Oil-immersed transformer with overvoltage protection structure

Abstract

According to the technical scheme, the oil-immersed transformer with the overvoltage protection structure is characterized in that the oil-immersed transformer comprises a transformer box body and a plurality of porcelain bottles which are located on the upper surface of the transformer box body and internally provided with high-voltage terminals, and the top ends of the porcelain bottles are each provided with a high-voltage copper cover and a first lightning rod connected to one side of the high-voltage copper cover; the length directions of the first lightning rods are parallel to the upper surface of the transformer box body, connecting frames corresponding to the porcelain bottles one to one and second lightning rods with one ends located on the connecting frames and located on one sides of the corresponding porcelain bottles are further arranged on the upper surface of the transformer box body, and the second lightning rods are perpendicular to the upper surface of the transformer box body. The top ends of the second lightning rods are lower than the first lightning rods, and the ends, not connected with the high-voltage copper cover, of the first lightning rods are bent downwards and face the top ends of the corresponding second lightning rods, so that the problem that the prior art is prone to being damaged due to overvoltage is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of oil-immersed transformers, and more specifically to an oil-immersed transformer with an overvoltage protection structure. Background Technique

[0002] Electricity is the cornerstone of modern industry, commerce, and residential life. It not only drives the operation of machines, supports the infrastructure of information and communication technologies, but also provides lighting and heating for households. The stable supply of electricity is an important indicator to measure the maturity of a country's infrastructure and the level of industrialization. With the development of the times, the power system has become one of the largest systems in the world, permeating all aspects of human social life. As the core part of the power system, the transformer plays a central role in current conversion and voltage conversion, and the operation of the entire system depends on whether the transformer can operate normally.

[0003] Currently, overvoltage phenomena exist in all oil-immersed transformers. The reasons for overvoltage phenomena are divided into external factors and internal factors. External factors mainly come from lightning strikes. Since the high-voltage terminals are usually sleeved in porcelain insulators and fixed above the oil tank, the terminal contacts are exposed to the outside. Therefore, once struck by lightning, due to the "point discharge principle", the high-voltage terminals will mainly bear the overvoltage brought by lightning strikes; internal factors mainly come from the damage of some components in the power system and the instantaneous closing or opening of components, which will cause overvoltage phenomena at the high-voltage terminals. Whether it is external factors or internal factors, they are very likely to cause irreversible damage to the transformer. Content of the Utility Model

[0004] Aiming at the deficiencies of the existing technology, the purpose of the utility model is to provide an oil-immersed transformer with stable operation and an overvoltage protection structure.

[0005] To achieve the above purpose, the utility model provides the following technical solution: An oil-immersed transformer with an overvoltage protection structure, including a transformer box body and a plurality of porcelain insulators positioned on the upper surface of the transformer box body and internally provided with high-voltage terminals. High-voltage copper caps are arranged at the tops of the plurality of porcelain insulators, and first lightning rods connected to one side of the high-voltage copper caps are provided. The length directions of the plurality of first lightning rods are all parallel to the upper surface of the transformer box body. A connecting frame corresponding to each of the plurality of porcelain insulators and a second lightning rod with one end positioned on the connecting frame and on one side of the corresponding porcelain insulator are further arranged on the upper surface of the transformer box body. The plurality of second lightning rods are all perpendicular to the upper surface of the transformer box body. The heights of the tops of the plurality of second lightning rods are lower than the heights of the first lightning rods. One ends of the plurality of first lightning rods not connected to the high-voltage copper caps are bent downward and towards the tops of the corresponding second lightning rods, and the electricity is led to the second lightning rods through the first lightning rods, so that the excess voltage is guided to the ground through the transformer box body.

[0006] As a further improvement of the present utility model, the first lightning rod and the second lightning rod connected to the same porcelain insulator are both in the same vertical plane.

[0007] As a further improvement of the present utility model, each of the plurality of connecting frames includes a square pressing plate sleeved outside the bottom end of the corresponding porcelain insulator and fixedly connected to the transformer box body by bolts, and a triangular bracket with both ends positioned on the square pressing plate and the tip extending towards one side of the transformer box body. Each of the plurality of second lightning rods is positioned at the tip of the corresponding triangular bracket.

