JP2002218610A - Gas insulated equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a simply method for preventing drop in dielectric breakdown voltage caused by the presence of a triple junction part TJ, instead of removing the triple junction part TJ which is hard to realize actually. SOLUTION: A shield electrode connected to a conductor at the same potential is provided so as to surround the triple junction part formed in a place in which the conductor, an insulating gas and an insulator meet. An insulation ring is closely mounted in a gap between the shield electrode and the insulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas insulating device using a gas having excellent insulating properties such as sulfur hexafluoride gas (hereinafter, SF6 gas) as an insulating medium.

[0002]

2. Description of the Related Art In recent years, a high voltage conductor is arranged in a metal container at a ground potential, and a gas having excellent insulation performance is interposed between these conductors.
For example, the use of gas-insulated equipment made by compression filling of SF6 gas has been increasing steadily. This SF6 gas shows very excellent insulation properties under a uniform electric field, but has a property that the insulation performance is extremely deteriorated under an uneven electric field.

Various factors can be considered as factors that disturb the electric field distribution in the gas-insulated equipment. Defects such as dents on the surface of the high-voltage conductor, poor contact of the high-voltage conductor due to assembly errors, defects in the insulating spacers such as voids, etc. is there.

One of the causes of the structure of the device is the presence of a triple junction. This will be described with reference to the drawings. FIG. 4 is a diagram showing a cross section of a tank type lightning arrester as an example of a gas insulated device. FIG.
In FIG. 1A, reference numeral 1 denotes a tank-type grounded metal container filled with an insulating gas 9 such as SF6 gas.
An insulating cylinder 3 having a thickness d having metal flanges 2a and 2b at both ends is fixed, and an internal element 4 in which a zinc oxide element is laminated is accommodated in the insulating cylinder 3.

[0005] Reference numerals 5a and 5b denote a high voltage side electrode and a ground side electrode of the internal element 4, respectively.
Is connected to a high-voltage side conductor 6, and the high-voltage side conductor 6 passes through an insulating spacer 7 and is connected to a gas insulated switchgear (not shown).

On the other hand, the ground side flange 5b is fixed to the bottom of the metal container 1 by welding or the like. The high pressure side flange 2
a, inner peripheral edge portion 8 of ground side flange 2b in contact with insulating cylinder 3
Are notched for the reason described later.

FIG. 4B is an enlarged cross-sectional view showing the details of this portion. The inner peripheral edge portion 8 of the high-pressure side flange 2a in contact with the insulating tube 3 intersects a metal, an insulating tube, and an insulating gas. , The so-called triple junction
Is formed.

The occurrence of an electric field peculiarity in the triple junction portion is described in, for example, "Houseroom";"Electric Field Concentration in Composite Dielectric", Journal of the Electrostatics Society of Japan, Vol. 14, No. 1, 199.
0 and Japanese Unexamined Patent Application Publication No. 11-214117.

By the way, as shown in FIG.
The main reason for providing the notch in the inner peripheral edge 8 is that it is due to machining, but the electric field in this portion has a considerably large value, and discharge D is easily generated on the surface of the insulating cylinder 3 and the dielectric breakdown voltage is significantly reduced. .

[0010]

In order to prevent such a decrease in breakdown voltage due to the presence of the triple junction section 8, it is best to eliminate the triple junction section 8. However, in practice, it is difficult. Accompany.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has as its object to provide a simple and highly reliable gas-insulated apparatus in which dielectric breakdown hardly occurs. Things.

[0012]

In order to achieve the above object, a gas-insulated apparatus according to the first aspect of the present invention is a gas-insulated apparatus in which a conductor supported by an insulator is disposed in a metal container filled with an insulating gas. In the insulating device, a triple junction formed by the conductor, the insulating gas, and the insulator intersecting each other is surrounded by a shield electrode having an arc portion protruding toward the insulator at a tip end. An insulating ring is closely attached to a gap between the shield electrode and the insulator. Further, in the invention of the gas insulated device according to claim 2, the dimensional relationship between the shield electrode and the insulating ring is determined by the height of the insulating ring as d.
2. When the length of the shield electrode is d1, d2 <(d
(２) is established.

[0013] With this configuration, the triple junction is located at the back of the gap,
It is possible to make it difficult for the discharge on the surface of the insulator to progress, and it is possible to improve the dielectric breakdown voltage.

According to a third aspect of the present invention, there is provided a gas insulated device wherein a fold is provided on the insulating ring, and the fold is covered with an arc formed at the tip of the shield electrode. With such a configuration, it is possible to make it more difficult for the discharge on the surface of the insulator to proceed, and it is possible to greatly improve the dielectric breakdown voltage.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. Figure 1
FIG. 1 is a longitudinal sectional view of the overall configuration when the present invention is applied to a tank type lightning arrester. In FIG. 1, the same parts as those in FIG. However, overlapping parts are omitted or minimally described.

Reference numeral 1 denotes a tank-shaped grounded metal container in which an insulating gas 9 such as SF6 gas is sealed. Inside the metal container 1, an insulating cylinder having a thickness of d having metal disk-shaped flanges 2a and 2b at both ends is provided. 3 is fixed, and an inner element 4 having a zinc oxide element laminated therein is accommodated in the insulating or other cylinder 3.

Reference numerals 5a and 5b denote a high voltage side electrode and a ground side electrode of the internal element 4, respectively. The high voltage side electrode 5a is connected to a gas insulated switchgear (not shown) through a high voltage side conductor 6 through an insulating spacer 7 and a ground. The side electrode 5b is fixed to the flange 2a forming the bottom of the metal container 1 by welding or the like.

