Oil-filled electrical equipment

Abstract

To always measure correct pressure by a pressure gauge by preventing an insulation oil from intruding into a piping in an oil containing electric apparatus provided with the pressure gauge for measuring the pressure of gas sealed in an upper space in a tank.SOLUTION: An oil containing electric apparatus includes: a tank storing an electric apparatus body; an insulation oil filled in the tank; gas for antioxidation sealed in an upper space above the insulation oil in the tank in a positive pressure state; first piping communicating with the upper space in the tank and extending outside the tank; sealed second piping with a tip part of the first piping connected thereto; third piping configured with a diameter smaller than that of the second piping and vertically extending so as to hermetically penetrate a lower part of the second piping with an upper end positioned on an upper part of the second piping; and a pressure gauge connected to the third piping to measure the pressure of the gas in the upper space in the tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an oil-filled electrical device in which an electrical device body is accommodated together with insulating oil in a tank. [Background technology]

[0002] In oil-filled electrical equipment, such as oil-filled transformers for high-voltage power distribution equipment, the transformer body is housed in a sealed tank together with insulating oil, and nitrogen gas is sealed at positive pressure in the upper space of the tank to prevent deterioration of the insulating oil (see, for example, Patent Document 1). In this type of oil-filled transformer, if nitrogen gas leaks from the upper space of the tank, it can cause deterioration of the insulating oil. Therefore, a pressure gauge is provided to measure the pressure of the nitrogen gas in the upper space of the tank, and regular inspections are carried out to ensure that the pressure gauge is detecting a positive pressure state.

[0003] In this case, for a relatively small tank, even if the pressure gauge is installed on the outer wall of the tank, workers can check it as is, but for a relatively large oil-filled transformer, the tank is tall and the upper space is located much higher than the eye level of the workers. Therefore, for such a large tank, in order for workers to visually check the pressure gauge, a pipe is installed along the outer wall of the tank so that its upper end communicates with the upper space and extends downward, and the pressure gauge is installed at the bottom end of the pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 56-132719 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the above-mentioned conventional configuration, there is a risk that insulating oil may enter the piping connected to the pressure gauge due to factors such as fluctuations or tilting of the oil surface caused by vibrations during transportation or earthquakes, etc. If insulating oil enters the piping, problems such as an inaccurate pressure measurement or damage to the pressure gauge may occur.

[0006] Therefore, we provide an oil-filled electrical device that is equipped with a pressure gauge to measure the pressure of the gas sealed in the upper space inside the tank, which prevents problems caused by insulating oil entering the piping and can always measure the correct pressure using the pressure gauge. [Means for solving the problem]

[0007] The oil-filled electrical device according to the embodiment comprises a tank that houses an electrical device body, insulating oil filled in the tank, an anti-oxidation gas sealed under positive pressure in the space above the insulating oil in the tank, a first pipe that communicates with the upper space of the tank and extends to the outside of the tank, a sealed second pipe to which the tip of the first pipe is connected, a third pipe that is smaller in diameter than the second pipe, extends in the vertical direction so as to airtightly penetrate the lower part of the second pipe, and has its upper end located at the top of the second pipe, and a pressure gauge that is connected to the third pipe and measures the pressure of the gas in the upper space of the tank. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view showing an embodiment of an oil-immersed transformer, schematically illustrating the overall configuration of the transformer. [Figure 2] Enlarged front view of the upper part of the piping [Figure 3] Enlarged front view of the lower part of the piping DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention, which is applied to an oil-filled transformer, an oil-filled static induction device for use in high-voltage power distribution equipment, will be described below with reference to the drawings. Fig. 1 shows the overall configuration of an oil-filled transformer 1 (hereinafter simply referred to as "transformer 1"), an oil-filled electrical device according to this embodiment. This transformer 1 is configured by housing a transformer body 2, which serves as the electrical device body, in a sealed tank 3, and a plurality of unit-shaped heat sinks 4 of a well-known configuration are connected to the left and right sides of the tank 3 in Fig. 1.

[0010] Although not shown in detail, the transformer body 2 has a well-known configuration including an iron core and three-phase coils attached to the iron core. The tank 3 has a rectangular box shape that is slightly elongated in the front-to-rear direction in the drawing, and is filled with insulating oil M, such as mineral oil, for insulation and cooling purposes so that the entire transformer body 2 is immersed. At this time, a gas, such as nitrogen gas, is sealed under positive pressure in the space 5 above the insulating oil M to prevent oxidation of the insulating oil M. In addition, a plurality of bushings 6 are provided on the top surface of the tank 3 for connecting each coil of the transformer body 2 to the outside.

[0011] Each unit of the radiator 4 is designed to cool the insulating oil M in the tank 3 through heat exchange, and includes an upper header 7, a lower header 8, and multiple radiator panels 9 connecting them, all made of a metal with good thermal conductivity. The upper header 7 is a cylindrical pipe extending left and right in the figure, with its tip connected to the upper end of each radiator panel 9. The lower header 8 is also a cylindrical pipe extending left and right in the figure, with its tip connected to the lower end of each radiator panel 9. The radiator panels 9 are shaped like thin, sealed boxes extending left and right in the figure.

