Deformation monitoring method of transformer winding and winding deformation monitoring experiment platform

Abstract

The embodiment of the invention discloses a deformation monitoring method of a transformer winding and a winding deformation monitoring experiment platform. The method comprises the steps of collecting a first electrical parameter waveform of a low-voltage side of a to-be-monitored transformer and a second electrical parameter waveform of a response side of the to-be-monitored transformer under triangular wave signals with different frequencies; calculating and drawing a frequency change response image of the to-be-monitored transformer according to the first electrical parameter waveform and the second electrical parameter waveform under the triangular wave signals with different frequencies; and extracting a frequency change characteristic value of the frequency change response image, and analyzing the deformation condition of the transformer winding to be monitored based on the frequency change characteristic value. A triangular wave signal is used as an excitation signal to simulate the winding state of the transformer under the normal operation condition, off-line detection and shutdown for detection are not needed, and normal production and operation of a power grid are not influenced; in addition, the frequency variation characteristic value of the transformer winding is analyzed according to the triangular wave signals with different frequencies, so that the state of the transformer winding can be determined according to the frequency variation characteristic value, and the deformation state of the transformer winding is effectively evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of winding deformation monitoring, and in particular to a transformer winding deformation monitoring method and a winding deformation monitoring experimental platform. Background Art

[0002] As an indispensable key equipment in the power system, the transformer undertakes the important tasks of voltage conversion and power transmission. However, during the long-term operation of the transformer, due to the influence of various factors such as mechanical stress, thermal stress, and electromagnetic force, its internal winding may deform, thus affecting the performance and safety of the transformer.

[0003] The main causes of transformer winding deformation include mechanical stress, thermal stress, electromagnetic force and material aging. Mechanical stress usually comes from the impact and vibration of the transformer during transportation, installation and operation; thermal stress is caused by the increase in winding temperature caused by load changes and ambient temperature; electromagnetic force is particularly significant in the case of short circuit faults or overloads, and huge electromagnetic forces can cause the windings to displace or deform; material aging causes the insulation material to gradually lose its mechanical strength, and the winding support structure loosens, causing deformation. Winding deformation not only affects the electrical performance of the transformer, but may also cause serious safety accidents, such as turn-to-turn short circuits, local overheating, and even fire and explosion. Therefore, timely detection of winding deformation is of great significance to ensure the safe operation of the transformer. At present, there is no effective method for detecting transformer winding deformation. Summary of the invention

[0004] Based on this, it is necessary to propose a transformer winding deformation monitoring method and a winding deformation monitoring experimental platform to address the above problems, so as to effectively monitor the transformer winding deformation condition.

[0005] To achieve the above-mentioned object, the present application provides, in a first aspect, a deformation monitoring method for transformer windings, the method comprising:

[0006] Injecting triangular wave signals of different frequencies into the low-voltage side winding of the transformer to be monitored through a preset injection method;

[0007] Collecting a first electrical parameter waveform at the low-voltage side of the transformer to be monitored and a second electrical parameter waveform at the response side under triangular wave signals of different frequencies;

[0008] Calculating and drawing a frequency-dependent response image of the transformer to be monitored according to a first electrical parameter waveform and a second electrical parameter waveform under triangular wave signals of different frequencies;

[0009] The frequency-varying characteristic values ​​of the frequency-varying response image are extracted, and the deformation condition of the transformer winding to be monitored is analyzed based on the frequency-varying characteristic values.

[0010] Furthermore, the electrical parameter waveform includes a voltage waveform and a current waveform, and the frequency-dependent response image of the transformer to be monitored is calculated and drawn according to the first electrical parameter waveform and the second electrical parameter waveform under the triangular wave signal of different frequencies, specifically including:

[0011] Obtaining first frequency-dependent response values ​​corresponding to different frequencies according to the first voltage waveform of the low-voltage side and the second current waveform of the response side under the triangular wave signal of different frequencies, and drawing a first frequency-dependent response image of the low-voltage side based on the first frequency-dependent response values ​​corresponding to the different frequencies;

[0012] According to the first voltage waveform of the low-voltage side and the second voltage waveform of the response side under the triangular wave signal of different frequencies, second frequency-dependent response values ​​corresponding to different frequencies are calculated, and a second frequency-dependent response image of the response side is drawn based on the second frequency-dependent response values ​​corresponding to different frequencies;

[0013] Wherein, the horizontal coordinate of the frequency response image is: lg f i ; The ordinate of the frequency response image is: 10lgU(i) / I(i); where f i is the target frequency, which is any frequency within a preset frequency range, U(i) is the voltage on the low-voltage side or the response side under the triangular wave signal of the target frequency, and I(i) is the current on the low-voltage side or the response side under the triangular wave signal of the target frequency.

