magnetization point is determined to be in the fourth area, 0.6 times the excitation current is started to demagnetize.

[0106] In an embodiment of the present application, a first equivalent inductance of the iron core of the transformer at a target frequency and a second equivalent inductance of the excitation winding of the transformer under a waveform signal are obtained; a curve fitting is performed on the first equivalent inductance to obtain a first curve, and a curve fitting is performed on the second equivalent inductance to obtain a second curve; the first curve and the second curve are compared to obtain a comparison result; in response to the comparison result being within an error range, an offset of the second curve is determined; based on the offset, the residual magnetism value of the transformer is determined. That is, the present application performs a curve fitting on the first equivalent inductance of the iron core of the transformer at a target frequency to obtain a first curve, and performs a curve fitting on the second equivalent inductance of the excitation winding of the transformer under a waveform signal to obtain a second curve, and further performs an error analysis on the obtained first curve and the second curve, and when the error analysis result is within the error range, the offset of the second curve is determined, and the residual magnetism value of the transformer is determined based on the determined offset of the second curve, thereby achieving a technical effect of reducing the complexity of determining the residual magnetism value of the transformer, thereby solving the high technical problem of the complexity of determining the residual magnetism value of the transformer.

[0107] In order to facilitate those skilled in the art to better understand the technical solution of the present application, a specific embodiment is now described.

[0108] The transformer is a hub device for mutual conversion between different voltage levels in the power system, and plays an extremely important role in the safe operation of the power system. After the direct resistance measurement and no-load closing operation, the residual magnetism will remain in the iron core of the transformer due to the hysteresis characteristics of the ferromagnetic material. The existence of residual magnetism causes the iron core to saturate. When the transformer is closed at no-load, a large excitation surge current may be generated. Excessive excitation surge current will cause the circuit breaker to trip, causing the transformer's protection device to malfunction, resulting in closing failure, which seriously affects the reliable operation of the transformer. Therefore, it is very necessary to perform residual magnetism detection on the transformer after the transformer test or before commissioning, and take effective demagnetization measures to eliminate it.

[0109] At present, the method for detecting the residual magnetism of the transformer core is usually to determine whether there is residual magnetic flux by measuring the second harmonic in the transformer excitation surge current. However, this method is complicated to operate and is contrary to the purpose of determining the residual magnetism before reclosing, so it is not suitable for field application. Since the demagnetization methods for the transformer core are generally divided into AC demagnetization method and DC demagnetization method. The AC demagnetization method has high requirements for the power supply, and the test is a high-voltage test, which is highly dangerous and not suitable for field application. In the DC demagnetization method, the amplitude and time of the demagnetization current cannot be determined, the demagnetization error is large, and the demagnetization effect cannot be evaluated. As a result, there are problems such as complex on-site residual magnetism detection methods for transformers, poor demagnetization effects, and inability to evaluate demagnetization effects.

[0110] In order to solve the above problems, this application proposes a residual magnetism detection and demagnetization method, which takes the linear relationship between relative magnetic permeability and transformer coil winding inductance as the starting point, measures the core residual magnetism and determines the residual magnetism direction by the transformer excitation inductance value under square wave signal, and can improve the demagnetization efficiency. In addition, different demagnetization strategies are customized for different residual magnetism areas, which is highly targeted and has a good demagnetization effect.

[0111] Figure 2 FIG. 1 is a flow chart of equivalent inductance calibration under a square wave signal according to an embodiment of the present application. Figure 2 As shown, the process of equivalent inductance calibration under the square wave signal may include the following steps:

[0112] Step S201, measuring the hysteresis loop of the transformer core material at the power frequency.

[0113] In the above step S201, the hysteresis loop of the transformer core material at the power frequency may be measured. Figure 3 is a schematic diagram of a hysteresis loop of a silicon steel sheet under an industrial frequency according to an embodiment of the present application, such as Figure 3As shown, this embodiment takes the same silicon steel sheet brand as one type (the silicon steel sheet brand is queried through the transformer finished product application) to obtain the hysteresis loop under the power frequency, wherein the horizontal axis can be used to represent the magnetic field intensity H, and the vertical axis can be used to represent the magnetic induction intensity B.

[0114] Step S202, performing scatter point processing on the hysteresis loop to obtain relative magnetic permeability.

