Device and method for diagnosing and locating deformation of power transformer winding based on pressure monitoring

Abstract

A device for diagnosing and locating deformation of a power transformer winding based on pressure monitoring, comprising a winding (1) formed by winding a coil around an iron core (5), wherein a plurality of sensor modules (6) are mounted at intervals in the winding length direction of the coil, and each sensor module (6) is wrapped around the coil in the circumferential direction of the cross-section of the coil; and each sensor module (6) wrapped around the coil comprises inter-turn pressure sensors (3) disposed oppositely and interlayer pressure sensors (2) disposed oppositely, the inter-turn pressure sensors (3) are attached to the corresponding coil surface in a horizontal state in the axial direction of the iron core (5), and the interlayer pressure sensors (2) are attached to the corresponding coil surface in a vertical state in the radial direction of the iron core (5). Thus, a three-dimensional radar chart of pressure value distribution on the winding (1) can be formed from feedback values of the sensor modules (6).

Description

A device and method for diagnosing and locating power transformer winding deformation based on pressure monitoring Technical Field

[0001] This invention relates to the field of power transformer technology, and in particular to a device and method for diagnosing and locating power transformer winding deformation based on pressure monitoring. Background Technology

[0002] Power transformers play a vital role in power transmission and conversion, and their safe and stable operation directly affects the safety and stability of the entire power system. Faults or damage to power transformers can result in significant direct economic losses. However, transformer fault repair is difficult to carry out due to various factors, and it is costly and time-consuming. Therefore, online condition monitoring and early fault diagnosis of transformers are of paramount importance.

[0003] The winding is the most important, complex, and fault-prone component of a transformer. Statistics show that winding failure accounts for approximately 60%-70% of all types of transformer failures. Therefore, online monitoring of winding deformation is one of the effective means to ensure the reliable operation of transformers.

[0004] The causes of winding deformation are multifaceted. On the one hand, mechanical collisions or squeezing during the transportation and installation of the transformer can cause bulging, twisting, tilting and collapse of the winding surface. On the other hand, during the operation of the transformer, sudden external short-circuit faults can generate large short-circuit impact currents multiple times. The extremely strong electromagnetic force generated by the short-circuit current can cause changes in the radial and axial structure and dimensions of the winding, resulting in winding deformation.

[0005] Traditional winding deformation fault diagnosis typically employs offline methods such as frequency response analysis, short-circuit impedance analysis, vibration signal analysis, low-voltage pulse analysis, and capacitance change analysis to perform non-destructive monitoring of transformer winding deformation. These methods not only require power outages, are time-consuming and expensive, but also cannot achieve real-time online monitoring of the transformer winding status.

[0006] The most direct reflection of transformer winding deformation is the change in inter-turn or inter-layer pressure. Online monitoring of the pressure on the winding is an effective and accurate technical means to diagnose winding deformation.

[0007] Patent document CN202311153684.4 discloses an online monitoring method for transformer winding deformation based on fiber optic grating sensing. It combines the monitoring results of various sensors installed inside the transformer to comprehensively analyze the deformation state of the winding. This monitoring system involves the installation and signal acquisition of multiple types of sensors, including electrical, magnetic, and optical sensors. Although it achieves online monitoring of the transformer winding state, the implementation method is complex, and it has stringent requirements on the performance of various signal acquisition devices. Furthermore, the accuracy of the results is greatly affected by objective environment and conditions. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a reasonably structured power transformer winding deformation diagnosis and location device and method based on pressure monitoring. This allows for online monitoring of pressure values ​​to diagnose and locate deformation faults. The device is simple to set up and operate, easy to implement, and yields highly accurate and practical results.

[0009] The technical solution adopted in this invention is as follows:

[0010] A power transformer winding deformation diagnosis and positioning device based on pressure monitoring includes a winding consisting of coils wound on an iron core. Multiple sensor modules are installed at intervals along the winding length of the coil. Each sensor module is wrapped around the circumference of the coil cross-section. Each sensor module wrapped around the coil includes inter-turn pressure sensors and inter-layer pressure sensors arranged opposite to each other. The inter-turn pressure sensors are attached to the surface of the corresponding coil in a horizontal state along the axial direction of the iron core, and the inter-layer pressure sensors are attached to the surface of the corresponding coil in a vertical state along the radial direction of the iron core.

