JPH1079314A - Gas insulated induction winding - Google Patents

Abstract

(57) [Summary] To reduce the combined force applied to a bobbin and a corrugated board by thermal shrinkage of an insulating film. The layered insulating film is wound around an insulating reel in a state where the layered insulating film is overlapped on a metal sheet narrower than the layered insulating film. An end insulating film 40 having a small heat shrinkage is interposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winding of a gas-insulated transformer or reactor, and more particularly to a winding having a small mechanical force applied to a bobbin even when an insulating film thermally contracts.

[0002]

2. Description of the Related Art In recent years, it has been recommended that underground substations in large cities adopt non-combustible electrical equipment from the viewpoint of disaster prevention, and the use of insulated electrical equipment such as transformers and reactors has been promoted by gas insulation. ing. FIG. 3 is a perspective view of a main part showing a configuration of a conventional gas insulated induction motor winding. The winding is wound around the outer periphery of the insulating winding frame 1 in a state where the layer 2 is laminated on the metal sheet 3 having a width smaller than that of the layer 2. An end insulating film 4 is interposed in a gap between the layer insulating films 2 at both ends in the axial direction of the metal sheet 3, and the end of the metal sheet 3 is covered with the insulating film. Inside the winding, a corrugated board 5 is interposed in a circulating manner, a cooling duct 6 is secured, and the entire winding is housed in a sealed container (not shown) in which insulating gas is sealed.

In FIG. 3, polyethylene terephthalate is used as a material of the layer insulating film 2 and the end insulating film 4, and an aluminum foil is used as a material of the metal sheet 3. Further, the winding frame 1 and the corrugated board 5 are made of FRP (reinforced plastics material in which glass fiber is impregnated with epoxy resin).

[0004]

However, the conventional apparatus as described above has a problem that the force applied to the bobbin and the corrugated board is increased due to the heat shrinkage of the end insulating film. That is, the temperature of the windings is increased by the heating and drying after being incorporated in the transformer or the reactor and the current supplied during operation, and the insulating film thermally contracts. In the case of polyethylene terephthalate, for example, once it reaches 200 ° C from 20 ° C, its width shrinks by 4%. This generates a mechanical force that clamps the winding radially inward. After that, even if the temperature of the winding falls from 200 ° C., the heat-shrinked portion does not return to its original state due to the properties of the insulating film.
On the other hand, since the metal sheet thermally expands due to the temperature rise, the thermal expansion force acts outward in the radial direction opposite to the contraction force due to the insulating film. This thermal expansion returns to its original value when the temperature of the winding decreases.

FIG. 4 is a perspective view of a main part showing a state of a force generated in the winding of FIG. The arrows in the figure indicate the force generated in the winding due to the temperature rise, the direction of the arrow indicates the direction of the force, and the length of the arrow indicates the relative magnitude of the force. In FIG. 4, when the winding temperature becomes high, the metal sheet 3
At the end of the winding where there is no shrinkage force F1 due to the layer insulation film 2 and the shrinkage force F2 due to the end insulation film 4.
Occur radially inward. Since both the layer insulating film 2 and the end insulating film 4 are made of polyethylene terephthalate, the contraction forces F1 and F2 are the same. Synthetic force F12 acting on reel 1 and corrugated board 5
Is the sum of F1 and F2 and points inward in the radial direction. On the other hand, in the portion where the metal sheet 3 is interposed, the contraction force F1 by the layer insulating film 2 is generated radially inward, and the expansion force F3 by the metal sheet 3 is generated radially outward. Therefore, the resultant force F13 acting on the bobbin 1 and the corrugated board 5 is the difference between F1 and F3 and is directed radially inward.

That is, in the configuration shown in FIG. 4, a large combined force F12, which is twice the contraction force F1, is generated in the winding frame 1 and the corrugated board 5 at the winding end. If the resultant force F12 is too large, the bobbin 1 is mechanically broken or the cooling duct 6 of the corrugated board 5 is crushed, so that the bobbin 1 and the corrugated board 5 are conventionally made thick and durable. I was for that reason,
This has led to a rise in material costs and an increase in the outer dimensions of the winding.

An object of the present invention is to reduce a combined force applied to a bobbin and a corrugated board due to heat shrinkage of an insulating film.

[0008]

According to the present invention, in order to achieve the above-mentioned object, according to the present invention, the layer insulating film is accommodated in a sealed container in which an insulating gas is sealed, and the metal sheet is narrower than the layer insulating film. Are wound coaxially around the outer periphery of the insulating winding frame in a state in which the end insulating films are interposed between the layer insulating films at both ends in the axial direction of the metal sheet. It is preferable that the heat shrinkage of the part insulating film is smaller than that of the layer insulating film. Since the thermal contraction of the end insulating film is small, the shrinking force of the end insulating film is weakened, and the combined force applied to the bobbin and the corrugated board is reduced.