[0014] Furthermore, the extracting of the frequency-varying characteristic value of the frequency-varying response image and analyzing the deformation condition of the transformer winding to be monitored based on the frequency-varying characteristic value specifically includes:

[0015] Extracting image features based on the first frequency-dependent response image and the second frequency-dependent response image to obtain a first frequency-dependent characteristic value and a second frequency-dependent characteristic value;

[0016] Calculating a first winding deformation factor and a second winding deformation factor according to the first frequency-dependent characteristic value and the second frequency-dependent characteristic value;

[0017] A comprehensive evaluation is performed on the transformer winding to be monitored according to the first winding deformation factor and the second winding deformation factor to determine the deformation condition of the transformer winding to be monitored.

[0018] Further, the first winding deformation factor and the second winding deformation factor are calculated according to the first frequency-dependent characteristic value and the second frequency-dependent characteristic value, specifically including:

[0019] Respectively obtaining reference phases of a first target current waveform, a first target voltage waveform, a second target current waveform, and a second target voltage waveform, wherein the first target current waveform, the first target voltage waveform, the second target current waveform, and the second target voltage waveform are respectively a first current waveform, a first voltage waveform, a second current waveform, and a second voltage waveform under a triangular wave signal of the target frequency;

[0020] Calculating an original current phase difference corresponding to the target frequency according to a reference phase of the first target current waveform and the second target current waveform;

[0021] Calculating an original voltage phase difference corresponding to the target frequency according to a reference phase of the first target voltage waveform and the second target voltage waveform;

[0022] The first winding deformation factor and the second winding deformation factor are calculated according to the original current phase difference, the original voltage phase difference, the first frequency-dependent characteristic value, and the second frequency-dependent characteristic value.

[0023] Furthermore, the frequency-dependent characteristic value includes an average value and a maximum value of the frequency-dependent response value, and the first winding deformation factor and the second winding deformation factor are obtained by fitting and calculating through the following formula:

[0024]

[0025] Where, E1 and E2 are the deformation factors of the first winding and the second winding, respectively. i is the target frequency, 1≤i≤N, N is the total number of frequency values, Π x(i) is the original voltage phase difference corresponding to the target frequency, Π y(i) is the original current phase difference corresponding to the target frequency, G 1(i) is the first frequency-dependent response value at the target frequency, G 1av is the average value of all first frequency response values, G 1m is the maximum value of all first frequency response values, G 2(i) is the second frequency response value at the target frequency, G 2av is the average value of all second frequency response values, G 2m is the maximum value of all second frequency response values.

[0026] Further, the injection methods include voltage transformer injection, capacitance sensor injection, and station transformer injection;

[0027] The step of comprehensively evaluating the transformer winding to be monitored according to the first winding deformation factor and the second winding deformation factor to determine the deformation condition of the transformer winding to be monitored specifically includes:

[0028] The comprehensive evaluation coefficient is calculated based on the first winding deformation factor and the second winding deformation factor under three injection modes: voltage transformer, capacitance sensor and station transformer;

[0029] The deformation condition of the transformer winding to be monitored is determined based on the comprehensive evaluation coefficient.

[0030] Furthermore, the comprehensive evaluation coefficient is calculated by the following formula:

[0031]

[0032] In the formula, E 1(a) 、E 1(b) 、E 1(c) are the first winding deformation factors under voltage transformer injection, capacitance sensor injection and station transformer injection, E 2(a) 、E 2(b) 、E 2(c) They are the second winding deformation factors under voltage transformer injection, capacitance sensor injection and station transformer injection respectively.

[0033] Further, determining the deformation condition of the transformer winding to be monitored based on the comprehensive evaluation coefficient specifically includes:

[0034] If the comprehensive evaluation coefficient is greater than a preset first coefficient threshold, the transformer winding to be monitored is severely deformed;

[0035] If the comprehensive evaluation coefficient is not greater than the first coefficient threshold and is not less than a preset second coefficient threshold, then the transformer winding to be monitored has a medium-level fault, wherein the first coefficient threshold is greater than the second coefficient threshold;

[0036] If the comprehensive evaluation coefficient is less than the second coefficient threshold, there is no deformation problem in the transformer winding to be monitored.

[0037] To achieve the above-mentioned purpose, the second aspect of the present application provides a transformer winding deformation monitoring experimental platform, which includes a host PC, a control module, a triangular wave generator, a low-voltage injection coil, a current-limiting power resistor, a signal injection module, a low-voltage side voltage detection module, a low-voltage side current detection module, a transformer to be monitored, a response side voltage detection module, a response side current detection module, and a simulated online operation device;

[0038] The host PC end is connected to the control module, the control module is connected to the first end of the triangular wave generator, the second end of the triangular wave generator is connected to one end of the current limiting power resistor, the low voltage injection coil is respectively connected to the other end of the current limiting power resistor and the third end of the triangular wave generator, the signal injection module is respectively connected to the low voltage injection coil and the low voltage side voltage detection module, the low voltage side voltage detection module is connected to the low voltage side current detection module, the low voltage side current detection module is connected to the transformer to be monitored, the transformer to be monitored is respectively connected to the response side voltage detection module and the response side current detection module, and the simulation online operation device is respectively connected to the low voltage side voltage detection module, the low voltage side current detection module, the response side voltage detection module, the response side current detection module and the host PC end.

