WO2015083280A1

WO2015083280A1 - Wound wire

Info

Publication number: WO2015083280A1
Application number: PCT/JP2013/082778
Authority: WO
Inventors: 孝丸横幕; 西浦　竜一; 賢一美濃
Original assignee: 三菱電機株式会社
Priority date: 2013-12-06
Filing date: 2013-12-06
Publication date: 2015-06-11
Also published as: JPWO2015083280A1

Abstract

In an insulating oil-filled transformer, this wound wire is wound around an iron core and immersed in an insulating oil (4). The wound wire is provided with: a conductor (1); an insulating paper (2) covering the conductor (1); and a cotton tape (6), which is constituted by plain-weaving or twill-weaving a cotton yarn having a lower permittivity than the insulating paper (2) but a higher permittivity than the insulating oil (4), is wound directly above the insulating paper (2), and whereof at least a portion is located between the insulating paper (2) and the insulating oil (4).

Description

Winding

The present invention relates to a winding, and more particularly to a winding used in an oil-filled transformer.

Japanese Patent Laid-Open No. 7-6628 (Patent Document 1) is a prior document disclosing a dislocation wire using a woven tape such as cotton tape as an outer periphery insulation. In the dislocation wire described in Patent Document 1, a plastic tape is wound around the dislocation conductor, and a woven fabric tape is wound around the upper layer of the plastic tape.

Japanese Patent Laid-Open No. 5-291060 (patent document) discloses a transformer winding using a wire coated with a combination of a high-density insulating paper and a low-density insulating paper or a material having a high oil impregnation rate, such as a nonwoven fabric. There is literature 2).

In the transformer winding described in Patent Document 2, an insulating material having a high oil impregnation rate, for example, a conventional insulating paper, is almost the same as a part of the conventional insulating paper as a plurality of layers of insulating paper forming an insulating coating. A low density insulating paper or non-woven fabric of the same thickness is used.

Japanese Patent Application Laid-Open No. 7-6628 JP-A-5-291060

In the dislocation wire described in Patent Document 1, a woven fabric tape is wound around a plastic tape. Patent Document 1 describes that a dislocation wire is used in an insulating gas because plastic tape is not oil-immersible and has poor oil resistance in electrical insulating oil.

The transformer winding described in Patent Document 2 uses low-density insulating paper or non-woven fabric, etc., so when forming an insulation coating, the low-density insulating paper or non-woven fabric is easily broken, and the winding is manufactured. Workability at the time was inferior.

The present invention has been made in view of the above-described problems, and provides an easily manufacturable winding having high dielectric strength by suppressing electric field concentration in a minute oil gap in a state immersed in insulating oil. The purpose is to do.

The winding according to the present invention is a winding wound around an iron core and immersed in insulating oil in a transformer containing insulating oil. The winding is composed of a plain weave or twill weave of a conductor, insulating paper covering the conductor, and cotton yarn having a dielectric constant lower than that of the insulating paper and higher than that of insulating oil. And a cotton tape positioned between the insulating paper and the insulating oil.

According to the present invention, it is possible to easily produce a winding having high dielectric strength by suppressing electric field concentration in a minute oil gap in a state immersed in insulating oil.

It is sectional drawing which shows the structure of the coil | winding which concerns on Embodiment 1 of this invention. It is the perspective view which looked at the coil | winding of FIG. 1 from the arrow II direction. It is a one part enlarged view of the cotton tape of the winding | winding which concerns on the same embodiment. It is a partial enlarged view of the cotton tape which concerns on the 1st modification of the embodiment. FIG. 2 is an enlarged view of a V portion surrounded by a dotted line in the winding of FIG. 1. It is an enlarged view of the V section of the coil | winding which concerns on the comparative example in which the cotton tape is not provided. It is a graph which shows the electric field distribution on the straight line 7 of FIG. It is a graph which shows the electric field distribution on the straight line 8 of FIG. In the coil | winding which concerns on the 2nd modification of the embodiment, it is a perspective view which shows the state which wound the cotton tape around the inner peripheral part of the coil | winding. It is sectional drawing which shows the structure of the coil | winding which concerns on Embodiment 2 of this invention. It is a figure which shows the state which has wound the cotton tape in the coil | winding which concerns on the same embodiment.

Hereinafter, the winding according to the first embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing the structure of a winding according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the winding of FIG. 1 as viewed from the direction of arrow II. 1 and 2, only half of the windings according to the present embodiment are shown. Moreover, in FIG. 2, the insulator 3 is not illustrated.

The winding according to the present embodiment is a winding wound around an iron core and immersed in insulating oil in a transformer containing insulating oil. As shown in FIGS. 1 and 2, the winding 9a according to the first embodiment of the present invention is wound in a disk shape around a shaft 9x where the iron core is located. A plurality of disk-shaped windings are wound around the iron core, and the disk-shaped windings adjacent to each other are electrically connected in series.

