JPH1196864A - Puffer type gas-blast circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase gas pressure and to provide strong gas blasting force without enlarging arc extinguishing chamber and increasing the operation force. SOLUTION: In a buffer type gas-blast circuit breaker, in which high pressure gas from a puffer chamber 10 is blasted to an arc generating between a moving contact 3 and a fixed contact 2 in the current shutting off operation for arc- extinguishing, and part of the gas blasted to the arc passes through a gas flow path 13 formed on the inside of a sliding rod 8 for holding the moving contact, a layer 9 made of PTFE is formed in the gas flow path on the inside of the sliding rod. The PTFE layer is sublimated by heating with the thermal energy of arc in the current shutting off operation, and gas is generated to have the gas pressure raised. Thereby, gas pressure blasted to the arc is increased and enables large current shut off.

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 used in a substation of an electric power system.

[0002]

2. Description of the Related Art In a puffer type gas circuit breaker, when a current is interrupted, gas is compressed by a cylinder and a piston against an arc generated between a movable contact and a fixed contact, thereby increasing the pressure. The arc is cooled by blowing gas onto the arc to extinguish the arc.

A conventional puffer type gas circuit breaker will be described with reference to FIG. FIG. 1 shows the main part of the circuit breaker in cross section,
The circuit breaker shown in FIG. 1 is in the state of a current interruption operation.
In this state, the sliding rod 8 is being rapidly moved downward in the figure by an operating device (not shown). The fixed main contact 1 and the movable main contact 4 and the fixed arc contact 2 and the movable arc contact 3 which were in contact with each other in the closed state of the circuit breaker were separated, and the arc 14 was separated from the fixed arc contact 2 and the movable arc. It occurs between the contacts 3.

During the current interruption operation, the cylinder 6 attached to the sliding rod 8 moves relatively to the fixed piston 7 and compresses the gas in the puffer chamber 10.
In the state shown in FIG. 1, the space communicating with the puffer chamber 10 is closed on the upper side because the fixed arc contact 2 is covered by the nozzle 5, and the gas flow provided on the inner side of the sliding rod 8 on the lower side. Since the hole 11 of the passage 13 is closed by the fixed piston 7, it is a closed space.

Accordingly, the gas in the closed space is compressed by the movement of the cylinder 6. Further, the gas around the arc 14 expands by being heated by the heat energy of the arc 14. Further, the nozzle 5 made of an insulating material receives the thermal energy of the arc 14, and a part of the nozzle 5 sublimates to emit gas. Due to these phenomena, the gas pressure in the enclosed space increases.

When the sliding rod 8 moves further downward in the figure, the nozzle 5 comes off the fixed contact 2, and the gas in the enclosed space is discharged to the outside through the space between the nozzle 5 and the fixed arc contact 2. . In addition, when the hole 11 of the sliding rod 8 communicates with the hole 12 provided in the fixed piston 7, the gas in the closed space is discharged to the outside through the communication holes 11, 12. At this time, since the gas from the puffer chamber 10 is blown to the arc 14, the arc 14 is cooled and extinguished by the gas, and the current is cut off.

[0007]

In the above-mentioned conventional puffer type gas circuit breaker, when the breaking current becomes large, the gas blowing force becomes insufficient and the current breaking becomes impossible. On the contrary,
In order to increase the gas blowing force, it is necessary to increase the gas pressure by increasing the size of the shut-off section or increasing the operating force of the operating device. However, in a situation in which the circuit breaker is required to be small and light, it cannot be dealt with by increasing the size of the arc-extinguishing chamber or increasing the operating force in order to increase the gas pressure.

The present invention provides a puffer type gas circuit breaker in which the gas pressure is further increased and a strong gas blowing force is obtained without increasing the size of the arc-extinguishing chamber and increasing the operating force. It is intended to do so.

[0009]

According to the present invention, in order to achieve the above object, a high-pressure gas from a puffer chamber is blown against an arc generated between a movable contact and a fixed contact during a current interruption operation. In a puffer type gas circuit breaker in which a part of the gas blown to the arc passes through a gas flow path formed inside a sliding rod holding the movable contact, the arc is extinguished. A layer made of polytetrafluoroethylene (hereinafter abbreviated as “PTFE”) is provided in the inner gas flow path.

At the time of the current interruption operation of the circuit breaker, the gas pressure in the closed space communicating with the puffer chamber is such that the gas is expanded by being heated by the compression force of the cylinder and the fixed piston, the arc energy, and the nozzle made of an insulator The PTFE provided in the gas flow path inside the inside and inside the sliding rod rises by sublimation by the arc energy. The gas pressurized in this manner is blown against the arc at a predetermined timing during the interruption operation, and cools the arc to extinguish the arc.

According to the present invention, the gas pressure of the PTFE provided in the gas flow path inside the sliding rod is increased by the arc energy. As a result, the gas blowing force can be increased as compared with the related art, and a large current can be cut off. The provision of the PTFE layer in the gas flow path inside the sliding rod does not affect the size of the entire circuit breaker, nor does it increase the operating force of the operating device.

Therefore, according to the present invention, even if the arc extinguishing chamber is not enlarged or the operating force is not increased, the gas pressure can be further increased, a strong gas blowing force can be obtained, and a large current can be cut off. A puffer-type gas circuit breaker can be obtained. Further, since the inside of the slide bar is covered with the PTFE layer, it is possible to prevent the inside of the slide bar from being damaged by the heat of the arc.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a cross-sectional view showing a breaking part of a puffer type gas circuit breaker. FIG. 2 shows a state in which the circuit breaker is in the middle of a current interruption operation, similarly to FIG. 1 of the above-described conventional example.
In FIG. 2, 1 is a fixed main contact and 2 is a fixed arc contact. These fixed main contact 1 and fixed arc contact 2
Are electrically connected at an upper electrode (not shown). Reference numeral 8 denotes a slide bar for holding a movable portion, which is driven in the vertical direction in the figure by an operating mechanism (not shown). The sliding rod 8 is electrically connected to the lower electrode by a sliding contact (not shown).

Reference numeral 3 denotes a movable arc contact, which is attached to the tip of the sliding rod 8 and separates from and separates from the fixed arc contact 2. Further, a gas flow path 13 through which gas blown to the arc passes is formed inside the movable arc contact 3 and the sliding rod 8. The pipe 9 made of PTFE is attached inside the gas passage 13, and a PTFE layer is formed in the gas passage 13 inside the sliding rod 8. This PTFE pipe 9 is arranged at a position near the arc 14.

Reference numeral 4 denotes a movable main contact, which is formed in a cylindrical shape and is supported by a sliding rod 8, and comes into contact with and separates from the fixed main contact 1. Reference numeral 5 denotes a nozzle, which is attached to the tip of the movable main contact 4 and has an opening arranged at a small distance from the outer periphery of the fixed arc contact 2. The nozzle 5 is formed of an insulating material that sublimates due to high heat and releases gas. 6 is a cylinder, 7 is a fixed piston, and both constitute a puffer chamber 10. The cylinder 6 is formed integrally with the movable main contact 4 formed in a cylindrical shape. Fixed piston 7
The cylinder 6 slides on its outer periphery and the sliding bar 3 slides on its inner periphery.

The shut-off operation of the puffer type gas circuit breaker will be described with reference to FIG. 3A and 3B show the shutoff operation of the puffer type gas circuit breaker over time, wherein FIG. 3A shows a closed state, FIGS. 3B and 3C show a state in the middle of opening, and FIG. 3D shows an open state. In the open state (A), the movable main contact 4 is in contact with the fixed main contact 1, and the movable arc contact 3 is in contact with the fixed arc contact 2. In this state, current mainly flows through the movable main contact 4 and the fixed main contact 1. The opening of the nozzle 5 is closed by the fixed arc contact 2, and the communication hole 11 of the gas passage 13 of the sliding rod 8 is formed.
Is closed by the fixed piston 7. Therefore,
The space communicating with the puffer room 10 is a closed space.

When the current is interrupted, the sliding rod 8 is rapidly driven downward by an operating mechanism (not shown). As the sliding rod 8 moves downward in the drawing, the movable main contact 4 is first separated from the fixed main contact 1. At this time, the current flowing between the contacts 1 and 4 is commutated to the movable arc contact 3 and the fixed arc contact 2 still in contact, and the current between the movable main contact 4 and the fixed main contact 1 is changed. Does not cause an arc.

Subsequently, as the slide rod 8 moves further, the movable arc contact 3 separates from the fixed arc contact 2 as shown in FIG.
Occurs. In the state shown in FIG. 3B,
The opening of the nozzle 5 is closed by the fixed arc contact 2, the communication hole 11 of the sliding rod 8 is closed by the fixed piston 7, and the space communicating with the puffer chamber 10 is a closed space. Therefore, as the sliding rod 8 moves downward in the figure, the cylinder 6 moves, and the gas in the puffer chamber 10 and the closed space communicating therewith is compressed, and the gas pressure increases. In this closed space, the gas is heated by the thermal energy of the arc 14 and expands, and the arc 1
Nozzle 5 and PTFE pipe 9 by thermal energy of 4.
Are heated and some of them sublimate to generate gas.

Although the gas pressure in the closed space increases due to each of the above factors, in the present embodiment, compared with the above-described conventional example, the PTFE disposed inside the sliding rod 8 is used.
Due to the increase in gas pressure due to the sublimation of the pipe 9, a higher gas pressure than before can be obtained. When the sliding rod 8 further moves downward in the drawing, the engagement between the fixed arc contact 2 and the nozzle 5 is released, as shown in FIG. Ejects from outside. At the same time, since the communication hole 11 of the sliding rod 8 and the communication hole 12 formed in the fixed piston 7 communicate with each other, high-pressure gas is ejected to the outside through the gas passage 13 inside the sliding rod 8.

As a result, gas is blown to the arc 14 generated between the fixed arc contact 2 and the movable arc contact 3 as shown by the arrows in the figure, and the arc 14 is cooled and extinguished. An arcing action is performed. In this embodiment, as compared with the conventional puffer type gas circuit breaker, the PTFE pipe 9 provided in the gas passage 13 inside the sliding rod 8 is provided.
Since the gas pressure due to the sublimation is applied, a stronger gas blowing force is obtained, and a large current interruption is possible. Since this effect can be obtained only by attaching the PTFE 9 to the gas flow path 13, there is no need to increase the size of the circuit breaker or increase the operating force.

The gas blown to the arc 14 has a high temperature and passes through the gas passage 13 inside the sliding rod 8. Since the inside of the gas passage 13 is covered with the heat-resistant PTFE pipe 9, it is possible to prevent the arc 14 from being damaged by heat energy without using an arc-resistant material for the slide rod 8. FIG. 3D shows an open state of the circuit breaker. In this state, the sliding rod 8 is at the lower limit position, and the cooled insulating gas enters between the fixed main contact 1 and the movable main contact 4 and between the fixed arc contact 2 and the movable arc contact 3. Thus, the insulation between the contacts is restored, and re-generation of the arc is prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a conventional puffer type gas circuit breaker.

FIG. 2 is a diagram showing a configuration of a puffer type gas circuit breaker according to the embodiment of the present invention.

FIG. 3 is a diagram showing the operation of the circuit breaker of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixed main contact 2 ... Movable arc contact 3 ... Movable arc contact 4 ... Movable main contact 5 ... Nozzle 6 ... Cylinder 7 ... Fixed piston 8 ... Sliding rod 9 ... PTFE pipe 10 ... Puffer chambers 11, 12 ... Communication hole 13 ... Gas flow path 14 ... Arc

Claims (1)

[Claims] An arc generated between a movable contact and a fixed contact during a current interruption operation is extinguished by blowing a high-pressure gas from a puffer chamber. In a puffer type gas circuit breaker in which a portion passes through a gas flow path formed inside a sliding rod holding the movable contact, a layer made of polytetrafluoroethylene is provided in a gas flow path inside the sliding rod. A puffer-type gas circuit breaker.