JPH0883545A - Gas-blast circuit breaker - Google Patents

Abstract

PURPOSE: To make a fixed contact hard to be damaged by arranging a projecting part in an arc-extinguishing chamber so as to protect the fixed contact from high temperature cracked gas. CONSTITUTION: A ring shaped projecting part 25 where an insulating nozzle 23 to surround a contact part between a movable contact 4 and a fixed contact 1 projects inward in the radial direction from an inner peripheral wall of an arc-extinguishing chamber 22, is provided. This projecting part 25 is formed so as to cover the fixed contact 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas switch such as a disconnect switch used in a gas insulated switchgear filled with SF ₆ gas.

[0002]

2. Description of the Related Art Unlike a circuit breaker, a gas switch has a variety of arc-extinguishing schemes because the required breaking capacity is, for example, thousands of volts and hundreds of amps. FIG. 6 is a cross-sectional view of a main part showing a configuration of a conventional gas switch, and shows a closed state. The fixed contact 1 is fixed to the base 2 by a ring-shaped spring 3. This base 2 is an insulating nozzle 5
And has a recessed portion 16 at the center of the shaft.
The fixed contact 1 is composed of a plurality of pieces divided in the circumferential direction, and a cylindrical bar-shaped movable contact 4 is formed by a spring 3.
Is pressed inward in the radial direction, and the fixed contact 1 is in slidable contact with the outer peripheral wall surface of the movable contact 4. The movable contact 4 is fitted into a nozzle hole 5A formed in the central axis of the insulating nozzle 5 and a recessed portion 16, and the movable contact 4 has a hole 12A extending axially from its tip.
An arc extinguishing hole 12 is formed by a hole 12B communicating with the hole 12A and extending in a direction perpendicular to the axis and extending to the outer periphery of the movable contact 4. Further, the movable contact 4 penetrates the support body 7 in the lower part of FIG. 6 and is supported by the slide ring 6 so as to be movable in the axial direction. The energizing contact 8 contacts the outer periphery of the movable contact 4, and is fixed to the supporting body 7 by a ring-shaped spring 9, and the shield 10 is also fixed to the supporting body 7. The energizing contact 8 is similar to the fixed contact 1 and is divided into a plurality of pieces in the circumferential direction. The entire gas switch is housed in a tank (not shown) and arranged in arc extinguishing gas.

In FIG. 6, the support 7 guides the movable contact 4 in the axial direction, and the shield 10 relaxes the electric field around the energizing contact 8. Power is supplied from the power contact 8 to the fixed contact 1 via the movable contact 4. The movable contact 1 is connected to a drive mechanism (not shown) provided in the lower part of FIG. 6, and is driven in the direction of arrow 11 when opened.

FIG. 7 is a cross-sectional view of essential parts showing a state in which the device of FIG. 6 is being opened. When the movable contact 4 moves downward, the space formed by the recess 16, the insulating nozzle 5, and the tip surface of the movable contact 4 increases, and this increases the space.
It becomes 7. Since the arc 13 is generated between the movable contact 4 and the fixed contact 1 when the movable contact 4 and the fixed contact 1 are separated from each other, arc-resistant metal portions 4A and 1A are provided on the movable contact 4 and the fixed contact 1, respectively.

In FIG. 7, the interior of the arc extinguishing chamber 17 is sealed. When the movable contact 4 starts further opening drive in the direction of the arrow 11, the arc 13 between the movable contact 4 and the fixed contact 1 grows, and the arc heat increases the internal pressure of the arc extinguishing chamber 17. FIG. 8 is a cross-sectional view showing a state in which the opening is further advanced than the state of FIG.
When the hole 12B reaches the position where it comes out of the nozzle hole 5A,
The high-pressure gas in the arc extinguishing chamber 17 blows out from the hole 12B to the outer periphery of the movable contact 4. By blowing out the gas, the arc 13 is drawn into the arc extinguishing hole 12 as shown in FIG. 8, so that the arc 13 is expanded, cooled, and the current is cut off. In the state where the gas switch is completely opened, the movable contact 4 is driven out of the nozzle hole 5A and is driven until the tip of the movable contact 4 reaches a position (dotted line 4B) near the opening of the shield 10 to complete the opening operation. The hole 12
B does not necessarily have to be opened at right angles to the axis, and the arc extinguishing hole 12 may be formed from the tip of the movable contact 4 to the outer periphery of the movable contact 4.