[0039] Furthermore, the host PC sends a monitoring command to the control module, and the control module controls the triangular wave generator to output triangular wave signals of different frequencies according to the monitoring command. The triangular wave signal flows into the low-voltage injection coil through the current-limiting power resistor, and the low-voltage injection coil couples the triangular wave signal to obtain a coupled injection electrical signal. The signal injection module injects the coupled injection electrical signal into the low-voltage side winding of the transformer to be monitored; the low-voltage side voltage detection module and the low-voltage side current detection module respectively collect the first voltage waveform and the first current waveform of the low-voltage side of the transformer to be monitored, and the response side voltage detection module and the response side current detection module respectively collect the second voltage waveform and the second current waveform of the response side of the transformer to be monitored. The simulated online operation device calculates and draws the frequency-dependent response image of the transformer to be monitored according to the first voltage waveform, the first current waveform, the second voltage waveform and the second current waveform, extracts the frequency-dependent characteristic value of the frequency-dependent response image, and analyzes the deformation condition of the transformer winding to be monitored based on the frequency-dependent characteristic value, and sends the deformation condition of the transformer winding to be monitored to the host PC.

[0040] The embodiments of the present invention have the following beneficial effects:

[0041] The embodiment of the present invention proposes a deformation monitoring method for transformer windings, the method comprising: injecting triangular wave signals of different frequencies into the low-voltage side windings of the transformer to be monitored through a preset injection method; collecting the first electrical parameter waveform of the low-voltage side of the transformer to be monitored and the second electrical parameter waveform of the response side under triangular wave signals of different frequencies; calculating and drawing the frequency-variable response image of the transformer to be monitored according to the first electrical parameter waveform and the second electrical parameter waveform under triangular wave signals of different frequencies; extracting the frequency-variable characteristic value of the frequency-variable response image, and analyzing the deformation condition of the transformer winding to be monitored based on the frequency-variable characteristic value. The triangular wave signal is used as an excitation signal to simulate the winding state of the transformer under normal operation, without offline detection and shutdown for inspection, and does not affect the normal production and operation of the power grid; in addition, the frequency-variable characteristic value of the transformer winding is analyzed according to the triangular wave signals of different frequencies, so that the state of the transformer winding can be determined according to the frequency-variable characteristic value, and effective transformer winding deformation state evaluation is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 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 of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] in:

[0044] Figure 1 A transformer winding deformation monitoring experimental platform built for an embodiment of the present invention;

[0045] Figure 2 Schematic diagram of the flow of a transformer winding deformation monitoring method in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The present invention proposes a transformer winding deformation monitoring method, which is implemented based on a transformer winding deformation monitoring experimental platform. Figure 1 , Figure 1The transformer winding deformation monitoring experimental platform (16) is constructed for an embodiment of the present invention, and comprises a host PC end (1), a control module (2), a triangular wave generator (3), a low-voltage injection coil (4), a current-limiting power resistor (5), a signal injection module (6), a low-voltage side voltage detection module (10), a low-voltage side current detection module (11), a transformer to be monitored (12), a response side voltage detection module (13), a response side current detection module (14), and a simulated online operation device (15); the host PC end (1) is connected to the control module (2), the control module (2) is connected to the first end of the triangular wave generator (3), the second end of the triangular wave generator (3) is connected to one end of the current-limiting power resistor (5), the low-voltage injection line (10) is connected to the control module (2), the control module (2) is connected to the first end of the triangular wave generator (3), the second end of the triangular wave generator (3) is connected to one end of the current-limiting power resistor (5), the low-voltage injection line (11) is connected to the control module (2), the control module (2) is connected to the first end of the triangular wave generator (3), the second end of the triangular wave generator (3) is connected to the first end of the current-limiting power resistor (5), the low-voltage injection line (10) is connected to the control module (2), the control module (2) is connected to the first end of the triangular wave generator (3), the second end of the triangular wave generator (3) is connected to the first end of the current-limiting power resistor (5), the low-voltage injection line (1 ... The coil (4) is respectively connected to the other end of the current limiting power resistor (5) and the third end of the triangular wave generator (3); the signal injection module (6) is respectively connected to the low voltage injection coil (4) and the low voltage side voltage detection module (10); the low voltage side voltage detection module (10) is connected to the low voltage side current detection module (11); the low voltage side current detection module (11) is connected to the transformer to be monitored (12); the transformer to be monitored (12) is respectively connected to the response side voltage detection module (13) and the response side current detection module (14); and the simulation online operation device (15) is respectively connected to the low voltage side voltage detection module (10), the low voltage side current detection module (11), the response side voltage detection module (13), the response side current detection module (14) and the host PC end (1).

