Oil-immersed transformer

Abstract

To reduce an amount of air leakage from both upper and lower sides of a cooling unit, and avoid arrangement of the cooling unit at a distance from a blower.SOLUTION: A cooling device (23) of an oil-immersed transformer (1) includes a plurality of cooling panels (30) that are arranged side by side in a state of being oriented in a vertical direction and through which insulating oil (L) flows, and a blower (31) that blows air toward the cooling panels. When a thickness direction of the cooling panels is defined as a Y direction and a direction orthogonal to the Y direction in a plan view is defined as an X direction, the cooling panels are arranged in plurality in the Y direction to form a cooling unit (34), and the plurality of the cooling units are arranged in the X direction. The blower takes in air from one surface in the X direction and blows air out from the other surface in the X direction, and is arranged to be sandwiched between the two cooling units in the X direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an oil-immersed transformer, and more particularly to an oil-immersed transformer that is cooled by insulating oil contained in a container. [Background technology]

[0002] Patent Document 1 discloses a cooling device for oil-filled electrical equipment that uses a cooling fan to cool multiple panel radiators arranged side by side. The cooling fans are installed to the sides of the panel radiators and blow cooling air between the panels of the panel radiators. In other words, the panel radiators are arranged in the direction of the central axis of the cooling fans, and the cooling fans are arranged outside the panel radiators in that direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 63-84002 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, a guide plate is provided between the panel radiator and the cooling fan, and the air coming out of the cooling fan is directed horizontally to reduce the amount of air leaking from both the top and bottom of the panel radiator. However, in Patent Document 1, the cooling fan is positioned outside the panel radiator, so the air volume of the cooling fan is reduced at the panel radiator that is farthest from the cooling fan in the direction of the central axis of the cooling fan, making it difficult to sufficiently improve cooling efficiency.

[0005] The present invention has been made in consideration of such problems, and one of its objects is to provide an oil-filled transformer that can reduce the amount of air leaking from both the top and bottom of the cooling unit and can avoid the cooling unit being placed far away from the blower. [Means for solving the problem]

[0006] One embodiment of the oil-filled transformer of the present invention is an oil-filled transformer comprising a container that houses windings, a magnetic core, and insulating oil, and a cooling device that is provided outside the container and cools the insulating oil, wherein the cooling device comprises a plurality of cooling panels that are arranged in a vertical direction and through which the insulating oil flows, and a blower that blows air toward the cooling panels, wherein the thickness direction of the cooling panels is defined as a first direction and a direction perpendicular to the first direction when viewed from above is defined as a second direction, and wherein the cooling panels are arranged in multiple in the first direction to form a cooling unit, and a plurality of the cooling units are arranged in the second direction, and the blower draws in air from one side in the second direction and blows air from the other side, and is arranged sandwiched between two of the cooling units in the second direction. [Effects of the Invention]

[0007] According to the present invention, the cooling units arranged on one side of the blower in the second direction can be cooled by the air flow caused by the intake air of the blower, and cooling by the intake air can eliminate air leakage and improve cooling efficiency. Moreover, by arranging the cooling units on one side of the blower in the second direction, the number of cooling units arranged side by side on the other side can be reduced, preventing the cooling units from being separated from the blower. This reduces the number of cooling units that reduce the air flow of their cooling fans among multiple cooling units, improving cooling efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a longitudinal sectional view schematically showing an oil-filled transformer according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 2 is a schematic perspective view of a cooling device. [Figure 6]FIG. 6A is a front view illustrating the flow of air blown in the cooling device of the embodiment, and FIG. 6B is a front view similar to FIG. 6A, illustrating the flow of air blown in a cooling device of a comparative example. [Figure 7] FIG. 7A is a graph showing the analysis results of the heat transfer coefficient in the embodiment and the comparative example, and FIG. 7B is a graph showing the analysis results of the temperature decrease of the insulating oil in the embodiment and the comparative example. [Figure 8] FIG. 10 is a front view similar to FIG. 2 of a cooling device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] An oil-immersed transformer according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Fig. 1 is a longitudinal cross-sectional view schematically showing an oil-immersed transformer according to this embodiment. As shown in Fig. 1, oil-immersed transformer 1 includes a magnetic core 2 that forms a magnetic circuit and a winding 3 that is wound around magnetic core 2 to form an electric circuit, and is supplied with AC power of a predetermined frequency from a commercial AC power source or the like. Oil-immersed transformer 1 also includes a container 10 that houses magnetic core 2 and winding 3.