[0012] The base end of each upper header 7 is connected to a portion of the side of the tank 3 near the top, below the upper space 5, and the base end of each upper header 7 is connected to the lower end of the side of the tank 3. As a result, the insulating oil M warmed by the heat of the transformer body 2 in the tank 3 flows by convection through the upper headers 7 of the radiators 4 into each radiator panel 9. The insulating oil M then exchanges heat with the outside as it flows down inside the radiator panels 9, where it is cooled. After this, the insulating oil M is circulated from the radiator panels 9 through the lower headers 8 and returned to the tank 3. By circulating the insulating oil M in this way, the insulating oil M in the tank 3 is cooled.

[0013] In the oil-filled transformer 1 of this embodiment, a pressure gauge 10 of a well-known configuration is provided to measure the pressure of the nitrogen gas in the upper space 5 inside the tank 3 and check for leaks. In this case, the pressure gauge 10 is provided in front of the right-side radiator 4 at a height that corresponds to the eye level of an operator, in this case, at the middle in the height direction of the radiator 4. In this embodiment, a piping structure for guiding the pressure of the nitrogen gas in the upper space 5 of the tank 3 to the pressure gauge 10 located below outside the tank 3 is provided as follows.

[0014] That is, as shown in FIG. 1, this piping structure includes a first pipe 11, a second pipe 12, a third pipe 13, and a branch pipe 14. As also shown in FIG. 2, the base end of the first pipe 11 is connected to the side wall of the tank 3 and communicates with the upper space 5, and the tip end extends almost horizontally to the right. The tip end of this first pipe 11 is airtightly connected to the lower outer peripheral surface of the second pipe 12 and communicates with the second pipe 12. The connection position of the tip of the first pipe 11 is located slightly above the bottom of the second pipe 12. This second pipe 12 has a larger diameter than the first pipe 11 and the third pipe 13, is cylindrical, and is elongated in the vertical direction, with both the top and bottom surfaces closed to form an airtight seal.

[0015] The third pipe 13 has a smaller diameter than the second pipe 12, extends vertically so as to airtightly penetrate the bottom portion of the second pipe 12, and has an upper end located at a position slightly lower than the ceiling wall portion at the upper portion of the second pipe 12. In this embodiment, as shown in Fig. 2, an upper end opening 13a of the third pipe 13 is cut obliquely. As also shown in Fig. 3, the lower end of the third pipe 13 extends to a position slightly lower than the installation height of the pressure gauge 10.

[0016] In this embodiment, the opening at the lower end of the third pipe 13 serves as an oil drain port 15, and a lid 16 is provided to open and close the oil drain port 15. The oil drain port 15 and the lid 16 are normally hermetically closed by mating flanges with each other and tightening with bolts 17. The branch pipe 14 has a lower end airtightly connected to a position on the right side slightly above the oil drain port 15 at the bottom of the third pipe 13, and extends from there while bending upward, with the pressure gauge 10 connected to its upper end.

[0017] As a result, the pressure of the nitrogen gas used to prevent oxidation of the insulating oil M sealed under positive pressure in the upper space 5 within the tank 3 passes through the first pipe 11 into the second pipe 12, then passes through the upper end opening 13a located at the top of the second pipe 12 into the third pipe 13, and then passes through the branch pipe 14 to the pressure gauge 10. In this case, the pressure gauge 10 is placed at a relatively low position corresponding to the eye level of the worker, so that the pressure indicated by the pressure gauge 10 can be easily confirmed visually by the worker when inspecting for nitrogen gas leaks.

[0018] According to this embodiment, the following actions and effects can be obtained. That is, in the oil-filled transformer 1 of this embodiment, the nitrogen gas sealed in the upper space 5 in the tank 3 can suppress deterioration of the insulating oil M due to oxidation. If nitrogen gas leaks from the tank 3, the anti-oxidation effect will decrease, so a nitrogen gas leak inspection is performed, for example, periodically. In this inspection, as described above, the pressure of the nitrogen gas in the upper space 5 passes through the first pipe 11, the second pipe 12, the third pipe 13, and the branch pipe 14 to the pressure gauge 10, and the pressure of the nitrogen gas in the upper space 5 can be monitored by the pressure gauge 10.

[0019] Here, if the oil level of insulating oil M in tank 3 fluctuates or tilts, it is possible that the oil level of insulating oil M may exceed the height of the mouth of the base end of first pipe 11, causing insulating oil M to infiltrate into first pipe 11 from upper space 5. Insulating oil M that leaks from tank 3 into first pipe 11 passes through first pipe 11 and accumulates at the bottom of second pipe 12. However, since the inlet of third pipe 13, i.e., upper end opening 13a, is located at the top of second pipe 12, insulating oil M is prevented from infiltrating into third pipe 13.

