JP2022118358A - transformer - Google Patents

Abstract

To provide a transformer capable of intensively cooling an upper winding.SOLUTION: An upper winding and a lower winding are formed by dividing a winding in the vertical direction in which a cooling medium circulates, and the cooling medium is introduced to the upper winding through an inlet formed between the upper winding and the lower winding to cool the upper winding intensively.SELECTED DRAWING: Figure 3

Description

The present invention relates to transformers.

Windings of oil-immersed distribution transformers are cooled by circulating insulating oil inside the tank. The insulating oil whose temperature has risen becomes less dense and moves to the top, while the cooled insulating oil becomes more dense and moves to the bottom of the tank and is drawn into the winding, taking heat from the winding and moving to the top. . The winding has a heat distribution similar to the temperature distribution of the insulating oil circulating above and below. In addition, cooling ducts are provided to cool the windings, and the number and arrangement of the cooling ducts are arranged so as to optimize cooling.

On the other hand, in this series of cooling systems, there is always a temperature difference between the upper and lower parts of the winding, and the upper part of the winding is always operated at a higher temperature than the lower part, and thermal deterioration occurs quickly. On the other hand, in order to cool only the upper portion of the winding, the current technology is to arrange many cooling ducts over the entire winding. As a technique related to this, there is Patent Document 1, for example. In Patent Document 1, an oil passage is provided to cool the winding.

JP 2009-2224690 A

In Patent Document 1, it is difficult to implement a cylindrical winding in which the winding is thickened in the radial direction of the cylindrical tube, and the winding is thickened in the radial direction of the circle, and it is stacked in many layers in the height direction. This is an application example for stacking disc windings.

In Patent Literature 1, it is difficult to reduce the temperature difference between the upper and lower windings to suppress thermal deterioration of the windings over a long period of time, and it is difficult to intensively cool the upper windings.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transformer capable of preferentially cooling the upper winding.

A transformer of one aspect of the present invention includes a tank in which an iron core and a winding wound around the iron core are arranged, the tank is filled with a cooling medium, and the winding contains the A transformer that passes a cooling medium to cool the winding, wherein the winding is divided in the vertical direction in which the cooling medium circulates to form an upper winding and a lower winding, and the upper winding and the lower winding, the cooling medium is introduced into the upper winding through a gap formed between the lower winding and the lower winding to cool the upper winding.

A transformer of one embodiment of the present invention is a transformer that includes an iron core and a winding wound around the iron core, wherein the winding is divided vertically to form an upper winding and a lower winding. A first cooling duct is arranged in the lower winding, a second cooling duct is arranged in the upper winding, and the number of the second cooling ducts is the second It is characterized in that the second cooling ducts are arranged in the upper winding so that the number of the cooling ducts is larger than that of one cooling duct.

According to one aspect of the invention, the cooling can be focused on the top winding of the transformer.

It is a perspective view which shows the structure of the transformer of related technology. FIG. 4 is a cross-sectional view of the inside of a tank showing the streamlines of insulating oil in a related art transformer; 1 is a perspective view showing a configuration of a transformer of Example 1; FIG. 4 is a cross-sectional view of the inside of the tank showing the streamlines of insulating oil in the transformer of Example 1. FIG. It is sectional drawing of the winding in the transformer of Example 2, (a) is a lower winding and (b) is an upper winding. It is sectional drawing of the winding in the transformer of Example 3, (a) is a lower winding and (b) is an upper winding. It is sectional drawing of the winding in the transformer of Example 4, (a) is a lower winding and (b) is an upper winding. FIG. 11 is a cross-sectional view of the inside of the tank showing the streamlines of the insulating oil in the transformers of Examples 3 and 4;

First, a related art transformer will be described with reference to FIGS.

As shown in FIG. 2, a transformer tank 6 is filled with insulating oil 7 as a cooling medium. A winding 5 is built in the tank 6 . The cooled insulating oil 7 then flows through the tank 6 as indicated by flow paths 8 . Moreover, as shown in FIG. 1, windings 5 are wound around the outer iron core 1 and the inner iron core 2 .

In general, the temperature of the insulating oil 7 rises as it is positioned higher. There is a hot spot (shaded area in FIG. 2), which is a portion that becomes hot.

The related art transformer has a structure in which the insulating oil 7 passes through the winding 5 to cool the entire winding 5, and it is difficult to cool the hot spots of the winding 5 directly. As a result, the winding temperature rises only at the hot spots of the winding 5 .

Embodiments of the present invention employ a configuration that permits simultaneous cooling of the hot spots of the winding 5 and cooling of the entire winding 5 .

