JPH02246103A - Stationary induction apparatus - Google Patents

Abstract

PURPOSE:To increase a radial fastening force of a foil winding and to improve reliability of a stationary induction apparatus by providing a metal sheet which is integral in an axial direction in the middle of the foil winding as a part of the foil winding. CONSTITUTION:A metal sheet 2 which is divided in axial direction is laminated and wound around an iron core leg 3. A metal sheet 4 which is integral in axial direction is provided in the middle of a foil winding 1 as a part of the foil winding 1 in a stationary induction apparatus which constitutes the foil winding 1. Thereby, it is possible to realize easy transposition, to improve a space factor and cooling characteristics and to increase radial fastening force of the foil winding 1.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to stationary induction appliances.

[Conventional technology]

Those equipped with foil windings made of metal sheets around the core legs have a better space factor than stationary induction appliances using regular windings, so they have the advantage of being smaller and lighter. It has been put to practical use in low-voltage, small-capacity transformers of about 10 kVA to several 100 kVA. Recently, in view of the excellent advantages of such foil-wound transformers, higher voltage and larger capacity transformers such as 275kV have been developed.

Research is being actively conducted to expand the application to 100 MVA class transformers.

[Problem to be solved by the invention]

Those equipped with foil windings can alleviate the problem of eddy current concentration near the upper and lower ends of the windings, which is a problem with foil-wound transformers, improve the cooling capacity of the windings, and have a robust winding tightening structure. However, there is still room for further improvement.

Regarding the problem of concentration of eddy current near the upper and lower ends of the winding, as shown in FIG. There are inventions in which the foil windings 1 are mutually transposed to reduce eddy currents, but in addition to the fact that special measures are required to transpose the wide foil windings 1, the foil windings 1 are divided into multiple pieces. Because of this, it has become more difficult to tighten the foil winding 1 in the radial direction, and a new problem has arisen in that it is difficult to securely hold the foil winding 1.

For this reason, Japanese Patent Publication No. 62-50047 discloses an invention in which cooling ducts having high robustness are sequentially inserted inside the foil winding in the radial and circumferential directions.

Since this cooling duct has a hollow structure made of stainless steel, which is different from the foil winding, the space factor of the foil winding inevitably decreases, and it also becomes difficult to cause dislocation to alleviate eddy current concentration. new ones will also arise.

The present invention has been made in view of the above points.

The purpose of the present invention is to provide a stationary induction electric appliance with improved reliability.

[Means to solve the problem]

The above purpose is achieved by providing an integral metal sheet in the axial direction in the middle of the foil winding and making it a part of the foil winding.

achieved.

[Effect]

Since the above means are provided, dislocation is easy and the space factor is low.

The cooling characteristics are improved, and the tightening force of the foil winding in the radial direction can be made more robust, so that the reliability of the stationary induction electric appliance can be improved.

In other words, the axially integrated (undivided) metal sheets that are sequentially placed in the middle of the axially divided foil winding form a part of the foil winding and have high rigidity, so the foil winding is Not only the space factor is greatly improved, but also a sufficient and robust tightening force in the radial direction of the foil winding can be ensured.

Further, since this axially integrated metal sheet has a shape with a space in the axial direction, this can be used as a flow path for a coolant for cooling the foil winding. Further, by changing the axial position of each split foil winding connected to both side walls of the axially integrated metal sheet, transposition can be easily performed with a degree of freedom.

As described above, the present invention improves the tightening force and cooling performance, which were considered problems with the conventional divided foil winding structure.

This makes it possible to solve problems such as simple dislocation all at once.

〔Example〕

The present invention will be described below based on two illustrated embodiments. FIG. 1 shows an embodiment of the invention. Note that parts that are the same as those in the conventional system are given the same reference numerals, and therefore their explanations will be omitted. The metal sheets 2 divided in the axial direction are overlapped and wound around the iron core leg 3, and in the stationary induction electric device constituting the foil winding 1, in this embodiment, the metal sheet 4 integrated in the axial direction is placed in the middle of the foil winding vA1. It was provided as a part of the foil winding 1. By doing this, dislocation is easy, the space factor and cooling characteristics are improved, and the tightening force of the foil winding 1 in the radial direction can be made strong, which has been a problem in the past. Problems such as dislocation, clamping force, and cooling performance can now be solved, and a stationary induction electric appliance with improved reliability can be obtained.

