Transformer winding deformation online monitoring method and system based on leakage magnetic field analytical model

Abstract

The invention relates to the technical field of transformer winding defect detection and diagnosis, in particular to a transformer winding deformation online monitoring method and system based on a leakage magnetic field analytic model, and the method comprises the steps: obtaining leakage magnetic induction intensity sampling data and current sampling data, and constructing the leakage magnetic field analytic model; calculating a coefficient matrix of the winding in a normal state and extracting a coefficient matrix after deformation, and calculating to obtain a coefficient difference matrix; taking the calculated corresponding coefficient difference value as a reference value to form a coefficient reference difference value matrix, and introducing an error coefficient to obtain a deformation threshold value matrix; according to a comparison result of the coefficient difference matrix and the deformation threshold matrix, a deformation winding and a deformation position are judged; and giving a corresponding early warning signal according to a judgment result, and making a subsequent maintenance decision by a user. The deformed winding is accurately positioned through the identified model parameters, the running state of the transformer winding is monitored online in real time, and the method plays an important role in equipment safety and long-term stable running of a power transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer winding defect detection and diagnosis, and in particular to an online transformer winding deformation monitoring method and system based on a leakage magnetic field analytical model. Background Art

[0002] Power transformers are one of the most critical large-scale equipment in the power system, and their health status is of great significance to the safe operation of the entire power grid. With the high proportion of new energy and nonlinear power electronic devices connected to the power system, the operating environment of the transformer is becoming more and more complex. When the transformer is affected by current shock or other abnormal operating conditions (generally deformation caused by short-circuit large current shock or collision), the winding is prone to deformation due to limited mechanical strength. Winding deformation is one of the most common faults of power transformers. Winding deformation can be divided into radial deformation and axial deformation. Specifically, there are three types: axial collapse deformation of the winding end, radial compression of the middle of the inner winding, and radial expansion deformation of the outer winding. Since winding deformation has a cumulative effect, slight deformation of the winding is not easy to be detected. With the accumulation of winding deformation, when severe working conditions occur again, it may cause severe deformation of the winding or even damage to the winding insulation, causing partial discharge and inter-turn short circuit and other faults.

[0003] At present, domestic and foreign scholars have conducted a lot of theoretical and experimental research on the identification of winding deformation defects, which are mainly divided into electrical quantity methods and non-electrical quantity methods. The electrical quantity methods mainly include short-circuit impedance method, leakage inductance parameter identification method, low-voltage pulse method and frequency response analysis method. The most basic principle of short-circuit impedance method and leakage inductance parameter identification method is to use the change of winding leakage reactance, that is, leakage magnetic field, of transformer winding to characterize the winding state after the winding structure changes; low-voltage pulse method is to inject low-voltage pulse signal into transformer winding, and when the coil is displaced, its response characteristics will also change accordingly. The principle of frequency response method is that under high frequency, transformer winding can be simplified to be equivalent to a two-port network composed of capacitors, inductors, etc., and the transfer function characteristic curve is obtained by input excitation and output response to identify the change of winding structure. Non-electrical quantity methods include vibration method, ultrasonic detection method, etc.; vibration method is to obtain a considerable database by placing a vibration sensor at the oil tank, and use the change of characteristic parameters contained in the vibration signal to identify the change of winding structure; ultrasonic detection method is to use the reflection characteristics of ultrasonic waves on different medium surfaces to identify winding defects.

[0004] However, most of these methods require the equipment to be out of operation and complete offline testing within a fixed maintenance cycle, which is not conducive to real-time monitoring of the transformer. In addition, the existing online monitoring methods are easily interfered by the complex on-site environment, and the repeatability of on-site applications is low. Maintenance personnel need to have rich experience to interpret the test results. At the same time, the existing detection methods cannot locate the position of winding deformation, and they are not sensitive to winding end faults. Summary of the invention

[0005] In order to solve the problem that axial and radial deformation defects of transformer windings are difficult to detect and diagnose accurately online, the present invention proposes an online monitoring method and system for transformer winding deformation based on a leakage magnetic field analytical model.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: an online monitoring method for transformer winding deformation based on leakage magnetic field analytical model, comprising the following steps:

[0007] S1. Obtain leakage magnetic induction intensity sampling data and current sampling data, and construct a leakage magnetic field analytical model;

[0008] S2. Obtain the corresponding structural parameters of the actual transformer and substitute them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding;

[0009] S3, based on the leakage magnetic induction intensity sampling data and the current sampling data, using the least squares fitting algorithm, extracting the coefficient matrix of each winding after deformation;

[0010] S4. Calculate a coefficient difference matrix based on the normal state coefficient matrix and the deformed coefficient matrix;

[0011] S5. Substitute the structural parameters of the transformer after deformation into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, use the coefficient difference of each winding as the reference value, construct a coefficient reference difference matrix, and introduce the error coefficient to obtain the deformation threshold matrix;

[0012] S6. Determine the deformation winding and deformation position according to the comparison result between the coefficient difference matrix and the deformation threshold matrix;

[0013] S7. Give a corresponding warning signal based on the judgment result, and let the user make subsequent maintenance decisions.

[0014] Furthermore, in step S1, leakage magnetic induction intensity sampling data and current sampling data are obtained, specifically:

[0015] Five measuring points are selected in the leakage magnetic field. The upper and lower ends of the high and low voltage windings are radially selected as measuring points 1, 2, 3 and 4, and magneto-optical measuring sensors are placed at measuring points 1-4 to measure the radial leakage magnetic induction intensity of the measuring points and monitor the deformation of the winding ends; the axial symmetry line in the middle oil channel of the high and low voltage windings is selected as measuring point 5, and a magneto-optical measuring sensor is placed at measuring point 5 to measure the axial leakage magnetic induction intensity of the point and monitor the radial deformation of the middle part of the winding;

[0016] The radial leakage magnetic induction intensity B of measuring points 1-4 is measured in real time by magneto-optical measuring sensors. x1 , B x2 , B x3 , B x4 and the axial leakage magnetic induction intensity B at measuring point 5 y5 , the high and low voltage winding outgoing current transformers obtain current sampling in real time synchronously l and i h .

[0017] Furthermore, in step S1, the construction process of the leakage magnetic field analytical model is as follows:

[0018] The leakage magnetic flux density sampling data and the current sampling data are used to form the leakage magnetic flux density matrix B and the current matrix I, and the relationship is formed through the coefficient matrix C, specifically:

[0019] B=CI

[0020] Select the data window length as 10ms, take the data window boundary point as the origin, establish a rectangular coordinate system, and get:

[0021] The relationship between the radial leakage magnetic induction intensity and the winding current is as follows:

[0022]

[0023] The relationship between the axial leakage magnetic induction intensity and the winding current is as follows:

[0024]

[0025] Among them, B xq is the radial leakage magnetic field of the qth measuring point inside the transformer core window; B yq is the axial leakage magnetic field of the qth measuring point; p represents the number of windings inside the core window; i corresponds to the winding number, C xqi is the radial coefficient corresponding to the i-th winding and the q-th measuring point in the analytical model; C yqi is the axial coefficient corresponding to the i-th winding and the q-th measuring point; i i represents the current flowing through the i-th winding;

[0026] The calculation formulas for the radial coefficient and the axial coefficient are:

[0027]

[0028] Where μ0 is the air magnetic permeability, which is ∞ when the core is not saturated, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b and h are the width and height of the core window respectively, J jk is the double Fourier coefficient value; x, y are the coordinates of the measuring point;

