JPH11111129A - Gas-blast circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-blast circuit breaker by which sufficient arc- extinguishing capability is obtained with a low mechanical operation force. SOLUTION: This gas-blast circuit-breaker is constituted of a cylinder installed at a fixed position and a piston installed in a movable contact and a pressure-rising chamber 10 to house a fixed contactor 1 and the movable contact 2 in the inside is formed. When an arc 5 is generated between the fixed contactor 1 and the movable contact 2 at the time of shutting off electric current, the gas in the pressure-rising chamber 10 is heated and expanded due to the arc 5 and the gas pressure in the pressure-rising chamber 10 is elevated and applies driving force to the piston. Shine the movable contactor 2 is driven by the gas pressure of the pressure-rising chamber, the mechanical operation force of an operation apparatus can be lowered. When the high pressure gas is discharged out of a communication hole 14, a gas is blown to the arc and thus electric current can be shut off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage gas circuit breaker.

[0002]

2. Description of the Related Art A conventional gas circuit breaker will be described with reference to the drawings. FIG. 1 shows the structure of a conventional puffer-type gas circuit breaker in cross section, and shows the operation thereof over time.
(A) shows the closed state of the circuit breaker, (B) shows the state in the middle of the current interrupting operation of the circuit breaker, and (C) shows the interrupted state of the breaker.

In the closed state shown in FIG. 1A, the fixed contact 1 and the movable contact 2 come into contact with each other, and a current flows through both contacts.
When the current is interrupted, the operating unit 12 drives the movable part including the movable contact 2, the nozzle 7, and the cylinder 9 at a high speed downward in the figure. When the fixed contact 1 and the movable contact 2 are separated from each other, an arc 5 is generated between the two contacts as shown in FIG. During the shutoff operation, the gas in the puffer chamber 11 is compressed by the fixed piston 8 and the cylinder 9. Then, when the movable portion further moves downward in the drawing and the nozzle 7 separates from the fixed contact 1, the compressed gas is ejected from the nozzle 7 to the outside. At this time, gas is blown against the arc 5 to cool the arc 5 and extinguish the arc.

When the movable portion is further driven downward in the figure,
As shown in (C), the insulation strength between the two contacts is restored due to the presence of the cold insulating gas between the fixed contact 1 and the movable contact 2, and the current interruption is completed. .

[0005]

In the conventional puffer type gas circuit breaker, in order to increase the arc extinguishing ability, the speed of compressing the gas in the puffer chamber 11 is increased or the sectional area of the fixed piston 8 is increased. It is necessary to take measures such as increasing the amount of gas in the puffer chamber 11. However, these measures will increase the mechanical operating force of the operating device 12. Such a measure is difficult to adopt in a situation where the size and weight of the gas circuit breaker are required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas circuit breaker which can obtain a sufficient arc extinguishing ability with a small mechanical operation force.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a fixed contact provided at a fixed position and a movable contact driven and driven by an operating mechanism to make and break contact with the fixed contact. A gas circuit breaker is constituted by a contact, a cylinder provided at a fixed position, and a piston provided at the movable contact, and a booster chamber in which a contact portion between the fixed contact and the movable contact is disposed.

In this gas circuit breaker, if the fixed contact and the movable contact are separated at the time of current interruption, an arc is generated between the two contacts in the boosting chamber. With this arc,
The gas in the pressurized chamber is heated and expanded, and the gas pressure in the pressurized chamber increases. The high-pressure gas in the pressurizing chamber exerts a force on a piston provided on the movable contact in the same direction as that driven by the operating device.

Therefore, according to the gas circuit breaker of the present invention, the movable contact moves by receiving the driving force of the operating device and the driving force of the gas expansion force due to the arc heat. Thereby, the mechanical operation energy of the operating device that drives the movable contact can be reduced, and the operating device can be downsized. In addition, since gas is blown to the arc by utilizing the thermal energy of the arc, an arc extinguishing effect at the time of current interruption is sufficiently obtained.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a cross-sectional view showing a configuration of a shut-off unit of a gas circuit breaker to which the present invention is applied. The circuit breaker shown is in a closed state. In FIG. 2, reference numeral 1 denotes a fixed contact provided at a fixed position. Reference numeral 3 denotes a cylinder attached to the fixed contact 1, which is formed of an insulating material. Reference numeral 2 denotes a movable contact, which is driven by the operating device 12 in the vertical direction in the figure to contact and separate from the fixed contact 1. Reference numeral 4 denotes a piston provided on the outer periphery of the movable contact 2, and together with the cylinder 3, forms a pressurizing chamber 10. The contact portion between the fixed contact 1 and the movable contact 2 is arranged inside the boosting chamber 10.

