Oil-immersed transformer

Abstract

To realize an oil-immersed transformer that allows easy replacement of insulating oil.SOLUTION: In the oil-immersed transformer, an oil introduction pipe is provided that extends from the outside of the transformer down to a position below the surface of the insulating oil.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an oil-immersed transformer. [Background technology]

[0002] As one type of transformer, an oil-immersed transformer using insulating oil is known. Patent Document 1 discloses an oil-immersed transformer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-138931 Summary of the Invention [Problem to be solved by the invention]

[0004] The oil in oil-filled transformers can deteriorate over time. In particular, since transformers are often used for decades, it may be necessary to change the insulating oil during their lifespan to maintain the transformer's performance.

[0005] Furthermore, if insulating oil with better performance than the insulating oil currently in use is developed in the future, it is expected that there will be a need to replace the insulating oil with a different type even if the insulating oil is still usable. However, there has been no clear consideration of the transformer structure suitable for such insulating oil replacement.

[0006] In view of the above circumstances, an object of the present invention is to provide an oil-filled transformer that allows for easy replacement of insulating oil. [Means for solving the problem]

[0007] An example of a means for solving the above problem is as follows. An oil-filled transformer having an oil inlet pipe extending from the outside of the transformer to the lower surface below the insulating oil. [Effects of the Invention]

[0008] It is possible to realize an oil-filled transformer that makes it easy to replace the insulating oil.

[0009] Further means and effects of the present invention will become apparent throughout the entire specification below. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of an oil-immersed transformer according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic top view of an oil-immersed transformer according to an embodiment of the present invention. [Figure 3] FIG. 10 is a schematic cross-sectional view of an oil-immersed transformer according to another embodiment of the present invention. [Figure 4] FIG. 10 is a schematic top view of an oil-immersed transformer according to another embodiment of the present invention. [Figure 5] FIG. 10 is a schematic cross-sectional view of an oil-immersed transformer according to another embodiment of the present invention. [Figure 6] 1 is a schematic cross-sectional view of an oil-immersed transformer according to an embodiment of the present invention. [Figure 7] FIG. 1 is a schematic top view of an oil-immersed transformer according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings as needed. [Example]

[0012] Figure 1 is a schematic cross-sectional view of an oil-immersed transformer according to one embodiment of the present invention. The oil-immersed transformer 10 has voltage conversion elements such as a coil 2 housed in a transformer case 1. The voltage conversion elements are submerged and held in insulating oil 3. Reference numeral 4 denotes an oil drain port, which is usually tightly sealed with a cap or the like.

[0013] FIG. 2 is a schematic top view of an oil-immersed transformer according to an embodiment of the present invention.

[0014] A feature of the present invention is that an oil inlet pipe 5 is provided in advance in the oil-filled transformer 10. The oil inlet pipe 5 is, for example, a long, hollow pipe, and has an inner-transformer-case portion 5a of the oil inlet pipe inside the transformer case 1 and an outer-transformer-case portion 5b of the oil inlet pipe outside the transformer case 1. Although the outer-transformer-case portion 5b of the oil inlet pipe is shown extending above the oil-filled transformer in Figures 1 and 2, the scope of the present invention also includes a case where the outer-transformer-case portion 5b of the oil inlet pipe changes direction midway inside or outside the oil-filled transformer and is positioned laterally of the oil-filled transformer.

[0015] By providing the oil inlet pipe 5, it becomes easy to drain the insulating oil from the waste oil port 4 and then introduce replacement insulating oil from the oil inlet pipe 5, making it easy to replace the insulating oil.

[0016] Note that a cleaning process may be carried out between draining the insulating oil and introducing replacement insulating oil to remove dirt and other contaminants that have accumulated on the inner surface of the transformer case and on the voltage conversion elements due to long-term use of the insulating oil.

[0017] It is desirable to provide a removable sealing member such as a cap at the end of the oil supply pipe outside the transformer case 5b, but this is not a limitation. [Example]

[0018] This embodiment is basically the same as the first embodiment, but is characterized in that the tip of the oil inlet pipe inside the transformer case 5a is located below the coil 2. This provides an additional effect of preventing damage to the coil and other components due to the force of the oil when insulating oil is introduced through the oil inlet pipe 5.

[0019] In addition, when a cleaning process is carried out before introducing new insulating oil, the cleaning liquid is sprayed from the oil inlet pipe 5 onto the bottom side of the transformer case 1, which increases the force of the cleaning liquid hitting the bottom, allowing for effective cleaning of debris and deteriorated dirt that has accumulated on the bottom. [Example]

[0020] This embodiment is basically the same as the second embodiment, but when the insulating oil is drained from the drain oil port 4, an inert gas is introduced from the oil inlet pipe 5.

[0021] As the type of inert gas, nitrogen gas or the like can be used in view of availability.

[0022] In this embodiment, it is possible to eliminate the risk of humid gas such as the outside air entering the oil-filled transformer during the insulating oil replacement work, which may cause deterioration of the insulating characteristics.

[0023] Furthermore, the introduced nitrogen gas or the like exerts pressure downward on the insulating oil surface from above the insulating oil 3, which also improves the speed of the insulating oil disposal work. [Example]

[0024] This embodiment is basically the same as embodiments 1 to 3. Fig. 3 is a view corresponding to Fig. 1, and Fig. 4 is a view corresponding to Fig. 2.

