JPH07249351A - Gas filled breaker - Google Patents

Abstract

PURPOSE:To reduce the outside diameter of a fixed shield and to prevent formation of an arc on the outer surface of the fixed shield by coating the outer surface of the fixed shield with a heat-resistant insulator, and providing a hemispherical projecting part at the end of a moving contact. CONSTITUTION:When a moving contact 21 separates from a fixed contact 6 to open a circuit, an arc 23 is formed between both contacts and one end of the arc is shifted to a hemispherical projecting part 22, while the other end is shifted on the contact piece 4 of a contact 6 toward the fixed shield 19 and extinguished. Even if the arc 23 is then fired at the shield 19, the shield 19 has a low-electric-field surface on its back and its withstand voltage is not lowered since its outer surface is coated with an insulator 20 made of a fluororesin such as Teflon. Therefore, the shield 19 can be made to have a minimum outside diameter at which it does not obstruct the motion of the contact piece 4, and a fixed base 3 and a cylinder 8 can also be made smaller in outside diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas disconnector, and more particularly to a gas disconnector having an improved shield covering a fixed contact and a tip of a movable contact.

[0002]

2. Description of the Related Art Gas-insulated switchgear includes circuit breakers, disconnectors,
It consists of a grounding switch, etc., and the disconnecting switch is generally turned on and off without cutting the current, but
Actually, it has a switching ability to open and close charging current and loop current to some extent.

FIG. 2 shows a disconnecting switch having this current switching capability, which is composed of a fixed unit 1 and a movable unit 2 provided in an insulating gas. The fixed unit is constructed as follows. .

A fixed base 3 which is fixed to a fixed portion (not shown) and has a cylindrical portion with a collar 3a at its tip, and a large number of radial grooves are provided on the outer peripheral portion of the collar 3a to insert a contact piece 4 into which two rings are inserted. The fixed contact 6 is attached to the fixed base 3 by the coil spring 5, and at the same time, the fixed contact 6 holds contact pressure between the fixed contact 6 and the inserted movable contact. It is composed of a fixed side shield 7 having large rounded corners.

On the other hand, the movable unit 2 has a cylindrical shape and a cylinder 8 fixed to a fixed portion (not shown) in the same axial center as the fixed base 3, and a ring embedded in the tip of the cylinder 8. -Shaped energizing contact 9 and fixed side shield 7
The movable side shield 10 provided for the same purpose as above, the movable contact 11 and the bearing 12 which are provided in the cylinder 8 so as to be slidable with respect to the energizing contacts 9 and which are interlocked and coupled with a driving means (not shown). Composed.

FIG. 2A is a cross-sectional view of a closed state. When opening (disconnecting) from this state, the movable contact 11 is driven to the right in FIG. 2A. When the movable contact 11 moves to the right side, the movable contact 11 is disconnected from the fixed contact 6 and is disconnected. However, when a loop current flows when the movable contact 11 separates, an arc is generated between both contacts and the arc is stretched and extinguished. It turns off and becomes disconnected.

[0007]

However, as shown in FIG. 2B, the arc 13 may ignite to the shield 7 side during the opening of the circuit. When the shield 7 is ignited, the arc 13 damages the outer surface of the fixed-side shield 7,
Concavities and convexities are generated, electric field concentration occurs, and flashover easily occurs.

When the outer diameter of the fixed side shield 7 is reduced and the inner diameter is brought closer to the movable contact 11, this tendency becomes more and more and it becomes an obstacle to the reduction of the disconnection portion.

That is, in order to avoid the ignition of the shield 7, the fixed-side shield 1 whose outer diameter is increased as shown in FIG.
If No. 4 is used, no arc is generated between the fixed-side shield 14 and the tip of the movable contact 11, but since the outer diameter of the fixed-side shield 14 becomes large, as shown in FIG.
If the disconnectors 15, 16 and 17 for the phases are to be attached together, there arises a problem that the outer diameter of the pipe 18 of the bus line must be made larger.

The present invention has been made in view of the above points, and it is possible to reduce the outer diameter of the fixed shield.
Moreover, it is an object of the present invention to provide a disconnector which does not generate an arc between the outer surface of the fixed side shield and the tip of the movable contact.

[0011]

Means for solving the above problems in the present invention include a fixed contact, a fixed shield for covering the fixed contact, and a cylindrical movable member which is inserted into the fixed contact to make a closed circuit. In a gas disconnecting switch provided with a contact in an insulating gas, the outer surface of the fixed side shield is coated with an insulator made of heat-resistant fluororesin such as Teflon.