[0011] As a further improvement to the above technical solution:

[0012] The interlayer pressure sensor and the inter-turn pressure sensor are both flexible thin-film pressure sensors. Four flexible thin-film pressure sensors are arranged horizontally at intervals and sealed to form a single sensor module.

[0013] The flexible thin-film pressure sensor is fabricated using nanomaterials, and its fabrication method is as follows:

[0014] Carbon nanotube films were transferred to the surface of copper foil, and graphene was grown in situ by chemical vapor deposition to obtain oriented carbon nanotube / graphene films.

[0015] A flexible substrate with multi-level microstructure was obtained by using the imprinting plant leaf method;

[0016] The obtained oriented carbon nanotube / graphene film is transferred to the surface of a flexible substrate to form a highly sensitive, low-detection-limit flexible thin-film pressure sensor.

[0017] The interlayer pressure sensor is located at the center of the interlayer gap of the corresponding coil, and the interturn pressure sensor is located at the centerline of the interturn gap of the corresponding coil.

[0018] Insulating paper is used to wrap and fix each group of sensor modules to the preset position of the coil; the sensor modules are arranged at equal intervals along the length of the coil, and the distance between adjacent sensor modules along the circumference of the coil is not less than 100mm and not more than 300mm.

[0019] The sensor modules are evenly distributed between layers and turns of the winding, and the total number of sensor modules is not less than 200.

[0020] There is a vertical main oil gap between adjacent coils wound on the iron core. The coils are grouped into groups of 3-5 layers. The communication lines of all sensor modules on each group of coils are led out from the side of the main oil gap according to the principle of proximity. The side of the transformer tank is opened and equipped with a connector. The communication lines led out from the main oil gap are connected to the data set port of the connector, and then connected to the external signal processing system through the port.

[0021] A method for diagnosing and locating deformation of power transformer windings using pressure monitoring, as described in any one of the above-mentioned methods, includes the following steps:

[0022] A scaled three-dimensional model is drawn based on the actual spatial dimensions of the transformer's internal windings. The signal processing system receives data from each set of sensor modules on the windings, plots the data at the corresponding positions on the scaled three-dimensional model, and marks the corresponding pressure values ​​to obtain a three-dimensional radar map of the pressure value distribution on the windings.

[0023] In the 3D radar chart, colors including but not limited to green, yellow, and red are used to mark the pressure values ​​located in each interval;

[0024] The winding deformation fault area can be determined by observing the color distribution in the 3D radar image.

[0025] Since the pressure value is more prominent closer to the center of the fault location, the location of the fault center is determined by the progressive relationship of the specific pressure values ​​of each sensor module in the fault area, thus completing the location of the winding deformation.

[0026] As a further improvement to the above technical solution:

[0027] Pressure values ​​below 10 MPa are marked in green, indicating that the pressure is within the safe range. Pressure values ​​between 10 MPa and 50 MPa are marked in yellow, indicating that there is a significant pressure anomaly. Pressure values ​​above 50 MPa are marked in red, indicating that there is a significant malfunction.

[0028] After locating the winding deformation, the vertical or horizontal deformation is determined based on the corresponding sensor module. When the values ​​of the two inter-turn pressure sensors in a single sensor module are prominent, it is determined that the winding is mainly deformed in the vertical direction. When the values ​​of the two inter-layer pressure sensors in a single sensor module are prominent, it is determined that the winding is mainly deformed in the horizontal direction.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention can construct a three-dimensional radar map of the pressure distribution on the winding using feedback values ​​from various sensor modules. It can diagnose and locate deformation faults by continuously monitoring the pressure values ​​online. The overall setup and operation are simple, easy to implement, and the results are highly accurate and practical.

[0031] The present invention also includes the following advantages:

[0032] This invention uses a thin-film pressure sensor to form a sensor module. By utilizing the significant difference in inter-turn or inter-layer pressure distribution characteristics between deformed and normal windings during transformer operation, the location and severity of transformer winding deformation faults can be determined, greatly ensuring the accuracy and reliability of diagnosis and location. Attached Figure Description

[0033] Figure 1 is a cross-sectional schematic diagram of the inner winding of the transformer of the present invention.

[0034] Figure 2 is a schematic diagram of a single-turn coil of the transformer inner winding of the present invention.

[0035] Figure 3 is a schematic diagram of the structure of a single sensor module of the present invention.

[0036] Figure 4 is a schematic diagram showing the connection between each group of sensor modules and the signal processing system of the present invention.