[0010] The container 10 is filled with insulating oil L as an insulating liquid to improve the cooling effect and insulation strength of the magnetic core 2 and the winding 3. The liquid level L1 of the insulating oil L is set at a position higher than the uppermost positions of the magnetic core 2 and the winding 3, so that the magnetic core 2 and the winding 3 are entirely immersed in the insulating oil L.

[0011] The oil-immersed transformer 1 is provided with an upper pipe 21, a lower pipe 22, a cooling device 23, and a circulation device 24 outside the container 10. One end of the upper pipe 21 is connected to the top of the container 10, and one end of the lower pipe 22 is connected to the top of the container 10. The other ends of the upper pipe 21 and the lower pipe 22 are each connected to the cooling device 23, and the circulation device 24 is provided midway through the upper pipe 21.

[0012] The circulation device 24 is composed of an oil pump or the like, and draws insulating oil L from inside the container 10 via the upper pipe 21 and returns the drawn insulating oil L to the container 10 via the cooling device 23 and lower pipe 22. In other words, by driving the circulation device 24, the insulating oil L is sent out in the following order: container 10, upper pipe 21, circulation device 24, cooling device 23, lower pipe 22, and container 10, and circulated within the device (see the arrows in FIG. 1 ). Through this circulation, the insulating oil L heated by heat generated from the magnetic core 2 and winding 3 is cooled by the cooling device 23. Note that the circulation of the insulating oil L may be natural circulation utilizing temperature changes of the insulating oil L, in which case the circulation device 24 may be omitted. In other words, the circulation device 24 is not essential and may not be used in some cases.

[0013] Next, the configuration of the cooling device 23 will be described. Here, the following description will be based on the X, Y, and Z directions indicated by arrows in each drawing. In the following embodiment, the X and Y directions are parallel to the horizontal direction, and the Z direction is parallel to the vertical direction, but these directions may be changed as long as the same functions as those in the embodiment can be achieved.

[0014] Fig. 2 is a front view of the cooling device, and Fig. 3 is a plan view of the cooling device. Fig. 4 is a side view of the cooling device, and Fig. 5 is a schematic perspective view of the cooling device. In Figs. 2 to 5, some components are omitted for simplicity of illustration. As shown in Figs. 2 to 5, the cooling device 23 includes a plurality of cooling panels 30 and a plurality of air blowers 31 that blow air toward the cooling panels 30.

[0015] A plurality of cooling panels 30 are arranged side by side facing in the vertical direction (Z direction). Each cooling panel 30 has a generally rectangular shape that is elongated in the vertical direction, and is formed in a bag shape that can form a space inside through which insulating oil L can flow.

[0016] In the cooling panel 30, the thickness direction is set as the first direction, which in this embodiment is set parallel to the Y direction. In addition, in the cooling panel 30, the direction perpendicular to the first direction when viewed from above, i.e., the direction parallel to the X direction, is set as the second direction.

[0017] A plurality of cooling panels 30 are arranged in the Y direction to form a cooling unit 34. In the cooling device 23, a plurality of cooling units 34 are arranged in the X direction. In the cooling device 23 of the present embodiment, four cooling units 34 are arranged in the X direction.

[0018] Each cooling unit 34 is provided with an upper flow path 35 connected to the upper end side of each of the plurality of cooling panels 30 that form the cooling unit 34, and a lower flow path 36 connected to the lower end side. The upper flow path 35 is connected to the upper piping 21 (see FIG. 1), and the lower flow path 36 is connected to the lower piping 22 (see FIG. 1) via a collecting pipe or the like (not shown). Thus, in each cooling unit 34, insulating oil L in the container 10 (see FIG. 1) flows from the upper piping 21 through the upper flow path 35 into the plurality of cooling panels 30, and is returned into the container 10 through the lower flow path 36 and the lower piping 22.