[0006]

However, the conventional device as described above has a problem that the fixed contact is easily damaged by the arc. That is, the arc 13 follows the route as shown in FIG. 8, but the arc 13 is filled with the high-temperature decomposed gas.
The insulating nozzle 5 is made of polytetrafluoroethylene, and the arc-resistant metal part 1A is made of a copper-tungsten alloy, so that it is resistant to high-temperature decomposed gas of the arc 13. However, the fixed contact 1 is made of copper because of its electrical conductivity. Copper is relatively easily damaged by high-temperature decomposed gas, and the life of the conventional gas switch is determined by the extent to which the fixed contact 1 is damaged. Further, if the spring 3 pressed from the outer circumference of the fixed contact 1 is made of stainless steel, the spring 3 is vulnerable to this high-temperature decomposed gas, so that the spring 3 is easily damaged.

An object of the present invention is to make the fixed contact less susceptible to damage by providing an insulating protrusion in the arc extinguishing chamber for protecting the fixed contact from high temperature decomposition gas.

[0008]

In order to achieve the above object, according to the present invention, a rod-shaped movable contact and an outer peripheral surface of the movable contact can be separated into and separated from each other in a container filled with an arc extinguishing gas. A fixed contact and an insulating nozzle fixed to the fixed contact are housed, and the insulating nozzle forms an arc extinguishing chamber that surrounds the contact portion between the fixed contact and the movable contact, and the nozzle is provided in this arc extinguishing chamber. With a hole drilled, the movable contact moves axially through the nozzle hole, and in the case where the movable contact has an arc extinguishing hole that extends from the tip of the fixed contact to the outer periphery of the movable contact, the insulating nozzle is A ring-shaped insulating protrusion protruding radially inward from the inner peripheral wall may be provided, and the protrusion may be formed so as to cover the fixed contact.

Further, in such a structure, the projection may be integrally formed of the same material as the insulating nozzle. Further, in such a configuration, the opening of the arc extinguishing hole on the fixed contact side may be formed wider than the inner cavity of the arc extinguishing hole.

[0010]

According to the structure of the present invention, the insulating nozzle is provided with the insulating protrusion which is close to the fixed contact. This protrusion interferes with the high-temperature decomposition gas formed by the arc and prevents it from reaching the fixed contact side. Therefore, the fixed contact is less likely to be damaged.

Further, in this structure, the protrusion is integrally formed from the same material as the insulating nozzle. This reduces the number of parts. Further, in such a configuration, the opening of the arc extinguishing hole on the fixed contact side is formed wider than the inner cavity of the arc extinguishing hole. This causes the arc to be elongated in the arc-extinguishing hole. As a result, the arc can be cooled rapidly and the current that can be interrupted is increased.

[0012]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a cross-sectional view of an essential part showing the configuration of a gas switch according to an embodiment of the present invention, showing a closed state. The insulating nozzle 23 includes a ring-shaped insulating protrusion 25 in the arc extinguishing chamber 22, and the protrusion 25 is formed so as to cover the fixed contact 1. Others are the same as the conventional configuration of FIG. The same parts are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 2 is a cross-sectional view of essential parts showing a state in which the apparatus of FIG. 1 is being opened. Since the fixed contact 1 and the movable contact 4 start to separate and an arc 13 is formed and the hole 12B enters the nozzle hole 5A, the arc extinguishing chamber 2
2 is contained and the internal pressure of the arc extinguishing chamber 22 begins to rise by the arc 13. FIG. 3 is a cross-sectional view of essential parts showing a state in which the opening has further advanced from the state of FIG. When the hole 12B reaches the position where it exits from the nozzle hole 5A, the high pressure gas in the arc extinguishing chamber 22 blows out from the hole 12B. By this gas blowing, the arc 13 is drawn into 12A as shown in FIG. 3, so that the arc 13 is cooled and the current is cut off.

In FIG. 3, the arc 13 is inside the arc extinguishing chamber 22.
Temporarily filled with high temperature decomposition gas. However, it is difficult for the decomposed gas to reach the fixed contact 1 and the spring 3 side because the protrusion 25 interferes. There may be some gap (about 2 to 5 mm) between the protrusion 25 and the fixed contact 1. Since the current interruption is a phenomenon of several tens of ms, the decomposed gas hardly enters in such a gap. Therefore, the protrusion 25 and the fixed contact 1 may be in contact with each other or may be separated by several mm. Protrusion 25 is fixed contact 1 so that decomposition gas does not enter.
Just cover it. As a result, the fixed contact 1
Since the spring 3 is less likely to be damaged, the life of the device is significantly extended. The protrusion 25 may be configured such that another one is attached to the insulating nozzle 23, but it is cheaper to integrally manufacture the protruding portion 25 from the same material as the insulating nozzle 23 because the number of parts is reduced.