That is, a foil winding 1, which is wound with a metal sheet 2 and an insulating sheet 5 superimposed on each other, is wound around the iron core leg 3 of the transformer in the @ direction.
It is divided into parts.

Then, integral metal sheets 4 are sequentially inserted in the radial and circumferential directions of the wound foil winding 1 in the axial direction of the corrugated shape, and each side wall of the integral metal sheet 4 is inserted in the axial direction. Split sheets are connected.

This axially integrated metal sheet 4 has a thickness ranging from several times to several tens of times that of the metal sheet 2 constituting the other divided foil windings 1.
Since it is twice as thick and has a wavy shape, a space 6 is secured in the axial direction of the foil winding 1.

Therefore, in such a configuration, a part of the foil winding 1 is integrated in the axial direction and is composed of the highly rigid metal sheet 4, so that the foil winding group 1a is divided into two parts without reducing the space factor.
, lb, lc, and ld can be firmly tightened in the radial direction, and the foil winding 1 can be held securely. In addition, the refrigerant can easily pass through the axially extending spaces 6 formed on both side walls of the axially integral metal sheet 4.

The heat generated by the foil winding 1 can be efficiently cooled down.

2. Although this example shows an example in which the foil winding is divided into four parts in the axial direction, the number of divisions is not particularly limited, and the width in the axial direction of the group of foil windings divided into one There is no need for them to be approximately equal as in this embodiment. In other words, in foil-wound transformers, eddy currents tend to concentrate near the top and bottom ends of the foil windings, so taking this into consideration, it is better to make the widths of the top and bottom foil windings smaller than near the center to reduce eddy currents. Naturally, it is also possible to apply such a foil winding structure to the two embodiments since concentration can be alleviated. Furthermore, the structure of the metal sheet that is integral in the axial direction provided in the middle of the foil winding is not limited to a simple wavy shape as in the nine embodiments, but can also have an axial structure such as a honeycomb structure or a hollow structure. Of course, it is also possible to have a structure that has both directional space and sufficient rigidity. Therefore, with such a highly rigid structure, the thickness of the metal sheet that is integrated in the axial direction does not necessarily have to be several to several tens of times the thickness of the metal sheet that constitutes the split foil winding, and it is almost It is also possible to have the same thickness.

Another embodiment of the invention is shown in FIG.

In this embodiment, the foil winding groups la and l are divided into four in the axial direction.
Although b, lc, and ld are connected to both side walls of an axially integrated corrugated metal sheet 4 provided midway in the radial and circumferential directions, the axial connection positions are different. The electric current is made to flow diagonally in the axial direction through the integrated metal scrap sheet 4 as shown by the arrow. That is, the axially integral metal sheets 4 arranged at four locations in the circumferential direction function to change the axial positions of the four foil winding groups 1a, lb, lc, and ld, respectively. .

With this configuration, it is now possible to easily realize the transposition of the wide foil winding 1, which conventionally required special measures.
Compared to the above-mentioned case, the phenomenon peculiar to foil-wound transformers in which overcurrent concentrates locally and heats two localized areas can be significantly alleviated.

FIG. 3 shows yet another embodiment of the invention. In this embodiment, metal sheets 7a, 7b, 7c, and 7d are integrally formed in the axial direction and are curved into an arc of approximately 360° in the middle of the foil wrap that is divided in the axial direction and wound in the radial direction. This is a case where they are overlapped in the radial direction and their end faces protrude in a stepped manner. In this way, the metal sheet 7a is integral in the axial direction.

The reason why the end faces of 7b, 7c, and 7d are made to protrude in a stepped manner is because
This is to facilitate attachment of the metal sheets constituting the split foil winding 1 connected to both side walls of the metal sheets 7a, 7b, 7c, and 7d. 4 layers in the radial direction.