[0019] Although the specific configuration of the air blower 31 is not shown, it can be exemplified by an axial fan (see FIG. 2) that is rotatably arranged inside a circular housing (see FIG. 4) when viewed from the Y direction. The air blower 31 takes in air from the -X side surface, which is one surface in the X direction, and blows air from the +X side surface, which is the other surface in the X direction. The air blower 31 is arranged to blow air to each cooling unit 34 roughly along the X direction, and to be able to cool (air-cool) the cooling panel 30 and the insulating oil L flowing inside the cooling panel 30.

[0020] The blower 31 is disposed between two cooling units 34 in the X direction. Here, when viewed from the blower 31, the number of cooling units 34 disposed on the -X side of the blower 31 is referred to as the "upstream installed number," and the number of cooling units 34 disposed on the +X side of the blower 31 is referred to as the "downstream installed number." Since two cooling units 34 are disposed between the blower 31 in the X direction, both the upstream installed number and the downstream installed number are one or more. Specifically, in this embodiment, the upstream installed number is one and the downstream installed number is three, with the downstream installed number being greater.

[0021] In this embodiment, two air blowers 31 are provided, and they have the same shape and the same air blowing performance. The width of each air blower 31 in the Y direction is smaller than the width of the cooling unit 34 in the Y direction and is larger than half the width of the cooling unit 34 in the Y direction. The width of each air blower 31 in the up-down direction is smaller than half the width of the cooling unit 34 in the up-down direction. The two air blowers 31 are arranged with their positions in the up-down direction and the Y direction offset from each other.

[0022] More specifically, the upper blower 31 is provided at a position where its upper end is slightly lower than the upper end of the cooling unit 34 and fits into the upper half of the cooling unit 34 in the vertical direction. Furthermore, the +Y side end of the upper blower 31 is disposed near the +Y side end of the cooling unit 34. The vertical position of the lower blower 31 is below the upper blower 31 and is disposed slightly below the vertical center of the cooling unit 34. Furthermore, the -Y side end of the lower blower 31 is disposed near the -Y side end of the cooling unit 34.

[0023] 5, the cooling device 23 may further be provided with guide members 40 that surround both sides in the vertical direction (Z direction) and both sides in the Y direction of the two blowers 31. The guide members 40 include a pair of short walls 41 that form both sides in the vertical direction and a pair of long walls 42 that form both sides in the Y direction, and are formed to form a continuous closed loop. The size of the guide members 40 in the vertical direction and Y direction is approximately the same as that of the cooling units 34, or is slightly larger so that the cooling units 34 can be accommodated when viewed from the X direction.

[0024] Here, the flow of air blown by cooling device 23 of the embodiment will be described by comparing the embodiment shown in Fig. 6A with a comparative example shown in Fig. 6B. Fig. 6A is a front view for explaining the flow of air blown in the cooling device of the embodiment, and Fig. 6B is a front view similar to Fig. 6A, showing the flow of air blown in the cooling device of the comparative example.

[0025] 6A does not include the guide member 40 of the above-described embodiment, and the four cooling units 34 are referred to as first to fourth cooling units in the order from the -X side to the +X side, and are assigned the reference numerals "34A" to "34D." Therefore, the two air blowers 31 in FIG. 6A are sandwiched between the first cooling unit 34A and the second cooling unit 34B in the X direction. Furthermore, in the configuration of the comparative example in FIG. 6B, the position of the air blower 31 in the embodiment is changed, and components common to the embodiment will be described using the same reference numerals. The air blower 31 in the comparative example in FIG. 6B is positioned on the -X side of the first cooling unit 34A and blows air toward each of the cooling units 34A to 34D, including the first cooling unit 34A.