By adopting the above configuration, it becomes possible to intensively cool the hot spots of the windings 5 . Specifically, the cooling of the hot spots of the winding 5 and the cooling of the entire winding 5 by passing the insulating oil 7 through the winding 5 are simultaneously performed.
An embodiment will be described below with reference to the drawings.

The transformer of Example 1 will be described with reference to FIGS. 3 and 4. FIG.

As shown in FIG. 3, the transformer of Example 1 comprises an upper winding 3 and a lower winding 4 by dividing the winding 5 of the transformer shown in FIG. do. An upper winding 3 and a lower winding 4 are wound around the outer iron core 1 and the inner iron core 2 .

As shown in FIG. 4 , an insulator 10 corresponding to the insulation class is inserted into a gap (space) formed between the upper winding 3 and the lower winding 4 . As for the material of the insulator 10, for example, the insulator 10 such as a press board is arranged to secure an insulation distance. Then, an inlet for introducing the insulating oil 7 for cooling in the space into the upper winding 3 is formed. This insulation distance is achieved, for example, by arranging a pressboard with a thickness of several millimeters.

In this manner, in the first embodiment, the insulating oil 7 is introduced into the upper winding 3 through the inlet, which is the gap formed between the upper winding 3 and the lower winding 4, so that the upper winding 3 is intensively cooled.

A transformer of Example 2 will be described with reference to FIG. (a) is a cross-sectional view of the lower winding 4, and (b) is a cross-sectional view of the upper winding 3. FIG.
The configuration of the transformer of Example 2 is substantially the same as the configuration of the transformer of Example 1 shown in FIGS. 3 and 4, so the description thereof will be omitted.

The tendency of heat deterioration differs depending on the difference between the top and bottom of the winding, but when many cooling ducts are installed considering the top of the winding, the volume of the entire transformer increases and it is not effective. In the second embodiment, the winding is divided into upper and lower parts, and the thickness and number of cooling ducts are changed between the upper and lower parts to equalize the temperature difference between the upper and lower parts of the winding.

In the transformer of Example 2, the number and thickness of the cooling ducts are arranged differently between the upper winding 3 and the lower winding 4 .

The upper winding 3 has cooling ducts 11 that are used for the lower winding 4, for example, with half the thickness of the cooling ducts 12 arranged twice as many layers of the winding. As a result, the cross-sectional areas of the upper winding 3 and the lower winding 4 are matched by matching the outer shape of the windings. This minimizes the influence on the electrical characteristics due to the imbalance between the upper and lower windings when the upper winding 3 and the lower winding 4 are connected in parallel.

In the transformer of Example 2, a cooling duct 11 is arranged in the lower winding 4 as shown in FIG. 5(a). A cooling duct 12 is arranged in the upper winding 3, as shown in FIG. 5(b).

The cross-sectional area of the contour of the lower winding 4 is equal to the cross-sectional area of the contour of the upper winding 3 . The number of cooling ducts 12 in the upper winding 3 is greater than the number of cooling ducts 11 in the lower winding 4 . Furthermore, the thickness of the cooling duct 12 of the upper winding 3 is less than the thickness of the cooling duct 11 of the lower winding 4 .

A transformer of Example 3 will be described with reference to FIG. (a) is a cross-sectional view of the lower winding 4, and (b) is a cross-sectional view of the upper winding 3. FIG.

Since the configuration of the transformer of Example 3 is substantially the same as that of the transformer of Example 1 shown in FIG. 3, the description thereof will be omitted.

In the transformer of Example 3, the numbers of cooling ducts are arranged differently between the upper winding 3 and the lower winding 4 .

As shown in FIG. 6A, the lower winding 4 has a length of A1 in the direction of the inside of the window (hatched area in FIG. 6) and a length of _B1 on the _side excluding the inside of the window. As shown in FIG. 6(b), the upper winding 3 has a length of _A2 in the window inner direction and a side length of B2 excluding the window inner _side .

Here, the length A1 of the lower winding 4 in the in-window direction is equal to the length _A2 of the upper winding ₃ in the in-window direction. In addition, the length B2 of the side of the upper winding 3 excluding the inside of the window is longer than the length _B1 of the _side of the lower winding 4 excluding the inside of the window.

As shown in FIG. 6( a ), a cooling duct 11 is arranged in the lower winding 4 . A cooling duct 11 is arranged in the upper winding 3, as shown in FIG. 6(b). Here, the number of cooling ducts 11 of the upper winding 3 is greater than the number of cooling ducts 11 of the lower winding 4, and the thickness of the cooling ducts 11 of the upper winding 3 is equal to that of the cooling ducts 11 of the lower winding 4. is the same as the thickness of

By arranging many cooling ducts 11 having the same thickness as the lower winding 4 in the upper winding 3, the area of the winding (electrical wire) in contact with the insulating oil 7 for cooling is increased. Since the outer shape of the core becomes large in the window inward directions A ₁ and A ₂ , more cooling ducts 11 are arranged on the two sides B ₂ of the upper winding 3 excluding the inside of the window.

