JP2000090789A - Puffer type gas-blast circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a puffer type gas breaker small and highly reliable. SOLUTION: A puffer compartment 8 is composed of an insulating cylinder 11 of a fixed part and a sliding part to compress insulating gas in the puffer compartment 8 by making slidable contact with the inner wall of the insulating cylinder 11. This sliding part is attached to a movable contact 3. Since the tip of the insulating cylinder 11 is provided so as to extend as far as a fixed contact 1, a passage for the insulating gas from an upper conductive cylinder 10 to a lower conductive cylinder 13 is formed between the insulating cylinder and an insulating wall 12. Thereby, hot gas coming from the upper conductive cylinder when a current is interrupted is prevented from coming between the fixed contact 1 and the movable contact 3. Therefore, there will be no occurrence of dielectric breakdown caused by the hot gas between the fixed contact 1 and the movable contact 3.

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 for interrupting a current by a puffer mechanism (hereinafter, may be abbreviated as "circuit breaker").

[0002]

2. Description of the Related Art FIG. 1 shows a cross section of an arc extinguishing chamber of a conventional circuit breaker. The illustrated state is a current cutoff state. In the conventional circuit breaker, the puffer chamber 8 includes a puffer piston 7 fixedly provided on the movable portion side, a puffer cylinder 6 attached to the movable arc contact 4 and moving together with the movable arc contact 4. Was composed of

In the closed state of the circuit breaker, the movable part is driven upward by the link mechanism 14, and the fixed main contact 1 and the movable main contact 3 come into contact with each other. In this state, the puffer chamber 8
Occupies a large volume. At the time of current interruption, the movable part is rapidly moved downward in the figure by the link mechanism 14, the fixed contact and the movable contact are separated, and an arc is generated between the fixed arc contact 2 and the movable arc contact 4. appear. As the movable part moves, the insulating gas in the puffer chamber 8 is compressed and discharged from the nozzle 5. This insulating gas is blown to the arc, cools the arc and extinguishes the arc.

At this time, the insulating gas is heated by the arc to become a hot gas, passes between the fixed main contact 1 and the fixed arc contact 2, is released into the upper conductive tube 10, and is cooled. The hot gas further passes from the upper conductive tube 10 to the space between the fixed main contact 1 and the movable main contact 3 through the space between the shield 9 of the fixed main contact 1 and the insulating tube 12.

[0005]

When the insulating gas is not sufficiently cooled in the upper conductive tube 10, the dielectric strength of the insulating gas that has flowed between the fixed main contact 1 and the movable main contact 3 decreases. Therefore, dielectric breakdown may occur between the fixed main contact 1 and the movable main contact 3, and it may not be possible to shut off. In order to solve this phenomenon, it has been considered to increase the size of the upper conductive cylinder 10 to increase the cooling capacity of the insulating gas, or to adopt a structure in which hot gas is blown out from the upper conductive cylinder 10 to the outside. However, these measures
The circuit breaker as a whole is increased in size, and a large amount of SF6 gas, which is an insulating gas, is required.

An object of the present invention is to reduce the size and reliability of a puffer type gas circuit breaker by preventing hot gas from flowing between contacts.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. The present invention relates to a puffer type gas circuit breaker having an arc-extinguishing chamber composed of an upper conductive cylinder, an insulating cylinder, and a lower conductive cylinder, and a fixed contactor, a movable contact, and a puffer chamber disposed in the arc-extinguishing chamber. The puffer chamber includes an insulating cylinder attached to a fixed portion, and a sliding portion that slidably contacts the inner wall of the insulating cylinder to compress the insulating gas in the puffer chamber.

[0008] The sliding portion is attached to the movable contact, and the tip of the insulating cylinder is extended to the fixed contact. In addition, forming a path of the insulating gas from the upper conductive cylinder to the lower conductive cylinder, thereby, hot gas coming from the upper conductive cylinder at the time of current interruption,
It is prevented that it goes around between the fixed contact and the movable contact.

According to the present invention, when current is interrupted, the hot gas released from the puffer chamber and heated by the arc is cooled through the inside of the upper conductive cylinder and then insulated between the fixed main contact and the arc-extinguishing chamber. The gas is discharged to the outside of the arc-extinguishing chamber through the passage between the cylinders and further through the passage between the insulating cylinder and the insulating cylinder of the arc-extinguishing chamber. Therefore, dielectric breakdown due to hot gas flowing between the fixed contact and the movable contact does not occur.

[0010] Therefore, since the interruption is not impossible, the reliability of the circuit breaker can be improved. In addition, since it is not necessary to increase the size of the upper conductive cylinder, the overall shape of the circuit breaker can be reduced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a puffer type gas circuit breaker according to the present invention will be described with reference to the drawings. FIG. 2 is a cross-sectional view of the arc-extinguishing chamber of the circuit breaker, showing a state in which the circuit breaker is shut off. Upper conductive tube 10, insulating tube 12, and lower conductive tube 1
3 forms an arc-extinguishing chamber. The upper conductive tube 10 is formed to have a lower height than the conventional one (FIG. 1). A fixed arc contact 2 is provided at the center of the upper conductive tube 10, and a fixed main contact 1 having a shape surrounding the fixed arc contact 2 is provided. The outer periphery of the fixed main contact 1 is covered by a cylindrical shield 9 for reducing the electric field. Puffer piston 7 in lower conductive tube 13
Is fixedly provided. A movable arc contact 4 is provided through the center of the puffer piston 7.