Specifically, the outer peripheral end of the winding 9a becomes the line end, the inner peripheral end of the winding 9a and the inner peripheral end of the winding 9b are electrically connected, and the outer peripheral end of the winding 9b and the winding 9c The outer peripheral end is electrically connected, and the inner peripheral end of the winding 9c and the inner peripheral end of the winding 9d are electrically connected.

In each of the windings 9a to 9d, a conductor 1 such as a flat copper wire is covered with an insulating paper 2 such as kraft paper. The winding 9a is provided with a cotton tape 6 wound immediately above the insulating paper 2 and at least partially positioned between the insulating paper 2 and the insulating oil.

FIG. 3 is an enlarged view of a part of the cotton tape of the winding according to the present embodiment. As shown in FIG. 3, the cotton tape 6 of the present embodiment is configured by plain weaving of cotton yarn having a dielectric constant lower than that of the insulating paper 2 and higher than that of the insulating oil.

It should be noted that the configuration of the cotton tape 6 is not limited to the above, and, for example, a cotton yarn may be twilled. FIG. 4 is an enlarged view of a part of the cotton tape according to the first modification of the present embodiment. As shown in FIG. 4, the cotton tape 6a of the first modification is configured by twilling cotton yarn having a dielectric constant lower than that of the insulating paper 2 and higher than that of the insulating oil.

As shown in FIG. 2, in the state where the winding 9a is wound around the iron core, the cotton tape 6 is wound so as to cover at least a part of the outer peripheral portion of the winding 9a. Specifically, the cotton tape 6 is wound so as to cover a portion other than the portion drawn out as the line end in the outer peripheral portion of the winding 9a.

In this embodiment, as shown in FIG. 1, an insulator 3 such as a press board is disposed outside the winding 9a. Specifically, the insulator 3 is bent and arranged so as to cover the cotton tape 6.

As shown in FIG. 1, the potential difference Vm between the outer periphery of the winding 9a closest to the line end and the outer periphery of the winding 9b adjacent to the winding 9a is less than the potential difference between the other windings. Is also big. Insulator 3 is disposed in order to secure an insulation distance between the outer periphery of winding 9a and the outer periphery of winding 9b.

FIG. 5 is an enlarged view of a V portion surrounded by a dotted line in the winding of FIG. FIG. 6 is an enlarged view of a V portion of a winding according to a comparative example in which no cotton tape is provided. FIG. 7 is a graph showing the electric field distribution on the straight line 7 in FIGS. FIG. 8 is a graph showing the electric field distribution on the straight line 8 of FIGS.

7 and 8, the vertical axis indicates the electric field, and the horizontal axis indicates the position on the

straight lines

7 and 8. 7 and 8, the electric field distribution of the winding according to this embodiment is indicated by a solid line, and the electric field distribution of the winding according to the comparative example is indicated by a dotted line.

As shown in FIGS. 5 and 6, a wedge-shaped minute oil gap filled with insulating oil 4 is provided between the inside of the corner of the bent insulator 3 and the outside of the corner of the outer periphery of the winding. 5 is formed. As shown in FIG. 5, in the winding 9 a according to this embodiment, the cotton tape 6 is positioned between the insulating paper 2 and the insulator 3. Therefore, the cotton tape 6 is located between the insulating paper 2 and the insulating oil 4 of the minute oil gap 5.

On the other hand, as shown in FIG. 6, in the winding according to the comparative example, the insulating paper 2 and the insulating oil 4 of the minute oil gap 5 are in contact with each other. The dielectric constant of the insulating oil 4 is 2.2, the dielectric constant of the insulator 3 is 4.2, and the dielectric constant of the cotton tape 6 is 2.8.

7 and 8, in the winding according to the comparative example, the electric field generated around the energized conductor 1 protrudes from the insulating oil 4 of the minute oil gap 5 and becomes high. In the winding 9a according to the present embodiment, since the cotton tape 6 shares a part of the electric field, the protruding degree of the electric field in the insulating oil 4 of the minute oil gap 5 is relaxed.

When the insulating paper 2 and the insulating oil 4 of the minute oil gap 5 are in contact like the winding according to the comparative example, the electric field generated around the conductor 1 is concentrated on the insulating oil 4 having the lowest dielectric constant. Discharge may occur.

In the winding 9a according to this embodiment, since the cotton tape 6 having a dielectric constant lower than that of the insulating paper 2 and higher than that of the insulating oil is wound directly on the insulating paper 2, the insulating oil 4 in the minute oil gap 5 is wound. The occurrence of partial discharge can be suppressed by reducing the concentration of the electric field on the substrate.

Also, the cotton tape 6 can be easily wound because it is harder to tear than an insulating paper or non-woven fabric. Specifically, the cotton tape 6 can be wound while being pulled so that the cotton tape 6 is not wrinkled.