[0037] Among them: 1. Winding; 2. Interlayer pressure sensor; 3. Interturn pressure sensor; 4. Insulating paperboard; 5. Iron core; 6. Sensor module; 7. Oil tank; 8. Through-hole; 9. Signal processing system; 61. First group of sensor modules; 62. Second group of sensor modules; 6n. nth group of sensor modules. Detailed Implementation

[0038] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0039] As shown in Figures 1, 2, and 3, the power transformer winding deformation diagnosis and positioning device based on pressure monitoring in this embodiment includes a winding 1 formed by coils wound on an iron core 5. Multiple sensor modules 6 are installed at intervals along the winding length of the coil. Each sensor module 6 is wrapped along the circumferential direction of the coil cross-section. The single sensor module 6 wrapped on the coil includes inter-turn pressure sensors 3 and inter-layer pressure sensors 2 arranged opposite to each other. The inter-turn pressure sensors 3 are attached to the corresponding coil surface in a horizontal state along the axial direction of the iron core 5, and the inter-layer pressure sensors 2 are attached to the corresponding coil surface in a vertical state along the radial direction of the iron core 5.

[0040] In this embodiment, the feedback values ​​of each group of sensor modules 6 can form a three-dimensional radar map of the pressure value distribution on the winding 1, and the deformation fault can be diagnosed and located by continuously monitoring the pressure value online.

[0041] Interlayer pressure sensor 2 and inter-turn pressure sensor 3 are both flexible thin-film pressure sensors. The four flexible thin-film pressure sensors are arranged horizontally at intervals and sealed to form a single sensor module 6.

[0042] In this embodiment, a pressure sensor based on a thin film is used to form a sensor module 6. By utilizing the significant difference in the inter-turn or inter-layer pressure distribution characteristics between the deformed winding and the normal winding during transformer operation, the location and severity of the transformer winding deformation fault can be determined, which greatly ensures the accuracy and reliability of diagnosis and location.

[0043] In one embodiment, the flexible thin-film pressure sensor is fabricated using nanomaterials, and the fabrication method is as follows:

[0044] Carbon nanotube films were transferred to the surface of copper foil, and graphene was grown in situ by chemical vapor deposition to obtain oriented carbon nanotube / graphene films.

[0045] A flexible substrate with multi-level microstructure was obtained by using the imprinting plant leaf method;

[0046] The obtained oriented carbon nanotube / graphene film is transferred to the surface of a flexible substrate to form a highly sensitive, low-detection-limit flexible thin-film pressure sensor.

[0047] The flexible thin-film pressure sensor in this embodiment can be customized in size according to actual application requirements and application environment, such as the cross-sectional size of the coil and the force applied.

[0048] In this embodiment, other flexible thin-film pressure sensors can also be used, which can be integrated and sealed to form sensor module 6, and can be wrapped around the circumferential cross-section of the coil for pressure monitoring.

[0049] Interlayer pressure sensor 2 is located at the center of the interlayer gap of the corresponding coil, and turn-to-turn pressure sensor 3 is located at the center line of the turn-to-turn gap of the corresponding coil, so as to effectively ensure the accuracy of the position monitoring.

[0050] Insulating paper is used to wrap and fix each group of sensor modules 6 to the preset position of the coil; the sensor modules 6 are arranged at equal intervals along the length of the coil, and the distance between adjacent sensor modules 6 along the circumference of the coil is not less than 100mm and not more than 300mm.

[0051] In this embodiment, the spacing and number of sensor modules 6 can be selected and determined according to actual needs such as the size of the coil and winding 1, or they can be adjusted according to actual needs.

[0052] If the spacing between adjacent sensor modules 6 is set to less than 100mm, not only will the number of sensor modules 6 be large, especially for large transformers, but it will also have a significant negative impact on the stability of transformer operation. If the spacing is set too large, exceeding 300mm, it may not only miss the pressure value measurement at the special location of the winding pad, but also the spatial distribution of the overall pressure value results will be too sparse, making it impossible to accurately determine the center location of the winding deformation fault.

[0053] For example, for transformer windings with a center diameter of 300-500mm, it is appropriate to wrap 12-20 pressure sensor modules on each turn of the coil.

[0054] Sensor modules 6 are evenly distributed between layers and turns of winding 1, and the total number of sensor modules 6 is not less than 200, in order to ensure the reliability and accuracy of monitoring results.

