Power transformer winding deformation diagnosis positioning device and method based on pressure monitoring

Abstract

The invention relates to a power transformer winding deformation diagnosis positioning device and method based on pressure monitoring, and the device comprises a winding which is formed by winding a coil on an iron core, a plurality of groups of sensor modules are installed at intervals in the winding length direction of the coil, and a single group of sensor modules is wrapped in the circumferential direction of the cross section of the coil; the single-group sensor module wrapping the coil comprises turn-to-turn pressure sensors arranged oppositely and interlayer pressure sensors arranged oppositely, and the turn-to-turn pressure sensors are attached to the surface of the corresponding coil in a horizontal state in the axial direction of the iron core. The interlayer pressure sensors are attached to the surfaces of the corresponding coils in a vertical state in the radial direction of the iron core, so that a three-dimensional radar map of pressure value distribution on the winding can be formed by feedback values of the sensor modules, and deformation faults are diagnosed and positioned by continuously monitoring the pressure values on line. The overall layout and operation are simple, implementation and implementation are convenient, and the result accuracy is high.

Description

Technical Field

[0001] The invention relates to the technical field of power transformers, and in particular to a device and method for diagnosing and locating deformation of power transformer windings based on pressure monitoring. Background Art

[0002] Power transformers play a huge role in the transmission and conversion of electric energy. Their safe and stable operation is directly related to the safety and stability of the entire power system. Once a power transformer fails or is damaged, it will cause huge direct economic losses. The fault maintenance of power transformers is difficult to carry out due to many factors, and the maintenance cost is high and time-consuming. Therefore, online status monitoring and early fault diagnosis of transformers are particularly important.

[0003] Winding is the most important, complex and fault-prone component in a transformer. Statistics show that winding damage accounts for about 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 the transformer.

[0004] There are many reasons for winding deformation. On the one hand, mechanical collision or extrusion during transportation and installation of the transformer causes bulging, twisting, tilting and collapse of the winding surface; on the other hand, during the operation of the transformer, sudden out-of-zone short-circuit faults will repeatedly generate large short-circuit impact currents. The extremely strong electromagnetic force caused by the short-circuit current will cause the structure and size of the winding in the radial and axial directions to change, resulting in deformation of the winding.

[0005] Traditional winding deformation fault diagnosis usually uses offline methods such as frequency response analysis, short-circuit impedance method, vibration signal method, low-voltage pulse method and capacitance change method to perform non-destructive monitoring of transformer winding deformation. These methods not only require power outage, 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 pressure between turns or layers. Online monitoring of winding pressure 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 grating sensing. It combines the monitoring results of various sensors installed inside the transformer to comprehensively analyze the deformation state of the winding. The monitoring system involves the installation and signal collection of multiple types of sensors such as electrical, magnetic, and optical sensors. Although it realizes online monitoring of the transformer winding state, the implementation method is complex and has strict performance requirements on various signal acquisition equipment. In addition, the accuracy of the results is greatly affected by the objective environment and conditions. Summary of the invention

[0008] To solve the above problems, the present invention provides a reasonably structured device and method for diagnosing and locating deformation of power transformer windings based on pressure monitoring, so as to diagnose and locate deformation faults by online monitoring of pressure values. The overall layout and operation are simple, easy to realize and implement, and the results are highly accurate and practical.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A device for diagnosing and locating deformation of a power transformer winding based on pressure monitoring, comprising a winding composed of a coil wound on an iron core, wherein a plurality of groups of sensor modules are installed at intervals along the winding length direction of the coil, and a single group of sensor modules is respectively coated along the circumferential direction of the coil cross section; the single group of sensor modules coated on the coil comprises relatively arranged inter-turn pressure sensors and relatively arranged inter-layer pressure sensors, the inter-turn pressure sensors are horizontally attached to the corresponding coil surface along the axial direction of the iron core, and the inter-layer pressure sensors are vertically attached to the corresponding coil surface along the radial direction of the iron core.

