JPH0132339Y2 - - Google Patents

Abstract

1. A winding for an air-cooled transformer or reactor comprising at least two winding layers and having the following structure : the innermost winding layer (1) extends continuously across the full axial length of the winding ; the winding layers (2, 3 ...) joining said innermost winding layer in radial outward direction are formed of a pair of essentially equally long sections (10, 11) which are divided in a position equal to about one-half of the axial length, said section alternatingly electrically connected or coupled to the overlying and underlying winding layer or winding sections, respectively, in their axial end and central regions ; the winding layer (s) is (are) isolated from the other concentrically positioned winding layer (s) by hollow spaces froming cooling channels (18) ; bar-shaped spacers (6, 7) are disposed in said hollow spaces so as to extend in axial direction, characterized in that distributed with a spacing around the circumference in said cooling channels (18) and extending in the axial direction, a pair of axially aligned spacer element (6, 7) are each positioned in the region of the electrical connections between the winding layers of said winding sections (10, 11), with the length of each spacer element being about 0,1 to 0,3, preferably slightly more than 0,25, of the axial length ; and that a peripheral outwardly open air channel (20) is interposed between said winding sections in a position corresponding to about one-half of the axial length.

Description

[Detailed description of the invention] [Industrial application field] This invention consists of at least two winding layers, a cooling passage formed between the winding layers, and a cooling passage arranged along the axial direction within the cooling passage. The present invention relates to a coil for an air-cooled dry transformer having a spacer member.

[Conventional technology]

In so-called dry type transformers or similar dry-type transformers or similar dry-type coils having an air cooling path, a winding construction method is known in which an innermost winding layer is provided over the entire length of the coil. When the winding reaches the axial end of the coil, a spacer member for the air cooling path is installed, and then the next winding layer is installed in the opposite direction over the entire axial length of the coil. This process of alternating direction reversals is repeated until the required number of winding layers in the coil is obtained. Such a conventional method is shown diagrammatically on the left side of FIG. The winding layers 1, 2, 3, 4 are alternately connected at opposite ends and separated by air channels or spacer members. It can also be seen from the figure that the voltage difference between the winding layers at the opposite end of the electrical connection reaches a considerably large value. It is known to transformer manufacturers that due to mechanical and electrical requirements, sufficient safety distances must be provided between windings to be mutually insulated between adjacent winding layers. It must also be noted that as the transformer ages, its initial high insulation properties may deteriorate due to contamination, material fatigue or change, or crack formation. Particular attention must be paid to the formation of leakage current paths.

[The problem that the idea aims to solve]

In designing the structure, transformer manufacturers must take care to ensure that the high-purity, high-insulating material used as the spacer member has sufficient durability. However, such materials are often very expensive and are therefore often replaced with cheaper materials that are less insulating and less durable. It is also necessary to take into account the insulating air present in the cooling path.

Because of these problems, in the conventional technology shown on the left side of Figure 1, insulation plays an important role because the voltage difference between adjacent winding layers is relatively large, and the cost thereof makes the transformer very expensive. .

It would therefore be desirable to create a coil for an air-cooled dry type transformer in which the maximum voltage difference between adjacent winding layers is generally smaller and the performance requirements for the insulation means are reduced compared to those of the prior art. However, in this case, in order to avoid difficulty in forming the coil, it is necessary to keep the width of the air cooling path small without impeding the air cooling effect.

[Means to accomplish the task]

In order to achieve these objectives, according to the air-cooled dry transformer coil of this invention, an innermost winding layer is provided over the entire length of the coil in the axial direction, and a winding layer radially outward from the innermost winding layer is provided. Each winding layer consists of a pair of partial windings of approximately the same length divided at approximately half the axial length. Each of the above winding layers is alternately electrically connected to the inner or outer winding layer at the shaft ends and the center, and each winding layer is concentrically connected to the other winding layer through a hollow part forming an air cooling path. separated. A pair of spacer member groups of rod-shaped spacers provided in the axial direction in the hollow portion are distributed in the circumferential direction within the air cooling path, and each spacer member pair is arranged in an electrical connection area between the winding layers of the partial winding. do.
The length of each spacer member is set to approximately 0.1 to 0.3, preferably slightly larger than 0.25, of the axial length, and the air gap 20 opened outward on the circumferential surface is partially wound at a position approximately half the axial length. It is characterized by being interposed between the lines.

Each conducting wire is preferably composed of a single-core wire, but if high output is required, it is also possible to wind multi-core wires at the same time.

By using a new winding method for the main load section, as shown on the right side of FIG. 1, the voltage difference between adjacent winding layers can be reduced and air insulation is fully possible. It is necessary to use a spacer member to fix each winding layer and improve its mechanical strength; however, the conventional method of fixing the winding layers, for example by resin injection, provides higher strength, so spacer members can be used as partial windings. It is not necessary to provide it over the entire length of the

〔Example〕

This invention will be explained below with reference to embodiments shown in the drawings.

The prior art has already been described in connection with the left half of FIG. In the coil of this invention, as shown in the right half of FIG. 1, an iron core is provided in the center as required. This figure shows the principle; other windings may be provided between the above-mentioned windings and the iron core, for example in a structure consisting of an iron core, a low voltage winding and a high voltage winding.