Further, a protrusion having a hemispherical tip shape is formed at the tip of the movable contact to prevent ignition to the fixed side shield, thereby enabling miniaturization.

[0013]

Since the outer surface of the fixed-side shield facing the movable contact is coated with a heat-resistant insulator, the arc does not ignite between the fixed-side shields.

Further, since the hemispherical protrusion having a diameter smaller than that of the movable contact is provided at the tip of the movable contact, the arc gathers on the protrusion on the central axis of the movable contact, so that the arc is present between the fixed contacts. It is concentrated and does not ignite between the outer surface of the fixed shield and the arc does not transfer to the fixed shield.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the drawings. Since the present invention is an improvement of a part of the conventional gas disconnecting switch, the same parts as those of the prior art are designated by the same reference numerals, and the description thereof will be omitted. Only different parts will be described.

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention. In FIG. 1, 19 is a fixed side shield, and 20 is a heat-resistant fluororesin such as Teflon coated on the outer surface of the fixed side shield 19. This coating does not necessarily have to be provided on the entire outer surface of the fixed-side shield, but at least on the outer surface facing the movable contact 21. Reference numeral 21 is a cylindrical movable contact, 22 is a hemispherical protrusion formed at the tip of the movable contact 21, and the spherical diameter (maximum) is the movable contact 2
The diameter is less than 1. Reference numeral 23 is an arc generated between the fixed contact 6 and the movable contact 21.

When the movable contact 21 moves to the right in FIG. 1 and separates from the fixed contact 6 when the circuit is opened, an arc 23 is generated between the movable contact 21 and the fixed contact 6, and one end of the arc 23 has a spherical shape. It moves to the protruding portion 22 and gathers on the central axis of the tip of the movable contact 21, and the other end moves on the contact piece 4 of the fixed contact 6 toward the fixed side shield 19 and disappears.

Even if the arc 23 ignites on the fixed side shield 19, the outer surface having a high electric field has a heat-resistant insulator 20.
Is a low electric field surface on the back surface, and the fixed-side shield 19 does not have a withstand voltage drop due to the trace of the arc 23. An outer surface of the fixed-side shield 19 coated with the heat-resistant insulator 20,
Since no arc 23 is generated between the movable contact 21 and the movable contact 21, the inner diameter of the fixed shield 19 is reduced to approach the outer diameter of the movable contact 21, and the outer diameter of the fixed shield 19 does not hinder the operation of the contact piece 4. It can be the smallest dimension. FIG. 1 shows a case where the outer diameters of the fixed base 3 and the cylinder 8 are made smaller in accordance with the outer diameter of the fixed shield 19 which is made smaller.

When the outer diameter of the fixed-side shield 19 is reduced in this way, the diameter of the conduit when the three phases are integrated can be reduced, and a more compact insulated switchgear can be provided. Further, since the pipeline can be made small, the pipeline and the parts attached to the pipeline are also downsized, and there is a great effect on the cost reduction.

[0020]

As can be seen from the above description, in the gas disconnector according to the present invention, the outer surface of the fixed-side shield that covers the fixed contact is coated with a heat-resistant insulator, and the tip of the movable contact has a spherical tip shape. Since the generated arc is concentrated on the central axis of the movable contact, the arc does not ignite to the high electric field surface of the fixed side shield, and the inner diameter of the fixed side shield is set to the movable contact. The outer diameter of the fixed-side shield can be reduced by bringing it closer to the outer diameter of the bus, and the outer diameter of the fixed-side shield can be reduced. It has an excellent effect that it is possible to provide the gas insulated switchgear.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional example. (A) shows a closed state, and (B) shows an open state.

FIG. 3 is an explanatory diagram of a conventional example.

FIG. 4 is an explanatory diagram when a disconnector is applied to a pipeline busbar.

[Explanation of symbols]

 6 ... Fixed contact 19 ... Fixed side shield 20 ... Insulator 21 ... Movable contact 22 ... Spherical protrusion

Claims (2)

[Claims] 1. A gas disconnecting switch, comprising: a fixed contact; a fixed shield that covers the fixed contact; and a cylindrical movable contact that is inserted into and removed from the fixed contact in an insulating gas. A gas disconnecting switch, characterized in that at least the surface facing the movable contact is coated with a heat-resistant insulator such as a fluororesin. 2. The gas disconnector according to claim 1, wherein a hemispherical protrusion having a diameter smaller than the diameter of the movable contact is provided at the tip of the movable contact.