[0008] As a further improvement of the present utility model, each of the plurality of connecting frames further includes a pressing foot positioned below the square pressing plate and pressing on the bottom end of the porcelain insulator.

[0009] As a further improvement of the present utility model, a support plate assembly corresponding to each of the plurality of porcelain insulators and a lightning arrester positioned on the support plate assembly are fixedly connected to one side wall of the transformer box body.

[0010] As a further improvement of the present utility model, each of the plurality of support plate assemblies includes a static plate fixedly connected to the side wall of the transformer box body and a moving plate slidably connected to the static plate. Each of the plurality of lightning arresters is positioned at one end of the corresponding moving plate. By moving the moving plate along the length direction of the static plate, the distance between the lightning arrester and the corresponding porcelain insulator is changed.

[0011] As a further improvement of the present utility model, a heat sink group is fixedly connected to the side wall of the transformer box body, and the heat sink group located below the moving plate can support the moving plate.

[0012] As a further improvement of the present utility model, a bracket connected to the corresponding moving plate is fixedly connected to the bottom end of each of the plurality of lightning arresters, and a reinforcing rib capable of abutting against the heat sink group is provided on each of the plurality of brackets.

[0013] The beneficial effects of the present utility model: The electricity is led to the second lightning rod by the first lightning rod, so that the redundant voltage is guided to the ground through the transformer box body. Such a design can make up for the defect that the transformer is damaged due to overvoltage caused by external factors or internal factors at the high-voltage terminal. In the case of overvoltage, a path is formed between the first lightning rod and the second lightning rod, and the redundant voltage is timely conducted away, which is beneficial to the rapid recovery of the transformer system to normal and provides a protection function; in the case of normal voltage, an open circuit is formed between the first lightning rod and the second lightning rod, so as to ensure that the voltage at the high-voltage terminal is stable and in a normal operating state. Description of the Drawings

[0014] Figure 1 is a three-dimensional structural schematic diagram of the present utility model;

[0015] Figure 2 is Figure 1Enlarged view of part A

[0016] Reference numerals: 1, transformer housing; 11, radiator group; 2, porcelain insulator; 3, high-voltage copper cover; 4, first lightning rod; 5, connecting frame; 51, square pressure plate; 52, triangular bracket; 53, pressure foot; 6, second lightning rod; 7, support plate assembly; 71, static plate; 72, moving plate; 8, arrester; 9, bracket; 91, reinforcing rib. Detailed implementation mode

[0017] The present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. The same components are denoted by the same reference numerals.

[0018] Refer to Figure 1 and Figure 2 As shown, an oil-immersed transformer with an overvoltage protection structure according to this embodiment includes a transformer housing 1 and a plurality of porcelain insulators 2 positioned on the upper surface of the transformer housing 1 and internally provided with high-voltage terminals. The transformer housing 1 is mostly made of metal material and is grounded. The porcelain insulator 2 is an insulator and has the same functions and effects as the existing high-voltage bushing.

[0019] Based on the aforementioned prior art, the first lightning rod 4 is bent, the second lightning rod 6 is straight. A connecting frame 5 is fixedly connected to the upper surface of the transformer housing 1. Then, one end of the second lightning rod 6 is inserted into the connecting frame 5 and the second lightning rod 6 is perpendicular to the upper surface of the transformer housing 1. The second lightning rod 6 is located on one side of the porcelain insulator 2. The height of the top end of the second lightning rod 6 relative to the upper surface of the transformer housing 1 is less than the height of the top end of the porcelain insulator 2 relative to the upper surface of the transformer housing 1. One end of the first lightning rod 4 can be positioned on the side wall of the high-voltage copper cover 3 by means of threaded connection or welding. The part of the first lightning rod 4 connected to the high-voltage copper cover 3 extends along the radial direction of the high-voltage copper cover 3. Then, the high-voltage copper cover 3 is positioned at the top end of the porcelain insulator 2 and is electrically connected to the part of the high-voltage terminal exposed outside the porcelain insulator 2. The end of the first lightning rod 4 away from the high-voltage copper cover 3 is inclined downward relative to the horizontal plane and faces the top end of the second lightning rod 6. The connecting frame 5 is made of conductive material and is fixedly connected to the transformer housing 1 by bolts, and the bolts used are made of conductive material.

