JPH0869924A - Gas-insulated stationary induction apparatus - Google Patents

Abstract

PURPOSE: To relieve the electric field distribution at the rail arranging parts of an electrostatic ring for relaxing electric field so as to improve the dielectric strength of gas insulation induction electric equipment by forming the ring so that the parts of the ring where no rail is arranged can be protruded toward an insulating cylinder from the rail arranging parts. CONSTITUTION: Rails 13 are successively arranged around an insulating cylinder 1 in the axial direction at prescribed intervals in a prescribed tank which is filled up with a gas insulator. Then a winding is wound around the cylinder 1 at the same intervals of the rails 13 and an electrostatic ring 12 for relieving electric field is put on the winding. The parts of the ring 12 where the rails 13 are not arranged are protruded toward the cylinder 1 from the parts of the ring 12 where the rails 13 are arranged so as to relax the electric field distribution at the parts where the rails 13 are arranged. Therefore, highly reliable compact gas insulation electric equipment can be obtained, because the dielectric strength of the apparatus can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static induction electric device such as a transformer having a coil wound around an iron core, and more particularly to a gas-insulated static induction electric device having an electrostatic ring at an end of a winding.

[0002]

2. Description of the Related Art In a substation or underground substation around a large city, if a fire explosion occurs, its impact on society is immeasurable. In particular, in the case of transformers, reactors, etc. that use insulating oil, there is a high risk of fire and explosion. Therefore, gas-insulated transformers using non-flammable insulating gas such as SF ₆ gas as the insulating medium have recently been used instead of insulating oil. The application of the vessel is under consideration.

FIG. 3 shows the structure of a general transformer winding.
A rail for securing a cooling path is arranged around the outer periphery of the basic insulation cylinder, and the wire with insulation coating is wound on it.A spacer is interposed between the sections, and the coil is wound a predetermined number of times, and the transformer winding is wound. It is set to 10.

Further, an electrostatic ring 12 is arranged in order to reduce the electric field at the winding end. The insulation strength of the thus configured transformer winding depends on the insulating medium, insulating oil or insulating gas. As is well known, the breakdown electric field of insulating oil changes depending on the gap length, and the breakdown electric field increases when the gap length is short. On the other hand, the breakdown electric field of the insulating gas has a small dependence on the gap length, and is the electric field dependent type in which the highest electric field is the starting point of the dielectric breakdown.

Further, due to the difference in relative permittivity between gas and insulating oil, the electric field in the gas portion is higher in the composite insulating structure such as a transformer than in the case of insulating oil. Therefore, in the insulation configuration of the gas insulation transformer, it is necessary to eliminate the electric field inequality more than the oil insulation transformer.

[0006]

In the gas-insulated transformer winding, an electrostatic ring for controlling the electric field at the winding end is arranged. The electrostatic ring is manufactured separately from the transformer winding and assembled during assembly. As a result, the size of the gas gap between the electrostatic ring and the material that makes up the transformer winding varies subtly. Particularly, in the gap between the electrostatic ring and the rail, the dimension of the gas gap portion changes depending on the working accuracy.

As described above, such a minute gap has not been a big problem because the dielectric breakdown electric field becomes high in the insulating structure using the insulating oil. However, in the case of gas insulation, the electric field in such a minute gap portion becomes the highest, and the insulation strength of the winding is determined. If the electric field at the end of the winding is relaxed by the electrostatic ring,
The portion where the electric field is highest is the R portion of the electrostatic ring.
Since the minute gap and the wedge gap depend on the gas gap portion composed of the R portion and the rail portion, it becomes a weak point in insulation.

In order to reduce the electric field in the minute gap portion, it is necessary to increase the insulation distance, but in the case of such an unequal electric field, the electric field does not decrease in proportion to the distance, so that a very large insulation distance is required. It becomes necessary, and eventually leads to the upsizing of gas-insulated transformers.

The present invention has been made in view of this point, and an object of the present invention is to provide a gas-insulated static induction generator having an electrostatic ring structure having an effective electric field relaxing structure. .

[0010]

DISCLOSURE OF THE INVENTION According to the present invention, a predetermined tank filled with a gas insulating medium is sequentially and at predetermined intervals around the outer circumference of an insulating cylinder in which an iron core is arranged. In a static induction electric device, in which rails are arranged in the axial direction of the insulating cylinder, and windings are wound around the outer circumference of the insulating cylinder with the rail width interval, in order to reduce the electric field at least at the upper end of the winding. An electrostatic ring is arranged, and the electrostatic ring is formed such that a portion where the rail is not arranged is projected toward the insulating cylinder side from a portion where the rail is arranged. It is characterized by having been relaxed.