[0025] This embodiment is characterized by having a plurality of oil inlet pipes 5. This makes it possible to use the plurality of oil inlet pipes 5 for separate purposes, with one pipe for oil discharge and the other for oil introduction. Oil can be discharged by pumping oil up using a pump or the like. In the present invention, even when used for oil discharge, the pipe is still called an oil inlet pipe, as it simply reverses the direction of introduction.

[0026] When draining insulating oil by opening the drain oil port 4 in Figure 1, there is a risk that the waste oil will leak out and contaminate the surrounding area during the draining process. This is because when the drain oil port 4 is opened, the weight of the insulating oil itself causes the waste oil to spray out of the drain oil port.

[0027] Furthermore, some old oil-filled transformers used PCBs, which are now banned from production due to their high toxicity, as insulating oil. When disposing of such oil-filled transformers, or when replacing the oil with another insulating oil that meets current standards, it is necessary to eliminate the risk of oil leakage.

[0028] According to this embodiment, in addition to the effects of the first to third embodiments, it is possible to perform the oil drainage work from the oil supply pipe 5, and therefore it is possible to obtain the effect of eliminating the risk of oil leakage to the outside. [Example]

[0029] This embodiment is a modification of the embodiment 4. Fig. 5 is a view corresponding to Fig. 3 .

[0030] This embodiment is the same as the fourth embodiment in that it has a plurality of oil supply pipes 5, but is further characterized in that the oil supply pipes have a plurality of different lengths.

[0031] The long oil supply pipe 5c is the portion inside the transformer case, and the short oil supply pipe 5d is the portion inside the transformer case. In this embodiment, it is possible to use 5c for waste oil and 5d for oil supply, for example. [Example]

[0032] This embodiment is a modification of the embodiment 4. Fig. 6 is a view corresponding to Fig. 3, and Fig. 7 is a view corresponding to Fig. 4.

[0033] This embodiment is characterized by having a bent portion 5e of the oil inlet pipe at the tip of the oil inlet pipe 5. This allows the introduced insulating oil to flow out in the lateral direction, which is particularly effective during cleaning.

[0034] Furthermore, as shown in Figure 7, by arranging the bent portions 5e of the oil supply pipes 5 so that they rotate clockwise or counterclockwise relative to each other in multiple oil supply pipes 5, the effect of cleaning while rotating can be obtained, particularly during cleaning, and the cleaning effect can be expanded.

[0035] The above examples illustrate the ideas and concepts of the present invention. Of course, the scope of the present invention also includes examples that are realized by combining the examples. Furthermore, as long as the disclosed ideas and concepts are used, any modifications or similar examples are also included within the scope of the present invention.

[0036] Furthermore, one example of the present invention described using the above embodiments can also be expressed as follows.

[0037] <Part 1> An oil-filled transformer having an oil inlet pipe extending from the outside of the transformer to the lower surface below the insulating oil.

[0038] <Part 2> The oil-filled transformer according to <Item 1> has a plurality of the oil introduction pipes.

[0039] <Part 3> In the oil-filled transformer described in <Item 1>, the lower surface of the oil inlet pipe is located below the transformer coil.

[0040] <Part 4> In the oil-filled transformer according to <Item 2>, the oil introduction pipe has a plurality of lengths.

[0041] <Part 5> <Item 2> The oil-filled transformer according to the present invention, wherein the lower end of the oil introduction pipe has a downward bent portion.

[0042] <Part 6> <Item 5> The oil-filled transformer according to the present invention, wherein the directions of the downward bend portions are different for the plurality of oil introduction pipes.

[0043] <Part 7> In the oil-filled transformer according to <Item 6>, the direction of the downward bend portion is arranged so that the direction of the plurality of oil introduction pipes is clockwise or counterclockwise. [Explanation of symbols]

[0044] 1: Transformer case 2: Coil 3: Insulating oil 4: Oil drain port 5: Oil introduction pipe 5a: Oil inlet pipe inside the transformer case 5b: Oil inlet pipe external part of transformer case 5c: Long oil inlet pipe inside the transformer case 5d: Short oil inlet pipe inside the transformer case 5e: Bent part of oil inlet pipe 10: Oil-immersed transformer

Claims

1. An oil-filled transformer having an oil inlet pipe extending from the outside of the transformer to the lower surface below the insulating oil.

2. 2. The oil-filled transformer according to claim 1, comprising a plurality of said oil supply pipes.

3. 2. An oil-filled transformer according to claim 1, wherein the bottom surface of said oil supply pipe is located below the coil of said transformer.

4. 3. The oil-filled transformer according to claim 2, wherein the oil supply pipe has a plurality of lengths.

5. 3. An oil-filled transformer according to claim 2, wherein the lower end of said oil inlet pipe has a downward bent portion.

6. 6. The oil-filled transformer according to claim 5, wherein the directions of the downward bend portions are different for each of the plurality of oil supply pipes.

7. 7. The oil-filled transformer according to claim 6, wherein the direction of the downward bends of the plurality of oil supply pipes is arranged to be clockwise or counterclockwise.

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