[0048] In one embodiment of the present invention, a host PC terminal (1) sends a monitoring command to a control module (2), and the control module (2) controls a triangular wave generator (3) to output a triangular wave signal of different frequencies according to the monitoring command. The triangular wave signal flows into a low-voltage injection coil (4) through a current-limiting power resistor (5), and the low-voltage injection coil (4) couples the triangular wave signal to obtain a coupled injection electrical signal. The signal injection module (6) injects the coupled injection electrical signal into a low-voltage side winding of a transformer to be monitored (12); a low-voltage side voltage detection module (10) and a low-voltage side current detection module (11) respectively collect the low-voltage side current of the transformer to be monitored (12). A first voltage waveform and a first current waveform, a response side voltage detection module (13) and a response side current detection module (14) respectively collect a second voltage waveform and a second current waveform on the response side of the transformer to be monitored (12), and a simulation online operation device (15) calculates and draws a frequency-dependent response image of the transformer to be monitored (12) according to the first voltage waveform, the first current waveform, the second voltage waveform, and the second current waveform, extracts a frequency-dependent characteristic value of the frequency-dependent response image, and analyzes a deformation condition of a winding of the transformer to be monitored (12) based on the frequency-dependent characteristic value, and sends the deformation condition of the winding of the transformer to be monitored (12) to a host PC end (1).

[0049] In the embodiment of the present invention, the host PC (1) indirectly controls the triangular wave generator (3) by sending a monitoring command to the control module (2). Under the control of the control module (2), the triangular wave generator (3) can output a triangular wave signal with an arbitrarily adjustable amplitude and frequency.

[0050] In order to prevent the circuit impedance from being too small, thereby causing the triangular wave generator (3) to have a short circuit fault, a current limiting power resistor (5) is added to the triangular wave injection loop. The triangular wave signal first flows through the current limiting power resistor (5) in the injection loop, and then flows through the low-voltage injection coil (4). The low-voltage injection coil (4) is to effectively couple the triangular wave signal to the low-voltage side of the winding of the transformer (12) to be monitored, thereby playing a role of coupling and protection.

[0051] The triangular wave signal obtained by the low-voltage injection coil (4) is injected into the low-voltage side winding of the transformer (12) to be monitored through the signal injection module (6). In one embodiment of the present invention, the signal injection module (6) may include a voltage transformer (7), a capacitance sensor (8) and a station transformer (9). The signal is injected into the low-voltage side winding monitored by the transformer (12) to be monitored through three different injection methods: the voltage transformer (7), the capacitance sensor (8) and the station transformer (9).

[0052] The four modules, namely a low-voltage side voltage detection module (10), a low-voltage side current detection module (11), a response side voltage detection module (13) and a response side current detection module (14), are used to measure current and voltage waveform signals on the low-voltage side and the response side of the transformer to be monitored (12), respectively.

[0053] The simulated online operation device (15) can simulate the power frequency operation status of the transformer (12) to be monitored. First, the current and voltage waveform signals of the low voltage side and the response side of the transformer measured by the detection module are obtained. According to the current and voltage waveform signals of the low voltage side and the response side of the transformer, the frequency response image of the transformer (12) to be monitored is calculated and drawn. Then, the frequency characteristic value in the frequency response image is extracted, and the deformation status of the winding of the transformer (12) to be monitored is analyzed based on the frequency characteristic value. Finally, the deformation status of the winding of the transformer (12) to be monitored is sent to the host PC end (1) so that the detection personnel can observe the current status of the transformer (12) to be monitored.

[0054] The embodiment of the present invention also provides a deformation monitoring method for transformer windings, which can be referred to Figure 2 , Figure 2 : is a flow chart of a deformation monitoring method for transformer windings in an embodiment of the present invention, the method comprising:

[0055] Step 210: Inject triangular wave signals of different frequencies into the low-voltage side winding of the transformer to be monitored through a preset injection method.

[0056] In the embodiment of the present invention, a triangular wave signal is injected into the transformer to be monitored as an excitation signal. Since the triangular wave signal has symmetry and linear slope characteristics, using it as an excitation signal can enable the system to operate more stably. In addition, the triangular wave signal is easy to generate, thereby making the monitoring process simpler.

[0057] Specifically, the triangular wave generator (3) can output triangular wave signals of different amplitudes and frequencies under the control of the control module (2). The triangular wave signals of different frequencies are respectively injected into the low-voltage side winding of the transformer to be monitored through the signal injection module (6) using the low-voltage injection coil (4).