[0020] When overvoltage occurs due to lightning strikes or voltage fluctuations in the power system, the voltage at the end of the high-voltage terminal rises rapidly. The voltage is directed to the first lightning rod 4 through the high-voltage copper cover 3. Then, there is a large voltage difference between the first lightning rod 4 and the second lightning rod 6. Due to the "point discharge principle", the air between the first lightning rod 4 and the second lightning rod 6 is broken down to form a path. The voltage on the first lightning rod 4 is successively conducted to the ground through the second lightning rod 6, the connecting frame 5, and the transformer tank 1. After the voltage stabilizes, the broken-down air between the first lightning rod 4 and the second lightning rod 6 quickly recovers, so that the first lightning rod 4 and the second lightning rod 6 are in an open-circuit state, and the entire transformer system will return to the normal working state;

[0021] This design can make up for the defect that the transformer is damaged due to overvoltage caused by external or internal factors of the high-voltage terminal. In the case of overvoltage, a path is formed between the first lightning rod 4 and the second lightning rod 6 to quickly conduct away the excess voltage, which is beneficial for the transformer system to quickly return to normal and provide a protective effect; in the case of normal voltage, an open circuit is formed between the first lightning rod 4 and the second lightning rod 6, so as to ensure the voltage stability at the high-voltage terminal and the normal operating state.

[0022] As a specific implementation of the improvement, refer to Figure 2 As shown, the first lightning rod 4 and the second lightning rod 6 connected to the same porcelain insulator 2 are both in the same vertical plane. This design can effectively shorten the straight-line distance between the ends of the first lightning rod 4 and the second lightning rod 6 compared with the design of setting the first lightning rod 4 and the second lightning rod 6 in different vertical planes, which is beneficial for the air between the ends of the first lightning rod 4 and the second lightning rod 6 to be quickly broken down, improve the efficiency of conducting away the excess voltage, and protect the transformer in time.

[0023] As a specific implementation of the improvement, refer to Figure 2As shown in the figure, multiple connecting brackets 5 each include a square pressing plate 51 and a triangular bracket 52. The square pressing plate 51 is a ring body with a square contour and an inner cavity through which the porcelain bottle 2 can pass. The triangular bracket 52 is in a V shape, and the two ends of the triangular bracket 52 can correspond to two of the corners of the square pressing plate 51. Through holes for bolts to pass through are provided at the corners of the square pressing plate 51 and the two ends of the triangular bracket 52. During the installation process, the square pressing plate 51 is sleeved outside the porcelain bottle 2. First, two bolts are passed through the through holes at two of the corners of the square pressing plate 51 and screwed into the transformer box body 1. Then, the two ends of the triangular bracket 52 are respectively placed above the two corners of the square pressing plate 51 where no bolts are installed. Then, two bolts are successively passed through the triangular bracket 52 and the square pressing plate 51 and screwed into the transformer box body 1. The tip of the triangular bracket 52 extends towards one side of the transformer box body 1. Finally, the second lightning rod 6 is positioned at the tip of the triangular bracket 52 by means of threaded connection or welding. Such a design can change the distance between the second lightning rod 6 and the porcelain bottle 2 by replacing the triangular brackets 52 of different specifications. The design of replacing the overall disassembly and assembly of the connecting bracket 5 with partial disassembly and assembly can simplify the disassembly and assembly steps, improve the disassembly and assembly efficiency, and at the same time will not affect the porcelain bottle 2.