A movable main contact 3 having a shape surrounding the movable arc contact 4 is provided at the tip of the movable arc contact 4,
Further, a nozzle 5 is provided at the tip of the movable main contact 3.
The movable arc contact 4 is moved up and down in the figure by a drive mechanism (not shown) via the link mechanism 14. In the closed state of the circuit breaker, the movable main contact 3 is fixed stationary contact 1
And the movable arc contact 4 comes into contact with the fixed arc contact 2. At this time, the opening of the nozzle 5 is closed by the movable arc contact 4.

A cylindrical insulating cylinder 11 is provided in contact with the outside of the puffer piston 7. Insulated cylinder 11
Is made of an insulating material and fixedly attached to the lower conductive tube 13, and the tip thereof contacts below the shield 9 for the fixed main contact 1. Thereby, between the insulating cylinder 12 and the insulating cylinder 11, the upper conductive cylinder 10
The gas passage which opens to the outside of the arc extinguishing chamber through 3 is formed.

The lower outer side of the movable main contact 3 is a sliding portion that comes into contact with the inner periphery of the insulating cylinder 11. A space surrounded by the movable main contact 3, the movable arc contact 4, the nozzle 5, the insulating cylinder 7, and the puffer piston 6 becomes a puffer chamber 8. The sliding portion of the movable main contact 3 is
The movable main contact 3 and another member may be used.

FIG. 3 is a diagram for explaining the breaking operation of the circuit breaker shown in FIG. (A) shows the closed state of the circuit breaker. In this state, the current flows through the path of the upper conductive tube 10-fixed main contact 1-movable main contact 3-movable arc contact 4-lower conductive tube 13. At this time, the volume of the puffer chamber 8 is the largest. Further, since the nozzle 5 is in contact with the fixed arc contact 2, the inside of the puffer chamber 8 is in a sealed state.

FIG. 2B shows a state in which the circuit breaker is in the middle of a breaking operation. At the time of the shut-off operation, the movable portion is rapidly moved downward in the figure by a drive mechanism (not shown). First, the movable main contact 3 separates from the fixed main contact 1. At this time, no arc is generated because the movable arc contact 4 and the fixed arc contact 2 maintain contact. Further, the movable portion moves and the volume in the puffer chamber 8 decreases. At this time, since the nozzle 5 is closed by the fixed arc contact 2, the gas in the puffer chamber 8 is compressed, and the pressure in the gas in the puffer chamber 8 increases.

FIG. 2C shows a state in which the movable arc contact 4 is further moved and is separated from the fixed arc contact 2. At this time, an arc 15 is generated between the two contacts 2 and 4. In this state, the opening of the nozzle 5 is disengaged from the fixed arc contact 2, so that the insulating gas that has been compressed in the puffer chamber 8 up to this point is displaced between the movable arc contact 4 and the nozzle 5 and the fixed arc contact. The gas is quickly discharged into the arc-extinguishing chamber through the space between the nozzle 2 and the nozzle 5. At this time, the arc is extinguished by the high-speed gas flow cooling the arc. Also, the insulating gas is heated by the arc to become a hot gas, and as indicated by the arrow,
It is discharged into the upper conductive tube 10 through between the fixed main contact 1 and the fixed arc contact 2.

(D) shows a state in which the arc is extinguished and the breaking operation is completed. At this time, the movable arc contact 4 is moving to the lowermost position. In this state, the hot gas released into the upper conductive cylinder 10 during the operation of (C) flows around through the passage between the insulating cylinder 12 and the shield 9, but is intact with the insulating cylinder 12. The gas passes through the space between the cylinders 11 while being cooled, and is discharged to the outside from below the arc extinguishing chamber.

Therefore, as in the conventional circuit breaker shown in FIG. 1, hot gas whose dielectric strength has not been restored flows between the fixed contacts 1 and 2 and the movable contacts 3 and 4, and both the contacts are damaged. No dielectric breakdown occurs between them. Further, since the upper conductive tube 10 may have a low ability to cool hot gas, the height of the upper conductive tube 10 can be reduced, and the overall shape of the circuit breaker can be reduced.

[0020]

According to the present invention, in a puffer type gas circuit breaker, by preventing hot gas from flowing between the contacts, the circuit breaker can be made small and highly reliable.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional puffer type gas circuit breaker.

FIG. 2 is a sectional view showing an embodiment of a puffer type gas circuit breaker of the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixed main contact 2 ... Fixed arc contact 3 ... Movable main contact 4 ... Movable arc contact 5 ... Nozzle 6 ... Puffer cylinder 7 ... Puffer piston 8 ... Puffer chamber 9 ... Shield 10 ... Upper conductive cylinder 11 ... Insulation Cylinder 12 ... Insulated cylinder 13 ... Lower conductive cylinder 14 ... Link mechanism 15 ... Arc

Claims (1)

[Claims] 1. A puffer type gas circuit breaker having an arc-extinguishing chamber constituted by an upper conductive cylinder, an insulating cylinder and a lower conductive cylinder, a fixed contactor, a movable contactor and a puffer chamber disposed in the arc-extinguishing chamber. In the above, the puffer chamber is composed of an insulating cylinder attached to a fixed portion, and a sliding portion that slidably contacts the inner wall of the insulating cylinder and compresses the insulating gas in the puffer chamber, The part is attached to the movable contact, and the insulating cylinder is provided with its tip extending to the fixed contact, so that the insulating cylinder is located between the upper conductive cylinder and the insulating wall of the arc-extinguishing chamber. Forming a passage for the insulating gas to the lower conductive cylinder, thereby preventing hot gas coming from the upper conductive cylinder from flowing between the fixed contact and the movable contact when current is interrupted; A puffer type gas circuit breaker characterized by the above.