Among the metal sheets 7a, 7b, 7c, and 7d that are integral in the axial direction, the third layer metal sheet 7c has a wavy shape, and the space 6 extending in the axial direction is secured over almost the entire circumference. It has become.

By adopting such a structure, compared to a structure in which the metal sheets 78 to 7d that are integrated in the axial direction are divided and arranged in the circumferential direction, not only can the divided foil winding 1 be supported more firmly,
Sufficient cooling performance can also be ensured.

Note that this embodiment shows a configuration in which a corrugated metal sheet is placed in the third layer from the inside.

Needless to say, achieving the above effects is not limited to the third layer.

FIG. 4 shows yet another embodiment of the invention. In this embodiment, in the middle of the foil winding 1 which is divided and wound in the axial direction,
It is curved into an arc that is roughly divided in half.

and axially integral metal sheets 8a, 8b*8c.

This is a case in which two sets of 8d are stacked on top of each other in the radial direction. These metal sheets 8a, 8b, 8c.

Among the metal sheets 8d, the outer layer portions of the metal sheets 8b and 8d have a corrugated shape, and have a structure in which a space 6 extending in the axial direction is secured over almost the entire circumference.

With such a structure, the production and workability of the axially integrated metal sheets 88 to 8d can be made easier than in the case described above.

The effect is not different from that of the embodiments described so far, but only to enhance them.

In this embodiment, a total of four metal sheets are inserted in the foil winding 1 in appropriate combinations, two sets of metal sheets in the radial direction and two sets in the circumferential direction. It is of course possible to vary the number of metal sheets combined.

According to the above-described first embodiment of the present invention, problems that have been regarded as problems in the foil winding structure divided into a plurality of pieces in the axial direction, such as improvement of the tightening force, space factor, and cooling characteristics, as well as realization of simple dislocation, can be solved. Since these problems can be solved all at once, a highly reliable foil-wound transformer can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the reliability of a stationary induction appliance is improved, and a stationary induction appliance with improved reliability can be obtained.

[Brief explanation of drawings]

Fig. 1 is a perspective view of one embodiment of the stationary induction appliance of the present invention, Fig. 2 is a perspective view of another embodiment of the stationary induction appliance of the invention, and Fig. 3 is a perspective view of another embodiment of the stationary induction appliance of the invention. FIG. 4 is a vertical side view of still another embodiment of the stationary induction device of the present invention, and FIG. 5 is an explanatory diagram showing the structure and transposition of a conventional stationary induction device. 1... Foil winding, la, lb, lc, ld-foil winding group. 2... Metal sheet divided in the axial direction, 3... Iron core leg, 4... Metal sheet integrated in the axial direction 1', 7a
, 7bt7c, 7d... Metal sheets integrated in the axial direction (L formed in an arc shape of 360") 8a, 8b
, 8c, 8d...A metal sheet (formed in a half-circular arc shape) that is integral in the axial direction. Figure 1

Claims (7)

[Claims] 1. In a stationary induction appliance in which metal sheets divided in the axial direction are overlapped and wound around a core leg to form a foil winding, an integral metal sheet is provided in the axial direction in the middle of the foil winding, and the foil winding is A stationary induction electric appliance characterized by having a part. 2. The stationary induction electric appliance according to claim 1, wherein the axially integral metal sheet has a plurality of axial gaps. 3. Claim 1, wherein the divided foil winding groups connected to both side walls of the integral metal sheet in the axial direction are configured such that their connection positions change in a predetermined relationship in the axial direction. stationary induction appliances. 4. The stationary induction electric appliance according to claim 1, wherein the axially integral metal sheet is arranged singly or in combination in the circumferential direction and radial direction of the foil winding. 5. The metal sheet that is integrated in the axial direction has a thickness ranging from several times to several tens of times that of the divided metal sheet.
The stationary induction electric appliance according to claim 1, which is twice as large. 6. 2. A stationary induction electric appliance according to claim 1, wherein said axially integral metal sheet is formed into a substantially 360° arc shape. 7. The stationary induction electric appliance according to claim 1, wherein the axially integral metal sheet is formed into an approximately half-circular arc shape.