A cylindrical shield electrode 10a is attached to the lower surface of the disk-shaped metal flange 2a in the drawing so as to have the same potential. The inner diameter of the shield electrode 10a is larger than the outer diameter of the insulating tube 3, and an annular gap 11a is formed by utilizing the dimensional difference between the two.

An insulating ring 12a is inserted into the annular gap 11a in close contact therewith. Here, the close insertion of the insulating ring 12a means that there is no gap between the contact surface of the insulating ring 12a and the metal flange 2a, the insulating cylinder 3, and the shield electrode 10a, that is, SF6 gas. This is to prevent triple junctions from being formed in gaps.

Similarly, at the bottom of the grounded metal container 1, a cylindrical shield electrode 1 concentrically arranged with the insulating tube 3 is provided.
0b is connected and fixed, and the shield electrode 10b and the insulating cylinder 3 are connected.
The insulating ring 12b is also tightly inserted into the annular gap 11b formed between them.

FIG. 2 is an enlarged sectional view of portions II and III surrounded by broken lines in FIG. As is clear from FIG. 2, when the height (length in the axial direction) of the insulating ring 12a is d2 and the length in the axial direction of the shield electrode 10a is d1, the height d2 of the insulating ring is equal to the length of the shield electrode. Less than half of d1 (d
2 <d1 / 2). Further, an arc portion 10a1 is provided on the inner peripheral portion of the lower portion of the shield electrode 10a so as to project toward the insulating cylinder 3 in order to prevent concentration of an electric field.

Also in the case of this embodiment, the shield electrode 1
A triple junction portion 8 (a portion indicated by a dashed circle) is formed by Oa, the insulating ring 12a, and the SF6 gas 9, but this portion is a right angle, and the electric field value should not increase.

However, even if the triple junction 8 cannot be made right-angled due to manufacturing reasons or the like and the actual electric field value becomes considerably large, the shield electrode 10a having the arcuate portion 10a1 protruding is provided. As a result, the triple junction portion 8 is located at the back of the annular gap portion 11a. As a result, the electric field is reduced, and even if a discharge occurs, the insulating cylinder 3 acts as a barrier,
Discharge progress can be suppressed.

(Second Embodiment) FIG. 3 is an enlarged sectional view of portions II and III surrounded by broken lines in FIG. There is no fundamental difference between the present embodiment and the first embodiment.
A fold 12a1 is formed on the side of the second electrode 2a in contact with the shield electrode 10a.
And a depression 10a2 in the arc portion 10a1 of the shield electrode 10a so as to cover the tip of the fold 12a1.
That is,

In order to cover the tip of the fold 12a1 with the circular arc portion 10a1, the width d3 of the depression 10a2 is selected to be larger than the thickness d4 of the tip of the fold 12a1 of the insulating ring 12a (d3> d4). is there.

In this embodiment, the height of the insulating ring 12a is d2, the length of the shield electrode 10a in the axial direction is d1, and the arc portion 10a1 is formed in the lower inner peripheral portion of the shield electrode 10a in the drawing. As a result, the triple junction portion (dotted line portion in FIG. 3) 8 is separated from the surface of the insulating cylinder 3 and the insulating ring 12a itself also functions as a barrier, so that the discharge on the surface of the insulating cylinder 3 becomes more difficult to progress.

Although the above-described embodiment is applied to the case where the present invention is applied to a tank type lightning arrester as a gas insulating device, the present invention is not limited to this, and other gas insulating devices forming a triple junction portion may be used. It can also be applied to equipment.

[0028]

As described above, according to the present invention, since the insulation ring and the shield electrode are provided to surround the triple junction, the dielectric breakdown voltage can be improved, and the structure can be simplified. A highly reliable gas insulation device can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of a first embodiment according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the first embodiment.

FIG. 3 is a partially enlarged cross-sectional view of a second embodiment according to the present invention.

4A and 4B are diagrams showing a conventional example of the present invention, in particular, FIG. 4A is an overall configuration diagram, and FIG.

[Description of Signs] 1 ... Metal container, 2a, 2b ... Flange, 3 ... Insulating cylinder, 4
... internal elements, 5a, 5b ... electrodes, 6 ... conductors, 7 ... insulating spacers, 8 ... triple junctions, 9 ... insulating gas,
10a, 10b ... shield electrode, 10a1 ... arc part, 1
0a2: recess, 12a, 12b: insulating ring, 12a1
... folds on the insulating ring.

Claims (3)

[Claims] 1. A gas insulated device in which a conductor supported by an insulator is disposed in a metal container filled with an insulating gas, wherein a triple junction formed by the intersection of the conductor, the insulating gas, and the insulator. Department
A gas characterized by being surrounded by a shield electrode having an arc portion protruding toward an insulator at a tip end thereof, and an insulating ring being closely attached to a gap between the shield electrode and the insulator. Insulation equipment. 2. The gas-insulated apparatus according to claim 1, wherein the dimensional relationship between the shield electrode and the insulating ring is such that the height of the insulating ring is d2 and the length of the shield electrode is d.
A gas-insulated device characterized in that d2 <(d1 / 2) holds when 1 is set. 3. The gas-insulated apparatus according to claim 1, wherein a fold is provided on a side of the insulating ring in contact with the shield electrode, and the fold is covered by an arc formed at a tip of the shield electrode. Gas insulated equipment characterized in that: