A method and system for diagnosing and locating power transformer winding deformation

Abstract

The application discloses a kind of power transformer winding deformation diagnosis positioning method and system, transformer adopts work type optical fiber magnetic field sensor to the winding leakage magnetic field signal collection, the work type optical fiber magnetic field sensor is installed on the insulation pad between transformer winding turns;According to the leakage magnetic field situation that the work type optical fiber magnetic field sensor is continuously monitored, the winding deformation fault is diagnosed;Based on the diagnosis result of the winding deformation fault, the positioning of the winding deformation fault position is realized by establishing fitting curve expression.This application can be aimed at the problem that the accuracy of existing transformer winding deformation monitoring method is not high, and on-line monitoring technology is not mature, by using work type optical fiber magnetic field sensor and setting on the insulation pad between winding turns, the radial and axial leakage magnetic component near transformer winding is measured, the winding state of transformer can be accurately judged, and the accurate diagnosis of winding deformation fault is realized.

Description

Technical Field

[0001] This invention relates to the field of power transformer testing technology, and in particular to a method and system for diagnosing and locating deformation in power transformer windings. Background Technology

[0002] As a core piece of equipment in the power grid's transmission and distribution system, the safe and reliable operation of power transformers directly impacts the normal supply of electricity. Power transformer failures can lead to widespread power outages and potentially cause significant economic losses and social impact. Maintenance of power transformers is difficult due to site conditions, and is costly and time-consuming. Therefore, online condition monitoring and early fault diagnosis of transformers are crucial. Current statistics show that most transformer failures are due to winding deformation; therefore, online monitoring of winding deformation is one of the effective means to ensure reliable transformer operation.

[0003] The cause of winding deformation may be mechanical collision or squeezing during the transportation, installation and commissioning of the transformer, causing winding deformation; bulging, twisting, tilting and collapse of the winding; it may also be that the transformer is subjected to the impact of multiple external short circuit fault electromagnetic forces during normal operation. The huge electromagnetic force generated by the short circuit impact current will cause the radial and axial dimensional changes of the winding, causing deformation at the ends or middle of the winding.

[0004] Existing research indicates that transformer winding deformation can be reflected by changes in its internal leakage flux. However, traditional magnetic field sensors typically convert magnetic field signals into electrical signals for sensing, resulting in problems such as large size and poor resistance to electromagnetic interference. Furthermore, the commonly used non-destructive monitoring methods for transformer winding deformation, such as the short-circuit impedance method, low-voltage pulse method, and capacitance change method, are generally offline monitoring methods and cannot achieve real-time online monitoring of the transformer winding status. Moreover, the accuracy of the monitoring is not high.

[0005] To address this issue, a method and system for diagnosing and locating deformation in power transformer windings are provided. Summary of the Invention

[0006] The present invention discloses a method and system for diagnosing and locating deformation of power transformer windings. By using an I-type fiber optic magnetic field sensor to collect leakage magnetic field signals from the windings, and by continuously monitoring the leakage magnetic field through the I-type fiber optic magnetic field sensor, the method diagnoses the winding deformation faults and establishes a fitted curve expression. This achieves the functions of locating the deformation position of the windings and online monitoring of the winding status, thus solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The present invention provides a method for diagnosing and locating deformation of a power transformer winding, comprising the following steps: the transformer uses an I-type fiber optic magnetic field sensor to collect leakage magnetic field signals from the winding, and the I-type fiber optic magnetic field sensor is installed on an insulating pad between the turns of the transformer winding.

[0009] Based on the leakage magnetic field continuously monitored by the I-type fiber optic magnetic field sensor, the winding deformation fault is diagnosed.

[0010] Based on the diagnostic results of the winding deformation fault, the location of the winding deformation fault is located by establishing a fitting curve expression.

[0011] Preferably, insulating pads are provided in both the radial and axial directions between the winding turns; I-shaped fiber optic magnetic field sensors are installed on both the radial and axial insulating pads between the winding turns.

[0012] Preferably, the I-shaped fiber optic magnetic field sensor is equipped with a protective device and has a pigtail, and the I-shaped fiber optic magnetic field sensor is bonded to the outer surface of the insulating pad with epoxy resin.

