JPH08339745A - Gas circuit breaker - Google Patents

Abstract

PURPOSE: To keep initial stable insulation performance without a flushshort accident even if fusing loss of a movable arc contact piece happens, by embedding an electrode, connected to a movable main contact piece, in a position near to a fixed arc contact piece of a nozzle. CONSTITUTION: An annular electrode 18, having a circular cross section, is embedded in a position near to a fixed arc contact piece 1, than a movable arc contact piece 8 of a nozzle 16, to be connected to a movable main contact piece 15. When an arc, between both arc contact pieces 1 and 8, is extinguished by an insulation gas, via pole-opening action halfway from a pole-closed condition, to become to a pole-opened condition; an equipotential line is positioned at a position nearer to the contact piece 1 than the contact piece 8 by an electrode 18, having electric potential same as that of the contact piece 15, to relax an electric field in the tip of the contact piece 8. Consequehtly, since an electric potential gradient is not increased to the degree of flush-short even when fusing loss due to an arc happens on the contact piece tip of the contact piece 8, thereby initial stable insulation performance can be kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in the field of electric power distribution as a single unit or in a gas-insulated switchgear, and is an arc generated when a fixed arc contact and a movable arc contact are opened. In addition, the present invention relates to a puffer-type gas circuit breaker in which compressed gas in a puffer chamber is blown to extinguish an arc.

[0002]

2. Description of the Related Art A conventional puffer type gas circuit breaker of this type will be described with reference to FIGS. 5 is a cross-sectional view in the closed state, FIG. 6 is a perspective view of the movable arc contactor in FIG. 5, FIG. 7A is a cross-sectional view in the middle of the opening operation of FIG. 5, and B is a cross-sectional view in the open state.

In these figures, 1 is a cylindrical fixed arc contactor, 2 is an annular fixed main contactor provided outside the fixed arc contactor 1, and a plurality of contactor pieces are provided in an annular shape. And is formed to cover the fixed arc contact 1. Reference numeral 3 denotes a piston which is fixed so as to face the fixed arc contactor 1 and has a hollow portion, 4 is a cylindrical body which supports the piston 3, 5 is a piston ring provided on the circumferential surface of the piston 3, and 6 is the piston 3 A cylindrical inner cylinder that is movably provided through the hollow portion of the inner cylinder, and 7 is an inner cylinder 6
Is a plurality of gas vent holes formed on the base side, and communicates the hollow portion of the inner cylinder 6 and the inside of the tubular body 4.

Reference numeral 8 denotes an annular movable arc contactor integrally provided at the tip of the inner cylinder 6, and as shown in FIG. 6, the tubular body is formed by being divided by a plurality of grooves 9 and has elasticity. The movable arc contactor 8 has an inner surface that contacts and separates from the outer surface of the fixed arc contactor 1. Reference numeral 11 is a cylindrical outer cylinder provided outside the inner cylinder 6, and 12 is an inner cylinder 6 and an outer cylinder 11.
A closed body that closes the tip of the cylinder, 13 is both cylinders 6, 1
1, a puffer chamber formed by the closing body 12 and the piston 3, 14 is a plurality of gas blowout holes formed in the closing body 12, the outside of the movable arc contact 8 and the puffer chamber 13
And communicate with.

Reference numeral 15 denotes a cylindrical movable main contactor which is provided integrally with the tip of the outer cylinder 11 and the closing body 12 and outside the movable arc contactor 8, and the outer surface of which is the fixed main contactor 2. Touch and separate from the inner surface. 16 is a movable main contactor 15 at the base
Is a nozzle made of an insulator mainly composed of ethylene tetrafluoride adhered to the inner surface of the
Covers.

Next, the operation will be described. In the closed state of FIG. 5, that is, the outer surface of the movable main contactor 15 contacts the inner surface of the fixed main contactor 2, the inner surface of the movable arc contactor 8 contacts the outer surface of the fixed arc contactor 1, and SF _6, etc. When both cylinders 6 and 11 move to the piston 3 side by the opening operation in a state where the insulating gas has flowed into the puffer chamber 13, as shown in FIG.
As shown in A, the movable main contact 15 is disengaged from the fixed main contact 2, the movable arc contact 8 is disengaged from the fixed arc contact 1, and an arc is generated between the arc contactors 1 and 8. To do.