[0058] Step 220: Collect the first electrical parameter waveform of the low-voltage side of the transformer to be monitored and the second electrical parameter waveform of the response side under triangular wave signals of different frequencies.

[0059] Specifically, the electrical parameters may be parameters such as voltage and current. A first electrical parameter waveform, that is, a first voltage waveform and a first current waveform, of the low-voltage side of the transformer to be monitored may be collected through a low-voltage side voltage detection module (10) and a low-voltage side current detection module (11), and a second electrical parameter waveform, that is, a second voltage waveform and a second current waveform, of the response side of the transformer to be monitored may be collected through a response side voltage detection module (13) and a response side current detection module (14).

[0060] Step 230: Calculate and draw a frequency-dependent response image of the transformer to be monitored according to the first electrical parameter waveform and the second electrical parameter waveform under the triangular wave signals of different frequencies.

[0061] In the embodiment of the present invention, the frequency-variable response of the transformer to be monitored is observed by measuring the voltage and current on the low-voltage side and the response side of the transformer to be monitored under triangular wave signals of different frequencies, and the frequency-variable response is plotted into an image for analysis.

[0062] Step 240: extract the frequency-varying characteristic values ​​of the frequency-varying response image, and analyze the deformation condition of the transformer winding to be monitored based on the frequency-varying characteristic values.

[0063] Specifically, the frequency response characteristics of the transformer to be monitored are obtained based on the frequency response image, and the frequency characteristic values ​​are obtained, so as to judge the deformation condition of the winding of the transformer to be monitored according to the frequency characteristic values.

[0064] The winding deformation monitoring method by injecting a triangular wave signal on the low-voltage side of the transformer to be detected in the embodiment of the present invention has many advantages. First, the frequency and amplitude of the excitation signal can be accurately controlled, and the slight deformation of the winding can be effectively detected to achieve high-sensitivity monitoring. Secondly, online monitoring can be realized to timely discover abnormal conditions of the transformer winding to be monitored and avoid potential safety hazards. In addition, the method is non-invasive and does not require disassembly of the transformer, reducing maintenance costs and downtime. Finally, the method is applicable to various types of transformers, including oil-immersed transformers and dry-type transformers, and has a wide range of applicability. Therefore, the winding deformation monitoring method by injecting a triangular wave signal on the low-voltage side of the transformer to be monitored has broad application prospects in transformer maintenance and fault diagnosis of power systems, and can significantly improve the operating reliability and safety of the transformer and reduce the risk of accidents caused by winding deformation.

[0065] In one embodiment of the present invention, step 230, calculating and drawing the frequency-dependent response image of the transformer to be monitored according to the first electrical parameter waveform and the second electrical parameter waveform under the triangular wave signal of different frequencies, specifically includes:

[0066] Step 310, obtaining first frequency-dependent response values ​​corresponding to different frequencies according to the first voltage waveform on the low-voltage side and the second current waveform on the response side under the triangular wave signals of different frequencies, and drawing a first frequency-dependent response image of the low-voltage side based on the first frequency-dependent response values ​​corresponding to different frequencies.

[0067] Step 310, calculate the second frequency-dependent response values ​​corresponding to different frequencies according to the first voltage waveform on the low-voltage side and the second voltage waveform on the response side under the triangular wave signal of different frequencies, and draw the second frequency-dependent response image of the response side based on the second frequency-dependent response values ​​corresponding to different frequencies; wherein the abscissa of the frequency-dependent response image is: lg f i ; The vertical coordinate of the frequency response image is: 10lg U(i) / I(i); where f i is the target frequency, the target frequency is any frequency within the preset frequency range, U(i) is the voltage on the low voltage side or the response side under the triangular wave signal of the target frequency, and I(i) is the current on the low voltage side or the response side under the triangular wave signal of the target frequency.

[0068] In the embodiment of the present invention, the deformation condition of the winding of the transformer to be monitored is determined according to the frequency response change of the transformer to be monitored under the frequency change of the triangular wave signal. Specifically, the frequency response of the transformer to be monitored can be determined by observing the frequency response value of the transformer to be monitored. The first frequency response value and the second frequency response value are calculated according to the voltage and current on the low voltage side and the response side, and the first frequency response value is 101 g U I (i) / I O (i), in the formula, U I(i) is the first voltage waveform data, I O (i) is the second current waveform data, i is the number of points corresponding to different frequencies, i = 1, 2...N; the second frequency response value is 10lg U O (i) / I I (i), in the formula, U O (i) is the second voltage waveform data, I I (i) is the first current waveform data.

