JPH02165527A - Gas insulation switching device - Google Patents

Abstract

PURPOSE:To reduce the size of the gas insulating switching device in its radial and axial directions by embedding a damping shield for electric fields at least at one end of an insulating tube and along the circumferential direction, and also connecting the damping shield to an outer shield. CONSTITUTION:A gas circuit breaker for one phase is comprised of fixed contact 15, 25 capable of making relative contact with and being separated form each other, a moving contact 17, outer shields 27, 28 surrounding the contact, and an insulating tube 29 provided between the outer shields. A damping shield 20 is embedded at one end of the insulating tube 29 and is further connected to the outer shields 27, 28. Equipotential lines are therefore distributed there except in the damping shield 20, and those equipotential lines which are distributed in the vicinity of the end portion of the fixed contact 15, 25 are kept away from the end portion, where the field concentration is thereby reduced. The curvature R of the angle portion of the contact 15, 25 can thus be reduced, by which the outside diameter of the contact 15, 25 can also be reduced. The distance of separation can also be shortened so that the size of the gas circuit breaker can be reduced in its axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a gas insulated switchgear that is downsized in the radial and axial directions by alleviating electric field concentration near contacts.

B0 Summary of the Invention The present invention provides fixed contacts that can be relatively contacted and separated;
In a gas-insulated switchgear in which a one-phase gas circuit breaker is constructed of a movable contact, a pair of cylindrical external shields that individually surround these, and an insulating tube provided between the pair of external shields, the insulating tube is By embedding a relaxation shield in at least one end and connecting the relaxation shield to an external shield, electric field concentration near the contact is alleviated and the size is reduced in the radial and axial directions.

C9 Prior Art A vertical switchgear in which the switch is placed vertically and housed in a bushing has a drawback of being vulnerable to earthquakes due to its high center of gravity. Therefore, a tank-type switchgear was developed in which the switch was placed horizontally and housed in a tank.

The configuration of the tank-type switchgear is shown in Figure 3. A gas circuit breaker l as a switch is housed in a horizontally placed metal tank 6. That is, the end plates 10a, 10 that close both ends of the tank 6
b is a pair of support insulator tubes 5a.

5b is attached, and one end of the gas circuit breaker l is supported on the support insulator tube 5a via the support fitting 4a, while the other end of the gas circuit breaker l is supported on the support insulator tube 5b via the support fitting 4b. . An operating mechanism IK is attached to the end plate 10a, and a movable rod 13 is connected via an insulating rod I2.

A pair of bushings 7a and 7b rising vertically upward is provided near both ends of the tank 6.
Conductors 8a and 8b are provided within a and 7b. Conductor 8a
, 8b are connected to the movable rod 13. through support fittings 4a, 4b. It is connected to the fixed rod 14. In addition, the conductor 8a
, 8b are connected to main circuit terminals 9a, 9b. In addition, 3a.

3b is a vibration-proof rubber.

The inside of the gas circuit breaker is constructed as shown in FIG.

That is, the fixed arcing contact 2 is attached to the fixed rod 14.
5 and a fixed main contact I5 surrounding the fixed arcing contact 25 are fixed, while the movable rod 14 has a movable arcing contact! 6 and movable main contact 17
and are fixed. The base end of the insulating nozzle I9 is connected between the movable arcing contact 16 and the movable main contact 17 to form a discharge path 18 for extinguishing the arc by blowing insulating gas from the buffer chamber 26 onto the arc. be done. A cylindrical outer shield 27 surrounding the fixed main contact 15 and a cylindrical outer shield 28 surrounding the movable main contact 17 are provided.
A cylindrical insulating tube 29 is fixed between the holes 28 .

When the movable arcing contact 16 separates from the fixed arcing contact 25 during interruption, an arc is generated.
The arc is extinguished by the insulating gas that is pushed out of the buffer chamber 26 by a piston (not shown) and then blown through the discharge path 18.

D0 Problem to be solved by the invention However, in the open state, the electric field concentrates at the tip of the fixed main contact 15 as shown in FIG. It is necessary to increase the distance from the fixed contact 15. In addition, in order to alleviate electric field concentration, efforts have been made to increase the curvature of the corners of the contacts to optimize the electric field distribution, but this approach has also reached its limit.

Gas circuit breakers are the most important components of tank-type switchgear, and they occupy more space than other devices. This is an important point for downsizing.

Therefore, an object of the present invention is to provide a gas insulated switchgear that solves the above problem.

81 Means for Solving the Problems The structure of the present invention for achieving the above object is to provide gas circuit breakers for three phases in parallel in an insulating gas, and to connect the gas circuit breakers to each other in relative contact with each other. In a gas-insulated switchgear consisting of a releasable nationally specified contact, a movable contact, a pair of cylindrical external shields that individually surround the fixed contact and the movable contact, and an insulating tube provided between the pair of external shields, The present invention is characterized in that a relaxation shield for electric field relaxation is embedded in at least one end of the cylinder along the circumferential direction, and the relaxation shield is connected to an external shield.

Since the relaxation shield is embedded in at least one end of the 10-effect insulating tube, the equipotential lines are distributed avoiding the relaxation shield portion.

Therefore, the equipotential lines near the tip of at least one of the movable contact and the fixed contact also gradually move away from the tip, and electric field concentration in this portion is significantly alleviated.

G. Examples The present invention will be explained in detail below using examples shown in the drawings. Note that this embodiment is an improvement on a part of the conventional gas insulated switchgear, so the same parts as the conventional gas insulated switchgear are given the same reference numerals, the explanation is omitted, and only the different parts will be explained.

