JPH10241961A - Gas insulated stationary induction winding - Google Patents

Abstract

(57) [Summary] [Object] To increase the breakdown voltage at the terminal end of a potential suppression conductor wound in a disk coil of a gas-insulated stationary induction winding. A terminal end portion of a potential suppressing conductor is integrally molded with a molded insulating material made of a thermoplastic resin, a thermoplastic elastomer, or a rubber, which is a polymer material, or a grease or an adhesive whose inner surface is conductive is applied. And covered with the formed cap-shaped molded insulator 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated stationary induction winding.

[0002]

2. Description of the Related Art In general, windings used for stationary induction windings such as transformers and reactors are wound in order to make the electric potential distribution in the windings uniform with respect to a steep wave voltage such as a lightning surge that enters from a line end. A winding structure of a vibration-shielding type in which a wire has a large series capacitance is employed. FIG. 6 shows an example of the winding configuration. In the winding, a plurality of disk coils 102 each formed by winding an insulated wire 101 in a disk shape are stacked in the winding axis direction, and each of the 102 disk coils is as shown in the figure. Are connected in series with each other, and each disc coil 102 is provided with a potential suppressing conductor 103 that is insulated and coated between turns of a predetermined electric wire 101.
Is involved. The potential suppressing conductor 103 has an inner end open, and the other end of the potential suppressing conductor 103 wound around the adjacent disc coil 102 or an even number of four or more disc coils 102. In this case, the series capacitance of the winding is increased as compared with the case where the potential suppressing conductor 103 is not involved, thereby suppressing the potential oscillation of the winding. In such a damping-shielding type winding, since the potential suppressing conductor 103 is wound in the disc coil 102 with the inner end open, the electric field concentrates on the end of the potential suppressing conductor 103 and the electric wire There is a weak point that causes dielectric breakdown between the substrate 101 and the substrate 101. By the way, as shown in FIG. 7 and FIG. 8 as a terminal insulating structure of the potential suppressing conductor 103 of the oil-immersed transformer, as shown in FIGS.
3, a strip-shaped filling 104 made of fluororesin, polyethylene resin, or polymethylpentene resin having a relative dielectric constant close to 2.2 of the insulating oil is provided at the terminal open end of the insulating oil. There is a structure formed by winding 105, and a minute gap 106 is formed at the end of the terminal. However, since the strip-shaped filling is close to the relative dielectric constant of the insulating oil, the electric field concentration in the minute gap due to the insertion of the filling is small. Is suppressed.

[0003]

However, in recent years, SF ₆
Commercialization of gas-insulated transformers using gas as an insulating medium has progressed,
It is expected that a damping and shielding type winding will be applied in response to an increase in high voltage and capacity. At this time, when the terminal structure of the potential suppression conductor similar to that of the conventional oil-filled transformer is adopted, the relative dielectric constant of SF ₆ gas, which is an insulating medium, is 1, whereas the solid insulating material such as filling is used. The relative permittivity is usually plural, and the ratio of these relative permittivities is larger than that of the insulating oil with respect to the insulator of the oil-immersed transformer. Therefore, in the gas insulating transformer, the electric field concentration in the minute gap 106 at the end of the terminal increases. This is inevitable, and there is a problem that the dielectric strength of the terminal portion of the potential suppressing conductor 103 is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas-insulated transformer winding provided with a potential suppressing conductor having a high dielectric strength, preventing formation of a minute gap in which an electric field is concentrated at the terminal end of the potential suppressing conductor. is there.

[0005]

In order to achieve the above object, according to the present invention, a molded insulator is formed so as to protrude in a winding direction that is open from a terminal of a potential suppressing conductor and cover a terminal end portion of the potential suppressing conductor. These structures were constructed by integrally molding a molded insulator by injection molding or hot press molding at the terminal tip of the potential suppression conductor, or by applying conductive grease or conductive adhesive on the inner surface in a cap shape The molded insulating material is configured to cover the end of the terminal of the potential suppressing conductor, using a thermoplastic resin or a thermoplastic elastomer or rubber which is a polymer material as the molded insulating material. An insulating piece having high hardness was built in the inside protruding in the turning direction.

According to the present invention, since the terminal end of the potential suppressing conductor is covered with the molded insulator, a minute gas gap to which an electric field is applied is not formed at the terminal end of the potential suppressing conductor. In such a configuration, the insulating strength of the molded insulator is higher than that of SF ₆ gas, and the relative dielectric constant is large, so that the electric field at the end of the terminal is also alleviated. As a result, from the end of the potential suppression conductor, It is possible to increase the breakdown voltage that causes dielectric breakdown of the electric wire forming the adjacent disk coil.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view showing the structure of the terminal end portion of the potential suppressing conductor, and FIG. 2 is a modified example of the same structure. The terminal end of 103 is covered with a molded insulating material 1 of a polymer material, and the molded insulating material 1 and the terminal portion of the insulating coating 107 of the potential suppressing conductor 103 are protected by an insulating coating 108 wound with an insulating tape or the like. The molded insulator 1 is formed by injection-molding a thermoplastic elastomer or a thermoplastic resin using a mold so that the potential suppressing conductor 103 is formed.
Is bonded to the front end portion or rubber is hot-pressed so as to sandwich the terminal portion of the potential suppressing conductor 103. In this case, from the viewpoint of heat resistance and electrical characteristics, a thermoplastic resin such as polybutylene terephthalate, polyarylate, or polyamide is preferable, and a thermoplastic elastomer such as olefin or polyester is preferable. The rubber material is preferably, for example, ethylene propylene rubber, silicone rubber, fluorine rubber, or the like.