[0029] The double Fourier coefficient value J jk The calculation formula is:

[0030]

[0031] Where N i is the number of turns of the i-th winding, S i is the cross-sectional area of ​​the i-th winding, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b i '-b i is the width of the i-th winding, h i '-h i are the heights of the i-th winding respectively;

[0032] According to the five measuring points corresponding to the magneto-optical measurement sensors specifically placed in the leakage magnetic field, the winding deformation leakage magnetic field analytical model is obtained, and the formula is:

[0033]

[0034] Among them, B x1 , B x2 , B x3 , B x4 is the radial leakage magnetic induction intensity of measuring points 1-4; B y5 is the axial leakage magnetic induction intensity of measuring point 5; C in the coefficient matrix C xqi , q represents the measurement point number 1-4, i represents the i-th winding, where i is 1 for low-voltage winding and 2 for high-voltage winding; C in the coefficient matrix C yqi , q represents the measuring point number 5, i represents the i-th winding, where i is 1 for low voltage winding and 2 for high voltage winding; i l and i h They are the low voltage winding current and the high voltage winding current respectively.

[0035] Furthermore, the coefficient difference matrix C △ The calculation process is:

[0036] Using the least squares fitting algorithm, the coefficient matrix after deformation is extracted, and the formula is:

[0037] C=B(IT I) -1 I T

[0038] Substitute the corresponding structural parameters of the actual transformer into the winding deformation leakage magnetic field analytical model to obtain the coefficient matrix C under normal conditions m , and by comparing the coefficient matrix C under normal conditions m And the deformed coefficient matrix C, get the coefficient difference matrix C △ , the formula is:

[0039] C △ =CC m

[0040] Among them, C △ is the coefficient difference matrix, C is the coefficient matrix after deformation, C m is the coefficient matrix under normal conditions.

[0041] Furthermore, the structural parameters of the deformed transformer are substituted into the leakage magnetic field analytical model to calculate the corresponding coefficient difference. The coefficient difference of each winding is used as the reference value to form a coefficient reference difference matrix, which is specifically:

[0042] Substitute the structural parameters after 5% end winding collapse displacement deformation into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the end reference value C Δxqi ;

[0043] The structural parameters after 5% radial displacement deformation of the middle winding are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the middle reference value C Δyqi ;

[0044] According to the end reference value C Δxqi and the central reference value C Δyqi , forming the corresponding coefficient reference difference matrix C △0 .

[0045] Furthermore, the error coefficient is introduced based on the coefficient reference difference matrix to obtain the deformation threshold matrix, which is:

[0046] C △set =K rel C △0

[0047] In the formula, K rel is the error coefficient, take 1.1; C △0 is the coefficient basis difference matrix.

[0048] Furthermore, according to the comparison result between the coefficient difference matrix and the deformation threshold matrix, the deformation winding and the deformation position are determined, specifically:

[0049] When |C △ | xqi >|C △set | xqi When , the end of the i-th winding undergoes axial deformation, and the deformation position is determined by the measuring point number q;

[0050] When |C △ | yqi >|C △set | yqi When , the i-th winding undergoes radial deformation in the middle;

[0051] Among them, |C △ | xqi 、|C △ | yqi is the difference matrix C of the deformation coefficients of the end and the middle △ The absolute value of the qth row and ith column in |C △set | xqi 、|C △set | yqi is the deformation threshold matrix C for the end and middle parts △set The absolute value of the qth row and ith column in .

[0052] The present invention also provides an online monitoring system for transformer winding deformation based on a leakage magnetic field analytical model, comprising:

[0053] Data acquisition and model building module: obtain leakage magnetic induction intensity sampling data and current sampling data, and build a leakage magnetic field analytical model;

[0054] Parameter calculation module: obtain the corresponding structural parameters of the actual transformer and substitute them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding;

[0055] Deformation detection module: Based on the leakage magnetic induction intensity sampling data and current sampling data, the least squares fitting algorithm is used to extract the coefficient matrix of each winding after deformation;

[0056] Difference calculation module: calculates the coefficient difference matrix according to the normal state coefficient matrix and the deformed coefficient matrix;

[0057] Reference difference and threshold calculation module: Substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, use the coefficient difference of each winding as the reference value, construct the coefficient reference difference matrix, and introduce the error coefficient to obtain the deformation threshold matrix;

[0058] Deformation judgment module: judges the deformation winding and deformation position according to the comparison result of the coefficient difference matrix and the deformation threshold matrix;

[0059] Early warning and maintenance decision module: Give corresponding early warning signals based on the judgment results, and let the user make subsequent maintenance decisions.

[0060] Furthermore, in step S1, leakage magnetic induction intensity sampling data and current sampling data are obtained, specifically:

[0061] Five measuring points are selected in the leakage magnetic field. The upper and lower ends of the high and low voltage windings are radially selected as measuring points 1, 2, 3 and 4, and magneto-optical measuring sensors are placed at measuring points 1-4 to measure the radial leakage magnetic induction intensity of the measuring points and monitor the deformation of the winding ends; the axial symmetry line in the middle oil channel of the high and low voltage windings is selected as measuring point 5, and a magneto-optical measuring sensor is placed at measuring point 5 to measure the axial leakage magnetic induction intensity of the point and monitor the radial deformation of the middle part of the winding;

[0062] The radial leakage magnetic induction intensity B of measuring points 1-4 is measured in real time by magneto-optical measuring sensors. x1 , B x2 , B x3 , B x4 and the axial leakage magnetic induction intensity B at measuring point 5 y5 , the high and low voltage winding outgoing current transformers obtain current sampling in real time synchronously l and i h .

[0063] Furthermore, the construction process of the leakage magnetic field analytical model is as follows:

[0064] The leakage magnetic flux density sampling data and the current sampling data are used to form the leakage magnetic flux density matrix B and the current matrix I, and the relationship is formed through the coefficient matrix C, specifically:

[0065] B=CI

[0066] Select the data window length as 10ms, take the data window boundary point as the origin, establish a rectangular coordinate system, and get:

[0067] The relationship between the radial leakage magnetic induction intensity and the winding current is as follows:

[0068]

[0069] The relationship between the axial leakage magnetic induction intensity and the winding current is as follows:

[0070]

[0071] Among them, B xq is the radial leakage magnetic field of the qth measuring point inside the transformer core window; B yq is the axial leakage magnetic field of the qth measuring point; p represents the number of windings inside the core window; i corresponds to the winding number, C xqiis the radial coefficient corresponding to the i-th winding and the q-th measuring point in the analytical model; C yqi is the axial coefficient corresponding to the i-th winding and the q-th measuring point; i i represents the current flowing through the i-th winding;

[0072] The calculation formulas for the radial coefficient and the axial coefficient are:

[0073]

[0074] Where μ0 is the air magnetic permeability, which is ∞ when the core is not saturated, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b and h are the width and height of the core window respectively, J jk is the double Fourier coefficient value; x, y are the coordinates of the measuring point;

[0075] The double Fourier coefficient value J jk The calculation formula is:

[0076]

[0077] Where N i is the number of turns of the i-th winding, S i is the cross-sectional area of ​​the i-th winding, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b i '-b i is the width of the i-th winding, h i '-h i are the heights of the i-th winding respectively;

[0078] According to the five measuring points corresponding to the magneto-optical measurement sensors specifically placed in the leakage magnetic field, the winding deformation leakage magnetic field analytical model is obtained, and the formula is:

[0079]

[0080] Among them, B x1 , B x2 , B x3 , B x4 is the radial leakage magnetic induction intensity of measuring points 1-4; B y5 is the axial leakage magnetic induction intensity of measuring point 5; C in the coefficient matrix C xqi , q represents the measurement point number 1-4, i represents the i-th winding, where i is 1 for low-voltage winding and 2 for high-voltage winding; C in the coefficient matrix C yqi , q represents the measuring point number 5, i represents the i-th winding, where i is 1 for low voltage winding and 2 for high voltage winding; i l and i h They are the low voltage winding current and the high voltage winding current respectively.