As described above, the winding 9a according to the present embodiment suppresses electric field concentration on the minute oil gap 5 while being immersed in the insulating oil 4 and has high dielectric strength, and the winding workability of the cotton tape 6 is improved. Can be easily manufactured.

In addition, when the insulator 3 is arrange | positioned inside the coil | winding 9a, the cotton tape 6 may be wound by the inner peripheral part of the coil | winding 9a. FIG. 9 is a perspective view showing a state in which the cotton tape is wound around the inner periphery of the winding in the winding according to the second modification of the present embodiment. In FIG. 9, only half of the winding is illustrated and viewed from the same direction as FIG. 2.

As shown in FIG. 9, in the second modification of the present embodiment, the cotton tape 6 covers at least a part of the inner periphery of the winding 9a when the winding 9a is wound around the iron core. It is rolled up. Specifically, the cotton tape 6 is wound so as to cover a part other than the part drawn out as the inner peripheral end in the inner peripheral part of the winding 9a.

Also in this case, since the cotton tape 6 is wound just above the insulating paper 2 on the inner periphery of the winding 9a, the electric field generated around the conductor 1 is concentrated on the insulating oil 4 in the minute oil gap 5. The occurrence of partial discharge can be suppressed by relaxing. Further, the cotton tape 6 may be wound around both the outer peripheral portion and the inner peripheral portion of the winding 9a.

Hereinafter, the winding according to the second embodiment of the present invention will be described. Since the winding according to the present embodiment is different from the winding 9a according to the first embodiment mainly in that the cotton tape 6 is wound so as to cover the conductor 1 on the insulating paper 2, the other configurations are the same. Will not repeat the description.

(Embodiment 2)
FIG. 10 is a cross-sectional view showing the structure of the winding according to Embodiment 2 of the present invention. FIG. 11 is a view showing a state in which a cotton tape is wound around the winding according to the present embodiment. In FIG. 10, only half of the winding according to the present embodiment is illustrated, and insulating oil is not illustrated.

The winding according to the present embodiment is also a winding wound around an iron core and immersed in insulating oil in a transformer containing insulating oil. As shown in FIG. 10, the

windings

9e and 9f according to the second embodiment of the present invention are wound in a disk shape around a shaft 9x where the iron core is located. The adjacent winding 9e and winding 9f are electrically connected in series. In each of the

windings

9e and 9f, a wedge-shaped minute oil gap 5 sandwiched between insulating papers 2 is formed between the conductors 1 adjacent to each other.

In the

windings

9e and 9f according to the present embodiment, the potential difference between the winding 9e and the winding 9f is not uniform, and the cotton tape 6 is wound around the conductor 1 located at a location where the potential difference is large. . Thereby, the cotton tape 6 is located between the insulating paper 2 and the insulating oil of the minute oil gap 5 where the electric field is most concentrated.

In the

windings

9e and 9f according to the present embodiment, since the cotton tape 6 having a dielectric constant lower than that of the insulating paper 2 and higher than that of the insulating oil is wound directly on the insulating paper 2, the insulation of the minute oil gap 5 is performed. The concentration of the electric field on the oil 4 can be relaxed and the occurrence of partial discharge can be suppressed.

As shown in FIG. 11, the cotton tape 6 can be easily wound because it is not easily torn compared to insulating paper or non-woven fabric. Specifically, the cotton tape 6 can be wound while being pulled so that the cotton tape 6 is not wrinkled.

As described above, the

windings

9e and 9f according to the present embodiment have high dielectric strength while suppressing electric field concentration on the minute oil gap 5 while being immersed in the insulating oil 4, and are wound with the cotton tape 6. Since workability is good, it can be easily manufactured.

The cotton tape 6 may be wound around at least a part of the conductor 1 on the insulating paper 2 and may be wound over the entire length of the conductor 1.

In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become the basis of a limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. In addition, meanings equivalent to the claims and all modifications within the scope are included.

1 conductor, 2 insulating paper, 3 insulator, 4 insulating oil, 5 fine oil gap, 6,6a cotton tape, 9a, 9b, 9c, 9d, 9e, 9f winding.

Claims

A winding wound around an iron core and immersed in insulating oil in a transformer containing insulating oil,
Conductors,
Insulating paper covering the conductor;
A cotton yarn having a dielectric constant lower than that of the insulating paper and having a dielectric constant higher than that of the insulating oil is formed by plain weaving or twilling, and is wound directly on the insulating paper and at least partly between the insulating paper and the insulating oil Winding comprising cotton tape located on the wire.
The winding according to claim 1, wherein the cotton tape is wound so as to cover at least one part of the outer peripheral part and at least one part of the inner peripheral part in a state of being wound around the iron core.
The winding according to claim 1, wherein the cotton tape is wound around at least a part of the conductor on the insulating paper.