At this time, the inside of the puffer chamber 13 is compressed as the two cylinders 6 and 11 move, and the insulating gas in the puffer chamber 13 flows from the gas outlet 14 to the nozzle 16 as shown by the arrow in the figure. Both arc contacts 1, which are blown out inside
8 is blown to the arc between 8 and the gas passes through the hollow portion of the inner cylinder 6, the gas vent hole 7 and the inside of the tubular body 4 and is guided into the tubular body 4, and at the same time, into the hollow portion of the fixed arc contactor 1. The arc is extinguished by the gas introduced and blown to the arc, and the open state shown in FIG. 7B is obtained.

Next, both cylinders 6, 11 are closed by the closing operation.
When is moved to the fixed contactor side, the movable arc contactor 8 comes into contact with the fixed arc contactor 1, and then the movable main contactor 15 comes into contact with the fixed main contactor 2, resulting in the closed state shown in FIG. .

[0009]

In the case of the conventional gas circuit breaker described above, the fixed arc contactor 1 and the movable arc contactor 8 are opened at the same time as the fixed main contactor 2 and the movable main contactor 15 are opened. Since it is necessary to be delayed from the pole time, and because both arc contactors 1 and 8 project from the fixed main contactor 2 and the movable main contactor 15 structurally, the tip of the movable arc contactor 8 in the open state is The potential gradient is high.

Further, as shown in FIG. 6, since the groove 9 is formed between the contact pieces 10 of the movable arc contact piece 8, the arc generated between the arc contact pieces 1 and 8 is the arc. Although it tries to move in the circumferential direction due to the irregularity of the shape, the imbalance such as spraying of the insulating gas, etc., it is difficult to move in the circumferential direction of the movable arc contactor 8 beyond the groove 9. When the corner portion 17 of the contact piece 10 is melted by the arc, a protrusion is formed on the corner portion 17, and the arc is extinguished during the opening state or during the opening operation, when a potential difference occurs between the two arc contacts 1 and 8, As shown in FIG. 7A, the equipotential line S is located at the position shown by the chain line, the electric field is concentrated on the protrusions, the potential gradient of the movable arc contactor 8 locally increases, and flashover easily occurs. Therefore, it is difficult to maintain the initial insulation performance by repeating interruption of the fault current.

In view of the above points, the present invention provides a gas circuit breaker capable of maintaining stable initial insulation performance without causing a flashover accident even if the movable arc contact is melted and damaged by an arc. The purpose is to do.

[0012]

In order to solve the above problems, a gas circuit breaker of the present invention comprises a cylindrical fixed arc contactor and an annular fixed main contactor provided outside the fixed arc contactor. And a cylindrical cylinder that constitutes the puffer chamber and is movably provided, and is integrally provided at the end of the cylinder.
An annular movable arc contact that comes into contact with and separates from a fixed arc contact, and a cylindrical movable main contact that is provided integrally with the end of the cylinder and outside the movable arc contact and that comes into contact with and separates from the fixed main contact. A nozzle that is provided at the end of the cylinder and covers the movable arc contactor and that blows the gas in the puffer chamber to the arc between the fixed arc contactor and the movable arc contactor at the time of opening, and is embedded in the nozzle. The movable arc contactor is provided at a position closer to the fixed arc contactor than the tip of the movable arc contactor, and has an annular electrode connected to the movable main contactor.

[0013]

In the gas circuit breaker of the present invention constructed as described above, the electrode connected to the movable main contact is embedded in the nozzle at a position closer to the fixed arc contact than the movable arc contact, so that the movable arc contact is formed. The electric field at the tip of the contact will be alleviated, and even if the contact piece of the movable arc contact piece is melted by the arc, the potential gradient will not locally increase, preventing a flashover accident. , The initial stable insulation performance is maintained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment will be described with reference to FIGS. 1 is a sectional view in a closed state, FIG. 2 is a sectional view of the electrode in FIG. 1, FIG. 3A is a sectional view in the middle of the opening operation in FIG. 1, and B is a sectional view in an open state.