[0081] Furthermore, the coefficient difference matrix C △ The calculation process is:

[0082] Using the least squares fitting algorithm, the coefficient matrix after deformation is extracted, and the formula is:

[0083] C=B(I T I) -1 I T

[0084] Substitute the corresponding structural parameters of the actual transformer into the winding deformation leakage magnetic field analytical model to obtain the coefficient matrix C under normal conditions m , and by comparing the coefficient matrix C under normal conditions m And the deformed coefficient matrix C, get the coefficient difference matrix C △ , the formula is:

[0085] C △ =CC m

[0086] Among them, C △ is the coefficient difference matrix, C is the coefficient matrix after deformation, C m is the coefficient matrix under normal conditions.

[0087] Furthermore, the structural parameters of the deformed transformer are substituted into the leakage magnetic field analytical model to calculate the corresponding coefficient difference. The coefficient difference of each winding is used as the reference value to form a coefficient reference difference matrix, which is specifically:

[0088] Substitute the structural parameters after 5% end winding collapse displacement deformation into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the end reference value C Δxqi ;

[0089] The structural parameters after 5% radial displacement deformation of the middle winding are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the middle reference value C Δyqi ;

[0090] According to the end reference value C Δxqi and the central reference value C Δyqi , forming the corresponding coefficient reference difference matrix C △0 .

[0091] Furthermore, based on the constructed coefficient reference difference matrix, the error coefficient is introduced to obtain the deformation threshold matrix, the formula is:

[0092] C △set =K rel C △0

[0093] In the formula, Krel is the error coefficient, take 1.1; C △0 is the coefficient basis difference matrix.

[0094] Furthermore, according to the comparison result between the coefficient difference matrix and the deformation threshold matrix, the deformation winding and the deformation position are determined, specifically:

[0095] When |C △ | xqi >|C △set | xqi When , the end of the i-th winding undergoes axial deformation, and the deformation position is determined by the measuring point number q;

[0096] When |C △ | yqi >|C △set | yqi When , the i-th winding undergoes radial deformation in the middle;

[0097] Among them, |C △ | xqi 、|C △ | yqi is the difference matrix C of the deformation coefficients of the end and the middle △ The absolute value of the qth row and ith column in |C △set | xqi 、|C △set | yqi is the deformation threshold matrix C for the end and middle parts △set The absolute value of the qth row and ith column in .

[0098] The present invention further provides an electronic device, comprising:

[0099] Processor and memory;

[0100] The processor is used to execute the steps of the transformer winding deformation online monitoring method by calling the program or instruction stored in the memory.

[0101] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a program or instruction, wherein the program or instruction is a step for a computer to execute the method for online monitoring of transformer winding deformation.

[0102] The beneficial effects of the present invention are as follows: the present invention constructs a winding deformation leakage magnetic field analytical model based on a leakage magnetic field calculation method decomposed based on a dual Fourier technology, in conjunction with a specifically placed magneto-optical measurement sensor; based on the changes in the leakage magnetic field analytical model coefficient matrix when the winding end is axially deformed and the middle is radially deformed, reliable detection of transformer winding deformations of more than 5% can be achieved, thereby ensuring safe and stable operation of the transformer.

[0103] When the winding is deformed, the change of the model coefficient matrix caused by the change of the winding spatial structure parameters can be used to accurately locate the deformed winding and the deformation position; and the monitoring points are reasonably arranged according to the positions where the winding is prone to deformation. The corresponding changes of the measuring points can be specifically derived from mathematical relationships, so the corresponding deformation thresholds can be set, so that the proposed scheme meets the sensitivity and reliability requirements of online monitoring, and does not require operation and maintenance personnel to have rich experience to analyze the detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0105] Figure 1 Flow chart of a transformer winding deformation online monitoring method according to an embodiment of the present invention;

[0106] Figure 2 A flow chart of determining a deformation winding and a deformation position in an embodiment of the present invention;

[0107] Figure 3 It is a layout diagram of the magneto-optical measurement sensor in an embodiment of the present invention;

[0108] Figure 4 : is a deformation diagram of the axial collapse displacement of the coil at the end of the winding in an embodiment of the present invention;

[0109] Figure 5 This is a deformation diagram of the axial collapse displacement of the low-voltage winding end coil in an embodiment of the present invention;

[0110] Figure 6 This is a radial compression deformation diagram of the wire cake in the middle of the inner winding in an embodiment of the present invention;

[0111] Figure 7 Radial expansion deformation diagram of the middle wire coil of the outer winding. DETAILED DESCRIPTION

[0112] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0113] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0114] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0115] like Figure 1-2 The transformer winding deformation online monitoring method based on the leakage magnetic field analytical model shown includes the following steps:

[0116] S1. Obtain leakage magnetic induction intensity sampling data and current sampling data, and construct a leakage magnetic field analytical model;

[0117] In step S1, the leakage magnetic induction intensity sampling data and the current sampling data are obtained, specifically:

[0118] Five measuring points are selected in the leakage magnetic field. The radial directions of the upper and lower ends of the high and low voltage windings are used as measuring points 1, 2, 3 and 4, and magneto-optical measuring sensors are placed at measuring points 1-4 to measure the radial leakage magnetic induction intensity of the measuring points and monitor the deformation of the winding ends; the axial symmetry line in the middle oil channel of the high and low voltage windings is used as measuring point 5, and a magneto-optical measuring sensor is placed at measuring point 5 to measure the axial leakage magnetic induction intensity of the point and monitor the radial deformation of the middle part of the winding; there are 5 measuring points in total for each phase winding; the placement diagram is as shown in the figure Figure 3 shown.

[0119] The radial leakage magnetic induction intensity B of measuring points 1-4 is measured in real time by magneto-optical measuring sensors. x1 , B x2 , B x3 , B x4 and the axial leakage magnetic induction intensity B at measuring point 5 y5 , the high and low voltage winding outgoing current transformers obtain current sampling in real time synchronously l and i h .

[0120] The required leakage magnetic data of the actual transformer is collected in real time by the magneto-optical measurement sensor installed at a fixed position, which can monitor the transformer winding status in real time. The collected leakage magnetic induction intensity and current data are the direct input for building the leakage magnetic field analytical model. These data provide the actual operating conditions required by the model, so that the model can more accurately reflect the actual status of the transformer.