[0055] There is a vertical main oil gap between adjacent coils wound on the iron core 5. The coils are grouped into groups of 3-5 layers. The communication lines of all sensor modules 6 on each group of coils are led out from the side of the main oil gap according to the principle of proximity. The transformer tank 7 has an opening on the side and is equipped with a connector 8. The communication lines led out from the main oil gap are connected to the data set port of the connector 8. The connection is then made to the external signal processing system 9 through the port to establish communication and achieve the purpose of real-time monitoring of the pressure on each turn of the winding 1.

[0056] In this embodiment, the main oil gap between the windings 1 of the transformer is cleverly utilized to lead out the communication line, which effectively reduces the impact of the communication line arrangement on the stability of transformer operation while ensuring the reliability of the communication line arrangement.

[0057] In this embodiment, the communication line is made of oil-resistant and heat-resistant materials, and commercial wires with ceramic, glass fiber or polyimide as the main components of the outer sheath material can be selected.

[0058] In the embodiment shown in Figure 4, n sets of sensor modules 6 are arranged on the winding 1 inside the oil tank 7, namely the first set of sensor modules 61, the second set of sensor modules 62, ... the nth set of sensor modules 6n. The communication lines of each set of sensor modules 6 are connected to the connector 8 of the oil tank 7, and are uniformly connected to the external signal processing system 9 through the data set port of the connector 8.

[0059] This embodiment also proposes a method for diagnosing and locating deformation of power transformer windings using a pressure monitoring device, comprising the following steps:

[0060] Step 1: Draw a scaled three-dimensional model based on the actual spatial dimensions of the transformer's internal winding 1. The signal processing system 9 receives the data information fed back by each set of sensor modules 6 on the winding 1, plots the data information at the corresponding positions on the scaled three-dimensional model, and marks the corresponding pressure values ​​to obtain a three-dimensional radar map of the pressure value distribution on the winding 1.

[0061] Step 2: In the 3D radar chart, use colors including but not limited to green, yellow, and red to mark the pressure values ​​located in each interval;

[0062] Step 3: Determine the deformation fault area of ​​winding 1 by observing the color distribution in the 3D radar image;

[0063] Since transformer winding 1 has a symmetrical structure, under normal circumstances, the pressure values ​​borne by winding 1 should also exhibit a symmetrical distribution. When an abnormal local pressure value distribution appears in the pressure radar chart, the winding deformation fault can be located quickly.

[0064] Step 4: Since the pressure value is more prominent closer to the center of the fault location, the location of the fault center is determined based on the specific pressure value progression relationship of each sensor module 6 in the fault area, thus completing the positioning of the deformation of winding 1.

[0065] In this embodiment, pressure values ​​below 10 MPa are marked in green, indicating that the pressure is within the safe range; pressure values ​​between 10 MPa and 50 MPa are marked in yellow, indicating that there is a significant pressure anomaly; and pressure values ​​above 50 MPa are marked in red, indicating that there is a significant malfunction.

[0066] In this embodiment, considering that for a conventional transformer in normal operation, the clamping force during the winding and assembly of its winding 1 is generally less than 10 MPa, while the alternating impact stress generated during a sudden short circuit is generally 50-100 MPa, three ranges are preset: less than 10 MPa, 10 MPa-50 MPa, and more than 50 MPa, and different colors are used to mark them accordingly, so as to facilitate monitoring in actual production.

[0067] In actual production, other interval values ​​can be preset according to the actual situation, or more than four intervals can be preset to match actual needs and facilitate monitoring in actual production.

[0068] In this embodiment, after the deformation of the winding 1 is located, the deformation in the vertical or horizontal direction is determined according to the corresponding sensor module 6. When the values ​​of the two inter-turn pressure sensors 3 in the single sensor module 6 are prominent, it is determined that the winding 1 mainly undergoes vertical deformation. When the values ​​of the two inter-layer pressure sensors 2 in the single sensor module 6 are prominent, it is determined that the winding 1 mainly undergoes horizontal deformation.

[0069] This invention diagnoses and locates deformation faults by continuously monitoring pressure values ​​online; it is simple to set up and operate, easy to implement, and yields highly accurate and practical results.