[0026] 6A and 6B, a simulation was performed in which air was blown from each blower 31. The analysis result showed that air was blown in the direction indicated by the white arrow in the figure. As shown in FIG. 6A, in the embodiment, it is possible to blow air to the first cooling unit 34A, which is arranged on the upstream side (-X side) of the blower 31 in the air blowing direction, by using the intake air of the blower 31. Since such air blowing by intake air is not performed in the comparative example of FIG. 6B, this is a function that can only be achieved in the embodiment, and in the embodiment, it is possible to utilize the air flow flowing into the blower 31 for cooling.

[0027] 6A and 6B, due to the swirling components of the fans in each air blower 31, part of the air blown by the upper air blower 31 is directed diagonally upward, and part of the air blown by the lower air blower 31 is directed diagonally downward. For this reason, in the embodiment of FIG. 6A, the amount of air leaking from both the top and bottom of the second to fourth cooling units 34B to 34D increases toward the downstream side (+X side) of the air blowing direction of the air blower 31 and away from the air blower 31.

[0028] 6B, the amount of air leakage from both the top and bottom of the first to fourth cooling units 34A to 34D increased with increasing distance from blower 31. In the comparative example, fourth cooling unit 34D, which is the farthest from blower 31, is the fourth cooling unit on the +X side from blower 31, and the amount of air leakage was particularly large, and the flow velocity of the air blown from blower 31 was also small.

[0029] 6A, the fourth cooling unit 34D, which is the farthest from the air blower 31, is the third cooling unit on the +X side from the air blower 31. Therefore, in the embodiment, the fourth cooling unit (fourth cooling unit 34D) on the +X side from the air blower 31 as in the comparative example is eliminated, and it is possible to eliminate a cooling unit that increases the leakage air volume and reduces the flow velocity of the blown air.

[0030] FIG. 7A is a graph showing the analysis results of the heat transfer coefficient in the embodiment and the comparative example, and FIG. 7B is a graph showing the analysis results of the temperature drop of the insulating oil in the embodiment and the comparative example. In both the embodiment and the comparative example, when air is blown by the blower 31 under the same conditions, the heat transfer coefficient (W / m 2 A simulation was performed on the cooling units 34A to 34D. The analysis results are shown in Fig. 7A. Fig. 7A also shows the average values ​​of the analysis results for the heat transfer coefficients in the cooling units 34A to 34D.

[0031] Furthermore, in both the embodiment and the comparative example, a simulation was performed on the temperature drop of the insulating oil L in the upper flow path 35 and the lower flow path 36 of the first to fourth cooling units 34A to 34D when air was blown by the blower 31 under the same conditions. The analysis results are shown in FIG. 7B. FIG. 7B also shows the average value of the analysis results of the temperature drop in each of the cooling units 34A to 34D. The values ​​in the graphs of FIGS. 7A and 7B indicate relative values.

[0032] 7A and 7B, in the embodiment, the heat transfer coefficient and the temperature drop (decreasing width) were greatest in the second cooling unit 34B adjacent to the +X side of the blower 31. In the embodiment, the heat transfer coefficient and the temperature drop gradually decreased in the order of the third and fourth cooling units 34C and 34D, which are located downstream in the air blowing direction (-X side) from the second cooling unit 34B. In the embodiment, it was also found that in the first cooling unit 34A adjacent to the intake side (-X side) of the blower 31, heat from the insulating oil L was transferred to the air flowing due to the intake of the blower 31, causing the temperature of the insulating oil L to drop.

[0033] In the comparative example, the heat transfer coefficient and temperature drop (decreasing width) were greatest in the first cooling unit 34A adjacent to the +X side of the blower 31. In the comparative example, the heat transfer coefficient and temperature drop gradually decreased in the order of the second to fourth cooling units 34B to 34D, which are located downstream in the airflow direction (-X side) from the first cooling unit 34A. Here, in the comparative example, the heat transfer coefficient and temperature drop were particularly small in the fourth cooling unit 34D, which is farthest from the blower 31. This is presumably due to a large amount of leakage air and a small flow velocity of the air blown from the blower 31.

[0034] The analysis results showed that the average value of the heat transfer coefficient shown in FIG. 7A was increased by +0.21% in the embodiment compared to the comparative example, and the average value of the temperature drop shown in FIG. 7B was increased by +0.34% in the embodiment compared to the comparative example.