[0121] Based on the above scheme, the construction process of the leakage magnetic field analytical model is as follows:

[0122] The leakage magnetic flux density sampling data and the current sampling data are used to form the leakage magnetic flux density matrix B and the current matrix I, and the relationship is formed through the coefficient matrix C, specifically:

[0123] B=CI

[0124] Select the data window length as 10ms, take the data window boundary point as the origin, establish a rectangular coordinate system, and get:

[0125] The relationship between the radial leakage magnetic induction intensity and the winding current is as follows:

[0126]

[0127] The relationship between the axial leakage magnetic induction intensity and the winding current is as follows:

[0128]

[0129] Among them, B xq is the radial leakage magnetic field of the qth measuring point inside the transformer core window; B yq is the axial leakage magnetic field of the qth measuring point; p represents the number of windings inside the core window; i corresponds to the winding number, C xqi is the radial coefficient corresponding to the i-th winding and the q-th measuring point in the analytical model; C yqi is the axial coefficient corresponding to the i-th winding and the q-th measuring point; i i represents the current flowing through the i-th winding;

[0130] The calculation formulas for the radial coefficient and the axial coefficient are:

[0131]

[0132] Where μ0 is the air magnetic permeability, which is ∞ when the core is not saturated, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b and h are the width and height of the core window respectively, J jk is the double Fourier coefficient value; x, y are the coordinates of the measuring point;

[0133] The double Fourier coefficient value J jk The calculation formula is:

[0134]

[0135] Where N i is the number of turns of the i-th winding, S i is the cross-sectional area of ​​the i-th winding, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b i '-b i is the width of the i-th winding, h i '-h i are the heights of the i-th winding respectively;

[0136] According to the five measuring points corresponding to the magneto-optical measurement sensors specifically placed in the leakage magnetic field, the winding deformation leakage magnetic field analytical model is obtained, and the formula is:

[0137]

[0138] Among them, B x1 , B x2 , B x3 , B x4 yes Figure 3 The radial leakage magnetic induction intensity of the measuring points 1-4; B y5 yes Figure 3 The axial leakage magnetic induction intensity of the measuring point 5; C in the coefficient matrix C xqi , q represents the measurement point number 1-4, i represents the i-th winding, where i is 1 for low-voltage winding and 2 for high-voltage winding; C in the coefficient matrix C yqi , q represents the measuring point number 5, i represents the i-th winding, where i is 1 for low voltage winding and 2 for high voltage winding; i l and i h They are the low voltage winding current and the high voltage winding current respectively.

[0139] The constructed winding deformation leakage magnetic field analytical calculation model can quickly and accurately calculate the linear relationship between the leakage magnetic induction intensity of the fixed measuring points inside the transformer core window and the winding current, providing a theoretical basis for realizing online monitoring of transformer winding deformation.

[0140] Specifically, taking the end as an example, when the coil at the end of the high-voltage winding collapses and deforms, the deformation diagram is as follows: Figure 4 As shown, the structural parameter h corresponding to the displacement line cake i ' and h i All become smaller, eventually causing the axial coefficient C corresponding to the measuring point 3 and the high-voltage winding x32 changes.

[0141] Taking the above end as an example, when the low-voltage winding end coil collapses and deforms, the deformation diagram is as follows Figure 5 As shown, the structural parameter h corresponding to the displacement line cakei ' and h i All become smaller, eventually causing the axial coefficient C corresponding to the measuring point 1 and the low-voltage winding x11 changes.

[0142] When the middle coil of the inner winding (high voltage winding) is radially compressed, the deformation diagram is as follows: Figure 6 As shown in the figure, when the inner winding middle coil is radially compressed, the structural parameter b corresponding to the displacement coil is i ' and b i All become larger, eventually causing the radial coefficient C corresponding to the measuring point 5 and the inner winding y52 changes.

[0143] When the middle coil of the outer winding (low voltage winding) expands radially, the deformation diagram is as follows: Figure 7 As shown in the figure, when the coil in the middle of the outer winding expands radially, the structural parameters bi' and b corresponding to the displacement coil are i All become smaller, eventually causing the radial coefficient C corresponding to the measuring point 5 and the outer winding y51 changes.

[0144] S2. Obtain the corresponding structural parameters of the actual transformer and substitute them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding;

[0145] Using the structural parameters of the actual transformer, the parameters are substituted into the leakage magnetic field analytical model constructed in step S1 to calculate the coefficient matrix of the winding under normal conditions. The normal coefficient matrix is ​​used as a reference to more accurately monitor and analyze the status of the transformer winding in actual operation.

[0146] S3, based on the leakage magnetic induction intensity sampling data and the current sampling data, using the least squares fitting algorithm, extracting the coefficient matrix of each winding after deformation;

[0147] The least squares method is a mathematical optimization technique that seeks the best function match for the data by minimizing the sum of squares of the errors. In a complex data set, the least squares method can help identify and extract the features most relevant to the winding deformation, simplifying the complexity of the problem. In step S3, the data in step S1 is used to more accurately extract the features of the winding deformation from the noise data through a mathematical model (such as a least squares fitting algorithm), thereby improving the accuracy of deformation detection.

[0148] S4. Calculate a coefficient difference matrix based on the normal state coefficient matrix and the deformed coefficient matrix;

[0149] The normal coefficient matrix calculated in step S2 is the theoretical value of the transformer winding without deformation. The actual measured value of the deformed state is extracted in step 3. Step S4 compares the theoretical value with the actual measured value to identify whether the winding is deformed. By calculating the coefficient difference between the normal state and the deformed state, it is possible to quantitatively identify whether the winding has been deformed and the degree of deformation.

[0150] Coefficient difference matrix C △ The calculation process is:

[0151] Using the least squares fitting algorithm, the coefficient matrix after deformation is extracted, and the formula is:

[0152] C=B(I T I) -1 I T

[0153] Substitute the corresponding structural parameters of the actual transformer into the winding deformation leakage magnetic field analytical model to obtain the coefficient matrix C under normal conditions m , and by comparing the coefficient matrix C under normal conditions m And the deformed coefficient matrix C, get the coefficient difference matrix C △ , the formula is:

[0154] C △ =CC m

[0155] Among them, C △ is the coefficient difference matrix, C is the coefficient matrix after deformation, C m is the coefficient matrix under normal conditions.

[0156] The above-mentioned model coefficient matrix under normal state and after deformation is only related to the transformer winding structure parameters, and has nothing to do with the operating environment of the transformer. The coefficient difference matrix can reflect the changes in the coefficient matrix caused by the actual transformer winding deformation, effectively monitor the health of the transformer winding, timely discover and deal with potential deformation problems, and ensure the safe and reliable operation of the power system.

[0157] S5. Substitute the structural parameters of the transformer after deformation into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, use the coefficient difference of each winding as the reference value, construct a coefficient reference difference matrix, and introduce the error coefficient to obtain the deformation threshold matrix;

[0158] In step S5, the structural parameters of the transformer after deformation are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference is calculated. The coefficient difference of each winding is used as a reference value to form a coefficient reference difference matrix, which is specifically:

[0159] Considering the accuracy and noise of the magneto-optical measurement sensor, for measuring points 1-4, the structural parameters after the 5% end winding collapse displacement deformation are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the end reference value C Δxqi ; The 5% winding end deformation here refers to the radial-axial displacement / winding height = 5%;

[0160] For measuring point 5, the structural parameters after 5% radial displacement of the middle winding are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the middle reference value C Δyqi ; The 5% winding middle deformation here refers to radial displacement / winding outer diameter = 5%.

[0161] According to the end reference value C Δxqi and the central reference value C Δyqi , forming the corresponding coefficient reference difference matrix C △0 .