Thus, in the transformer of Example 3, the number of cooling ducts is different between the upper winding 3 and the lower winding 4, and the outer shape B2 of the _two sides of the upper winding 3 is larger than the outer shape _B1 of the lower winding 4. growing.

As shown in FIG. 8, in the outer winding (electric wire) having a large outer diameter, the insulating oil 7 introduced from below does not flow through the gap between the upper winding 3 and the lower winding 4, but rather flows through the insulating oil 7. It is introduced directly from below via the streamline 9 . When the upper winding 3 and the lower winding 4 are connected in series, even if the upper winding 3 and the lower winding 4 have different outer shapes, the electrical characteristics are hardly affected.

The cooling ducts 11 for windings (electric wires) on the outer periphery are easily cooled directly by the insulating oil 7, so the number of the cooling ducts 11 may be the same and the thickness may be reduced. The inner windings (electric wires) introduced through the gap between the upper winding 3 and the lower winding 4 are made to have the same thickness as the cooling duct 11, and the number of the windings is increased to increase the number of inner windings that are difficult to cool. You may make it cool.

In Example 3, the cooling effect can be maintained while suppressing an increase in external dimensions. As for the in-window directions A ₁ and A ₂ , the outer shape of the upper winding 3 is matched with the outer shape of the lower winding 4 to suppress an increase in core size.

A transformer of Example 4 will be described with reference to FIG. (a) is a cross-sectional view of the lower winding 4, and (b) is a cross-sectional view of the upper winding 3. FIG.

The configuration of the transformer of Example 4 is substantially the same as the configuration of the transformer of Example 1 shown in FIG. 3, so the description thereof will be omitted.

In the transformer of Example 4, the numbers of cooling ducts are arranged differently between the upper winding 3 and the lower winding 4 .

As shown in FIG. 7A, the lower winding 4 has a length of A1 in the direction of the inside of the window (hatched area in FIG. 7), and a length of _B1 on the _side excluding the inside of the window. As shown in FIG. 7(b), the upper winding 3 has a length of _A2 in the window inner direction and a _side length of B2 excluding the inside of the window.

Here, the length A2 of the upper winding 3 in the in-window direction is greater _than the length A1 of the lower winding ₄ in the in-window direction. In addition, the length of the side of the upper winding 3 excluding the inside of the window is B2, and the length of the _side of the lower winding 4 excluding the inside of the window is longer than _B1 .

As shown in FIG. 7( a ), a cooling duct 11 is arranged in the lower winding 4 . A cooling duct 11 is arranged in the upper winding 3, as shown in FIG. 7(b). Here, the number of cooling ducts 11 of the upper winding 3 is greater than the number of cooling ducts 11 of the lower winding 4, and the thickness of the cooling ducts 11 of the upper winding 3 is equal to that of the cooling ducts 11 of the lower winding 4. is the same as the thickness of

By arranging many cooling ducts 11 having the same thickness as that of the lower winding 4 in the upper winding 3, the area of the winding (electrical wire) in contact with the insulating oil 7 for cooling is increased. A large number of cooling ducts 11 are arranged in the upper winding 3 on the two sides B ₁ and B ₂ excluding the inner direction A ₁ and A ₂ of the window where the core outer shape is large and the inside of the window where the core outer shape is large.

Thus, in Example 4, the numbers of cooling ducts are different between the upper winding 3 and the lower winding 4, and the outline A2 of _two sides of the upper winding ₃ is larger than the outline A1 of the lower winding 4. FIG. Furthermore, the outer shape B2 of _two sides of the upper winding 3 is larger than the outer shape _B1 of the lower winding 4 .

As shown in FIG. 8, a cooling duct 13 is arranged in the gap between the upper winding 3 and the lower winding 4 to fill the gap by introducing insulating oil 7 into the upper winding 3 . Specifically, as shown in FIG. 7 , a cooling duct 13 is arranged over the entire circumference of the lower winding 4 by attaching an insulating material (not shown) such as a rectangle to a backing paper.

In the fourth embodiment, as shown in FIG. 8, in the outer winding (electric wire) having a large outer diameter, the insulating oil 7 introduced from below is not introduced from the gap between the upper winding 3 and the lower winding 4. , directly from below via streamlines 9 of the insulating oil 7 flowing in the cooling duct 13 .
Moreover, when the upper winding 3 and the lower winding 4 are connected in series, even if the outer shape of the upper winding 3 and the lower winding 4 are different, the electrical characteristics are hardly affected.

