JP2003229038A - Puffer type gas-blast circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a puffer type gas-blast circuit breaker having excellent large-current breaking performance by certainly blocking retrogression of a puffer cylinder during the breaking operation, preventing rapid pressure reduction, and holding high gas-blowing pressure in an instance of a current break. <P>SOLUTION: This breaker is provided with a retrogression prevention device blocking the retrogression of the puffer cylinder during the breaking operation between the puffer cylinder provided inside a tank, moving together with a movable arc contact contactable/separatable to/from a fixed arc contact and an operation device driving the puffer cylinder. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a puffer type gas circuit breaker, and more particularly to a puffer type gas circuit breaker suitable for use with an operating device having a weak operating force such as a spring.

[0002]

2. Description of the Related Art Generally, in a puffer type gas circuit breaker, a puffer cylinder and a puffer piston are slidably fitted together to form a gas compression device called a puffer chamber, and the puffer cylinder is driven by an operating device. The arc extinguishing gas in the puffer chamber is compressed. When shutting off,
An arc is generated due to the opening of the contactor. Particularly, when the large current is cut off, the arc extinguishing gas around the arc is heated to a high temperature by the arc, a high pressure gas is generated and flows into the puffer chamber.

Therefore, in the puffer type gas circuit breaker of this type, during the large current interruption operation, the pressure of the high temperature high pressure gas flowing into the puffer chamber causes the puffer cylinder pressure acting on the puffer cylinder pressure receiving surface in a direction opposite to the interruption action direction. Power will be generated. This puffer reaction force is not a problem when using a large-sized operation device that can generate a large operation force, but due to the downsizing of the operation device, the operation force of a spring operation device is When a weak actuator is used, the above-mentioned puffer reaction force causes the shut-off section to go backwards, causing a sharp pressure drop due to pressure vibration, and the required gas blowing pressure can be secured at the instant of large-current shut-off. As a result, the large current interruption performance is deteriorated.

In order to prevent this, Japanese Patent Publication No. 57-32
In the puffer type gas circuit breaker described in Japanese Patent No. 452,
The bypass groove provided on the inner wall surface of the puffer cylinder that engages with the puffer piston at the final position of the shutoff operation releases the high-pressure gas in the puffer chamber to the surroundings, reducing the puffer reaction force and ensuring the shutoff performance. There is.

[0005]

However, in the conventional puffer type circuit breaker, part of the high pressure gas generated only at the final position of the breaking operation is discharged to the surroundings to reduce the puffer reaction force. However, depending on the magnitude of the breaking current and the arcing time, there is a drawback that the stroke reverses even at the middle position of the breaking operation, the spray pressure drops, and the breaking performance is impaired.

The present invention has been made in view of the above points,
The purpose of this is to ensure that the reverse stroke is prevented, a sudden pressure drop is prevented, and a high gas blowing pressure is maintained at the instant when the current is cut off. The purpose is to provide a gas breaker.

[0007]

In order to achieve the above object, the present invention is characterized by having the structure described in claim 1.

That is, in the puffer type gas circuit breaker according to the present invention, the puffer cylinder in the course of the breaking operation is surely prevented from going backward, so that a rapid pressure drop due to the pressure vibration due to the backward movement is prevented and the breaking performance is improved. Since the gas spray pressure at the moment of the most interrupted current interruption can be maintained at a high value,
It is possible to obtain a puffer type gas circuit breaker having a significantly excellent large current breaking performance.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a puffer type gas circuit breaker in a closed state according to an embodiment of the present invention, and FIG. 2 shows a retrograde prevention device 3 employed therein.

As shown in FIG. 1, the circuit breaker 1 of this embodiment is
It is roughly configured by a shutoff portion 2, a retrograde prevention device 3, an operating device 4, and a dashpot 5 that reduces the driving force of the operating device 4.