[0020] Therefore, even if insulating oil M leaks from tank 3 into first pipe 11, the leaked insulating oil M will simply collect at the bottom of second pipe 12 and will not block the pipeline connecting first pipe 11 to pressure gauge 10. This allows the pressure of the nitrogen gas in upper space 5 to be guided directly to pressure gauge 10, and the leaked insulating oil M will not interfere with the measurement of the nitrogen gas pressure, allowing pressure gauge 10 to measure the correct pressure of the nitrogen gas in upper space 5.

[0021] As a result, according to this embodiment, in a device equipped with a pressure gauge 10 that measures the pressure of the nitrogen gas sealed in the upper space 5 inside the tank 3, it is possible to obtain the excellent effect of preventing problems caused by the intrusion of insulating oil M into the piping and always being able to measure the correct pressure using the pressure gauge 10.

[0022] In this embodiment, the upper end opening 13a of the third pipe 13 is configured to be cut at an angle. As a result, even if the upper end of the third pipe 13 is disposed near the ceiling of the second pipe 12, the upper end opening 13a of the third pipe 13 is cut at an angle, which prevents the upper end opening 13a of the third pipe 13 from coming into contact with the ceiling surface of the second pipe and being blocked due to dimensional errors during assembly, etc. As a result, the upper end opening 13a of the third pipe 13 is always open, and communication between the second pipe 12 and the third pipe 13 can always be ensured.

[0023] In particular, in this embodiment, a branch pipe 14 is provided that branches off at a position above the lower end of the third pipe 13, and the pressure gauge 10 is connected to the branch pipe 14. As a result, even if, for example, a large amount of insulating oil M leaks and the insulating oil M enters the third pipe 13, the insulating oil M simply collects at the lower end of the third pipe 13, ensuring communication of nitrogen gas to the pressure gauge 10 through the branch pipe 14. Therefore, the third pipe 13 is not clogged with insulating oil M, and the nitrogen gas pressure can be correctly guided to the pressure gauge 10 through the branch pipe 14, making it possible to always measure the correct pressure.

[0024] In addition, an oil drain port 15 and a lid 16 that can be opened and closed to cover the oil drain port 15 are provided at the lower end of the third pipe 13. As a result, if insulating oil M enters the third pipe 13, the lid 16 can be opened to open the oil drain port 15, and the insulating oil M that has accumulated at the lower end can be easily drained.

[0025] In the above embodiment, the upper end opening 13a of the third pipe 13 is cut at an angle, but if there is no risk of the upper end opening being blocked, it may be opened horizontally. In the above embodiment, the branch pipe 14, the oil drain port 15, and the lid 16 are provided, but it may simply be configured to provide a pressure gauge at the lower end of the third pipe. Furthermore, in the above embodiment, mineral oil is used as an example of the insulating oil M, but insulating oils other than mineral oil, liquid silicone, etc. may also be used.

[0026] The anti-oxidation gas is not limited to nitrogen gas, and other inert gases can also be used. The overall configuration of the transformer can also be modified in various ways, such as by including a circulation pump for forcibly circulating the insulating oil M around the radiator, or a fan device for forced cooling. Additionally, although an oil-filled transformer has been used as an example, the oil-filled electrical equipment is not limited to transformers, and can also be applied to other static induction equipment such as reactors, and further to switches, circuit breakers, relays, etc.

[0027] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0028] In the drawing, 1 is an oil-filled transformer (oil-filled electrical equipment), 2 is the transformer body (electrical equipment body), 3 is a tank, 4 is a radiator, 5 is an upper space, 10 is a pressure gauge, 11 is a first pipe, 12 is a second pipe, 13 is a third pipe, 13a is an upper end opening, 14 is a branch pipe, 15 is an oil drain port, 16 is a lid, and M is insulating oil.

Claims

1. a sealed tank in which the electrical equipment body is housed; insulating oil filled in the tank; an anti-oxidation gas sealed under positive pressure in the space above the insulating oil in the tank; a first pipe communicating with the upper space of the tank and extending to the outside of the tank; a sealed second pipe to which a tip end of the first pipe is airtightly connected; a third pipe having a smaller diameter than the second pipe, extending in the vertical direction so as to airtightly penetrate a lower portion of the second pipe, and having an upper end portion located at an upper portion within the second pipe; a pressure gauge connected to the third pipe for measuring the pressure of the gas in the upper space of the tank, the pressure of the gas in the space above the tank is introduced to the pressure gauge via the first pipe, the second pipe, and the third pipe. Oil-filled electrical equipment.

2. 2. The oil-filled electrical device according to claim 1, wherein the upper end opening of the third pipe is cut obliquely.

3. 3. The oil-filled electrical device according to claim 1, further comprising a branch pipe branching off from the third pipe at a position above a lower end of the third pipe, the pressure gauge being connected to the branch pipe.

4. 4. The oil-filled electrical device according to claim 3, wherein a lower end of the third pipe is provided with an oil drain port and a cover that can open and close the oil drain port.

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