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

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

[0013] The flexible thin film pressure sensor is made of nano functional materials, and the preparation method is as follows:

[0014] The carbon nanotube film is transferred to the surface of the copper foil, and graphene is grown in situ by chemical vapor deposition to obtain an oriented carbon nanotube / graphene film;

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

[0016] The obtained aligned carbon nanotube / graphene film is transferred to the surface of a flexible substrate to form a flexible thin film pressure sensor with high sensitivity and low detection limit.

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

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

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

[0020] There is a main oil gap in the vertical direction between adjacent coils wound on the iron core. The coils are grouped into 3-5 layers, and 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. A hole is opened on the side of the transformer oil tank and a through-hole is installed. The communication line led out from the main oil gap is connected to the data set port of the through-hole, and is uniformly connected to the external signal processing system through the port.

[0021] A method for diagnosing and locating a pressure-monitored power transformer winding deformation device as described in any one of the above, comprising the following steps:

[0022] A proportional three-dimensional model is drawn according to the actual spatial dimensions of the transformer internal windings. The signal processing system receives the data information fed back by each group of sensor modules on the windings, draws the data information at the corresponding positions of the proportional three-dimensional model and marks the corresponding pressure values, and obtains a three-dimensional radar map of the pressure value distribution on the windings.

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

[0024] Determine the winding deformation fault area by observing the color distribution in the 3D radar map;

[0025] Since the closer to the center of the fault position, the more prominent the pressure value, the fault center position can be determined based on the progressive relationship of the specific pressure values ​​of each sensor module in the fault area to locate the winding deformation.

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

[0027] Pressure values ​​below 10Mpa are marked in green, indicating that the pressure is within a safe range; pressure values ​​between 10Mpa-50Mpa are marked in yellow, indicating that there is a large pressure abnormality; pressure values ​​above 50Mpa are marked in red, indicating that there is a major fault.

[0028] After locating the deformation of the winding, 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 set of sensor modules 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 set of sensor modules 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] The present invention can form a three-dimensional radar map of the pressure value distribution on the winding by the feedback values ​​of each group of sensor modules, and diagnose and locate the deformation fault by continuously monitoring the pressure value online; the overall layout and operation are simple, easy to realize and implement, and the result is highly accurate and practical;

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

[0032] The present invention forms a sensor module based on a thin film pressure sensor, and utilizes the significant difference in the inter-turn or inter-layer pressure distribution characteristics of the deformed winding and the normal winding during the operation of the transformer to determine the location and severity of the transformer winding deformation fault, thereby greatly ensuring the accuracy and reliability of diagnosis and positioning. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0036] Figure 4 It is a schematic diagram of 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. Insulation cardboard; 5. Iron core; 6. Sensor module; 7. Oil tank; 8. Through-hole; 9. Signal processing system; 61. The first group of sensor modules; 62. The second group of sensor modules; 6n. The nth group of sensor modules. DETAILED DESCRIPTION

[0038] The specific implementation of the present invention is described below in conjunction with the accompanying drawings.

[0039] like Figure 1 , Figure 2 and Figure 3 As shown, the power transformer winding deformation diagnosis and positioning device based on pressure monitoring of this embodiment includes a winding 1 composed of a coil wound on an iron core 5, and a plurality of groups of sensor modules 6 are installed at intervals along the winding length direction of the coil, and a single group of sensor modules 6 is respectively wrapped along the circumferential direction of the coil cross section; the single group of sensor modules 6 wrapped on the coil includes relatively arranged inter-turn pressure sensors 3 and relatively arranged inter-layer pressure sensors 2, the inter-turn pressure sensors 3 are horizontally attached to the corresponding coil surface along the axial direction of the iron core 5, and the inter-layer pressure sensors 2 are vertically attached to the corresponding coil surface 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] The interlayer pressure sensor 2 and the interturn pressure sensor 3 are both flexible film-type pressure sensors. Four flexible film-type pressure sensors are arranged horizontally at intervals and sealed to form a single sensor module 6 .

[0042] In this embodiment, the sensor module 6 is composed of a thin film-based pressure sensor, which utilizes the significant difference in the inter-turn or inter-layer pressure distribution characteristics between the deformed winding and the normal winding during the operation of the transformer to determine the location and severity of the transformer winding deformation fault, thereby greatly ensuring the accuracy and reliability of diagnosis and positioning.