[0035] 7A can be cooled by the intake air of the blower 31, and cooling by intake air can eliminate leakage air volume and improve cooling efficiency. Moreover, by arranging the cooling unit 34 (first cooling unit 34A) on the intake side (-X side) of the blower 31, it is possible to reduce the number of cooling units 34 arranged on the blower side (+X side) of the blower 31 compared to the comparative example. This makes it possible to reduce the number of cooling units 34 that have a large leakage air volume on both the upper and lower sides, and improve the cooling efficiency of the cooling device 23.

[0036] In addition, the number of cooling units 34 installed upstream of the air blower 31 is one, and the number of cooling units 34 installed downstream is three, so that the number of cooling units 34 cooled by air blowing on the +X side of the air blower 31 is increased, thereby improving cooling efficiency.

[0037] Furthermore, since the two blowers 31 are arranged at different positions in the vertical direction and in the Y direction, the range in which the cooling effect of the blowers 31 can be obtained in those directions can be widened.

[0038] Furthermore, when the blower 31 is surrounded by a guide member 40, the flow rate of air flowing into the first cooling unit 34A on the -X side of the blower 31 can be increased, thereby further improving the cooling efficiency of the first cooling unit 34A.

[0039] The embodiments of the present invention are not limited to the above-described embodiments, and may be variously changed, substituted, or modified without departing from the spirit and scope of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention.

[0040] In this embodiment, the present invention has been described as being applied to an oil-immersed transformer 1, but it can also be applied to other static induction devices as long as the above-described effects can be obtained.

[0041] The contents illustrated in the above embodiment may be modified in terms of the shapes of the magnetic core 2, winding 3, container 10, cooling panel 30, guide member 40, etc., as long as the above-mentioned effects can be achieved.

[0042] Furthermore, the positional relationship between the multiple cooling units 34 and the air blower 31 in the cooling device 23 can be changed in various ways as long as the air blower 31 is sandwiched between two cooling units 34 in the X direction. For example, as shown in Fig. 8, the number of cooling units 34 installed upstream and downstream of the air blower 31 may be the same (two in Fig. 8), or the number installed downstream in the embodiment may be changed to two, four or more.

[0043] Furthermore, the installation position and number of the air blowers 31 may be changed as long as the same functions as those in the above embodiment can be obtained. For example, the number of air blowers 31 may be one, three or more. [Explanation of symbols]

[0044] 1: Oil-immersed transformer 2:Magnetic core 3: Winding 10: Container 23: Cooling device 30: Cooling panel 31: Air blower 34: Cooling unit 40: Guide member L: insulating oil

Claims

1. An oil-immersed transformer comprising: a container that contains a winding, a magnetic core, and insulating oil; and a cooling device that is provided outside the container and cools the insulating oil, the cooling device includes a plurality of cooling panels arranged in parallel in a vertical direction, with the insulating oil flowing inside, and an air blower that blows air toward the cooling panels, wherein a thickness direction of the cooling panels is defined as a first direction, and a direction perpendicular to the first direction as viewed from above is defined as a second direction, a plurality of the cooling panels are arranged in the first direction to form a cooling unit, and a plurality of the cooling units are arranged in the second direction; The oil-immersed transformer is characterized in that the blower device draws in air from one side in the second direction and blows air from the other side, and is positioned between two of the cooling units in the second direction.

2. The oil-filled transformer of claim 1, characterized in that, when viewed from the blower device, the number of upstream cooling units arranged on one side in the second direction and the number of downstream cooling units arranged on one side in the second direction are the same or the number of downstream cooling units arranged is greater.

3. 2. The oil-immersed transformer according to claim 1, wherein the number of the cooling units arranged upstream on one side in the second direction as viewed from the air blower is one.

4. 2. The oil-immersed transformer according to claim 1, wherein a plurality of the blower devices are provided, and at least two of the plurality of blower devices are offset in position in the vertical direction and in the first direction.

5. 5. The oil-immersed transformer according to claim 1, further comprising guide members surrounding the blower on both sides in the up-down direction and on both sides in the first direction.

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