The pressurizing chamber 10 communicates with a gas passage 13 formed inside the movable contact 2. The gas flow path 13 opens to the outside through a communication hole 14 provided below the movable contact 2. In the closed state of the circuit breaker shown in FIG.
Since the cover 4 is closed by the lid 16 attached to the fixed position, the pressurizing chamber 10 and the space communicating therewith are in a sealed state.

Next, the operation of the gas circuit breaker shown in FIG. 2 will be described with reference to FIG. 3A and 3B show the operation of the gas circuit breaker over time, wherein FIG. 3A shows a closed state of the circuit breaker, FIG. 3B shows a first state in the middle of a current break operation of the circuit breaker, and FIG. Indicates a second state in the middle of the current interrupting operation of the circuit breaker, and (D) indicates an interrupted state of the circuit breaker. In the closed state of the circuit breaker of (A),
The movable contact 2 is positioned upward in the figure by the operating device 12 and is in contact with the fixed contact 1. The current flows through the fixed contact 1 and the movable contact 2.

When a current cutoff command is issued, the operating device 12
Drives the movable part downward at high speed in the figure. During the interruption operation (B), the movable contact 2 is separated from the fixed contact 1 and an arc 5 is generated between the two contacts. This arc 5 heats the surrounding gas, and the heated gas expands. In the initial stage of the shut-off operation, the communication hole 14 is still closed by the lid 6 and the pressurizing chamber 10 is sealed, so that the heated and expanded gas increases the gas pressure in the pressurizing chamber 10.

The gas pressure in the pressurizing chamber 10 is
, A driving force in the same direction as the driving direction by the operating device 12 is applied. Therefore, since the movable contact 2 is driven by the driving force of the operating device 12 and the driving force of the gas pressure, the mechanical operating force of the operating device 12 can be reduced. Thereby, the operation device 12 can be reduced in size.

When the movable contact 2 is further driven downward in the figure, the communication hole 14 shown in FIG. Then, the high-pressure gas accumulated in the pressurizing chamber 10 is discharged from the pressurizing chamber 10 through the gas passage 13 to the outside through the communication hole 14 at a high speed as indicated by an arrow in the drawing. At this time, gas is blown to the arc 5 to cool the arc and extinguish the arc. In the circuit breaker of this example, gas is blown to the arc by the thermal energy of the arc, and a sufficient arc extinguishing action can be obtained without depending on the mechanical operating force of the operating device 12.

When the movable part is further driven downward in the figure,
As shown in (D), the distance between the fixed contact 1 and the movable contact 2 is sufficiently widened, and the dielectric strength between the two contacts is increased by interposing a cold insulating gas between the two contacts. Recovers, and the current interruption is completed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the configuration and operation of a conventional puffer type gas circuit breaker.

FIG. 2 is a sectional view showing the configuration of the gas circuit breaker of the present invention.

FIG. 3 is a view for explaining the operation of the gas circuit breaker of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixed contact 2 ... Movable contact 3 ... Cylinder 4 ... Piston 5 ... Arc 6 ... Lid 7 ... Nozzle 8 ... Fixed piston 9 ... Cylinder 10 ... Boosting chamber 11 ... Puffer chamber 12 ... Operating device 13 ... Gas flow path 14 ... communication hole

Claims (1)

[Claims] A fixed contact provided at a fixed position; a movable contact driven by an operating mechanism to make contact with and separate from the fixed contact; a cylinder provided at the fixed position and the movable contact; A gas circuit breaker, comprising: a pressurizing chamber formed by a piston provided in a child and in which a contact portion between the fixed contact and the movable contact is arranged.