JPH11154615A - Gas insulating transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas insulating transformer in excellent productivity without losing mechanical strength and the dielectric strength as insulating spacers, while reducing an excessive concentration of electric field on spacer parts. SOLUTION: In a gas insulating transformer composed of a plurality of low potential windings 2 and high potential windings 3 concentrically arranged with an iron core as well as a plurality of insulating cylinders 10A, 10B also concentrically arranged with the iron core between mutual windings 2, 3 besides, a plurality of insulating spacers 4 arranged between these insulating cylinders, at least one insulating spaces 4 is composed of a plurality of laminated bodies of insulating sheets while inside the laminated bodies 430, cavities 4B are formed between respective insulating sheets adjacent in the radius direction of the windings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated transformer, and more particularly to a core-insulated gas-insulated transformer in which a plurality of windings are concentrically wound around an iron core.

[0002]

2. Description of the Related Art In a gas insulated transformer, a spacer is inserted between windings to secure an insulation distance between windings concentrically arranged with respect to an iron core.

However, when the spacer is used, the electric field strength of the gas in the minute gap portion is greatly increased as compared with the portion without the spacer, and this portion is a weak point in insulation.

Therefore, for example, Japanese Patent Laid-Open No. 4-162407
Japanese Patent Application Laid-Open Publication No. H11-157, discloses a gas insulated transformer in which a notch is formed in a spacer in accordance with the position of a line end of a winding, and the notch is used as a gas space. According to this configuration, since the notch provided in the spacer serves as a gas space, the ratio of the gas occupied by the gap between the windings can be equivalently increased, and the gas in the minute gap portion due to the use of the spacer is reduced. It is said that the electric field strength is greatly reduced, and this portion does not become a weak point on insulation.

Further, Japanese Patent Application Laid-Open No. 7-212553 discloses a spacer in which insulating materials are arranged in a staggered manner on spacers. That is, a non-arranged space is formed in at least one between the insulating cylinders in the same radial direction as the windings between the windings,
It is stated that the concentration of an electric field generated in a minute gap caused by the use of the spacer can be reduced without lowering the strength of the spacer, and the dielectric strength of the portion can be improved.

In addition, Japanese Patent Application Laid-Open No. 4-155806 discloses a corrugated plastic sheet having an insulating layer formed by laminating another plastic sheet on both sides. In addition, Japanese Patent Application Laid-Open No. H5-291055 discloses a hollow pipe-shaped spacer.

[0007]

SUMMARY OF THE INVENTION Among the above prior arts,
JP-A-4-155806, JP-A-5-29105
The structure described in Japanese Patent Publication No. 5 and JP-A-6-26776, in which the shape and arrangement of the spacers are taken into consideration, is considered to be difficult to implement because of the strength of the spacers and the difficulty in manufacturing.

Also, Japanese Patent Application Laid-Open Nos. 4-162407, 5-29155 and 7-21155.
It is considered that the method described in Japanese Patent Publication No. 3 such as forming a notch in the spacer has insufficient strength of the spacer.

It is an object of the present invention to provide a gas-insulated transformer that solves the above-mentioned problems of the prior art and reduces the occurrence of excessive concentration of an electric field.

Another object of the present invention is to provide a gas insulating transformer which is excellent in manufacturability without lowering mechanical strength and dielectric strength as an insulating spacer.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of windings arranged concentrically with respect to an iron core, and a plurality of windings which are concentric with the iron core between the respective windings. A plurality of insulating cylinders, and a plurality of insulating spacers disposed between the insulating cylinders and between the windings and the insulating cylinder, wherein at least one of the plurality of insulating spacers is provided. One is constituted by a laminated body of a plurality of insulating sheets, and inside the laminated body, a gap having a gap is formed between the insulating sheets adjacent in the radial direction of the winding. .

Another feature of the present invention is that a plurality of windings are disposed concentrically with respect to the iron core, and a plurality of insulating cylinders are disposed between the respective windings concentrically with respect to the iron core. In a gas insulating transformer having a plurality of insulating spacers disposed between the insulating cylinders and between the windings and the insulating cylinder, at least one of the plurality of insulating spacers is formed by stacking a plurality of insulating sheets. A sheet-shaped insulating sheet arranged in the circumferential direction of the winding, and a plurality of columnar insulating sheets arranged in the circumferential direction of the winding via a gap inside the laminated body. Are alternately laminated to form voids.

Another feature of the present invention is that the volume of the void portion of the laminate is 10 to 30% of the volume of the laminate.
It is to be.

According to the present invention, since the insulating spacer having the laminated structure has a sufficiently large gap in each layer, it is possible to reduce the occurrence of excessive concentration of the electric field in the spacer portion disposed between the windings. I do.