FIG. 4 is a sectional view of the essential parts of a gas switch according to another embodiment of the present invention. 18 of the arc-extinguishing hole 18 in which the movable contact 40 is formed
A has a step 26 on the inner wall. The opening 27 on the upper side of the hole 18A is formed wider than the inner cavity 28 on the lower side. Others are the same as the configuration of FIG. In FIG. 4, the hole 18
Since the opening 27 of A is wide, the arc 20 follows the path opened in a V shape in the hole 18A. Originally, the arc 20 is V
When the V shape is taken, the flow directions of the electric currents are opposite to each other with the V-shaped valley portion 20A as a boundary, so that the arcs 20 repel each other and a force acts on the arc 20 to further open the V shape. As the V-shape is opened, the arc 20 is stretched longer, so that the arc 20 is cooled more and the current cutoff characteristic is improved.

Note that, in FIG. 4, the protrusion 25 is not always necessary, so that the blocking characteristic is not deteriorated.
However, since the arc 20 opens in the hole 18A more than the conventional one, the filling rate of the decomposed gas into the arc extinguishing chamber 22 is high. Therefore, providing the insulating nozzle 23 with the protrusion 25 prolongs the life of the apparatus. FIG. 5 is a cross-sectional view of essential parts of a gas switch according to still another embodiment of the present invention. A fixed contact side hole 19A of the arc extinguishing hole 19 formed in the movable contact 41 is tapered toward the opening 29 side. The opening 29 on the upper side of the hole 19A is formed wider than the inner cavity 28 on the lower side. Others are the same as the configuration of FIG.

In FIG. 5, since the opening 29 of the hole 19A is wide, the arc 21 follows the path opened in the V-shape in the hole 19A. This is exactly the same as that described with reference to FIG. 4, and the formation of the hole 19A allows the arc 21 to be cooled more and the current cutoff characteristic to be improved.

[0018]

As described above, according to the present invention, the insulating nozzle has the protrusion that covers the fixed contact. This protrusion interferes with the high-temperature decomposition gas formed by the arc and prevents it from reaching the fixed contact side. As a result, the fixed contacts are less susceptible to damage and the life of the device is significantly extended.

Further, in such a structure, the protrusion is integrally formed from the same material as the insulating nozzle. As a result, the number of parts is reduced and the cost of the device can be reduced. Further, in such a configuration, the opening of the arc extinguishing hole on the fixed contact side is formed wider than the inner cavity. This allows
The arc becomes elongated in the arc extinguishing hole.
Therefore, the arc can be rapidly cooled, the current that can be interrupted is increased, and the device can be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing the configuration of a gas switch according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a state in which the structure of FIG. 1 is being opened.

FIG. 3 is a cross-sectional view of an essential part showing a state in which the opening is further advanced from the state of FIG.

FIG. 4 is a cross-sectional view of essential parts showing the configuration of a gas switch according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of an essential part showing the configuration of a gas switch according to still another embodiment of the present invention.

FIG. 6 is a sectional view of an essential part showing a configuration example of a conventional gas switch.

FIG. 7 is a cross-sectional view of essential parts showing a state in which the structure shown in FIG. 6 is being opened.

FIG. 8 is a cross-sectional view of essential parts showing a state in which the opening has advanced further than the state in FIG.

[Explanation of symbols]

1: fixed contact, 4, 40, 41: movable contact, 23: insulating nozzle, 5A: nozzle hole, 12, 18,
19: arc extinguishing hole, 22: arc extinguishing chamber, 25: protrusion, 27, 2
9: opening, 28: lumen

Claims (3)

[Claims] 1. A rod-shaped movable contact, a fixed contact that can be brought into contact with and separated from an outer peripheral surface of the movable contact, and an insulating nozzle fixed to the fixed contact are housed in a container filled with arc-extinguishing gas. The insulating nozzle has an arc-extinguishing chamber inside which surrounds the contact part between the fixed contact and the movable contact, and a nozzle hole is formed in this arc-extinguishing chamber, and the movable contact moves axially through the nozzle hole. In addition, in the case where an arc extinguishing hole is formed from the tip of the fixed contact to the outer circumference of the movable contact, the insulating nozzle is provided with a ring-shaped insulating protrusion protruding radially inward from the inner peripheral wall of the arc extinguishing chamber. The gas switch, wherein the protrusion is formed so as to cover the fixed contact. 2. The gas switch according to claim 1, wherein the protrusion is integrally formed of the same material as the insulating nozzle. 3. The gas switch according to claim 1, wherein an opening of the arc extinguishing hole on the fixed contact side is formed wider than a bore of the arc extinguishing hole.