In this configuration, the end insulating film is preferably made of polyethylene naphthalate, and the layer insulating film is preferably made of polyethylene terephthalate. Since the heat shrinkage of polyethylene naphthalate is smaller than that of polyethylene terephthalate, the combined force applied to the bobbin and the corrugated board is reduced. In this configuration, the end insulating film may be made of polyphenylene sulfide, and the layer insulating film may be made of polyethylene terephthalate. Since the heat shrinkage of polyphenylene sulfide is smaller than that of polyethylene terephthalate, the resultant force applied to the bobbin and the corrugated board is reduced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 is a perspective view of a main part showing a configuration of a gas insulated induction motor winding according to an embodiment of the present invention. The configuration different from the conventional one is that a material smaller than the heat shrinkage of the layer insulating film 2 is used as the end insulating film 40. Other configurations are the same as those of the conventional configuration, and the same portions as those of the conventional configuration are denoted by the same reference numerals, and detailed description is omitted. As the end insulating film 40, for example, polyethylene naphthalate (hereinafter abbreviated as PEN) or polyphenylene sulfide (hereinafter abbreviated as PPS) is used. Table 1 shows the thermal shrinkage of these insulating films together with polyethylene terephthalate (hereinafter abbreviated as PET).

[0011]

[Table 1] The thermal shrinkage ratios in Table 1 are as follows.
The shrinkage rate in a state where the sample was heated at 10 ° C. for 10 minutes was obtained for a state where the temperature was 20 ° C. For example, PEN,
The thermal shrinkage of PPS is 0.5 times and 0.675 times that of PET, respectively.

FIG. 2 is a perspective view of an essential part showing a state of a force generated in the winding of FIG. As in FIG. 4, the arrows in the figure indicate the force generated in the winding due to the temperature rise, the direction of the arrow indicates the direction of the force, and the length of the arrow indicates the relative magnitude of the force. . In FIG. 2, when the temperature of the winding becomes high, at the winding end where the metal sheet 3 is not interposed, the contraction force F1 by the layer insulating film 2 and the end insulating film 4
A contraction force F4 due to 0 is generated inward in the radial direction. Since the layer insulating film 2 is made of PET and the end insulating film 40 is made of a material having a smaller heat shrinkage than the layer insulating film 2, such as PEN or PPS, the shrinking force F4 is equal to the shrinking force. It becomes smaller than F1. The resultant force F14 acting on the bobbin 1 and the corrugated board 5 is
The sum of F1 and F4 becomes radially inward. On the other hand, the portion where the metal sheet 3 is interposed is the same as in the related art, and the resultant force F13 acting on the bobbin 1 and the corrugated board 5 becomes the difference between F1 and F3 and is directed radially inward.

That is, in the configuration of FIG. 2, the resultant force F14 acting on the winding frame 1 and the corrugated board 5 at the winding end is smaller than the resultant force F12 (FIG. 4) of the conventional configuration. Therefore, the winding frame 1 and the corrugated board 5 can be made thinner than in the conventional case, so that the cost of the material can be reduced and the outer dimensions of the winding can be reduced. As described above, the resultant force F12 in the conventional configuration in FIG.

[0014]

## EQU1 ## [F12] = [F1] + [F2] = [F1] + [F1] = 2.times. [F1] In FIG.
Assuming that N, the resultant force F14 using the values in Table 1 is

[0015]

[F14] = [F1] + [F4] = [F1] + 0.5 × [F1] = 1.5 × [F1]

[0016]

[F14] / [F12] = 0.75, and the resultant force F14 is reduced to 75%. On the other hand, when the end insulating film 40 is PPS, the resultant force F14 is

[0017]

[F14] = [F1] + [F4] = [F1] + 0.675 × [F1] = 1.675 × [F1] Therefore,

[0018]

[F14] / [F12] = 0.84, and the resultant force F14 is reduced to 84%.

[0019]

According to the present invention, as described above, an end insulating film having a heat shrinkage smaller than that of a layer insulating film, for example, polyethylene naphthalate or polyphenylene sulfide is used. Thereby, the winding frame and the corrugated board can be made thinner than in the conventional case, so that the cost of the material can be reduced and the outer dimensions of the winding can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing a configuration of a gas insulated induction motor winding according to an embodiment of the present invention.

FIG. 2 is an essential part perspective view showing a state of a force generated in a winding of FIG. 1;

FIG. 3 is a perspective view of a main part showing a configuration of a conventional gas insulated induction motor winding.

FIG. 4 is a perspective view of an essential part showing a state of a force generated in a winding of FIG. 3;

[Explanation of symbols]

1: reel, 2: layer insulation film, 3: metal sheet,
4, 40: end insulation film, 5: corrugated board, 6: cooling duct

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahiro Miyamoto 1-1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd.

Claims (3)

[Claims] An insulated winding frame is accommodated in an airtight container filled with an insulating gas, and is wound coaxially around the outer periphery of an insulating reel in a state where the layer insulating film is superimposed on a metal sheet narrower than the layer insulating film. In the gas-insulated induction motor winding in which the end insulating film is interposed between the layer insulating films at both ends in the axial direction of the metal sheet, the heat shrinkage of the end insulating film is smaller than that of the layer insulating film. And gas insulated induction motor winding. 2. A gas insulated induction motor winding according to claim 1, wherein the end insulating film is made of polyethylene naphthalate and the layer insulating film is made of polyethylene terephthalate. 3. The winding according to claim 1, wherein the end insulating film is made of polyphenylene sulfide and the layer insulating film is made of polyethylene terephthalate.