In the figure, the innermost winding layer 1 adjacent to the iron core
is provided over the entire length of the coil in the axial direction.
This point is common to all embodiments. The winding layers 2, 3, . A portion that is electrically connected to an adjacent outer or inner winding layer at an axial end or a central portion by connecting wires 12, 13, and is therefore substantially symmetrical between one end and the other end of the coil. winding 10',
11' is formed. Each partial winding has an external terminal 14, 15. Inside the coil, the two partial windings 10', 11' are interconnected via the innermost winding layer 1.

Spacer members 6 and 7 are provided between each winding layer to form a cooling path and to insulate the winding layers.

Next, the specific structure shown in FIGS. 2 and 3 will be explained.
A mantle 21 is provided on the innermost side of the coil, and a parallel winding layer 1 preferably made of insulated copper wire or aluminum wire is provided on the outside thereof. 1st
A glass fiber mantle 23 is provided on the outside of the winding layer by a wet winding method. In this case glass fibers impregnated with epoxy resin are used, the curing of which results in a mechanically very strong cylinder. After this glass fiber mantle layer 23 is cured, a spacer member 6 is placed on the outside thereof, and a mantle layer 25 made of impregnated insulating glass fiber is further provided. The spacer member 6 is thereby fixed. A next winding layer 27 is then applied, followed by an intermediate layer of insulating and curable material. The subsequent layer configurations are also provided in the manner described above. The outermost part is a mantle 3 made of glass fiber reinforced synthetic resin.
2 is provided.

Figure 3 shows the characteristics of the winding. The inner layer 1 is composed of a tightly wound wire and is provided over the entire length of the coil in the axial direction. After providing the glass fiber mantle layer 23, a spacer member 6 is placed, the length of which is preferably slightly greater than one quarter of the axial length of the coil. The next spacer member is placed so as to slightly overlap this. It is also possible to use shorter spacer members. The winding layer 2 provided on the outside of this spacer member has two partial windings 1 of substantially equal length, which divide the axial length of the coil into two.
0 and 11, which are electrically connected to the inner winding layer 1 at the shaft end by connecting wires 12 and 13. The partial windings 10, 11 are wound symmetrically to each other up to approximately the center of the coil, leaving an air gap 20 in the center. Both partial windings 10, 11
are now electrically connected to the outer winding layer by connecting wires 29, 30. Then the partial windings of the third winding layer are wound. A terminal 14 is provided at the end of the left partial winding in FIG. The right partial winding in FIG. 3 is provided with a plurality of taps and thus has, in addition to the outermost terminal 15, an intermediate tap terminal 15'.
This allows tapping to achieve voltage balance as is known in transformer technology.
In the coil arrangement shown, the air gap 20 is outwardly open at the circumference, so that the outer mantle is not continuous. This improves insulation and cooling and prevents the formation of leakage current paths.

[Effect of idea]

As mentioned above, the spacer members 6, 7 do not span the entire axial length of the coil, but about 4 axial lengths at each end.
It only accounts for one-third of the total. The length of the spacer member is determined by the mechanical load and ranges from one-fifth to three-fifths of the semi-axial length.

Between the ends with a large voltage difference, the air gap completely insulates the winding layers from each other, so that no leakage current paths are formed. Furthermore, air gap 2 in the center
0 electrically separates both partial windings 10', 11'. The foregoing arrangement allows the use of cheaper and lower performance insulation materials and provides improved cooling efficiency with narrow cooling channels without other disadvantages.

[Brief explanation of the drawing]

FIG. 1 is a theoretical explanatory diagram showing a comparison between a conventional coil and a coil according to this invention, FIG. 2 is a cross-sectional view showing an embodiment of this invention, and FIG. 3 is a longitudinal sectional view of the same. 1... Innermost winding layer, 2, 3, 4... Outer winding layer, 6, 7... Spacer member, 10, 11... Partial winding, 12, 13... Connection wire.

Claims (1)

[Scope of utility model registration request] A coil for an air-cooled dry type transformer having at least two winding layers, wherein the innermost winding layer 1 is provided over the entire axial length of the coil, and the innermost winding layer is radially outward. Each winding layer 2, 3
is composed of a pair of partial windings 10 and 11 of approximately the same length divided at a position approximately half the shaft length, and each of the winding layers is connected to the inner or outer winding layer at the end of the shaft and at the center. A pair of spacer members 6, each of which is electrically connected alternately and each winding layer is concentrically spaced from another winding layer through a hollow portion forming an air cooling path, and a rod-shaped spacer is provided in the hollow portion in the axial direction. 7 groups are distributed in the circumferential direction within the air cooling path, and each pair of spacer members is arranged in the electrical connection area between the winding layers of the partial winding, and the length of each spacer member 6, 7 is approximately equal to the axial length.
An air-cooled dry transformer characterized in that an air gap 20, which is slightly larger than 0.1 to 0.3, preferably slightly larger than 0.25, and which opens outward on the circumferential surface is interposed between the partial windings at a position approximately half of the axial length. Dexterity coil.