In such a structure of the terminal end portion of the potential suppressing conductor 103, the terminal end portion of the potential suppressing conductor 103 where the electric field is concentrated is covered with the molded insulator 1, and a small gas gap to which the electric field is applied as in the prior art is formed. It is not formed. Generally, the molded insulator 1 has a higher insulation strength and a higher relative dielectric constant than SF ₆ gas, so that the electric field at the terminal end of the potential suppressing conductor 103 is also reduced. Therefore, although not shown, the breakdown voltage of the dielectric breakdown from the distal end of the potential suppressing conductor 103 to the electric wire forming the adjacent disk coil can be increased.

FIG. 3 shows another embodiment, in which a cap-shaped molded insulator 2 having a gap corresponding to the shape of the terminal end of the potential suppressing conductor 103 is manufactured in advance, and the winding is wound. During the operation, conductive grease or conductive adhesive 3 is applied to the inner surface of the terminal, so that the cap portion of the molded insulator 1 covers the terminal end of the potential suppressing conductor 103, and the terminal end portion is covered with the molded insulator 2. Even if a small gap should be formed between the inner surface of the molded insulator 2 after covering and the potential suppressing conductor 103, the gap is surrounded by the conductive grease or the conductive adhesive 3 so that the small gap is formed. No electric field is applied to the terminal, and an effect of improving the dielectric strength similar to that of the embodiment can be expected. When this configuration is applied, the terminal tip of the long potential suppressing conductor 103 that is simply wound as in the above-described embodiment is applied. Molded insulation Compared with the case of manufactured integrally molded, it can be advantageously manufactured molded insulator in easy handling.

FIG. 4 is a sectional view showing another embodiment, and FIG.
Shows a modified example thereof. When rubber is applied to the molded insulator 4 and the terminal end portion of the potential suppressing conductor 103 is molded, an insulating piece made of a thermoplastic resin or the like having a higher hardness than rubber is used as a terminal. It was built into the open part and molded integrally. In this configuration, when insulating the terminal opening, the deformation of the flexible rubber can be suppressed, so that the insulating tape can be densely wound, and the insulation strength of the insulating coating 108 can be prevented from lowering due to the loosening of the insulating tape.

[0011]

According to the present invention, the formation of a minute gas gap where an electric field is concentrated can be prevented by covering the end of the terminal of the potential suppressing conductor with a molded insulator having a higher insulation strength than SF ₆ gas. Since the electric field can also be reduced, the breakdown voltage from the terminal end of the potential suppressing conductor to the electric wire constituting the adjacent disc coil can be increased,
As a result, the dielectric strength of the gas insulation transformer winding can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a structure of a terminal of a potential suppressing conductor of a winding of a gas-insulated stationary induction device showing one embodiment of the present invention.

FIG. 2 is an explanatory view of a modification of FIG. 1;

FIG. 3 is a perspective view of a second embodiment of the present invention.

FIG. 4 is a sectional view of a potential suppressing conductor terminal structure according to a third embodiment of the present invention.

FIG. 5 is an explanatory view of a modification of FIG. 4;

FIG. 6 is a sectional view of a conventional potential suppressing conductor terminal structure.

FIG. 7 is an explanatory view of a modification of FIG. 6;

FIG. 8 is an explanatory view of another modification of FIG. 6;

[Explanation of symbols]

1, 2, 4, molding insulator, 3 conductive grease or conductive adhesive, 5 insulating piece, 101 electric wire, 102 disk coil, 103 potential suppressing conductor, 104 filling, 10
5, 108: insulating coating; 106: minute gap.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoto Hiraishi 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside the Kokubu Plant, Hitachi, Ltd. No. 1 in the Kokubu Plant of Hitachi, Ltd.

Claims (8)

[Claims] 1. A gas-insulated stationary body in which a tank is filled with an insulating gas, and a potential suppression conductor which is insulated and covered at predetermined times of a plurality of turns of the electric wire and has an open end is wound at least once. In the induction winding, a gas-insulated stationary induction winding, which is formed by projecting in a winding direction that is open from a terminal of the potential suppressing conductor and covering a terminal end portion of the potential suppressing conductor with a molded insulator. line. 2. The gas-insulated stationary induction motor winding according to claim 1, wherein the molded insulator is manufactured by injection molding or hot press molding. 3. The gas according to claim 1, wherein said molded insulator is formed by applying a conductive grease or a conductive adhesive to an inner surface of said cap so as to cover a terminal end of said potential suppressing conductor. Insulated stationary induction winding. 4. The gas-insulated stationary induction winding according to claim 1, wherein said molded insulator is a polymer material. 5. The gas-insulated stationary induction motor winding according to claim 4, wherein said polymer material is a thermoplastic resin. 6. The gas-insulated static induction motor winding of claim 1 wherein said polymeric material is a thermoplastic elastomer. 7. The gas-insulated stationary induction winding according to claim 1, wherein said polymer material is rubber. 8. The gas insulated stationary induction winding according to claim 6, wherein an insulator having a high hardness is built in a portion of the rubber potential suppression conductor protruding from a terminal end position.