According to another feature of the present invention, since the gap portion is formed by alternately stacking the plate-like insulating sheets and the column-like insulating sheets, a decrease in compressive strength is small and a mechanical strength required for the insulating spacer is obtained. Does not decrease. Also, since the insulating spacer is constituted by a laminate of a plurality of plate-like insulating sheets,
Excellent manufacturability.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a configuration example of the gas insulating transformer, and FIG. 2 is an axially enlarged sectional view of a winding portion of the gas insulating transformer of FIG. The gas-insulated transformer includes a low-voltage winding 2 and a high-voltage winding 3 that are concentrically arranged with respect to the iron core 1, an insulating spacer 4 for securing an absolute distance between these windings, and It has a tank 5 for housing. 6 is a gas space. The cooling gas in the tank 5 is sent to the heat exchanger 9 via the duct 8 by the gas blower 7, cooled, and then returned to the tank 5 again.

The insulating spacer 4 is, as shown in FIG.
It has an inter-coil spacer 41 and linear spacers (a first linear spacer 42, a second linear spacer 43, and a third linear spacer 44) disposed between the insulating cylinders 10A and 10B. The material of each of these spacers is synthetic paper.

At least one of the linear spacers 42 to 44 is constituted by a laminate 430 of a plurality of insulating sheets. As shown in the enlarged sectional view in the circumferential direction of FIG. 3, in this linear spacer, plate-like insulating sheets and column-like insulating sheets are alternately laminated at both end portions 4A in the axial direction. I do not have. Also, the laminate 43
Inside 0, a gap 4B having a gap is formed between each insulating sheet adjacent in the radial direction.

As shown in the enlarged sectional view in the axial direction of FIG. 4 and the enlarged sectional view in the circumferential direction of FIG. 5, the gap 4B is formed by a laminate 4 of a plurality of plate-shaped insulating sheets 431 and columnar insulating sheets 432.
In each layer of the laminated body 430, each plate-shaped insulating sheet 431 has a gap between the plate-shaped insulating sheet 431 and an adjacent plate-shaped insulating sheet 431. That is, inside the laminate 430, a plate-shaped insulating sheet 431 continuous in the circumferential direction is provided.
Columnar insulating sheet 43 arranged in the circumferential direction with a gap therebetween
A gap 433 is formed by alternately laminating the two.

The columnar insulating sheet 432 of the laminate 430 is
As shown in FIG. 4, they are arranged so as to overlap with the gap 433 of the adjacent layer via the plate-shaped insulating sheet 431 in the radial direction. Further, the columnar insulating sheets 432 are arranged in a staggered manner in the radial direction so as to partially overlap with the columnar insulating sheets 432 of the adjacent layer via the plate-shaped insulating sheet 431.

Since the plate-like insulating sheet 431 is interposed, no overlapping portion is provided, and the end surface of the column-like insulating sheet 432 is formed in the radial direction with the column-like insulating sheet 432 of the adjacent layer via the plate-like insulating sheet 431. You may make it correspond with an end surface.

As described above, between the upper and lower layers of the laminate 430, each plate-like insulating sheet 430 overlaps with the gap 4B of the adjacent layer. The columnar insulating sheets 432 are stacked near the plate-like insulating sheets 431 of the adjacent layers near both ends of the stacked body 430, and do not have voids inside.

As an example, the thickness (the height direction in FIG. 4) of each of the plate-shaped insulating sheet 431 and the columnar insulating sheet 432 is 4 mm, the width (the horizontal direction in FIG. 4) is 7 mm, and the gap (the horizontal direction in FIG. 4). Is 5 mm.

According to the present invention, since the insulating spacer 4 having the laminated structure has a sufficiently large gap in each layer, the concentration of the electric field is reduced in the spacer portion disposed between the windings. .

This will be described with reference to FIG. E ₀ is the average electric field, ε ₀ , ε ₁ are the specific idle rates of the gas space and the insulating spacer, D is the gap length, t is the spacer thickness,
Assuming that E ₁ and E ₂ are electric fields of a minute gap between the spacer and the winding, E ₁ = V / (Dt (1−ε ₀ / ε ₁ )) and E ₀ =
V / D, the concentration of the electric field is When t ≒ D, that is, when there is no void, E ₁ / E ₀
= 3.0.

On the other hand, t = 0.85D, that is, 15%
When there is a void, E ₂ / E ₀ = D / (D−0.67 × 0.6.
85D). Therefore, E ₁ / E ₂ = (D−0.67D) / (D−0.67 × 0.85D) = 0.33 / 0.43 = 0.77.