[0013] Preferably, the protection device is a hollow cuboid structure, and the sensing part of the I-shaped fiber optic magnetic field sensor is installed in the cavity of the protection device. The two ends of the cavity are sealed with ultraviolet resin adhesive.

[0014] Preferably, when the winding is in normal condition, the magnetic induction intensity of the winding has symmetrical characteristics in the transverse and longitudinal directions, and the leakage magnetic field exhibits an axial distribution; when the winding experiences a deformation fault, the axial magnetic induction intensity in the deformation area of ​​the winding decreases.

[0015] Preferably, fault diagnosis is performed by comparing the difference in magnetic field measured by each I-type fiber optic magnetic field sensor on the three-phase windings of the transformer; when the magnetic field magnitude of one phase winding of the transformer deviates from that of the other two phase windings by more than 10%, the winding has a deformation fault.

[0016] Preferably, after determining that the winding has a deformation fault, the sensing results of the I-shaped fiber optic magnetic field sensor with the windings on the same vertical line are fitted to obtain the fitting curve expression:

[0017]

[0018] In the fitted curve expression, H is the magnetic field strength, i is the expression for the applied power frequency current, D is the horizontal spacing between the high and low voltage windings, d is the diameter of the winding turns, and n is the number of turns of the high voltage winding.

[0019] Preferably, by comparing the deviations between the measurement results of each measuring point of the winding and the fitted curve, the point with the largest deviation is selected as the location of the winding deformation fault.

[0020] The present invention discloses a power transformer winding deformation diagnosis and positioning system, comprising: a signal acquisition module, wherein the transformer uses an I-type fiber optic magnetic field sensor to acquire leakage magnetic field signals of the winding, and the I-type fiber optic magnetic field sensor is installed on the insulating pad of the transformer winding;

[0021] The fault diagnosis module diagnoses the winding deformation fault based on the leakage magnetic field continuously monitored by the I-type fiber optic magnetic field sensor.

[0022] The fault location module, based on the diagnostic results of the winding deformation fault, locates the position of the winding deformation fault by establishing a fitting curve expression.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. The present invention provides a method and system for diagnosing and locating deformation of power transformer windings. Addressing the issues of low accuracy and immature online monitoring technology in existing transformer winding deformation monitoring methods, this invention utilizes an I-shaped fiber optic magnetic field sensor mounted on an insulating pad between the winding turns to measure the radial and axial leakage magnetic components near the transformer winding. This allows for precise determination of the transformer winding condition and accurate diagnosis of winding deformation faults. The I-shaped fiber optic magnetic field sensor is small in size and has strong anti-electromagnetic interference capabilities. The protective device installed on the I-shaped fiber optic magnetic field sensor effectively protects it from the effects of transformer vibration and oil flow, thus improving the operational reliability of the sensor.

[0025] 2. The present invention provides a method and system for diagnosing and locating deformation of a power transformer winding. After diagnosing and confirming the deformation fault of the winding using an I-type fiber optic magnetic field sensor, the sensing results of the I-type fiber optic magnetic field sensor with the winding on the same vertical line are fitted to establish a fitting curve expression. By comparing the deviation between the measurement results of each measuring point of the winding and the fitting curve, the point with the largest deviation is selected as the location of the winding deformation fault, thus realizing the location of the winding fault. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a method for diagnosing and locating deformation of power transformer windings according to the present invention;

[0027] Figure 2 This is a schematic diagram of a power transformer winding deformation diagnosis and positioning system according to the present invention;

[0028] Figure 3This is a schematic diagram of the installation arrangement of the I-shaped fiber optic magnetic field sensor of the present invention.

[0029] Explanation of key figure labels:

[0030] 1. Transformer housing; 2. Iron core; 3. Insulating pads; 11. Signal acquisition module; 12. Fault diagnosis module; 13. Fault location module. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides a method for diagnosing and locating deformation in power transformer windings, combined with... Figure 1 To explain, the steps include:

[0033] S11, Signal acquisition module: The transformer uses an I-type fiber optic magnetic field sensor to acquire leakage magnetic field signals from the windings. The I-type fiber optic magnetic field sensor is installed on the insulating pad 3 of the transformer windings.

[0034] S12, Fault diagnosis module, which diagnoses winding deformation faults based on the leakage magnetic field continuously monitored by the I-type fiber optic magnetic field sensor.