[0115] In the above step S202, the obtained hysteresis loop may be subjected to scatter point processing to obtain relative magnetic permeability. Figure 4 is a schematic diagram of a change law of relative magnetic permeability according to an embodiment of the present application, such as Figure 4 As shown, the relative permeability μ of the rising and falling curves of the hysteresis loop is obtained. r The values ​​are fitted by curve fitting to obtain the variation law of relative magnetic permeability during the rising and falling process, where the horizontal axis can be used to represent the magnetic field intensity H, and the vertical axis can be used to represent the relative magnetic permeability μ r .

[0116] Step S203, based on the proportional relationship between relative magnetic permeability and inductance, obtain a fitting curve of the equivalent inductance of the power frequency transformer.

[0117] In the above step S203, since the relative magnetic permeability is proportional to the inductance, the variation law diagram of the excitation inductance can be obtained based on the obtained variation law diagram of the relative magnetic permeability. Figure 5 is a schematic diagram of a variation law of excitation inductance according to an embodiment of the present application, such as Figure 5 As shown, due to the equivalent inductance L AC and relative magnetic permeability μ r is proportional to, therefore, the equivalent inductance L AC The regularity diagram of the change with magnetic field strength H is consistent with the regularity diagram of the change with magnetic field strength H, where the horizontal axis can be used to represent the magnetic field strength H and the vertical axis can be used to represent the excitation inductance L AC .

[0118] Step S204, using a square wave signal to sequentially measure the stabilization time and current under k times the excitation current.

[0119] In the above step S204, Figure 6 is a schematic diagram of a square wave signal according to an embodiment of the present application, such as Figure 6 As shown, the peak voltage applied to the excitation winding is adjusted, and the current waveforms under k times the excitation current are measured in sequence to obtain the time Δt and current ΔI when the current reaches stability.

[0120] Step S205: using an empirical formula to calculate the equivalent inductance.

[0121] In the above step S205, Figure 7 is a schematic diagram of an excitation current waveform under square wave excitation according to an embodiment of the present application, such as Figure 7 As shown, after obtaining the time Δt and current ΔI when the current reaches stability, the equivalent inductance L in the square wave scenario can be calculated using the empirical formula u=L*ΔI / Δt. DC . Where k is 0.1*i (i=1,…,20).

[0122] Step S206, performing curve fitting on the obtained equivalent inductance value to obtain a fitting curve of the equivalent inductance under square wave excitation.

[0123] In the above step S206, Figure 8 is a schematic diagram of an equivalent inductance of a power frequency transformer and an equivalent inductance under square wave excitation according to an embodiment of the present application, such as Figure 8 As shown, the horizontal axis can be used to represent the magnetic field intensity H, and the vertical axis can be used to represent the inductance. Figure 8 L AC Can be used to represent the equivalent inductance of the power frequency transformer, L DC It can be used to represent the equivalent inductance under square wave excitation.

[0124] Step S207, correcting a first fitting parameter of a fitting curve of the equivalent inductance of the power frequency transformer.

[0125] In the above step S207, Fig. 9 is a schematic diagram of the equivalent inductance of the power frequency transformer and the equivalent inductance under square wave excitation during a calibration process according to an embodiment of the present application, such as Fig. 9 As shown, L can be obtained DC and L AC The saturation value is compared with that of the original value, and the LAC curve fitting parameter a is corrected to obtain aL AC , so that its saturation value is close. Among them, ΔH can be used as the bias.

[0126] Step S208, correcting the offset of the fitting curve of the equivalent inductance under square wave excitation, and performing error analysis with the fitting curve of the equivalent inductance of the power frequency transformer.

[0127] In the above step S208, Fig.10 is a schematic diagram of an equivalent inductance of an industrial frequency transformer after a bias correction and an equivalent inductance under square wave excitation according to an embodiment of the present application, such as Fig.10 As shown, the modified L DC The offset of the curve, that is, the overall rightward shift. DC and aL AC Perform error analysis.

[0128] Step S209, determining whether the error analysis result is within the error range.

[0129] In the above step S209, when the error analysis result is within the error range, the process proceeds to step S210, otherwise, the process proceeds to step S211.

[0130] Step S210, obtaining a corrected fitting curve of the power frequency transformer equivalent inductance.

[0131] In the above step S210, when the error analysis result RSS<0.1, the requirement is met to obtain aL AC .

[0132] Step S211, correcting the second fitting parameter and the third fitting parameter of the fitting curve of the equivalent inductance of the power frequency transformer.