[0011]

With this structure, since the electrostatic ring arranged at the end of the winding is projected at the portion in contact with the gas gap as compared with the portion in contact with the rail, the electrostatic ring becomes a high electric field portion. Since the electric field of the gas gap where the rails are in contact can be relaxed by the electrostatic ring itself, the dielectric strength is improved, and the gas-insulated static induction machine can be made compact.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The same parts as those in FIG. 3 are denoted by the same reference numerals.
In FIG. 1, a transformer winding 10 is composed of a transformer winding 10 formed by winding a wire 11 a predetermined number of times and an electrostatic ring 12 for relaxing an electric field at an end. As shown in FIG. 2, the electrostatic ring 12 is formed so that the inner diameter of the portion which contacts the rail 13 and the inner portion of the gas gap which does not contact the rail are different.

That is, since the wedge portion between the electrostatic ring 12 and the rail 13 which has been liable to be a weak point in insulation in the related art, the electrostatic ring at the portion contacting the gas gap is projected to the inner diameter side, Since the electric field in the wedge gap portion generated in the ring and the rail portion can be relaxed, the insulating performance is improved and the increase in the insulating distance can be avoided.

As described above, the wedge ring gap formed by the rail and the electrostatic ring 12 forming the winding end insulation of the transformer is improved by improving the shape of the electrostatic ring itself and reducing the electric field. , It is possible to obtain a transformer winding with high insulation strength because it is possible to prevent the electric field rise in the minute gas gap and gas wedge part, which were the weak points in the conventional insulation, and, by extension, compact and highly reliable gas insulation. A stationary induction device can be provided.

In FIG. 1, the disk winding has been described as an example, but the present invention can be applied to a structure in which an electrostatic ring is attached to an end of a cylindrical winding or the like. Here, since a large effect can be expected in the gas-insulated transformer, the gas-insulated transformer is described, but the same effect can be obtained also in the conventional oil-insulated transformer.

Further, since the diameter of the ring core constituting the electrostatic ring is different from the diameter of the rail portion and the portion facing the gas gap, when the rail core and the gas gap are integrated, the rail portion is reworked to form the ring core. . On the other hand, parts with different diameters are manufactured separately and combined and molded according to the rail,
It is also possible to use an electrostatic ring core. Further, by forming the material of the inner protruding portion from a flexible material such as an elastomer, it is possible to absorb a change in the diameter of the electrostatic ring, and therefore standardization is possible. Although the electrostatic ring configuration of the inner peripheral portion of the outer winding is described here, the configuration of the present invention can be applied to the outer peripheral portion of the inner winding.

[0017]

As described above, by changing the shape of the electrostatic ring that constitutes the end insulation of the winding, the electric field in the rail portion where the electric field becomes high can be alleviated by the electrostatic ring itself. It is possible to provide a gas-insulated static induction generator which has a high insulation strength, is compact, and has high reliability, because it can control an electric field in a minute gas gap or gas wedge portion, which has conventionally been a weak point in insulation.

[Brief description of drawings]

FIG. 1 is a front view of a winding structure according to an embodiment of the present invention.

FIG. 2 is a top plan view of FIG.

FIG. 3 is a front view of a general winding configuration.

[Explanation of symbols]

1 ... Basic insulation cylinder 10 ... Winding 11 ... Wire 12 ... Electrostatic ring
13 ... Rail

Claims (3)

[Claims] 1. Rails are sequentially arranged in a predetermined tank filled with a gas insulating medium at predetermined intervals around the outer circumference of an insulating cylinder arranged in a form of arranging an iron core inside and in the axial direction of the insulating cylinder. In addition, in a static induction electric device having a winding around the outside of the insulating cylinder with the rail width interval, an electrostatic field relaxing electrostatic ring is arranged at least at the upper end of the winding. The electrostatic ring is formed in a shape in which a portion where the rail is not arranged protrudes toward the insulating cylinder side from a portion where the rail is arranged, and the electric field distribution of the rail arrangement portion is relaxed. Gas-insulated static induction. 2. The gas-insulated static induction generator according to claim 1, wherein the electrostatic ring is formed by combining the protruding portion and the ring having a predetermined width other than the protruding portion. 3. The gas-insulated static induction generator according to claim 2, wherein the protruding shape portion is formed of a flexible member.