[0069] In one embodiment of the present invention, step 240, extracting the frequency-dependent characteristic value of the frequency-dependent response image, and analyzing the deformation condition of the transformer winding to be monitored based on the frequency-dependent characteristic value, specifically includes:

[0070] Step 410: extract image features based on the first frequency-dependent response image and the second frequency-dependent response image to obtain a first frequency-dependent characteristic value and a second frequency-dependent characteristic value.

[0071] In an embodiment of the present invention, the frequency-varying characteristic value may be a maximum value, a minimum value, an average value, etc. of a frequency-varying response value.

[0072] Step 420, calculating the first winding deformation factor and the second winding deformation factor according to the first frequency-dependent eigenvalue and the second frequency-dependent eigenvalue.

[0073] A winding deformation factor for determining a degree of transformer winding deformation is calculated by using the first frequency-dependent characteristic value and the second frequency-dependent characteristic value.

[0074] In one embodiment of the present invention, Step 420, calculating the first winding deformation factor and the second winding deformation factor according to the first frequency-dependent characteristic value and the second frequency-dependent characteristic value, specifically includes:

[0075] Step 421, respectively obtain the reference phases of the first target current waveform, the first target voltage waveform, the second target current waveform and the second target voltage waveform, wherein the first target current waveform, the first target voltage waveform, the second target current waveform and the second target voltage waveform are respectively the first current waveform, the first voltage waveform, the second current waveform and the second voltage waveform under the triangular wave signal of the target frequency.

[0076] Specifically, the first target current waveform, the first target voltage waveform, the second target current waveform, and the second target voltage waveform are decomposed to obtain a reference phase of each waveform.

[0077] Step 422, calculating the original current phase difference corresponding to the target frequency according to the reference phase of the first target current waveform and the second target current waveform.

[0078] Step 423, calculating the original voltage phase difference corresponding to the target frequency according to the reference phase of the first target voltage waveform and the second target voltage waveform.

[0079] Step 424, calculate the first winding deformation factor and the second winding deformation factor according to the original current phase difference, the original voltage phase difference, the first frequency-dependent characteristic value and the second frequency-dependent characteristic value.

[0080] In one embodiment of the present invention, the frequency-dependent characteristic value includes an average value and a maximum value of the frequency-dependent response value, and the first winding deformation factor and the second winding deformation factor are obtained by fitting and calculating the following formula:

[0081]

[0082] Where, E1 and E2 are the deformation factors of the first winding and the second winding, respectively. i is the target frequency, 1≤i≤N, N is the total number of frequency values, Π x(i) is the original voltage phase difference corresponding to the target frequency, Π y(i) is the original current phase difference corresponding to the target frequency, G 1(i) is the first frequency response value at the target frequency, G 1av is the average value of all first frequency response values, G 1m is the maximum value of all first frequency response values, G 2(i) is the second frequency response value at the target frequency, G 2av is the average value of all second frequency response values, G 2m is the maximum value of all second frequency response values.

[0083] Step 430, comprehensively evaluate the transformer winding to be monitored according to the first winding deformation factor and the second winding deformation factor to determine the deformation condition of the transformer winding to be monitored.

[0084] In the embodiment of the present invention, a comprehensive evaluation is performed on the winding condition of the transformer to be monitored based on the first winding deformation factor and the second winding deformation factor to reduce the error of the evaluation result.

[0085] In one embodiment of the present invention, the signal injection module (6) includes a voltage transformer (7), a capacitance sensor (8) and a station transformer (9). Based on this, the triangular wave signal can be injected into the transformer to be monitored respectively through three signal injection devices, and the deformation condition of the winding can be determined according to the winding deformation factors under the three injection modes. Specifically, Step 430, based on the first winding deformation factor and the second winding deformation factor, a comprehensive evaluation is performed on the transformer winding to be monitored to determine the deformation condition of the transformer winding to be monitored, which specifically includes:

[0086] Step 431, calculate the comprehensive evaluation coefficient according to the first winding deformation factor and the second winding deformation factor under the three injection modes of voltage transformer, capacitance sensor and station transformer.

[0087] In one embodiment of the present invention, the comprehensive evaluation coefficient is calculated by the following formula:

[0088]

[0089] In the formula, E 1(a) 、E 1(b) 、E 1(c) are the first winding deformation factors under voltage transformer injection, capacitance sensor injection and station transformer injection, E 2(a) 、E 2(b) 、E 2(c) They are the second winding deformation factors under voltage transformer injection, capacitance sensor injection and station transformer injection respectively.

[0090] Step 432, determine the deformation condition of the transformer winding to be monitored based on the comprehensive evaluation coefficient.

[0091] Specifically, if the comprehensive evaluation coefficient is greater than the preset first coefficient threshold, the deformation of the transformer winding to be monitored is serious; if the comprehensive evaluation coefficient is not greater than the first coefficient threshold and not less than the preset second coefficient threshold, there is a moderate fault in the transformer winding to be monitored, wherein the first coefficient threshold is greater than the second coefficient threshold; if the comprehensive evaluation coefficient is less than the second coefficient threshold, there is no deformation problem in the transformer winding to be monitored.