First, the detailed structure of the blocking section 2 will be described. The blocking unit 2 includes a tank 6, and a conductor 7 is provided in the tank 6.
And an insulating cylinder 8 for supporting the conductor 7 on the tank 6. In the tank 6, as an arc extinguishing gas, for example, SF ₆
Gas is enclosed. And in the tank 6,
A fixed main contactor 9, a fixed arc contactor 10, a movable main contactor 11 and a movable arc contactor 12, which are provided so as to be able to contact and separate from the fixed main contactor 9 and the fixed arc contactor 10,
A puffer cylinder 13 that moves integrally with the movable main contactor 11 and the movable arc contactor 12, and a puffer cylinder 1
3 and a fixed piston 14 that is inserted into the puffer cylinder 13 and slides on the inner wall surface of the puffer cylinder 13.

On the other hand, the inner wall surface of the puffer cylinder 13, the outer peripheral surface of the movable arc contactor 12, and the fixed piston 14 form a puffer chamber 15. The puffer chamber 15 is configured such that the volume thereof is reduced during the opening operation of the fixed main contactor 9 and the fixed arc contactor 10 and the movable main contactor 11 and the movable arc contactor 12, and the compressed gas is compressed. The puffer cylinder 13 is provided with a through hole 16 serving as a discharge port to the fixed arc contact 10 and the movable arc contact 12 side.

Further, the puffer cylinder 13 has a through hole 1
The nozzle 17 is fixed so that the gas discharged from 6 is sprayed onto the arc generated between the fixed arc contact 10 and the movable arc contact 12.

At both ends of the movable arc contact 12 opposite to the fixed arc contact 10 side, the piston base 1 is attached.
8 and the insulating rod 20 penetrating the insulating cylinder 19 are rotatably connected to each other around a pin 21 which is the center of rotation. The insulating rod 20 is formed of an insulating material so as to have electrical insulation.

A conductor 22 from the outside is electrically connected to the fixed main contactor 9 and the fixed arc contactor 10 via the conductor 7. Further, the conductor 23 is electrically connected to the outside through the conductor 24.

Next, the structure of the operating device 4 will be described. The operating device 4 is a spring operating device, and the driving force of the blocking spring 25 is transmitted to the retrograde prevention device 3 by the shaft 26. At this time, the shaft 26 may be a member integrally formed with the breaking spring 25, or may be a separate member connected to the breaking spring 25. Also, the breaking spring 25 is the lever 2
It is connected to the closing spring 29 connected to the dashpot 5 and the control mechanism 33 controlled by the control unit 28 via 7. The dashpot 5 is composed of a piston 32 formed integrally with a rod 31 that slides on the inner surface of a cylinder 30 having a large number of small holes.

Next, the mechanism case 40 will be described. The mechanism case portion 40 includes an input lever 34, an output lever 35 longer than the input lever 34, and a link 37. The input lever 34 and the output lever 35 are provided so as to be rotatable (swingable) about a pin 36 which is a common rotating shaft. At this time, the angular relationship between the input lever 34 and the output lever 35 is maintained constant. Further, at the end opposite to the pin 36 which is the rotation shaft of the input lever 34,
A link 37 is rotatably connected about a pin 38 which is a rotation shaft. An end portion of the link 37 opposite to the pin 38 is connected to the anti-return device 3. Further, the insulating rod 20 is rotatably connected to the end portion of the output lever 35 opposite to the pin 36 which is the rotating shaft about the pin 39 which is the rotating shaft.

Next, the structure of the retrograde prevention device 3 will be described with reference to FIG. The retrograde prevention device 3 includes a mechanism case portion 4
Base 301 and guide pin 30 fixed to 0 by welding or the like
A ratchet claw 303 having 2 and a toggle spring 304 are housed, and a spring case 306 having a lid 305 and a guide plate 308 having a guide groove 307 are integrated by screwing or welding to have a rectangular cross section and ratchet teeth 309 provided on one surface thereof. It is composed of a rod 310.