(a) First Embodiment The configuration of a gas insulated switchgear according to the present invention will be explained based on FIG.

As shown in the figure, relaxation shields 20 are embedded at both ends of the insulating cylinder 29. This relaxation shield 20 includes a metal ring 20
a is embedded along the circumferential direction, and the metal ring 20a is connected to the external shield 27 or 28 via another metal 20b.

Since the relaxation shield 20 is provided in this way, the equipotential line moves a little to avoid the relaxation shield 20, as shown in FIG.

As a result, the equipotential lines at the tip A of the fixed main contact 15 also move away from the tip, the interval between the equipotential lines increases, and electric field concentration is alleviated. In addition, electric field concentration is similarly alleviated at the tip portion B of the fixed arcing contact 25. In this way, electric field concentration is relaxed and the potential distribution between the electrodes becomes uniform.

(b) Other Embodiments Next, other embodiments will be described based on FIGS. 2(a) to 2(c).

FIG. 2(a) shows a second embodiment of the present invention. As shown in the figure, at both ends of the insulating tube 29 in the length direction,
A mitigation shield 21 is embedded.

That is, the metal ring 21 section is embedded, and the metal ring 21a is connected to the external shield 27, 28 via the connection wire 21b formed in a mesh shape.

FIG. 2(b) shows a third embodiment of the present invention. Similar to the above, relaxation shields 23 are provided at both ends of the insulating cylinder 29.
is embedded. This relaxation shield 23 has a shielding effect by forming a recess inside an insulating cylinder 29 made of epoxy and injecting conductive rubber into the recess.

FIG. 2(c) shows a fourth embodiment of the present invention. A relaxation shield 24 is embedded in the same manner as in the third embodiment. This relaxation shield 24 is formed by injecting a high dielectric constant material such as barium titanate into four parts in the same manner as in the third embodiment. In this case, the mitigation shield 24 does not necessarily need to be in contact with the outer shield 27,28.

FIG. 2(d) shows a fifth embodiment of the present invention. This is a combination of the second to fourth embodiments, and a metal ring 30a is covered with a conductive rubber 30b to form a relaxation shield 30 in consideration of crack resistance.

The sixth embodiment shown in FIG. 2(e) and the seventh embodiment shown in FIG. The relaxation shield 20 is embedded only on the fixed side of the shield 29. Further, in the seventh embodiment, a short insulating cylinder 29 is coupled only to the outer shield 27, and a relaxation shield 20 is embedded.

H0 Effects of the invention As can be seen from the above explanation, the gas insulated switchgear according to the invention has the following effects.

(1) Since the relaxation shield is embedded in at least one end of the insulating cylinder, electric field concentration near the tip of at least one of the movable contact and the fixed contact is alleviated. As a result, it is possible to reduce the curvature of the radius of the corner of the contact, and the outer diameter of the contact can be reduced accordingly.

(2) By easing the electric field concentration near the tip of the contact, it becomes possible to reduce the separation distance, making it possible to downsize the gas circuit breaker in the axial direction and furthermore, to make the operating device of the gas circuit breaker smaller. can be made smaller.

(3) Since the gas circuit breaker can be made smaller in both the radial and axial directions, it is possible to further downsize the three-phase, tank-type switchgear.

[Brief explanation of the drawing]

1 and 2 relate to an embodiment of the gas insulated switchgear according to the present invention, FIG. 1 is an enlarged view showing the main parts of the first embodiment, and FIG. 2 (λ) is the main part of the second embodiment. Enlarged view showing the section, Figure 2 (
b) is an enlarged view showing the main parts of the third embodiment, Fig. 2(c) is an enlarged view showing the main parts of the fourth embodiment, and Fig. 2(d) shows the main parts of the fifth embodiment. An enlarged view, FIG. 2(e) is an enlarged view showing the main part of the sixth embodiment, FIG. 2(f) is an enlarged view showing the main part of the seventh embodiment, and FIG. 3 is an enlarged view of the tank type switchgear. Configuration diagram, 4th
The figure is an enlarged view showing the main parts of a conventional gas circuit breaker. l...Gas circuit breaker, 15...Fixed main contact, 1
6... Movable arcing contact, I7... Movable main contact, 18... Ejection path, I9... Insulating nozzle, 20.21.23.24.30... Relaxation shield,
25... Fixed arcing contact, 26... Buffer chamber, 27.28... External shield, 29... Insulating tube. Figure 1: Enlarged view showing the main parts of the gas circuit breaker 9 (first embodiment) - Gas circuit breaker 15 - Fixed main contact 16 Movable arcing contact 17 - Movable main contact 18 Discharge path 19 Disconnected nozzle 24.30・・Relaxation Nord 25・Fixed Arcing Connector 26 Buffer Room 2728-External Nord 29 Zekko Interchange Figure 3 Tank Cedar Opening and Closing Device Rumored Diagram

Claims (1)

[Claims] (1) Install a three-phase gas circuit breaker in parallel in the insulating gas,
Each gas circuit breaker has a fixed contact and a movable contact that can be brought into and out of relative contact, a pair of cylindrical outer shields that individually surround the fixed contact and the movable contact, and insulation provided between the pair of outer shields. A gas insulated switchgear configured with a cylinder, characterized in that a relaxation shield for mitigating an electric field is buried in at least one end of the insulating cylinder along the circumferential direction, and the relaxation shield is connected to an external shield. Insulated switchgear.