[0024] As a specific implementation of the improvement, refer to Figure 2 As shown in the figure, multiple connecting brackets 5 further include pressing feet 53 positioned below the square pressing plate 51 and pressing on the bottom end of the porcelain bottle 2. The number of pressing feet 53 required for each connecting bracket 5 is two. The pressing feet 53 are made of insulating materials, and through holes for bolts to pass through are provided on the pressing feet 53. During the installation process, the two pressing feet 53 are arranged diagonally on the upper surface of the transformer box body 1. One end of each of the two pressing feet 53 presses on the bottom end of the porcelain bottle 2. Then, the square pressing plate 51 is sleeved outside the porcelain bottle 2 and moved down to a position in contact with the top surface of the pressing feet 53. Subsequently, a bolt is first passed through the square pressing plate 51 and one of the pressing feet 53 and screwed into the transformer box body 1. Then, the two ends of the triangular bracket 52 are placed above the square pressing plate 51. Another bolt is continuously passed through one end of the triangular bracket 52, the square pressing plate 51, and the other pressing foot 53 and screwed into the transformer box body 1. Finally, two bolts are installed corresponding to the remaining two corners of the square pressing plate 51. Such a design can save a set of bolts compared with the design of directly passing bolts through the bottom end of the porcelain bottle 2 and screwing them into the transformer box body 1. At the same time, it can reduce the size of the bottom end of the porcelain bottle 2 and simplify the processing technology of the porcelain bottle 2. The design of using insulating materials for the pressing feet 53 can further reduce the interference of voltage on the porcelain bottle 2 compared with the design of bolts passing through the bottom end of the porcelain bottle 2, ensure the stability of the circuit inside the porcelain bottle 2, and have higher safety.

[0025] As a specific implementation of the improvement, refer to Figure 1As shown, on one side wall of the transformer box body 1, there is fixedly connected a support plate assembly 7 corresponding to a plurality of porcelain insulators 2 one by one, and a lightning arrester 8 positioned on the support plate assembly 7. The support plate assembly 7 can be a straight plate, and one end of it is positioned on the side wall of the transformer box body 1. The straight plate is horizontally arranged and insulated. The lightning arrester 8 is vertically positioned at the end of the straight plate far from the transformer box body 1. A grounding wire is electrically connected below the lightning arrester 8. The design of the lightning arrester 8 can greatly reduce the voltage generated by lightning strikes, resulting in a small voltage value reaching the first lightning rod 4, further ensuring the effective use of the first lightning rod 4 and reducing the possibility of damage to the first lightning rod 4.

[0026] As a specific embodiment of the improvement, refer to Figure 1 As shown, a plurality of support plate assemblies 7 each include a static plate 71 and a moving plate 72. The static plate 71 and the moving plate 72 are made of insulating materials. A long hole extending along the width direction of the transformer box body 1 is opened in the static plate 71. Through holes through which bolts pass are opened in the moving plate 72. One end of the static plate 71 is positioned on the side wall of the transformer box body 1. A part of the moving plate 72 is placed below the static plate 71 and the through holes are aligned with the long hole. Bolts are successively passed through the moving plate 72 and the static plate 71 from bottom to top, and nuts are screwed on the ends of the bolts protruding from the static plate 71. By loosening the nuts, the moving plate 72 can move along the length direction of the long hole. Such a design can change the linear distance between the lightning arrester 8 and the porcelain insulator 2 according to the use environment, thereby effectively reducing the voltage generated in different environments and having a wide range of applications.

[0027] As a specific embodiment of the improvement, as the distance between the lightning arrester 8 and the porcelain insulator 2 increases, the moving plate 72 and the static plate 71 are more likely to bend and be damaged under the gravity of the lightning arrester 8. To solve the foregoing problems, refer to Figure 1 As shown, a heat sink group 11 is fixedly connected to the side wall of the transformer box body 1. The heat sink group 11 located below the moving plate 72 can support the moving plate 72. The design of the heat sink group 11 can improve the heat dissipation of the transformer box body 1, thereby reducing the temperature inside the transformer box body 1 and ensuring the normal use of each component; the design of using the heat sink group 11 to support the moving plate 72 can slow down the degree of downward bending of the moving plate 72 and the static plate 71, indirectly improving the structural stability of the static plate 71 and the moving plate 72.