[0043] In one embodiment, the flexible film pressure sensor is made of nano-functional materials, and the preparation method is as follows:

[0044] The carbon nanotube film is transferred to the surface of the copper foil, and graphene is grown in situ by chemical vapor deposition to obtain an oriented carbon nanotube / graphene film;

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

[0046] The obtained aligned carbon nanotube / graphene film is transferred to the surface of a flexible substrate to form a flexible thin film pressure sensor with high sensitivity and low detection limit.

[0047] The flexible 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 and force of the coil.

[0048] In this embodiment, flexible film pressure sensors of other structural forms may also be used, which can be integrated and sealed to form a sensor module 6 and can be wrapped around the circumference of the coil cross section to perform pressure monitoring.

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

[0050] Each group of sensor modules 6 is wound and fixed at a preset position of the coil using insulating paper; the sensor modules 6 are arranged at equal intervals along the length direction of the coil, and the distance between adjacent sensor modules 6 along the circumferential path of the coil is not less than 100 mm and not more than 300 mm.

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

[0052] If the interval between adjacent sensor modules 6 is set to be 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 operating stability of the transformer; and if the distance is set too large, exceeding 300mm, not only may the pressure value measurement at the special position of the winding pad be missed, but the spatial distribution of the overall pressure value result is too sparse, making it impossible to accurately determine the center position of the winding deformation fault.

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

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

[0055] There is a main oil gap in the vertical direction between adjacent coils wound on the iron core 5. The coils are grouped into 3-5 layers, and 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. A hole is opened on the side of the transformer oil tank 7 and a through-hole 8 is installed. The communication line led out from the main oil gap is connected to the data set port of the through-hole 8, and is uniformly connected to the external signal processing system 9 through the port, so as 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, combined with the structural characteristics of the transformer winding 1, the main oil gap between the windings 1 is cleverly used to lead out the communication line, while ensuring the reliability of the communication line arrangement, effectively reducing the impact of the communication line arrangement on the transformer operation stability.

[0057] In this embodiment, the communication line is made of oil-resistant and heat-resistant materials, and commercial conductors with ceramic, glass fiber, polyimide, etc. as the main component of the surface material can be selected.

[0058] like Figure 4 In the illustrated embodiment, n groups of sensor modules 6 are arranged on the winding 1 in the oil tank 7, namely the first group of sensor modules 61, the second group of sensor modules 62, ... the nth group of sensor modules 6n, and the communication lines of each group of sensor modules 6 are respectively connected to the through-hole 8 of the oil tank 7, and are uniformly connected to the external signal processing system 9 via the data set port of the through-hole 8.

[0059] This embodiment also proposes a method for diagnosing and locating a pressure-monitored power transformer winding deformation, comprising the following steps:

[0060] Step 1: Draw a proportional three-dimensional model according to the actual spatial size of the winding 1 inside the transformer, receive the data information fed back by each group of sensor modules 6 on the winding 1 by the signal processing system 9, draw the data information at the corresponding position of the proportional three-dimensional model and mark the corresponding pressure value, and obtain a three-dimensional radar map of the pressure value distribution on the winding 1;

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

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

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

[0064] Step 4: Since the closer to the center of the fault position, the more prominent the pressure value, the fault center position is determined according to the progressive relationship of the specific pressure values ​​of each sensor module 6 in the fault area, and the deformation of the winding 1 is located.

[0065] In this embodiment, pressure values ​​below 10 MPa are marked as green, indicating that the pressure is within a safe range; pressure values ​​between 10 MPa-50 MPa are marked as yellow, indicating that there is a large pressure abnormality; and pressure values ​​above 50 MPa are marked as red, indicating that there is a major fault.

[0066] In this embodiment, considering that for a conventional transformer in normal operation, the compression force of its winding 1 during winding and assembly is generally lower than 10Mpa, and the alternating impact stress generated during a sudden short circuit is generally 50-100Mpa. Therefore, three intervals of lower than 10Mpa, 10Mpa-50Mpa, and higher than 50Mpa are preset, and different colors are used for corresponding marking to facilitate monitoring in actual production.