In this embodiment, the puffer cylinder 13 is operated in the horizontal direction, but it may be arranged in the vertical direction.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 1 shows a closing state of the blocking unit 2, and FIG. 2 shows a retrograde prevention device 3 at a closing position.
The positional relationship between the ratchet claw 303 and the ratchet tooth 309 is shown. Further, FIG. 3 shows a state in which the shutoff operation of the shutoff unit 2 is in progress.
FIG. 4 shows the positional relationship between the ratchet pawl 303 and the ratchet tooth 309 of the retrograde prevention device 3 during the shutoff operation. FIG. 5 shows the interruption completion state of the interruption unit 2. FIG. 6 shows the positional relationship between the ratchet pawl 303 and the ratchet tooth 309 of the retrograde prevention device 3 when the shutoff operation is completed. FIG. 7 shows the stroke characteristic and the puffer pressure characteristic in the breaking operation.

In the closed state of FIG. 1, current flows from one end of the circuit breaker 1 and flows through the conductor 22, the conductor 7, the fixed main contactor 9, the puffer cylinder 13, the conductor 23, and the conductor 24.
It is flowing to the other end. As shown in FIG. 2, the retrograde prevention device 3 has the operation rod 310 moved to the left side in the drawing, the guide pin 302 of the ratchet claw 303 is driven downward by the guide groove 307, and the ratchet teeth 309 are driven by the toggle spring 304. Has been pressed.

When a cutoff command is given to the control unit 28 of the operation device 4 shown in FIG. 1, the dead center of the control mechanism 33, which prevents the lever 27 from rotating counterclockwise, collapses, and the cutoff is in a compressed state. The spring 25 is released and the shaft 2
The operation rod 310 of the retrograde prevention device 3 is driven to the right in the drawing via 6. As a result, the ratchet teeth 309 and the operating rod 310 of the retrograde prevention device 3 are driven to the right. This causes the ratchet teeth 309 to move the ratchet pawl 3
While pushing 03, move to the right.

By moving the link 37 shown in FIG. 1 connected to the operating rod 310 to the right, the input lever 3
4 starts rotating clockwise, and the movable arc contact 12 is driven to the right through the output lever 35 and the insulating rod 20. First, the fixed main contact 9 and the movable main contact 11 are separated, then the fixed arc contact 10 and the movable arc contact 12 are separated, and as shown in FIG. 41 occurs. At the same time, the puffer cylinder 13 integrated with the movable arc contact 12 is driven to the right, the compression of the gas in the puffer chamber 15 starts, the distance between the electrodes increases, and the gas pressure gradually rises. The high pressure gas generated in the puffer chamber 15 passes through the through hole 16,
The arc 41 is sprayed through the nozzle 17. When the current to be interrupted is a large current, the gas in the puffer chamber 15 is heated by the arc 41, and the pressure in the puffer chamber 15 is further increased. Puffer reaction force is increased. On the other hand, the driving force of the shutoff spring 25 gradually decreases,
The driving force is stronger and the puffer cylinder 13 moves in the blocking direction. Eventually, the puffer reaction force becomes stronger than the driving force of the spring, and the stroke tends to start moving backward, as shown in FIG. At this time, the operation rod 310 of the retrograde prevention device 3 tries to move to the left side in FIG.
Block the movement of 10 to the left.

Finally, as the puffer pressure is attenuated, the driving force of the spring is excellent and the spring is driven again in the blocking direction to reach the blocking position shown in FIG. At this time, as shown in FIG. 6, the ratchet claw 303 is driven upward by the guide groove 307,
It is held upward by a toggle spring 304. That is, the retrograde prevention device 3 is reset, and the operating rod 310 of the retrograde prevention device 3 can be moved to the left side without trouble during the closing operation.

The stroke characteristic of the puffer cylinder 13 and the puffer pressure characteristic of the puffer chamber 15 during the shutoff operation will be compared with the conventional case.