[0028] As a specific embodiment of the improvement, refer to Figure 1As shown in the figure, the bottom ends of multiple lightning arresters 8 are fixedly connected to brackets 9 connected to the corresponding moving plates 72. Reinforcing ribs 91 capable of abutting against the heat sink group 11 are arranged on multiple brackets 9. The design of the brackets 9 enables quick disassembly and assembly between the lightning arresters 8 and the moving plates 72, and can replace the lightning arresters 8 in time after they are damaged; the design of the reinforcing ribs 91 improves the bending resistance of the suspended part of the brackets 9. The design that the reinforcing ribs 91 abut against the heat sink group 11 can provide a safety distance for the adjustable distance between the lightning arrester 8 and the insulator 2, and can make up for the defect that the distance between the lightning arrester 8 and the insulator 2 is too small, resulting in the lightning arrester 8 being unable to fully relieve the voltage, so that the voltage borne by the first lightning rod 4 and the second lightning rod 6 is too large and damaged.

[0029] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. An oil-immersed transformer with an overvoltage protection structure, comprising a transformer box (1) and a plurality of porcelain bottles (2) positioned on the upper surface of the transformer box (1) and having built-in high-voltage terminals, characterized in that: The tops of the plurality of porcelain bottles (2) are all provided with high-voltage copper covers (3) and first lightning rods (4) connected to one side of the high-voltage copper covers (3); the length directions of the plurality of first lightning rods (4) are all parallel to the upper surface of the transformer box (1); the upper surface of the transformer box (1) is also provided with connecting frames (5) corresponding to the plurality of porcelain bottles (2) one by one and second lightning rods (6) with one end positioned on the connecting frame (5) and located on one side of the corresponding porcelain bottle (2); the plurality of second lightning rods (6) are all perpendicular to the upper surface of the transformer box (1); the tops of the plurality of second lightning rods (6) are located at a height lower than that of the first lightning rod (4); the ends of the plurality of first lightning rods (4) not connected to the high-voltage copper covers (3) are all bent downward and directed toward the tops of the corresponding second lightning rods (6); electricity is led to the second lightning rod (6) through the first lightning rod (4), so that excess voltage is led to the ground through the transformer box (1).

2. The oil-immersed transformer with an overvoltage protection structure according to claim 1, characterized in that: The first lightning rod (4) and the second lightning rod (6) connected to the same porcelain bottle (2) are both located in the same vertical plane.

3. The oil-immersed transformer with an overvoltage protection structure according to claim 1 or 2, characterized in that: The plurality of connecting frames (5) each comprises a square pressure plate (51) which is sleeved outside the bottom end of the corresponding porcelain bottle (2) and fixedly connected to the transformer box (1) by bolts, and a triangular bracket (52) with both ends positioned on the square pressure plate (51) and the tip extending toward one side of the transformer box (1), and the plurality of the second lightning rods (6) are positioned at the tips of the corresponding triangular brackets (52).

4. The oil-immersed transformer with an overvoltage protection structure according to claim 3, characterized in that: The plurality of connecting frames (5) further include a pressure foot (53) positioned below the square pressure plate (51) and pressing on the bottom end of the porcelain bottle (2).

5. The oil-immersed transformer with an overvoltage protection structure according to claim 1 or 2, characterized in that: A support plate assembly (7) corresponding one-to-one to a plurality of porcelain bottles (2) and a lightning arrester (8) positioned on the support plate assembly (7) are fixedly connected to one side wall of the transformer box (1).

6. The oil-immersed transformer with an overvoltage protection structure according to claim 5, characterized in that: The plurality of support plate assemblies (7) each comprise a stationary plate (71) fixedly connected to the side wall of the transformer box (1) and a movable plate (72) slidably connected to the stationary plate (71); the plurality of lightning arresters (8) are each positioned at one end of a corresponding movable plate (72); the movable plate (72) is moved along the length direction of the stationary plate (71) so that the distance between the lightning arrester (8) and the corresponding porcelain bottle (2) is changed.

7. The oil-immersed transformer with an overvoltage protection structure according to claim 6, characterized in that: A heat sink group (11) is fixedly connected to the side wall of the transformer box (1), and the heat sink group (11) located below the moving plate (72) is capable of supporting the moving plate (72).

8. The oil-immersed transformer with an overvoltage protection structure according to claim 7, characterized in that: The bottom ends of the plurality of lightning arresters (8) are fixedly connected to a bracket (9) connected to the corresponding moving plate (72), and the plurality of brackets (9) are all provided with reinforcing ribs (91) capable of contacting the heat sink group (11).

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