[0133] In the above step S211, when the error analysis result is not within the error range, correct aL AC The curve fitting parameters b and c are used to finally obtain the new aL under square wave drive. AC .

[0134] Since the offset ΔH has different characteristics under different working conditions, according to the no-bias L DC and with bias L AC The curve equation under the bias value ΔH and the third fitting parameter c are linearly fitted to establish a corresponding mathematical relationship, and the inductance curves under different bias values ​​ΔH can be expressed by the fitting equation.

[0135] Furthermore, the magnetic field strength H can be determined by the excitation current, and the offset ΔH can be determined by the above fitting equation. Based on the determined offset ΔH, the residual magnetism can be determined. DC The direction of residual magnetism can be determined by numerical comparison. DC At this time, the residual magnetism value is small, and the applied square wave signal has a demagnetizing effect, and the curve changes towards zero. <L DC When , the residual magnetization deviates from the center position, and the square wave signal has a magnetizing effect, and the curve changes toward the saturation magnetization direction.

[0136] Fig.11 is a flow chart of a demagnetization method according to an embodiment of the present application, such as Fig.11 As shown, the process of the demagnetization method may include the following steps:

[0137] Step S1101, select the first square wave signal and measure the equivalent inductance value L.

[0138] In the above step S1101, the first square wave (for example, 0.2-0.4 times the excitation current) is selected and applied to the transformer excitation winding, and the equivalent inductance L is calculated by the empirical formula u=L*ΔI / Δt, and L DC contrast.

[0139] Optionally, Fig.12 is a schematic diagram of a residual magnetic point area division according to an embodiment of the present application, such as Fig.12 As shown, after applying the first square wave to obtain the residual magnetism result, the demagnetization current is started according to the position of the residual magnetism point.

[0140] Step S1102, determine L and L DC Is the error greater than 20%.

[0141] In the above step S1102, when L and L DC When the error is less than 20%, it is determined that there is no residual magnetism and the process goes to step S1103; otherwise, it is determined that there is residual magnetism and the process goes to step S1104 and step S1105.

[0142] Step S1103, determining that there is no residual magnetism.

[0143] In the above step S1103, when L and L DC When the error between them is less than 20%, it is determined that the residual magnetization point is in the first area. At this time, there is no residual magnetism and demagnetization is not required. The horizontal axis can be used to represent time and the vertical axis can be used to represent voltage.

[0144] Step S1104, when L>L DC When the excitation current is 0.3 times, the demagnetization is started.

[0145] In the above step S1104, when L>L DC When the remanent magnetization point is determined to be in the second region, the remanent magnetization value is smaller. Fig.13 is a schematic diagram of a square wave excitation change of a residual magnetic point in the second region corresponding to an embodiment of the present application, such as Fig.13 As shown, in this case, 0.3 times the excitation current can be started for demagnetization.

[0146] Step S1105, L <L DC .

[0147] In the above step S1105, for L <L DC In the two cases, go to step S1106 and step S1107 respectively.

[0148] Step S1106, when L<0.5*L DC When the excitation current direction is changed immediately, 1 times the excitation current is applied to demagnetize.

[0149] In the above step S1106, when L<0.5*L DC When the remanent magnetization point is determined to be in the third area, the remanent magnetization value is very large. Fig.14 is a schematic diagram of a square wave excitation change corresponding to a residual magnetic point in the third region according to an embodiment of the present application, such as Fig.14 As shown, in this case, the direction of the excitation current should be changed immediately and 1 times the excitation current should be applied to demagnetize.

[0150] Step S1107, when L is 0.5-0.8 times L DC When the excitation current is 0.6 times, the demagnetization is started.

[0151] In the above step S1107, when L is 0.5-0.8 times L DC , it is determined that the residual magnetization point is in the fourth area. Fig.15 is a schematic diagram of a square wave excitation change corresponding to a residual magnetic point in the fourth region according to an embodiment of the present application, such as Fig.15 As shown, in this case, 0.6 times the excitation current can be started for demagnetization.

[0152] In response to the problems of complex on-site residual magnetism detection methods for transformers, poor demagnetization effects, and inability to evaluate demagnetization effects, this application proposes a residual magnetism detection and demagnetization method based on the mathematical relationship between relative magnetic permeability and hysteresis loop, and the equivalent correspondence between magnetic permeability and transformer coil winding inductance. This method can not only quantitatively estimate the residual magnetism, but also determine the residual magnetism direction and improve the demagnetization efficiency. In addition, different demagnetization strategies are customized for different residual magnetism areas, which is highly targeted and can solve the shortcomings of poor demagnetization effects of traditional DC demagnetization methods.