[0035] S13, Fault Location Module: Based on the diagnostic results of winding deformation faults, the module locates the position of the winding deformation fault by establishing a fitted curve expression.

[0036] Insulating pads 3 are provided radially and axially between the winding turns; I-type fiber optic magnetic field sensors are installed on the radially and axially insulating pads 3 between the winding turns. A protective device is set on the I-type fiber optic magnetic field sensor and a pigtail is led out. The I-type fiber optic magnetic field sensor is pasted to the outer surface of the insulating pad 3 with epoxy resin. The protective device is a hollow cuboid structure. The sensing part of the I-type fiber optic magnetic field sensor is installed in the cavity of the protective device. The two ends of the cavity are sealed with ultraviolet resin glue.

[0037] An I-shaped fiber optic magnetic field sensor is placed on each insulating pad 3 between turns of the winding. The I-shaped fiber optic magnetic field sensor can be placed symmetrically or in the middle of the insulating pad 3. The insulating pad 3 serves both as support and as reinforcement of the fiber optic encapsulation structure. For low-voltage transformers of 35kV and below, one I-shaped fiber optic magnetic field sensor is installed every two insulating pads 3 radially along the winding. For high-voltage transformers of 110kV and above, since the leakage magnetic field distribution characteristics are related to the winding shape, the actual winding deformation modes are numerous and complex when subjected to short-circuit electrodynamic impacts. Therefore, it is necessary to increase the number of I-shaped fiber optic magnetic field sensors to better analyze the leakage magnetic field distribution when the winding deforms. That is, one I-shaped fiber optic magnetic field sensor is installed on each insulating pad 3 radially between the turns of the winding; and in the axial direction between the turns of the winding, the I-shaped fiber optic magnetic field sensor is installed on each insulating pad 3 of one turn. The installation method of the I-shaped fiber optic magnetic field sensor is the same for both high-voltage and low-voltage windings. Meanwhile, the number and location of I-type fiber optic magnetic field sensors can be dynamically adjusted according to the actual size of the transformer, ensuring that the total number of I-type fiber optic magnetic field sensors is not less than 100, so as to accurately diagnose winding deformation faults.

[0038] When the winding is in normal condition, the magnetic induction intensity of the winding has symmetrical characteristics in both the transverse and longitudinal directions, and the leakage magnetic field exhibits an axial distribution. When a deformation fault occurs in the winding, the axial magnetic induction intensity in the deformation area of ​​the winding decreases. Fault diagnosis is performed by comparing the difference in magnetic field measured by various I-type fiber optic magnetic field sensors on the three-phase windings of the transformer. When the magnetic field magnitude of one phase winding of the transformer deviates from that of the other two phase windings by more than 10%, a deformation fault is found in the winding. After determining that a deformation fault exists in the winding, the sensing results of the I-type fiber optic magnetic field sensors with the windings on the same vertical line are fitted to obtain the fitted curve expression:

[0039]

[0040] In the fitted curve expression, H is the magnetic field strength, i is the expression for the applied power frequency current, D is the horizontal spacing between the high and low voltage windings, d is the winding turn diameter, and n is the number of turns in the high voltage winding.

[0041] By comparing the measurement results of each measuring point of the winding with the deviation of the fitted curve, the point with the largest deviation is selected as the location of the winding deformation fault, thus realizing the location of the winding fault.

[0042] Furthermore, a narrowband laser is connected to the incident light of the I-type fiber optic magnetic field sensor, and a spectrometer is connected to the emitted light to monitor the changes in light intensity in real time. When the spectrum of a certain phase in the three-phase transformer changes abruptly, it indicates that there is a fault in the winding of that phase. After further analysis of the faulty winding, the measurement values ​​of the abnormal I-type fiber optic magnetic field sensor on that phase winding are calculated and analyzed, and the location of the winding deformation is realized by corresponding to the number of the I-type fiber optic magnetic field sensor.

[0043] This invention provides a power transformer winding deformation diagnosis and positioning system, such as... Figure 2 As shown, it includes:

[0044] Signal acquisition module 11: The transformer uses an I-type fiber optic magnetic field sensor to acquire leakage magnetic field signals from the windings. The I-type fiber optic magnetic field sensor is installed on the insulating pad 3 of the transformer windings.