In FIG. 7, the solid line shows the case of this embodiment, and the broken line shows the case of the conventional example. In the present embodiment, the retrograde prevention device 3 causes the stroke characteristic to be in a state close to a stop during the stroke, and the puffer pressure characteristic holds the high pressure at the time of the stop. On the other hand, in the conventional example, the volume of the puffer chamber increases with the reverse stroke, and the puffer pressure sharply decreases. Eventually, in any case, the operation is performed again in the shutoff direction, but the gas in the puffer chamber 15 is exhausted and the pressure is attenuated. In this embodiment, there is no abrupt pressure drop due to pressure oscillation due to reverse stroke during the breaking operation, a high blowing pressure can be maintained at the current zero point, and a puffer type with outstandingly large current breaking performance. A gas circuit breaker can be obtained.

[0027]

According to the puffer type gas circuit breaker of the present invention described above, it is possible to reliably prevent the puffer cylinder from going backward during the shut-off operation, and to prevent a sudden pressure drop due to pressure oscillation due to the backward movement. Then, since the gas spray pressure at the moment of the current interruption, which most affects the interruption performance, can be maintained at a high value, it is possible to obtain a puffer type gas circuit breaker having a significantly excellent large current interruption performance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a puffer type gas circuit breaker of the present invention in a closed state.

FIG. 2 is an enlarged view of the retrograde prevention device used in the puffer type gas circuit breaker shown in FIG. 1 in a closed state.

FIG. 3 is a sectional view of the puffer type gas circuit breaker shown in FIG. 1 during a breaking operation.

FIG. 4 is an enlarged view of a retrograde prevention device used in the puffer type gas circuit breaker shown in FIG. 1 during a breaking operation.

5 shows a cross-sectional view of the puffer type gas circuit breaker shown in FIG. 1 in a shut-off state.

FIG. 6 is an enlarged view of a retrograde prevention device in a shut-off state adopted in the puffer type gas circuit breaker shown in FIG.

FIG. 7 is a characteristic diagram showing a stroke characteristic and a puffer pressure characteristic of the puffer cylinder according to the present invention in comparison with a conventional example.

[Explanation of symbols]

2 ... Breaking part, 3 ... Retrograde prevention device, 4 ... Operator, 5 ... Dashpot, 6 ... Tank, 9 ... Fixed main contactor, 10 ... Fixed arc contactor, 11 ... Movable main contactor, 12 ... Movable arc Contactor, 13 ... Puffer cylinder, 14 ... Fixed piston, 15 ... Puffer chamber, 40 ... Mechanism case, 41 ... Arc, 302 ... Guide pin, 303 ... Ratchet pawl, 30
4 ... Toggle spring, 305 ... Lid, 306 ... Spring case, 3
07 ... Guide groove, 308 ... Guide plate, 309 ... Ratchet teeth, 310 ... Operation rod.

Continued front page    (72) Inventor Yoichi Oshita             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Makoto Yano             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. F-term (reference) 5G001 AA13 BB04

Claims (2)

[Claims] 1. A tank in which an insulating gas is sealed,
A fixed arc contactor, a movable arc contactor which is provided so as to be able to come in contact with and separate from the fixed arc contactor, a puffer cylinder that moves integrally with the movable arc contactor, and a puffer cylinder inserted into the puffer cylinder. A fixed piston that slides with the inner wall surface is housed, and an operating device that generates a driving force that drives the puffer cylinder that operates integrally with the movable arc contactor is provided, and the fixed arc contactor and the movable arc contactor are provided. A puffer-type gas circuit breaker configured to blow off the gas compressed by the puffer cylinder and the fixed piston to the arc generated between the fixed arc contact and the movable arc contact when the contact is opened. In the above, a retrograde prevention device for preventing retrograde movement of the puffer cylinder during the shutoff operation is provided between the puffer cylinder and the operating device. Puffer type gas circuit breaker. 2. The anti-reverse device comprises a ratchet pawl connected to a toggle spring and having a guide pin, and ratchet teeth integrally formed with a guide plate having a guide groove for controlling the position of the guide pin. The puffer type gas circuit breaker according to claim 1, wherein the puffer type gas circuit breaker is formed by a ratchet mechanism.