[0162] Taking into account the influence of factors such as the error in optical fiber magnetic field measurement and the error in sensor installation position, the error coefficient is introduced to obtain the deformation threshold matrix, the formula is:

[0163] C △set =K rel C △0

[0164] In the formula, K rel is the error coefficient, take 1.1; C △0 is the coefficient basis difference matrix.

[0165] The structural parameters of the transformer winding after deformation are input into the leakage magnetic field analytical model established previously. These parameters may include the size, shape, position, etc. of the winding, which will change after the winding is deformed. The new coefficient matrix calculated in the leakage magnetic field analytical model using the deformed parameters is compared with the normal coefficient matrix before deformation to obtain the coefficient difference. The coefficient difference is used as a reference value, which represents the difference between the winding in the deformed state and the normal state. The reference values ​​of each winding are organized into a coefficient reference difference matrix, which contains the deformation information of all windings for the convenience of overall analysis. The deformation threshold matrix is ​​a reference difference matrix adjusted based on the error coefficient. It sets a judgment standard, that is, when the actual measured coefficient difference exceeds this threshold, it can be considered that the winding has been deformed.

[0166] S6. Determine the deformation winding and deformation position according to the comparison result between the coefficient difference matrix and the deformation threshold matrix;

[0167] In step S6, the deformation winding and the deformation position are determined according to the comparison result between the coefficient difference matrix and the deformation threshold matrix, specifically:

[0168] When |C △ | xqi >|C △set | xqi When , the end of the i-th winding undergoes axial deformation, and the deformation position is determined by the measuring point number q;

[0169] When |C △ | yqi >|C △set | yqi When , the i-th winding undergoes radial deformation in the middle;

[0170] Among them, |C △ | xqi 、|C △ | yqi is the difference matrix C of the deformation coefficients of the end and the middle △ The absolute value of the qth row and ith column in |C △set | xqi 、|C △set | yqi is the deformation threshold matrix C for the end and middle parts △set The absolute value of the qth row and ith column in .

[0171] By comparing the coefficient difference matrix with the deformation threshold matrix, it is determined whether the winding is deformed and the specific location of the deformation, and the deformed winding is discovered and located in time. Targeted maintenance reduces unnecessary inspection and maintenance work.

[0172] S7. Give a corresponding warning signal based on the judgment result, and let the user make subsequent maintenance decisions.

[0173] This method is based on the constructed analytical model of normal and deformed leakage magnetic fields of transformer windings. The model parameters are identified through the actually measured leakage magnetic induction intensity and winding current. The winding state is judged by the change of model parameters. The deformed winding can be accurately located and defects can be diagnosed in advance. This method has high sensitivity, is not affected by the electromagnetic environment, and can monitor the deformation state of transformer windings in operation online without the need to shut down the equipment for inspection. It is of great significance to the long-term stable operation of power equipment and the power supply reliability of the power system.

[0174] The present invention also provides an online monitoring system for transformer winding deformation based on a leakage magnetic field analytical model, comprising:

[0175] Data acquisition and model building module: obtain leakage magnetic induction intensity sampling data and current sampling data, and build a leakage magnetic field analytical model;

[0176] Parameter calculation module: obtain the corresponding structural parameters of the actual transformer and substitute them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding;

[0177] Deformation detection module: Based on the leakage magnetic induction intensity sampling data and current sampling data, the least squares fitting algorithm is used to extract the coefficient matrix of each winding after deformation;

[0178] Difference calculation module: calculates the coefficient difference matrix according to the normal state coefficient matrix and the deformed coefficient matrix;

[0179] Reference difference and threshold calculation module: Substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, use the coefficient difference of each winding as the reference value, construct the coefficient reference difference matrix, and introduce the error coefficient to obtain the deformation threshold matrix;

[0180] Deformation judgment module: judges the deformation winding and deformation position according to the comparison result of the coefficient difference matrix and the deformation threshold matrix;

[0181] Early warning and maintenance decision module: Give corresponding early warning signals based on the judgment results, and let the user make subsequent maintenance decisions.

[0182] The system detects whether the winding is deformed by analyzing the leakage magnetic field of the transformer, and can accurately determine the deformation position after the winding is deformed.

[0183] Select appropriate measuring points in the leakage magnetic field, and obtain leakage magnetic induction intensity sampling data and current sampling data for the selected measuring points, specifically:

[0184] Five measuring points are selected in the leakage magnetic field. The radial directions of the upper and lower ends of the high and low voltage windings are used as measuring points 1, 2, 3 and 4, and magneto-optical measuring sensors are placed at measuring points 1-4 to measure the radial leakage magnetic induction intensity of the measuring points and monitor the deformation of the winding ends; the axial symmetry line in the middle oil channel of the high and low voltage windings is used as measuring point 5, and a magneto-optical measuring sensor is placed at measuring point 5 to measure the axial leakage magnetic induction intensity of the point and monitor the radial deformation of the middle part of the winding; there are 5 measuring points in total for each phase winding; the placement diagram is as shown in the figure Figure 3 shown.

[0185] The radial leakage magnetic induction intensity B of measuring points 1-4 is measured in real time by magneto-optical measuring sensors. x1 , B x2 , B x3 , B x4 and the axial leakage magnetic induction intensity B at measuring point 5 y5 , the high and low voltage winding outgoing current transformers obtain current sampling in real time synchronously l and i h .

[0186] The construction process of the leakage magnetic field analytical model in the present invention is:

[0187] The leakage magnetic flux density sampling data and the current sampling data are used to form the leakage magnetic flux density matrix B and the current matrix I, and the relationship is formed through the coefficient matrix C, specifically:

[0188] B=CI

[0189] Select the data window length as 10ms, take the data window boundary point as the origin, establish a rectangular coordinate system, and get:

[0190] The relationship between the radial leakage magnetic induction intensity and the winding current is as follows:

[0191]

[0192] The relationship between the axial leakage magnetic induction intensity and the winding current is as follows:

[0193]

[0194] Among them, B xq is the radial leakage magnetic field of the qth measuring point inside the transformer core window; B yq is the axial leakage magnetic field of the qth measuring point; p represents the number of windings inside the core window; i corresponds to the winding number, C xqi is the radial coefficient corresponding to the i-th winding and the q-th measuring point in the analytical model; C yqi is the axial coefficient corresponding to the i-th winding and the q-th measuring point; i i represents the current flowing through the i-th winding;

[0195] The calculation formulas for the radial coefficient and the axial coefficient are:

[0196]

[0197] Where μ0 is the air magnetic permeability, which is ∞ when the core is not saturated, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b and h are the width and height of the core window respectively, J jk is the double Fourier coefficient value; x, y are the coordinates of the measuring point;

[0198] The double Fourier coefficient value J jk The calculation formula is:

[0199]

[0200] Where N i is the number of turns of the i-th winding, S i is the cross-sectional area of ​​the i-th winding, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b i '-b i is the width of the i-th winding, h i '-hi are the heights of the i-th winding respectively;

[0201] According to the five measuring points corresponding to the magneto-optical measurement sensors specifically placed in the leakage magnetic field, the winding deformation leakage magnetic field analytical model is obtained, and the formula is:

[0202]

[0203] Among them, B x1 , B x2 , B x3 , B x4 yes Figure 3 The radial leakage magnetic induction intensity of the measuring points 1-4; B y5 yes Figure 3 The axial leakage magnetic induction intensity of the measuring point 5; C in the coefficient matrix C xqi , q represents the measurement point number 1-4, i represents the i-th winding, where i is 1 for low-voltage winding and 2 for high-voltage winding; C in the coefficient matrix C yqi , q represents the measuring point number 5, i represents the i-th winding, where i is 1 for low voltage winding and 2 for high voltage winding; i l and i h They are the low voltage winding current and the high voltage winding current respectively.