[0067] In actual production, other interval values ​​may be preset according to actual conditions, or more than four intervals may 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 direction or the 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 group of sensor modules 6 are prominent, it is determined that the winding 1 is mainly deformed in the vertical direction; when the values ​​of the two inter-layer pressure sensors 2 in the single group of sensor modules 6 are prominent, it is determined that the winding 1 is mainly deformed in the horizontal direction.

[0069] The present invention diagnoses and locates deformation faults by continuously monitoring pressure values ​​online; the overall layout and operation are simple, easy to realize and implement, and the result is highly accurate and practical.

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

[0071] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A device for diagnosing and locating deformation of a power transformer winding based on pressure monitoring, comprising a winding (1) composed of a coil wound on an iron core (5), characterized in that: A plurality of sensor modules (6) are installed at intervals along the length direction of the coil winding, and a single sensor module (6) is respectively coated along the circumferential direction of the coil cross section; the single sensor module (6) coated on the coil comprises relatively arranged inter-turn pressure sensors (3) and relatively arranged inter-layer pressure sensors (2), the inter-turn pressure sensors (3) are horizontally attached to the corresponding coil surface along the axial direction of the iron core (5), and the inter-layer pressure sensors (2) are vertically attached to the corresponding coil surface along the radial direction of the iron core (5).

2. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring according to claim 1, characterized in that: The interlayer pressure sensor (2) and the interturn pressure sensor (3) are both flexible film-type pressure sensors, and four flexible film-type 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 according to claim 2 is characterized in that: The flexible thin film pressure sensor is made of nano functional materials, and the preparation method is as follows: The carbon nanotube film is transferred to the surface of the copper foil, and graphene is grown in situ by chemical vapor deposition to obtain an oriented carbon nanotube / graphene film; A flexible substrate with multi-level microstructure was obtained by the impression plant leaf method; The obtained aligned carbon nanotube / graphene film is transferred to the surface of a flexible substrate to form a flexible thin film pressure sensor with high sensitivity and low detection limit.

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

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

6. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring according to 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 the sensor modules (6) is not less than 200.

7. The power transformer winding deformation diagnosis and positioning device based on pressure monitoring according to claim 1, characterized in that: There is a main oil gap in a vertical direction between adjacent coils wound on an iron core (5), and 3 to 5 layers of coils are grouped together. 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. A hole is opened on the side of the transformer oil tank (7) and a through-hole (8) is installed. The communication lines led out from the main oil gap are connected to the data set port of the through-hole (8) and are uniformly connected to an external signal processing system (9) through the port.

8. A method for diagnosing and locating a pressure-monitored power transformer winding deformation device according to any one of claims 1 to 7, characterized in that: The steps include: A proportional three-dimensional model is drawn according to the actual spatial dimensions of the transformer internal winding (1), and the signal processing system (9) receives data information fed back by each group of sensor modules (6) on the winding (1), and the data information is drawn at the corresponding position of the proportional three-dimensional model and the corresponding pressure value is marked, thereby obtaining a three-dimensional radar map of the pressure value distribution on the winding (1); In the three-dimensional radar chart, colors including but not limited to green, yellow, and red are used to mark the pressure values ​​in each interval; Determine the winding (1) deformation fault area by observing the color distribution in the three-dimensional radar map; Since the closer to the center of the fault position, the more prominent the pressure value, the fault center position is determined based on the progressive relationship of the specific pressure values ​​of each sensor module (6) in the fault area, thereby completing the positioning of the deformation of the winding (1).

9. The method for diagnosing and locating a pressure-monitored power transformer winding deformation according to claim 8, characterized in that: Pressure values ​​below 10Mpa are marked in green, indicating that the pressure is within a safe range; pressure values ​​between 10Mpa-50Mpa are marked in yellow, indicating that there is a large pressure abnormality; pressure values ​​above 50Mpa are marked in red, indicating that there is a major fault.

10. The method for diagnosing and locating a pressure-monitored power transformer winding deformation according to claim 8, characterized in that: After the deformation of the winding (1) is located, the deformation in the vertical direction or the horizontal direction is determined based on 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) is mainly deformed 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) is mainly deformed in the horizontal direction.

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