[0092] For example, the first coefficient threshold is 0.9 and the second coefficient threshold is 0.65. If γ>0.9, it indicates that the transformer winding to be monitored is seriously deformed and the power should be shut down for maintenance in time; if 0.65≤γ≤0.9, it indicates that the transformer winding to be monitored has a moderate fault and the power should also be shut down for maintenance in time; if γ<0.65, it indicates that there is no deformation problem in the transformer winding to be monitored.

[0093] The transformer winding deformation monitoring method proposed in the present invention uses a triangular wave signal as an excitation signal to simulate the winding state of the transformer under normal operation. There is no need to shut down for offline detection and inspection, and the normal production and operation of the power grid are not affected. In addition, the frequency-varying characteristic values ​​of the transformer winding are analyzed according to triangular wave signals of different frequencies, so that the state of the transformer winding can be determined according to the frequency-varying characteristic values, thereby realizing effective evaluation of the transformer winding deformation state.

Claims

1. A deformation monitoring method for transformer windings, characterized in that: The method comprises: Injecting triangular wave signals of different frequencies into the low-voltage side winding of the transformer to be monitored through a preset injection method; Collecting a first electrical parameter waveform at the low-voltage side of the transformer to be monitored and a second electrical parameter waveform at the response side under triangular wave signals of different frequencies; Calculating and drawing a frequency-dependent response image of the transformer to be monitored according to a first electrical parameter waveform and a second electrical parameter waveform under triangular wave signals of different frequencies; The frequency-varying characteristic values ​​of the frequency-varying response image are extracted, and the deformation condition of the transformer winding to be monitored is analyzed based on the frequency-varying characteristic values.

2. The method according to claim 1, characterized in that The electrical parameter waveform includes a voltage waveform and a current waveform. The frequency-dependent response image of the transformer to be monitored is calculated and drawn according to the first electrical parameter waveform and the second electrical parameter waveform under the triangular wave signal of different frequencies, specifically including: Obtaining first frequency-dependent response values ​​corresponding to different frequencies according to the first voltage waveform of the low-voltage side and the second current waveform of the response side under the triangular wave signal of different frequencies, and drawing a first frequency-dependent response image of the low-voltage side based on the first frequency-dependent response values ​​corresponding to the different frequencies; According to the first voltage waveform of the low-voltage side and the second voltage waveform of the response side under the triangular wave signal of different frequencies, second frequency-dependent response values ​​corresponding to different frequencies are calculated, and a second frequency-dependent response image of the response side is drawn based on the second frequency-dependent response values ​​corresponding to different frequencies; Wherein, the horizontal coordinate of the frequency response image is: lg f i ; The ordinate of the frequency response image is: 10lg U(i) / I(i); where f i is the target frequency, which is any frequency within a preset frequency range, U(i) is the voltage on the low-voltage side or the response side under the triangular wave signal of the target frequency, and I(i) is the current on the low-voltage side or the response side under the triangular wave signal of the target frequency.

3. The method according to claim 2, characterized in that The extracting the frequency-varying characteristic value of the frequency-varying response image and analyzing the deformation condition of the transformer winding to be monitored based on the frequency-varying characteristic value specifically includes: Extracting image features based on the first frequency-dependent response image and the second frequency-dependent response image to obtain a first frequency-dependent characteristic value and a second frequency-dependent characteristic value; Calculating a first winding deformation factor and a second winding deformation factor according to the first frequency-dependent characteristic value and the second frequency-dependent characteristic value; A comprehensive evaluation is performed on the transformer winding to be monitored according to the first winding deformation factor and the second winding deformation factor to determine the deformation condition of the transformer winding to be monitored.

4. The method according to claim 3, characterized in that The calculating of the first winding deformation factor and the second winding deformation factor according to the first frequency-dependent characteristic value and the second frequency-dependent characteristic value specifically includes: Respectively obtaining reference phases of a first target current waveform, a first target voltage waveform, a second target current waveform, and a second target voltage waveform, wherein the first target current waveform, the first target voltage waveform, the second target current waveform, and the second target voltage waveform are respectively a first current waveform, a first voltage waveform, a second current waveform, and a second voltage waveform under a triangular wave signal of the target frequency; Calculating an original current phase difference corresponding to the target frequency according to a reference phase of the first target current waveform and the second target current waveform; Calculating an original voltage phase difference corresponding to the target frequency according to a reference phase of the first target voltage waveform and the second target voltage waveform; The first winding deformation factor and the second winding deformation factor are calculated according to the original current phase difference, the original voltage phase difference, the first frequency-dependent characteristic value, and the second frequency-dependent characteristic value.