[0070] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0071] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A power transformer winding deformation diagnosis and positioning device based on pressure monitoring, comprising a winding (1) consisting of coils wound on an iron core (5), characterized in that: Multiple sensor modules (6) are installed at intervals along the winding length of the coil. Each sensor module (6) is wrapped along the circumferential direction of the coil cross section. The single sensor module (6) wrapped on the coil includes a turn pressure sensor (3) and a layer pressure sensor (2) arranged opposite to each other. The turn pressure sensor (3) is attached to the surface of the corresponding coil in a horizontal state along the axial direction of the iron core (5), and the layer pressure sensor (2) is attached to the surface of the corresponding coil in a vertical state along the radial direction of the iron core (5).

2. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring as described in claim 1, characterized in that: The interlayer pressure sensor (2) and the inter-turn pressure sensor (3) are both flexible thin-film pressure sensors. The four flexible thin-film pressure sensors are arranged horizontally at intervals and sealed to form a single sensor module (6).

3. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring as described in claim 2, characterized in that: The flexible thin-film pressure sensor is fabricated using nanomaterials, and its fabrication method is as follows: Carbon nanotube films were transferred to the surface of copper foil, and graphene was grown in situ by chemical vapor deposition to obtain oriented carbon nanotube / graphene films. A flexible substrate with multi-level microstructure was obtained by using the imprinting plant leaf method; The obtained oriented carbon nanotube / graphene film is transferred to the surface of a flexible substrate to form a highly sensitive, low-detection-limit flexible thin-film pressure sensor.

4. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring as described in claim 1, characterized in that: The interlayer pressure sensor (2) is located at the center of the interlayer gap of the corresponding coil, and the turn-to-turn pressure sensor (3) is located at the center line of the turn-to-turn gap of the corresponding coil.

5. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring as described in claim 1, characterized in that: Insulating paper is used to wrap and fix each group of sensor modules (6) to the preset position of the coil; the sensor modules (6) are arranged at equal intervals along the length of the coil, and the distance between adjacent sensor modules (6) along the circumference of the coil is not less than 100mm and not more than 300mm.

6. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring as described in claim 1, characterized in that: The sensor modules (6) are evenly distributed between layers and turns of the winding (1), and the total number of sensor modules (6) is not less than 200.

7. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring as described in claim 1, characterized in that: There is a vertical main oil gap between adjacent coils wound on the iron core (5). The coils are grouped into groups of 3-5 layers. The communication lines of all sensor modules (6) on each group of coils are led out from the side of the main oil gap according to the principle of proximity. The transformer tank (7) has an opening on the side and is equipped with a connector (8). The communication lines led out from the main oil gap are connected to the data set port of the connector (8) and are uniformly connected to the external signal processing system (9) through the port.

8. A method for diagnosing and locating deformation of power transformer windings using pressure monitoring as described in any one of claims 1 to 7, characterized in that: Includes the following steps: A proportional three-dimensional model is drawn based on the actual spatial dimensions of the transformer internal winding (1). The signal processing system (9) receives the data information fed back by each group of sensor modules (6) on the winding (1), and draws and marks the corresponding pressure values ​​at the corresponding positions of the proportional three-dimensional model to obtain a three-dimensional radar map of the pressure value distribution on the winding (1). In the 3D radar chart, colors including but not limited to green, yellow, and red are used to mark the pressure values ​​located in each interval; The deformation fault area of ​​winding (1) is determined by observing the color distribution in the three-dimensional radar image; Since the pressure value is more prominent closer to the center of the fault location, the location of the fault center is determined based on the specific pressure value progression relationship of each sensor module (6) in the fault area, and the deformation of the winding (1) is located.

9. The method for diagnosing and locating deformation of power transformer windings as described in claim 8, characterized in that: Pressure values ​​below 10 MPa are marked in green, indicating that the pressure is within the safe range. Pressure values ​​between 10 MPa and 50 MPa are marked in yellow, indicating that there is a significant pressure anomaly. Pressure values ​​above 50 MPa are marked in red, indicating that there is a significant malfunction.

10. The method for diagnosing and locating deformation of power transformer windings by pressure monitoring as described in claim 8, characterized in that: After the deformation positioning of the winding (1), the deformation in the vertical or horizontal direction is determined according to the corresponding sensor module (6). When the values ​​of the two inter-turn pressure sensors (3) in the single sensor module (6) are prominent, it is determined that the winding (1) mainly undergoes deformation in the vertical direction. When the values ​​of the two inter-layer pressure sensors (2) in the single sensor module (6) are prominent, it is determined that the winding (1) mainly undergoes deformation in the horizontal direction.

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