[0204] Specifically, taking the end as an example, when the coil at the end of the high-voltage winding collapses and deforms, the deformation diagram is as follows: Figure 4 As shown, the structural parameter h corresponding to the displacement line cake i ' and h i All become smaller, eventually causing the axial coefficient C corresponding to the measuring point 3 and the high-voltage winding x32 changes.

[0205] Taking the above end as an example, when the low-voltage winding end coil collapses and deforms, the deformation diagram is as follows Figure 5 As shown, the structural parameter h corresponding to the displacement line cake i ' and h i All become smaller, eventually causing the axial coefficient C corresponding to the measuring point 1 and the low-voltage winding x11 changes.

[0206] When the middle coil of the inner winding (high voltage winding) is radially compressed, the deformation diagram is as follows: Figure 6 As shown in the figure, when the inner winding middle coil is radially compressed, the structural parameter b corresponding to the displacement coil is i ' and b i All become larger, eventually causing the radial coefficient C corresponding to the measuring point 5 and the inner winding y52 changes.

[0207] When the middle coil of the outer winding (low voltage winding) expands radially, the deformation diagram is as follows: Figure 7As shown in the figure, when the coil in the middle of the outer winding expands radially, the structural parameter b corresponding to the displacement coil is i ' and b i All become smaller, eventually causing the radial coefficient C corresponding to the measuring point 5 and the outer winding y51 changes.

[0208] The core point of the present invention is to construct a winding deformation leakage magnetic field analytical model based on a leakage magnetic field calculation method based on dual Fourier technology decomposition and a specifically placed magneto-optical measurement sensor;

[0209] In the preferred embodiment, the coefficient difference matrix C △ The calculation process is:

[0210] Using the least squares fitting algorithm, the coefficient matrix after deformation is extracted, and the formula is:

[0211] C=B(I T I) -1 I T

[0212] Substitute the corresponding structural parameters of the actual transformer into the winding deformation leakage magnetic field analytical model to obtain the coefficient matrix C under normal conditions m , and by comparing the coefficient matrix C under normal conditions m And the deformed coefficient matrix C, get the coefficient difference matrix C △ , the formula is:

[0213] C △ =CC m

[0214] Among them, C △ is the coefficient difference matrix, C is the coefficient matrix after deformation, C m is the coefficient matrix under normal conditions.

[0215] The coefficient difference matrix can reflect the changes in the coefficient matrix caused by the actual transformer winding deformation, effectively monitor the health of the transformer winding, timely discover and deal with potential deformation problems, and ensure the safe and reliable operation of the power system.

[0216] Substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, and use the coefficient difference of each winding as the reference value to form a coefficient reference difference matrix, which is:

[0217] Considering the accuracy and noise of the magneto-optical measurement sensor, for measuring points 1-4, the structural parameters after the 5% end winding collapse displacement deformation are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the end reference value C Δxqi ; The 5% winding end deformation here refers to the radial-axial displacement / winding height = 5%;

[0218] For measuring point 5, the structural parameters after 5% radial displacement of the middle winding are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the middle reference value C Δyqi ; The 5% winding middle deformation here refers to radial displacement / winding outer diameter = 5%.

[0219] According to the end reference value C Δxqi and the central reference value C Δyqi , forming the corresponding coefficient reference difference matrix C △0 .

[0220] Taking into account the influence of factors such as the error in optical fiber magnetic field measurement and the error in sensor installation position, the error coefficient is introduced to obtain the deformation threshold matrix, the formula is:

[0221] C △set =K rel C △0

[0222] In the formula, K rel is the error coefficient, take 1.1; C △0 is the coefficient basis difference matrix.

[0223] In a preferred embodiment of the present invention, the deformation winding and the deformation position are determined according to the comparison result between the coefficient difference matrix and the deformation threshold matrix, specifically:

[0224] When |C △ | xqi >|C △set | xqi When , the end of the i-th winding undergoes axial deformation, and the deformation position is determined by the measuring point number q;

[0225] When |C △ | yqi >|C △set | yqi When , the i-th winding undergoes radial deformation in the middle;

[0226] Among them, |C △ | xqi 、|C △ | yqi is the difference matrix C of the deformation coefficients of the end and the middle △ The absolute value of the qth row and ith column in |C △set | xqi 、|C △set | yqi is the deformation threshold matrix C for the end and middle parts △set The absolute value of the qth row and ith column in .

[0227] The present invention also includes an electronic device, which includes: a processor and a memory; the processor is used to execute the steps of the transformer winding deformation online monitoring method by calling the program or instruction stored in the memory, and the steps include S1, obtaining leakage magnetic induction intensity sampling data and current sampling data, and constructing a leakage magnetic field analytical model; S2, obtaining the corresponding structural parameters of the actual transformer and substituting them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding; S3, based on the leakage magnetic induction intensity sampling data and the current sampling data, using the least squares fitting algorithm to extract the coefficient matrix of each winding after deformation; S4, according to the normal state coefficient matrix and the deformed coefficient matrix, calculate the coefficient difference matrix; S5, substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, and use the coefficient difference of each winding as the reference value to form a coefficient reference difference matrix, and introduce the error coefficient to obtain the deformation threshold matrix; S6, according to the comparison result of the coefficient difference matrix and the deformation threshold matrix, judge the deformed winding and the deformation position;

[0228] S7. Give a corresponding warning signal based on the judgment result, and the user makes subsequent maintenance decisions. The present invention is based on the leakage magnetic field calculation method decomposed by dual Fourier technology, and cooperates with a specifically placed magneto-optical measurement sensor to construct a winding deformation leakage magnetic field analytical model; based on the change of the leakage magnetic field analytical model coefficient matrix when the winding end is axially deformed and the middle is radially deformed, reliable detection of transformer winding deformation of more than 5% is achieved, ensuring the safe and stable operation of the transformer.

[0229] The present invention also provides a computer-readable storage medium, which stores a program or instruction. The program or instruction is a step of a computer executing a transformer winding deformation online monitoring method, which includes: S1, obtaining leakage magnetic induction intensity sampling data and current sampling data, and constructing a leakage magnetic field analytical model; S2, obtaining the corresponding structural parameters of the actual transformer and substituting them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding; S3, based on the leakage magnetic induction intensity sampling data and the current sampling data, using the least squares fitting algorithm to extract the coefficient matrix of each winding after deformation; S4, according to the normal state coefficient matrix and the deformed coefficient matrix, calculating the coefficient difference matrix; S5, substituting the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculating the corresponding coefficient difference, and using the coefficient difference of each winding as the reference value to form a coefficient reference difference matrix, and introducing the error coefficient to obtain the deformation threshold matrix; S6, judging the deformed winding and the deformation position according to the comparison result of the coefficient difference matrix and the deformation threshold matrix; S7, giving a corresponding early warning signal according to the judgment result, and the user makes a subsequent maintenance decision. The present invention is based on a leakage magnetic field calculation method based on double Fourier technology decomposition, and cooperates with a specifically placed magneto-optical measurement sensor to construct a winding deformation leakage magnetic field analytical model; based on the changes in the leakage magnetic field analytical model coefficient matrix when the winding end is axially deformed and the middle is radially deformed, reliable detection of transformer winding deformation of more than 5% is achieved, thereby ensuring safe and stable operation of the transformer.

[0230] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0231] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0232] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0233] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0234] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0235] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A transformer winding deformation online monitoring method based on leakage magnetic field analytical model, characterized in that: The following steps are involved: S1. Obtain leakage magnetic induction intensity sampling data and current sampling data, and construct a leakage magnetic field analytical model; S2. Obtain the corresponding structural parameters of the actual transformer and substitute them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding; S3, based on the leakage magnetic induction intensity sampling data and the current sampling data, using the least squares fitting algorithm, extracting the coefficient matrix of each winding after deformation; S4. Calculate a coefficient difference matrix based on the normal state coefficient matrix and the deformed coefficient matrix; S5. Substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, use the coefficient difference of each winding as the reference value, construct a coefficient reference difference matrix, and introduce the error coefficient to obtain the deformation threshold matrix; S6. Determine the deformation winding and deformation position according to the comparison result between the coefficient difference matrix and the deformation threshold matrix; S7. Give a corresponding warning signal based on the judgment result, and let the user make subsequent maintenance decisions.

2. The transformer winding deformation online monitoring method based on the leakage magnetic field analytical model according to claim 1 is characterized in that: In step S1, the leakage magnetic induction intensity sampling data and the current sampling data are obtained, specifically: Five measuring points are selected in the leakage magnetic field. The upper and lower ends of the high and low voltage windings are radially selected as measuring points 1, 2, 3 and 4, and magneto-optical measuring sensors are placed at measuring points 1-4 to measure the radial leakage magnetic induction intensity of the measuring points and monitor the deformation of the winding ends; the axial symmetry line in the middle oil channel of the high and low voltage windings is selected as measuring point 5, and a magneto-optical measuring sensor is placed at measuring point 5 to measure the axial leakage magnetic induction intensity of the point and monitor the radial deformation of the middle part of the winding; The radial leakage magnetic induction intensity B of measuring points 1-4 is measured in real time by magneto-optical measuring sensors. x1 , B x2 , B x3 , B x4 and the axial leakage magnetic induction intensity B at measuring point 5 y5 , the high and low voltage winding outgoing current transformers obtain current sampling in real time synchronously l and i h .

3. The transformer winding deformation online monitoring method based on the leakage magnetic field analytical model according to claim 2 is characterized in that: In step S1, the construction process of the leakage magnetic field analytical model is as follows: The leakage magnetic flux density sampling data and the current sampling data are used to form the leakage magnetic flux density matrix B and the current matrix I, and the relationship is formed through the coefficient matrix C, specifically: B=CI Select the data window length as 10ms, take the data window boundary point as the origin, establish a rectangular coordinate system, and get: The relationship between the radial leakage magnetic induction intensity and the winding current is as follows: The relationship between the axial leakage magnetic induction intensity and the winding current is as follows: Among them, B xq is the radial leakage magnetic field of the qth measuring point inside the transformer core window; B yq is the axial leakage magnetic field of the qth measuring point; p represents the number of windings inside the core window; i corresponds to the winding number, C xqi is the radial coefficient corresponding to the i-th winding and the q-th measuring point in the analytical model; C yqi is the axial coefficient corresponding to the i-th winding and the q-th measuring point; i i represents the current flowing through the i-th winding; The calculation formulas for the radial coefficient and the axial coefficient are: Where μ0 is the air magnetic permeability, which is ∞ when the core is not saturated, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b and h are the width and height of the core window respectively, J jk is the double Fourier coefficient value; x, y are the coordinates of the measuring point; The double Fourier coefficient value J jk The calculation formula is: Where N i is the number of turns of the i-th winding, S i is the cross-sectional area of ​​the i-th winding; j and k are positive integers from 0 to ∞, j and k are not 0 at the same time; b′ i -b i is the width of the i-th winding, h′ i -h i are the heights of the i-th winding respectively; According to the five measuring points corresponding to the magneto-optical measurement sensors specifically placed in the leakage magnetic field, the winding deformation leakage magnetic field analytical model is obtained, and the formula is: Among them, B x1 , B x2 , B x3 , B x4 is the radial leakage magnetic induction intensity of measuring points 1-4; B y5 is the axial leakage magnetic induction intensity of measuring point 5; C in the coefficient matrix C xqi , q represents the measurement point number 1-4, i represents the i-th winding, where i is 1 for low-voltage winding and 2 for high-voltage winding; C in the coefficient matrix C yqi , q represents the measuring point number 5, i represents the i-th winding, where i is 1 for low voltage winding and 2 for high voltage winding; i l and i h They are the low voltage winding current and the high voltage winding current respectively.

4. The transformer winding deformation online monitoring method based on leakage magnetic field analytical model according to claim 1 is characterized in that: The coefficient difference matrix C △ The calculation process is: Using the least squares fitting algorithm, the coefficient matrix after deformation is extracted, and the formula is: C=B(I T I) -1 I T Substitute the corresponding structural parameters of the actual transformer into the winding deformation leakage magnetic field analytical model to obtain the coefficient matrix C under normal conditions m , and by comparing the coefficient matrix C under normal conditions m And the deformed coefficient matrix C, get the coefficient difference matrix C △ , the formula is: C △ =C-C m Among them, C △ is the coefficient difference matrix, C is the coefficient matrix after deformation, C m is the coefficient matrix under normal conditions.

5. The transformer winding deformation online monitoring method based on leakage magnetic field analytical model according to claim 1 is characterized in that: Substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, and use the coefficient difference of each winding as the reference value to form a coefficient reference difference matrix, which is: Substitute the structural parameters after 5% end winding collapse displacement deformation into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the end reference value C Δxqi ; The structural parameters after 5% radial displacement deformation of the middle winding are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the middle reference value C Δyqi ; According to the end reference value C Δxqi and the central reference value C Δyqi , forming the corresponding coefficient reference difference matrix C △0 .

6. The transformer winding deformation online monitoring method based on leakage magnetic field analytical model according to claim 5 is characterized in that: Based on the coefficient reference difference matrix, the error coefficient is introduced to obtain the deformation threshold matrix C △set , the formula is: C △set =K rel C △0 In the formula, K rel is the error coefficient, take 1.1; C △0 is the coefficient basis difference matrix.

7. The transformer winding deformation online monitoring method based on leakage magnetic field analytical model according to claim 1 is characterized in that: According to the comparison results between the coefficient difference matrix and the deformation threshold matrix, the deformation winding and deformation position are determined, specifically: When |C △ | xqi >|C △set | xqi When , the end of the i-th winding undergoes axial deformation, and the deformation position is determined by the measuring point number q; When |C △ | yqi >|C △set | yqi When , the i-th winding undergoes radial deformation in the middle; Among them, |C △ | xqi 、|C △ | yqi is the difference matrix C of the deformation coefficients of the end and the middle △ The absolute value of the qth row and ith column in C △set | xqi 、|C △set | yqi is the deformation threshold matrix C for the end and middle parts △set The absolute value of the qth row and ith column in .