In the above embodiment, in the winding structure of the oil-immersed transformer, the winding is divided vertically, insulating oil is introduced from the space, and the upper winding is actively cooled by arranging cooling ducts above and below the winding. do. In this way, by dividing the winding into upper and lower parts and changing the thickness and number of cooling ducts in the upper and lower parts, the temperature difference between the upper and lower parts of the winding can be made uniform.

Furthermore, by lowering the temperature of the upper winding, the average temperature of the winding is lowered and uniformed, thereby eliminating the imbalance of thermal deterioration. Also, by lowering the high temperature of the upper part, the entire cooling mechanism such as the tank and insulating oil is compressed. This allows a compact transformer to be provided.

Thus, in the above-described embodiment, the temperature difference between the upper and lower sides of the winding can be reduced to suppress thermal deterioration of the winding over a long period of time. In addition, when the temperature of the transformer itself is raised, for example, by raising the heat resistance class, the temperature of the upper part of the winding can be lowered and the transformer can be made compact by using an inexpensive insulating material.

1 Outer core 2 Inner core 3 Upper winding 4 Lower winding 5 Winding 6 Tank 7 Insulating oil 8 Insulating oil flow line 9 Insulating oil flow line 10 Insulator 11 Cooling duct (lower winding)
12 cooling duct (upper winding)
13 Cooling duct (periphery)

Claims (12)

It has a tank in which an iron core and a winding wound around the iron core are arranged, the inside of the tank is filled with a cooling medium, and the cooling medium is passed through the winding to cool the winding. A cooling transformer,
An upper winding and a lower winding are configured by dividing the winding in the vertical direction in which the cooling medium circulates,
A transformer characterized in that the cooling medium is introduced into the upper winding through a gap formed between the upper winding and the lower winding to cool the upper winding intensively. . An insulator is arranged between the upper winding and the lower winding,
2. A transformer as claimed in claim 1, wherein the insulator forms the gap introducing the cooling medium into the upper winding by ensuring a predetermined insulation distance. A first cooling duct is arranged in the lower winding,
A second cooling duct is arranged in the upper winding,
2. The transformer according to claim 1, wherein said second cooling ducts are arranged in said upper winding such that the number of said second cooling ducts is greater than the number of said first cooling ducts. . the outer shape of the upper winding is the same as the outer shape of the lower winding,
4. The transformer of claim 3, wherein the thickness of said second cooling duct is less than the thickness of said first cooling duct. the lower winding and the upper winding are configured so that their horizontal cross-sectional profiles are equal to each other and the upper winding has a larger cross-sectional profile in the vertical direction than the lower winding;
3. The second cooling ducts are arranged such that the number of the second cooling ducts is greater than the number of the first cooling ducts in the portion having the outer shape in the vertical direction of the cross section. 3. The transformer according to 3. The lower winding and the upper winding are configured such that the upper winding has a larger profile in the horizontal and vertical cross-sectional directions than the lower winding,
The second cooling ducts are arranged such that the number of the second cooling ducts is greater than the number of the first cooling ducts in the portion having the horizontal cross-sectional shape and the portion having the vertical cross-sectional shape. 4. A transformer according to claim 3, characterized in that it is arranged with further disposing a third cooling duct;
7. A transformer as claimed in claim 6, characterized in that the cooling medium is introduced into the upper winding via the third cooling duct. A transformer having an iron core and a winding wound around the iron core,
An upper winding and a lower winding are configured by dividing the winding in the vertical direction,
A first cooling duct is arranged in the lower winding,
A second cooling duct is arranged in the upper winding,
A transformer, wherein the second cooling ducts are arranged in the upper winding so that the number of the second cooling ducts is greater than the number of the first cooling ducts. the outer shape of the upper winding is the same as the outer shape of the lower winding,
9. The transformer of claim 8, wherein the thickness of said second cooling duct is less than the thickness of said first cooling duct. the lower winding and the upper winding are configured so that their horizontal cross-sectional profiles are equal to each other and the upper winding has a larger cross-sectional profile in the vertical direction than the lower winding;
3. The second cooling ducts are arranged such that the number of the second cooling ducts is greater than the number of the first cooling ducts in the portion having the outer shape in the vertical direction of the cross section. 8. The transformer according to 8. The lower winding and the upper winding are configured such that the upper winding has a larger profile in the horizontal and vertical cross-sectional directions than the lower winding,
The second cooling ducts are arranged such that the number of the second cooling ducts is greater than the number of the first cooling ducts in the portion having the horizontal cross-sectional shape and the portion having the vertical cross-sectional shape. 9. A transformer according to claim 8, characterized in that it is arranged with further disposing a third cooling duct;
9. A transformer as claimed in claim 8, characterized in that a cooling medium is introduced into the upper winding through the third cooling duct.

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