5. The method according to claim 4, characterized in that The frequency-dependent characteristic value includes an average value and a maximum value of the frequency-dependent response value. The first winding deformation factor and the second winding deformation factor are obtained by fitting and calculating the following formula: Where, E1 and E2 are the deformation factors of the first winding and the second winding, respectively. i is the target frequency, 1≤i≤N, N is the total number of frequency values, Π x(i) is the original voltage phase difference corresponding to the target frequency, Π y(i) is the original current phase difference corresponding to the target frequency, G 1(i) is the first frequency-dependent response value at the target frequency, G 1av is the average value of all first frequency response values, G 1m is the maximum value of all first frequency response values, G 2(i) is the second frequency response value at the target frequency, G 2av is the average value of all second frequency response values, G 2m is the maximum value of all second frequency response values.

6. The method according to claim 3, characterized in that Injection methods include voltage transformer injection, capacitance sensor injection and station transformer injection; The step of comprehensively evaluating the transformer winding to be monitored according to the first winding deformation factor and the second winding deformation factor to determine the deformation condition of the transformer winding to be monitored specifically includes: The comprehensive evaluation coefficient is calculated based on the first winding deformation factor and the second winding deformation factor under three injection modes: voltage transformer, capacitance sensor and station transformer; The deformation condition of the transformer winding to be monitored is determined based on the comprehensive evaluation coefficient.

7. The method according to claim 6, characterized in that The comprehensive evaluation coefficient is calculated by the following formula: In the formula, E 1(a) 、E 1(b) 、E 1(c) are the first winding deformation factors under voltage transformer injection, capacitance sensor injection and station transformer injection, E 2(a) 、E 2(b) 、E 2(c) They are the second winding deformation factors under voltage transformer injection, capacitance sensor injection and station transformer injection respectively.

8. The method according to claim 6, characterized in that The step of determining the deformation condition of the transformer winding to be monitored based on the comprehensive evaluation coefficient specifically includes: If the comprehensive evaluation coefficient is greater than a preset first coefficient threshold, the transformer winding to be monitored is severely deformed; If the comprehensive evaluation coefficient is not greater than the first coefficient threshold and is not less than a preset second coefficient threshold, then the transformer winding to be monitored has a medium-level fault, wherein the first coefficient threshold is greater than the second coefficient threshold; If the comprehensive evaluation coefficient is less than the second coefficient threshold, there is no deformation problem in the transformer winding to be monitored.

9. A transformer winding deformation monitoring experimental platform, characterized in that: The platform includes a host PC, a control module, a triangular wave generator, a low-voltage injection coil, a current-limiting power resistor, a signal injection module, a low-voltage side voltage detection module, a low-voltage side current detection module, a transformer to be monitored, a response side voltage detection module, a response side current detection module, and a simulated online operation device; The host PC end is connected to the control module, the control module is connected to the first end of the triangular wave generator, the second end of the triangular wave generator is connected to one end of the current limiting power resistor, the low voltage injection coil is respectively connected to the other end of the current limiting power resistor and the third end of the triangular wave generator, the signal injection module is respectively connected to the low voltage injection coil and the low voltage side voltage detection module, the low voltage side voltage detection module is connected to the low voltage side current detection module, the low voltage side current detection module is connected to the transformer to be monitored, the transformer to be monitored is respectively connected to the response side voltage detection module and the response side current detection module, and the simulation online operation device is respectively connected to the low voltage side voltage detection module, the low voltage side current detection module, the response side voltage detection module, the response side current detection module and the host PC end.

10. The transformer winding deformation monitoring experimental platform according to claim 9, characterized in that: The host PC sends a monitoring command to the control module, and the control module controls the triangular wave generator to output triangular wave signals of different frequencies according to the monitoring command. The triangular wave signal flows into the low-voltage injection coil through the current-limiting power resistor, and the low-voltage injection coil couples the triangular wave signal to obtain a coupled injection electrical signal. The signal injection module injects the coupled injection electrical signal into the low-voltage side winding of the transformer to be monitored; The low-voltage side voltage detection module and the low-voltage side current detection module respectively collect the first voltage waveform and the first current waveform of the low-voltage side of the transformer to be monitored, and the response side voltage detection module and the response side current detection module respectively collect the second voltage waveform and the second current waveform of the response side of the transformer to be monitored. The simulated online operation device calculates and draws the frequency-dependent response image of the transformer to be monitored according to the first voltage waveform, the first current waveform, the second voltage waveform and the second current waveform, extracts the frequency-dependent characteristic value of the frequency-dependent response image, analyzes the deformation condition of the winding of the transformer to be monitored based on the frequency-dependent characteristic value, and sends the deformation condition of the winding of the transformer to be monitored to the host PC.

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