In these drawings, the same reference numerals as those in FIGS. 5 to 7 indicate the same or corresponding ones, and the different points are as follows.

An electrode 18 having a circular cross section and an annular shape is embedded in the nozzle 16 at a position closer to the fixed arc contact 1 than the movable arc contact 8 and is connected to the movable main contact 15.

The electrode 18 embedded in the nozzle 16 is
Since the dielectric constant of the nozzle 16 is about twice as high as that of the insulating gas, the surface potential gradient is low and there is no deterioration due to interruption.
It does not adversely affect the breaking performance.

The electrode 18 can be embedded by setting it in a mold at the time of molding the nozzle 16 and is easy to manufacture.

Next, the operation is almost the same as that of the conventional case, but the arc between the two arc contacts 1 and 8 is extinguished by the insulating gas through the closed state of FIG. 1 and the opening operation of FIG. 3A. 3B, the equipotential line S shown in FIG. 3A is positioned closer to the fixed arc contactor 1 than the movable arc contactor 8 by the electrode 18 having the same potential as the movable main contactor 15 when the contact state of FIG. 3B is reached. However, since the electric field at the tip of the movable arc contact 8 is relaxed, even if the contact piece 10 of the movable arc contact 8 shown in FIG. It never gets higher.

Next, in addition to the case where the electrode 18 has a circular cross section as shown in FIG. 2, it is sufficient that the electrode 18 has a curved surface on the counter electrode side.
The electrode 19 has a semicircular cross section as shown in FIG.
As shown in B, a circular electrode 20 having a cross section of 1/4,
Further, as shown in FIG. 4C, it may be an electrode 21 having an arc-shaped cross section, and has the same effect as the electrode 18.

[0021]

Since the present invention is constructed as described above, it has the following effects.

The gas circuit breaker of the present invention comprises a movable main contactor 15
The electrodes 18, 19, 20, 21 connected to the nozzle 1
Since it is embedded at a position closer to the fixed arc contactor 1 than the movable arc contactor 8 of FIG. 6, the electric field at the tip of the movable arc contactor 8 can be relaxed, and the contact piece 10 of the movable arc contactor 8 is arced by the arc. Even if the melting loss occurs, it is possible to prevent the potential gradient from locally increasing and prevent a flashover accident, and it is possible to maintain stable initial insulation performance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention in a closed state.

2 is a cross-sectional view of the electrode of FIG.

3A is a sectional view in the middle of the contact opening operation of FIG. 1, and B is a sectional view in the contact opening state.

4A, 4B and 4C are cross-sectional views of another example of the electrode of FIG.

FIG. 5 is a sectional view of a conventional example in a closed state.

6 is a perspective view of the movable arc contactor of FIG.

7A is a cross-sectional view in the middle of the contact opening operation of FIG. 5, and B is a sectional view in the contact opening state.

[Explanation of symbols]

 1 Fixed arc contactor 2 Fixed main contactor 6 Cylinder 8 Movable arc contactor 11 Cylinder 13 Puffer chamber 15 Movable main contactor 16 Nozzle 18 Electrode 19 Electrode 20 Electrode 21 Electrode

Claims (1)

[Claims] 1. A cylindrical fixed arc contactor, an annular fixed main contactor provided on the outer side of the fixed arc contactor, and a cylindrical cylinder movably provided which constitutes a puffer chamber. An annular movable arc contactor which is integrally provided at an end of the cylinder and which is brought into contact with and separated from the fixed arc contactor, integrally provided at an end of the cylinder and outside the movable arc contactor A cylindrical movable main contact that comes in contact with and separates from the fixed main contact, and a movable arc contact that is provided at an end of the cylinder and covers the movable arc contact, and that gas in the puffer chamber is opened when the electrode is opened to the fixed arc contact. A nozzle for blowing an arc between the movable arc contactor and the movable arc contactor, embedded in the nozzle, positioned at a position closer to the fixed arc contactor than the tip of the movable arc contactor, and connected to the movable main contactor. With annular electrodes Gas circuit breaker equipped.