[0153] This application proposes a method for determining whether a transformer contains residual magnetism by measuring the excitation inductance of a transformer using a square wave signal. The method is simple to operate, has a short detection time, and a low detection cost. The residual magnetism can be quantitatively estimated, and the residual magnetism direction can be determined to improve the demagnetization efficiency, which is suitable for engineering applications. Furthermore, different demagnetization strategies are customized for different residual magnetization areas to achieve rapid zeroing of residual magnetism, which is highly targeted and has a good demagnetization effect.

[0154] In an embodiment of the present application, a first equivalent inductance of the iron core of the transformer at a target frequency and a second equivalent inductance of the excitation winding of the transformer under a waveform signal are obtained; a curve fitting is performed on the first equivalent inductance to obtain a first curve, and a curve fitting is performed on the second equivalent inductance to obtain a second curve; the first curve and the second curve are compared to obtain a comparison result; in response to the comparison result being within an error range, an offset of the second curve is determined; based on the offset, the residual magnetism value of the transformer is determined. That is, the present application performs a curve fitting on the first equivalent inductance of the iron core of the transformer at a target frequency to obtain a first curve, and performs a curve fitting on the second equivalent inductance of the excitation winding of the transformer under a waveform signal to obtain a second curve, and further performs an error analysis on the obtained first curve and the second curve, and when the error analysis result is within the error range, the offset of the second curve is determined, and the residual magnetism value of the transformer is determined based on the determined offset of the second curve, thereby achieving a technical effect of reducing the complexity of determining the residual magnetism value of the transformer, thereby solving the high technical problem of the complexity of determining the residual magnetism value of the transformer.

[0155] The embodiment of the present application also provides a device for determining the residual magnetism value of a transformer. It should be noted that the device for determining the residual magnetism value of a transformer in this embodiment can be used to implement the method for determining the residual magnetism value of a transformer in the embodiment of the present invention.

[0156] Fig.16 is a schematic diagram of a structure of a device for determining a residual magnetism value of a transformer according to an embodiment of the present application, such as Fig.16 As shown, the device 1600 for determining the residual magnetism value of the transformer may include: an acquisition unit 1602 , a fitting unit 1604 , a comparison unit 1606 , a first determination unit 1608 , and a second determination unit 1610 .

[0157] The acquisition unit 1602 is used to acquire the first equivalent inductance of the iron core in the transformer under the target frequency, and the second equivalent inductance of the excitation winding in the transformer under the waveform signal.

[0158] The fitting unit 1604 is used to perform curve fitting on the first equivalent inductance to obtain a first curve, and to perform curve fitting on the second equivalent inductance to obtain a second curve.

[0159] The comparison unit 1606 is used to compare the first curve and the second curve to obtain a comparison result.

[0160] The first determining unit 1608 is configured to determine an offset of the second curve in response to the comparison result being within the error range.

[0161] The second determining unit 1610 is configured to determine a residual magnetism value of the transformer based on the offset.

[0162] Optionally, the acquisition unit 1602 includes: an acquisition module, used to obtain the hysteresis loop of the iron core in the transformer at the target frequency; a processing module, used to perform scattered point processing on the hysteresis loop to obtain magnetic induction intensity and magnetic field intensity; a first determination module, used to determine the relative magnetic permeability based on the magnetic induction intensity and the magnetic field intensity; and a second determination module, used to determine the first equivalent inductance based on the relative magnetic permeability.

[0163] Optionally, the second determination module includes: a determination submodule, configured to determine the first equivalent inductance based on the relative magnetic permeability when the relative magnetic permeability and the first equivalent inductance are in a proportional relationship.

[0164] Optionally, the acquisition unit 1602 includes: an adjustment module, used to adjust the waveform signal on the excitation winding in the transformer; a measurement module, used to measure the excitation current of the excitation winding using the adjusted waveform signal to obtain the target time and target current when the excitation current reaches stability; a third determination module, used to determine the second equivalent inductance of the excitation winding in the transformer under the waveform signal based on the target time and target current.

[0165] Optionally, the fitting unit 1604 includes: a first fitting module, used to perform curve fitting on the first equivalent inductance to obtain a first initial curve; a first correction module, used to correct a first fitting parameter of the first initial curve to obtain the first curve, wherein the first fitting parameter is used to represent the longitudinal scaling of the first initial curve.

[0166] Optionally, the device also includes: a correction unit, used to correct the second fitting parameter and the third fitting parameter of the first curve in response to the comparison result being not within the error range, so as to obtain a corrected first curve, wherein the second fitting parameter is used to represent the lateral offset of the first curve, and the third fitting parameter is used to represent the longitudinal offset of the first curve.

[0167] Optionally, the fitting unit 1604 includes: a second fitting module, used for performing curve fitting on the second equivalent inductance to obtain a second initial curve; and a second correction module, used for correcting the offset of the second initial curve to obtain a second curve.

[0168] Optionally, the first determination unit 1608 includes: an establishment module, used to establish a fitting relationship between the offset of the second initial curve and the third fitting parameter of the first initial curve in response to the comparison result being within the error range; and a fourth determination module, used to determine the offset of the second curve based on the fitting relationship.

[0169] Optionally, the device also includes: a third determination unit, used to determine a target area of ​​the residual magnetization point based on the residual magnetization value; a fourth determination unit, used to determine a demagnetization strategy for demagnetizing the residual magnetization point based on the target area; and a demagnetization unit, used to demagnetize the residual magnetization point based on the demagnetization strategy.

[0170] In the device, the first equivalent inductance of the iron core in the transformer at the target frequency and the second equivalent inductance of the excitation winding in the transformer under the waveform signal are obtained by the acquisition unit 1602. The first equivalent inductance is curve-fitted by the fitting unit 1604 to obtain a first curve, and the second equivalent inductance is curve-fitted by the fitting unit 1604 to obtain a second curve. The first curve and the second curve are compared by the comparison unit 1606 to obtain a comparison result. The first determination unit 1608 determines the offset of the second curve in response to the comparison result being within the error range. The second determination unit 1610 determines the residual magnetism value of the transformer based on the offset. That is to say, the present application performs curve fitting on the first equivalent inductance of the iron core of the transformer at the target frequency to obtain a first curve, and performs curve fitting on the second equivalent inductance of the excitation winding of the transformer under the waveform signal to obtain a second curve, and further performs error analysis on the obtained first curve and second curve. When the error analysis result is within the error range, the offset of the second curve is determined, and the residual magnetism value of the transformer is determined based on the determined offset of the second curve, thereby achieving the technical effect of reducing the complexity of determining the residual magnetism value of the transformer, and further solving the technical problem of high complexity in determining the residual magnetism value of the transformer.

[0171] According to another aspect of an embodiment of the present application, a non-volatile storage medium is also provided, the non-volatile storage medium including a stored program, wherein when the program is running, the device where the non-volatile storage medium is located is controlled to execute any method for determining the residual magnetism value of a transformer.

[0172] Specifically, the above storage medium is used to store program instructions for the following functions to implement the following functions:

[0173] Obtain a first equivalent inductance of an iron core in a transformer at a target frequency, and a second equivalent inductance of an excitation winding in the transformer under a waveform signal; perform curve fitting on the first equivalent inductance to obtain a first curve, and perform curve fitting on the second equivalent inductance to obtain a second curve; compare the first curve and the second curve to obtain a comparison result; determine an offset of the second curve in response to the comparison result being within an error range; and determine a residual magnetism value of the transformer based on the offset.

[0174] Optionally, in this embodiment, the above-mentioned storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the above-mentioned contents. More specific examples of the above-mentioned storage medium may include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above-mentioned contents.

[0175] In an exemplary embodiment of the present application, a computer program product is further provided, including a computer program, and when the computer program is executed by a processor, any of the above-mentioned methods for determining the residual magnetism value of a transformer is implemented.

[0176] Optionally, the computer program may implement the following steps when executed by a processor:

[0177] Obtain a first equivalent inductance of an iron core in a transformer at a target frequency, and a second equivalent inductance of an excitation winding in the transformer under a waveform signal; perform curve fitting on the first equivalent inductance to obtain a first curve, and perform curve fitting on the second equivalent inductance to obtain a second curve; compare the first curve and the second curve to obtain a comparison result; determine an offset of the second curve in response to the comparison result being within an error range; and determine a residual magnetism value of the transformer based on the offset.

[0178] In an exemplary embodiment of the present application, a computer program product is also provided, including a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and the computer program is configured to execute any of the above-mentioned methods for determining the residual magnetism value of the transformer when running.