[0045] Fault diagnosis module 12 diagnoses winding deformation faults based on the leakage magnetic field continuously monitored by the I-type fiber optic magnetic field sensor.

[0046] The fault location module 13 locates the position of the winding deformation fault by establishing a fitting curve expression based on the diagnostic results of the winding deformation fault.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for diagnosing and locating deformation in the windings of a power transformer, characterized in that, Includes the following steps: The transformer uses an I-type fiber optic magnetic field sensor to collect leakage magnetic field signals from the windings. The I-type fiber optic magnetic field sensor is installed on the insulating pad between the turns of the transformer windings. Based on the leakage magnetic field continuously monitored by the I-type fiber optic magnetic field sensor, the winding deformation fault is diagnosed. Based on the diagnostic results of the winding deformation fault, the location of the winding deformation fault is located by establishing a fitting curve expression. After determining that the winding has a deformation fault, the sensing results of the I-shaped fiber optic magnetic field sensor with the windings on the same vertical line are fitted to obtain the fitting curve expression: ； In the fitted curve expression, H is the magnetic field strength, i is the expression for the applied power frequency current, D is the horizontal spacing between the high and low voltage windings, d is the winding turn diameter, and n is the number of turns of the high voltage winding. By comparing the measurement results of each measuring point of the winding with the deviation of the fitted curve, the point with the largest deviation is selected as the location of the winding deformation fault, thus realizing the location of the winding fault.

2. The method for diagnosing and locating deformation of power transformer windings according to claim 1, characterized in that, Insulating pads are provided in both the radial and axial directions between the winding turns; I-shaped fiber optic magnetic field sensors are installed on both the radial and axial insulating pads between the winding turns.

3. The method for diagnosing and locating deformation of power transformer windings according to claim 2, characterized in that, The I-shaped fiber optic magnetic field sensor is equipped with a protective device and a pigtail is led out. The I-shaped fiber optic magnetic field sensor is attached to the outer surface of the insulating pad with epoxy resin.

4. The method for diagnosing and locating deformation of power transformer windings according to claim 3, characterized in that, The protection device is a hollow cuboid structure. The sensing part of the I-shaped fiber optic magnetic field sensor is installed inside the cavity of the protection device, and the two ends of the cavity are sealed with ultraviolet resin glue.

5. The method for diagnosing and locating deformation of power transformer windings according to claim 1, characterized in that, When the winding is in normal condition, the magnetic induction intensity of the winding has symmetrical characteristics in the transverse and longitudinal directions, and the leakage magnetic field exhibits an axial distribution; when the winding has a deformation fault, the axial magnetic induction intensity in the deformation area of ​​the winding decreases.

6. The method for diagnosing and locating deformation of power transformer windings according to claim 5, characterized in that, Fault diagnosis is performed by comparing the differences in the magnetic fields measured by the fiber optic magnetic field sensors on the three-phase windings of the transformer; when the magnetic field magnitude of one phase winding of the transformer deviates from that of the other two phase windings by more than 10%, the winding has a deformation fault.

7. A power transformer winding deformation diagnosis and positioning system, characterized in that, include: The signal acquisition module uses an I-type fiber optic magnetic field sensor to acquire leakage magnetic field signals from the transformer windings. The I-type fiber optic magnetic field sensor is installed on the insulating pad of the transformer windings. The fault diagnosis module diagnoses the winding deformation fault based on the leakage magnetic field continuously monitored by the I-type fiber optic magnetic field sensor. The fault location module, based on the diagnostic results of the winding deformation fault, locates the position of the winding deformation fault by establishing a fitting curve expression; After determining that there is a deformation fault in the winding, the sensing results of the I-shaped fiber optic magnetic field sensor with the windings on the same vertical line are fitted to obtain the fitted curve expression: ； In the fitted curve expression, H is the magnetic field strength, i is the expression for the applied power frequency current, D is the horizontal spacing between the high and low voltage windings, d is the winding turn diameter, and n is the number of turns of the high voltage winding. By comparing the measurement results of each measuring point of the winding with the deviation of the fitted curve, the point with the largest deviation is selected as the location of the winding deformation fault, thus realizing the location of the winding fault.

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