As described above, when there is a gap of 15%, the degree of concentration of the electric field is reduced by 23% as compared with the case where there is no gap.

According to the structure of the laminate of the present invention, the ratio of the voids can be set to 10 to 30% of the volume of the laminate. As described above, the insulating spacer 4 having a laminated structure is used.
However, since each layer has a sufficiently large void portion 4B, it is possible to reduce the occurrence of excessive concentration of the electric field in the spacer portion disposed between the windings.

Further, since the gap portion is formed by alternately laminating the plate-like insulating sheets and the column-like insulating sheets, the decrease in compressive strength is small, and the mechanical strength required for the spacer does not decrease. Further, since the spacer is constituted by a laminate of a plurality of plate-shaped insulating sheets, it is excellent in manufacturability.

The second linear spacer 43 has been described above as an example, but other linear spacers can also be provided with voids.

[0031]

According to the present invention, since the insulating spacer having the laminated structure has a sufficiently large gap in each layer, an excessive concentration of the electric field occurs in the spacer portion disposed between the windings. Has the effect of reducing Further, the decrease in compressive strength is small, and the mechanical strength required for the insulating spacer does not decrease. Further, since the insulating spacer is constituted by a laminate of a plurality of plate-like insulating sheets, it is excellent in manufacturability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration example of a gas-insulated transformer to which an embodiment of the present invention is applied.

FIG. 2 is an axially enlarged sectional view of a winding portion of the gas-insulated transformer of FIG.

FIG. 3 is an enlarged circumferential sectional view of a winding portion of the gas-insulated transformer of FIG. 1;

FIG. 4 is an enlarged sectional view in the axial direction of the insulating spacer of FIG. 2;

5 is an enlarged sectional view in the circumferential direction of the insulating spacer of FIG. 2;

FIG. 6 is a diagram illustrating concentration of an electric field in an insulating space portion.

[Explanation of symbols]

10A, 10B ... insulating cylinder, 4 ... insulating spacer, 4A ...
Both ends in the axial direction, 4B: gap, 41: spacer between coils, 42: first linear spacer, 43: second linear spacer, 44: third linear spacer, 430: laminated body, 431
... Plate-shaped insulating sheet, 432 ... Column-shaped insulating sheet, 433 ...
Void

Claims (6)

[Claims] A plurality of windings arranged concentrically with respect to the iron core, and a plurality of insulating cylinders arranged concentrically with respect to the iron core between the respective windings; In a gas insulating transformer in which a plurality of insulating spacers are disposed between a winding and the insulating cylinder, at least one of the plurality of insulating spacers is formed of a laminate of a plurality of insulating sheets, and A gas-insulated transformer, wherein a gap having a gap is formed between each of the insulating sheets radially adjacent to the winding inside the body. 2. A plurality of windings arranged concentrically with respect to an iron core, and a plurality of insulating cylinders arranged concentrically with respect to the iron core between the respective windings. In a gas insulating transformer in which a plurality of insulating spacers are disposed between a winding and an insulating cylinder, at least one of the plurality of insulating spacers is formed of a laminate of a plurality of insulating sheets, and the laminate Inside, a gap portion in which a plate-shaped insulating sheet arranged in the circumferential direction of the winding and a plurality of columnar insulating sheets arranged in the circumferential direction of the winding via a gap are alternately laminated. A gas insulated transformer characterized by being formed. 3. The laminate according to claim 2, wherein the columnar insulating sheets of the laminate are arranged so as to overlap with the gaps of adjacent layers via the plate-like insulating sheets in the radial direction. Gas-insulated transformer. 4. The columnar insulating sheet according to claim 3, wherein the columnar insulating sheet of the laminate is arranged so as to partially overlap with the empty columnar insulating sheet of an adjacent layer via the plate-like insulating sheet in the radial direction. A gas-insulated transformer. 5. A plurality of windings arranged concentrically with respect to an iron core, and a plurality of insulating cylinders arranged concentrically with respect to the iron core between the respective windings. In a gas insulating transformer in which a plurality of insulating spacers are disposed between a winding and the insulating cylinder, at least one of the plurality of insulating spacers is formed of a laminate of a plurality of insulating sheets, and Inside the body, a gap portion in which a plate-shaped insulating sheet arranged in the circumferential direction of the winding and a plurality of columnar insulating sheets arranged in the radial direction of the winding via a gap are alternately laminated. The gas insulating transformer, wherein the plate-shaped insulating sheets and the columnar insulating sheets are alternately laminated at both ends in the axial direction of the laminate. 6. The gas-insulated transformer according to claim 1, wherein the volume of the voids in the laminate is 10 to 30% of the volume of the laminate.