[0179] Optionally, the computer program may implement the following steps when executed by a processor:

[0180] Obtain a first equivalent inductance of an iron core in a transformer at a target frequency, and a second equivalent inductance of an excitation winding in the transformer under a waveform signal; perform curve fitting on the first equivalent inductance to obtain a first curve, and perform curve fitting on the second equivalent inductance to obtain a second curve; compare the first curve and the second curve to obtain a comparison result; determine an offset of the second curve in response to the comparison result being within an error range; and determine a residual magnetism value of the transformer based on the offset.

[0181] In an exemplary embodiment of the present application, a computer program is further provided. The computer program is configured to execute the steps in any of the above method embodiments when running.

[0182] Optionally, the computer program may implement the following steps when executed by a processor:

[0183] Obtain a first equivalent inductance of an iron core in a transformer at a target frequency, and a second equivalent inductance of an excitation winding in the transformer under a waveform signal; perform curve fitting on the first equivalent inductance to obtain a first curve, and perform curve fitting on the second equivalent inductance to obtain a second curve; compare the first curve and the second curve to obtain a comparison result; determine an offset of the second curve in response to the comparison result being within an error range; and determine a residual magnetism value of the transformer based on the offset.

[0184] According to an embodiment of the present application, an electronic device is provided, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute any of the above-mentioned methods for determining the residual magnetism value of the transformer.

[0185] Optionally, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0186] Fig.17 A schematic block diagram of an example electronic device 1700 that can be used to implement an embodiment of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present application described and / or required herein.

[0187] like Fig.17 As shown, the device 1700 includes a computing unit 1701, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 1702 or a computer program loaded from a storage unit 1708 into a random access memory (RAM) 1703. In the RAM 1703, various programs and data required for the operation of the device 1700 can also be stored. The computing unit 1701, the ROM 1702, and the RAM 1703 are connected to each other via a bus 1704. An input / output (I / O) interface 1705 is also connected to the bus 1704.

[0188] A number of components in the device 1700 are connected to the I / O interface 1705, including: an input unit 1706, such as a keyboard, a mouse, etc.; an output unit 1707, such as various types of displays, speakers, etc.; a storage unit 1708, such as a disk, an optical disk, etc.; and a communication unit 1709, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 1709 allows the device 1700 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0189] The computing unit 1701 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 1701 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 1701 performs the various methods and processes described above, such as a method for determining the residual magnetism value of a transformer. For example, in some embodiments, the method for determining the residual magnetism value of a transformer may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 1708. In some embodiments, part or all of the computer program may be loaded and / or installed on the device 1700 via the ROM 1702 and / or the communication unit 1709. When the computer program is loaded into the RAM 1703 and executed by the computing unit 1701, one or more steps of the method for determining the residual magnetism value of the transformer described above may be performed. Alternatively, in other embodiments, the calculation unit 1701 may be configured to execute the method for determining the residual magnetism value of the transformer in any other appropriate manner (for example, by means of firmware).

[0190] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0191] The program code for implementing the method of the present application can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, implements the functions / operations specified in the flow chart and / or block diagram. The program code can be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0192] In the context of the present application, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0193] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0194] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.

[0195] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0196] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0197] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0198] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0199] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0200] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0201] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0202] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for determining the residual magnetism value of a transformer, characterized in that: include: Obtaining a first equivalent inductance of an iron core in a transformer at a target frequency, and a second equivalent inductance of an excitation winding in the transformer under a waveform signal; Performing curve fitting on the first equivalent inductance to obtain a first curve, and performing curve fitting on the second equivalent inductance to obtain a second curve, wherein the first curve is used to represent the relationship between the first equivalent inductance and the change of magnetic field strength, and the second curve is used to represent the relationship between the second equivalent inductance and the change of the magnetic field strength; comparing the first curve and the second curve to obtain a comparison result; In response to the comparison result being within the error range, determining an offset of the second curve, wherein the offset of the second curve is used to represent a lateral shift of the second curve; Based on the bias, determining a residual magnetism value of the transformer; Performing curve fitting on the second equivalent inductance to obtain the second curve includes: performing curve fitting on the second equivalent inductance to obtain a second initial curve; correcting an offset of the second initial curve to obtain the second curve, wherein the offset of the second initial curve is used to represent a lateral offset of the second initial curve; In response to the comparison result being within the error range, determining the offset of the second curve, including: in response to the comparison result being within the error range, establishing a fitting relationship between the offset of the second initial curve and a third fitting parameter of the first curve, wherein the third fitting parameter is used to represent the longitudinal offset of the first curve; based on the fitting relationship, determining the offset of the second curve.