8. An online monitoring system for transformer winding deformation based on leakage magnetic field analytical model, characterized in that: include: Data acquisition and model building module: obtain leakage magnetic induction intensity sampling data and current sampling data, and build a leakage magnetic field analytical model; Parameter calculation module: obtain the corresponding structural parameters of the actual transformer and substitute them into the leakage magnetic field analytical model to calculate the normal state coefficient matrix of the winding; Deformation detection module: Based on the leakage magnetic induction intensity sampling data and current sampling data, the least squares fitting algorithm is used to extract the coefficient matrix of each winding after deformation; Difference calculation module: calculates the coefficient difference matrix according to the normal state coefficient matrix and the deformed coefficient matrix; Reference difference and threshold calculation module: Substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, use the coefficient difference of each winding as the reference value, construct the coefficient reference difference matrix, and introduce the error coefficient to obtain the deformation threshold matrix; Deformation judgment module: judges the deformation winding and deformation position according to the comparison result of the coefficient difference matrix and the deformation threshold matrix; Early warning and maintenance decision module: Give corresponding early warning signals based on the judgment results, and let the user make subsequent maintenance decisions.

9. The transformer winding deformation online monitoring system based on leakage magnetic field analytical model according to claim 8 is characterized in that: In step S1, the leakage magnetic induction intensity sampling data and the current sampling data are obtained, specifically: Five measuring points are selected in the leakage magnetic field. The upper and lower ends of the high and low voltage windings are radially selected as measuring points 1, 2, 3 and 4, and magneto-optical measuring sensors are placed at measuring points 1-4 to measure the radial leakage magnetic induction intensity of the measuring points and monitor the deformation of the winding ends; the axial symmetry line in the middle oil channel of the high and low voltage windings is selected as measuring point 5, and a magneto-optical measuring sensor is placed at measuring point 5 to measure the axial leakage magnetic induction intensity of the point and monitor the radial deformation of the middle part of the winding; The radial leakage magnetic induction intensity B of measuring points 1-4 is measured in real time by magneto-optical measuring sensors. x1 , B x2 , B x3 , B x4 and the axial leakage magnetic induction intensity B at measuring point 5 y5 , the high and low voltage winding outgoing current transformers obtain current sampling in real time synchronously l and i h .

10. The transformer winding deformation online monitoring system based on leakage magnetic field analytical model according to claim 8, characterized in that: The construction process of the leakage magnetic field analytical model is as follows: The leakage magnetic flux density sampling data and the current sampling data are used to form the leakage magnetic flux density matrix B and the current matrix I, and the relationship is formed through the coefficient matrix C, specifically: B=CI Select the data window length as 10ms, take the data window boundary point as the origin, establish a rectangular coordinate system, and get: The relationship between the radial leakage magnetic induction intensity and the winding current is as follows: The relationship between the axial leakage magnetic induction intensity and the winding current is as follows: Among them, B xq is the radial leakage magnetic field of the qth measuring point inside the transformer core window; B yq is the axial leakage magnetic field of the qth measuring point; p represents the number of windings inside the core window; i corresponds to the winding number, C xqi is the radial coefficient corresponding to the i-th winding and the q-th measuring point in the analytical model; C yqi is the axial coefficient corresponding to the i-th winding and the q-th measuring point; i i represents the current flowing through the i-th winding; The calculation formulas for the radial coefficient and the axial coefficient are: Where μ0 is the air magnetic permeability, which is ∞ when the core is not saturated, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b and h are the width and height of the core window respectively, J jk is the double Fourier coefficient value; x, y are the coordinates of the measuring point; The double Fourier coefficient value J jk The calculation formula is: Where N i is the number of turns of the i-th winding, S i is the cross-sectional area of ​​the i-th winding, j and k are positive integers from 0 to ∞, j and k are not 0 at the same time, b′ i -b i is the width of the i-th winding, h′ i -h i are the heights of the i-th winding respectively; According to the five measuring points corresponding to the magneto-optical measurement sensors specifically placed in the leakage magnetic field, the winding deformation leakage magnetic field analytical model is obtained, and the formula is: Among them, B x1 , B x2 , B x3 , B x4 is the radial leakage magnetic induction intensity of measuring points 1-4; B y5 is the axial leakage magnetic induction intensity of measuring point 5; C in the coefficient matrix C xqi , q represents the measurement point number 1-4, i represents the i-th winding, where i is 1 for low-voltage winding and 2 for high-voltage winding; C in the coefficient matrix C yqi , q represents the measuring point number 5, i represents the i-th winding, where i is 1 for low voltage winding and 2 for high voltage winding; i l and i h They are the low voltage winding current and the high voltage winding current respectively.

11. The transformer winding deformation online monitoring system based on leakage magnetic field analytical model according to claim 8, characterized in that: The coefficient difference matrix C △ The calculation process is: Using the least squares fitting algorithm, the coefficient matrix after deformation is extracted, and the formula is: C=B(I T I) -1 I T Substitute the corresponding structural parameters of the actual transformer into the winding deformation leakage magnetic field analytical model to obtain the coefficient matrix C under normal conditions m , and by comparing the coefficient matrix C under normal conditions m And the deformed coefficient matrix C, get the coefficient difference matrix C △ , the formula is: C △ =C-C m Among them, C △ is the coefficient difference matrix, C is the coefficient matrix after deformation, C m is the coefficient matrix under normal conditions.

12. The transformer winding deformation online monitoring system based on leakage magnetic field analytical model according to claim 8, characterized in that: Substitute the structural parameters of the deformed transformer into the leakage magnetic field analytical model, calculate the corresponding coefficient difference, and use the coefficient difference of each winding as the reference value to form a coefficient reference difference matrix, which is: Substitute the structural parameters after 5% end winding collapse displacement deformation into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the end reference value C Δxqi ; The structural parameters after 5% radial displacement deformation of the middle winding are substituted into the leakage magnetic field analytical model, and the corresponding coefficient difference calculated is used as the middle reference value C Δyqi ; According to the end reference value C Δxqi and the central reference value C Δyqi , forming the corresponding coefficient reference difference matrix C △0 .

13. The transformer winding deformation online monitoring system based on leakage magnetic field analytical model according to claim 12 is characterized in that: Based on the constructed coefficient benchmark difference matrix, the error coefficient is introduced to obtain the deformation threshold matrix, the formula is: C △set =K rel C △0 In the formula, K rel is the error coefficient, take 1.1; C △0 is the coefficient basis difference matrix.

14. The transformer winding deformation online monitoring system based on leakage magnetic field analytical model according to claim 8, characterized in that: According to the comparison results between the coefficient difference matrix and the deformation threshold matrix, the deformation winding and deformation position are determined, specifically: When |C △ | xqi >|C △set | xqi When , the end of the i-th winding undergoes axial deformation, and the deformation position is determined by the measuring point number q; When |C △ | yqi >|C △set | yqi When , the i-th winding undergoes radial deformation in the middle; Among them, |C △ | xqi 、|C △ | yqi is the difference matrix C of the deformation coefficients of the end and the middle △ The absolute value of the qth row and ith column in |C △set | xqi 、|C △set | yqi is the deformation threshold matrix C for the end and middle parts △set The absolute value of the qth row and ith column in .

15. An electronic device, characterized in that: The electronic device comprises: Processor and memory; The processor is used to execute the steps of the transformer winding deformation online monitoring method as described in any one of claims 1 to 7 by calling the program or instruction stored in the memory.

16. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program or instruction, and the program or instruction is a step for a computer to execute the method for online monitoring of transformer winding deformation according to any one of claims 1 to 7.

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