2. The method according to claim 1, characterized in that: Obtaining the first equivalent inductance of the iron core in the transformer at the target frequency includes: Obtaining a hysteresis loop of the iron core in the transformer at the target frequency; Performing scatter point processing on the hysteresis loop to obtain magnetic induction intensity and the magnetic field intensity; Determining relative magnetic permeability based on the magnetic induction intensity and the magnetic field intensity; Based on the relative magnetic permeability, the first equivalent inductance is determined.

3. The method according to claim 2, characterized in that Determining the first equivalent inductance based on the relative magnetic permeability includes: In a case where the relative magnetic permeability and the first equivalent inductance are in a proportional relationship, the first equivalent inductance is determined based on the relative magnetic permeability.

4. The method according to claim 1, characterized in that Obtaining the second equivalent inductance of the excitation winding in the transformer under the waveform signal includes: Adjusting the waveform signal on the excitation winding in the transformer; Using the adjusted waveform signal, measuring the excitation current of the excitation winding to obtain a target time and a target current when the excitation current reaches stability; The second equivalent inductance of the excitation winding in the transformer under the waveform signal is determined based on the target time and the target current.

5. The method according to claim 1, characterized in that Performing curve fitting on the first equivalent inductance to obtain the first curve includes: Performing curve fitting on the first equivalent inductance to obtain a first initial curve; The first fitting parameter of the first initial curve is modified to obtain the first curve, wherein the first fitting parameter is used to represent the longitudinal scaling of the first initial curve.

6. The method according to claim 1, characterized in that The method further comprises: In response to the comparison result not being within the error range, the second fitting parameter and the third fitting parameter of the first curve are corrected to obtain a corrected first curve, wherein the second fitting parameter is used to represent a lateral offset of the first curve.

7. The method according to any one of claims 1 to 6, characterized in that: After determining the residual magnetism value of the transformer, the method further includes: Based on the residual magnetization value, determining a target area of ​​residual magnetization points; Based on the target area, determining a demagnetization strategy for demagnetizing the residual magnetization point; Based on the demagnetization strategy, the residual magnetization point is demagnetized.

8. A device for determining the residual magnetism value of a transformer, characterized in that: include: An acquisition unit, used to acquire a first equivalent inductance of an iron core in a transformer at a target frequency, and a second equivalent inductance of an excitation winding in the transformer under a waveform signal; a fitting unit, configured to perform curve fitting on the first equivalent inductance to obtain a first curve, and to perform curve fitting on the second equivalent inductance to obtain a second curve, wherein the first curve is used to represent a relationship between the first equivalent inductance and a change in magnetic field strength, and the second curve is used to represent a relationship between the second equivalent inductance and a change in the magnetic field strength; A comparison unit, configured to compare the first curve and the second curve to obtain a comparison result; a first determining unit, configured to determine an offset of the second curve in response to the comparison result being within an error range, wherein the offset of the second curve is used to represent a lateral shift of the second curve; A second determining unit, configured to determine a residual magnetism value of the transformer based on the bias; The fitting unit is further used for: performing curve fitting on the second equivalent inductance to obtain a second initial curve; and correcting an offset of the second initial curve to obtain the second curve, wherein the offset of the second initial curve is used to represent a lateral offset of the second initial curve; The first determination unit is also used for: in response to the comparison result being within the error range, establishing a fitting relationship between the offset of the second initial curve and a third fitting parameter of the first curve, wherein the third fitting parameter is used to represent the longitudinal offset of the first curve; and determining the offset of the second curve based on the fitting relationship.

9. A non-volatile storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is executed, the device where the storage medium is located is controlled to execute the method for determining the residual magnetism value of the transformer according to any one of claims 1 to 7.

10. An electronic device, characterized in that: include: processor; a memory for storing instructions executable by the processor; The processor is configured to execute the instructions to implement the method for determining the residual magnetism value of the transformer according to any one of claims 1 to 7.

11. A computer program product, characterized in that The computer program product comprises a computer program, wherein the computer program is configured to execute the method for determining the residual magnetism value of the transformer as claimed in any one of claims 1 to 7 when being executed by a processor.

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