JPH0745165A - Puffer type gas-blast circuit breaker - Google Patents

Abstract

PURPOSE:To prevent dielectric strength from being deteriorated by reduction in gas density since pressure in a space between a fixed main contact and a movable main contact is reduced at cutoff time. CONSTITUTION:When a driving rod 8 is moved rightward at cutoff time, insulating gas in a puffer chamber 9 is blown against an arc 19 through a passage 12. A communicating hole 17b is formed in a support conductor 22 so that the insulating gas flowing into the driving rod 8 thereafter can move smoothly to a space S between a fixed main contact 3 and a movable main contact 14 along the inner peripheral surface of an insulating cylinder 29, and an opening and closing valve 30 is arranged to open a communicating hole 8a when internal pressure of the driving rod 8 becomes larger than prescribed pressure P1.

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 extinguishing an insulating gas in a puffer chamber by blowing it onto an arc.

[0002]

2. Description of the Related Art A puffer type gas circuit breaker is used as a power circuit breaker.

The structure of a conventional puffer type gas circuit breaker is shown in FIG.
Shown in. As shown in the figure, the puffer type gas circuit breaker is configured by accommodating a fixed unit 1 and a movable unit 2 in a tank 6 filled with an insulating gas. The fixed unit 1 is composed of a hollow cooling cylinder 21, a plurality of fixed main contacts 3 provided at one end of the cooling cylinder 21, and a fixed arcing contact 4 provided in the center of the inside thereof through a support portion 18. 20
Is a conductor and 27 is a contact.

On the other hand, the movable unit 2 is connected to a drive means via a connecting shaft 5 and a support conductor 22 attached to the fixed portion 15 via a support insulator 16 and connected to a conductor 23 via a contact 28. A drive rod 8 which has a movable arcing contact 7 at its tip and is slidably driven with respect to the support conductor 22 in the left-right direction in the drawing.
And a puffer cylinder 10 that is integrally formed at the tip of the drive rod 8 and forms a puffer chamber 9 between the drive rod 8 and the movable arc contact 7, and is fitted into the puffer cylinder 10. In addition, an insulating nozzle 13 having an insertion hole 11 for inserting the fixed arcing contact 4 in an intermediate portion and forming a flow path 12 between the movable arcing contact 7 and the flow path guide 7a, and a puffer cylinder 10. A movable main contact 14 formed at the tip of the piston, and a piston 17 as a suction / discharge means for slidably provided between the drive rod 8 and the puffer cylinder 10 for sucking and discharging insulating gas into the puffer chamber 9. , An insulating cylinder 29 provided across the cooling cylinder 21 and the support conductor 22. The contact is divided into a main contact and an arcing contact in order to distribute the functions so that they can be used properly.

In such a puffer type gas circuit breaker,
When the drive rod 8 is driven to the left in the figure and is put in,
Insulating gas is sucked into the puffer chamber 9 through the insertion hole 11 and the communication holes 17a and 8a. When the drive rod 8 is driven to the right in the figure to shut off, an arc 19 is generated between the fixed arcing contact 4 and the movable arcing contact 7 immediately after the opening, and the insulating gas heats the arc 19. As a result, the volume increases and some flow into the puffer chamber 9 and some flow into the drive rod 8 via the flow path 12. For this reason,
The pressure in the puffer chamber 9 rises due to the inflow of heated insulating gas and the decrease in volume. At the cut-off position, the arc current passes through the zero point, the thermal energy generated by the arc 19 is suddenly reduced, and the fixed arcing contact 4 is removed from the insertion hole 11, so that the pressure in the space of the arc generation portion is increased. Then, the pressure in the puffer chamber 9 becomes relatively higher than the pressure in the arc generating portion. Therefore, the insulating gas in the puffer chamber 9 is discharged from the flow path 12. The insulating gas is extinguished by being blown to the arc 19 generated between the fixed arcing contact 4 and the arcing contact 7, and then flows into the cooling cylinder 21 through the insertion hole 11 or the driving rod 8 Through the insertion holes 8a and 17a from inside the insulating cylinder 2
Flows out of 9. The arc generating portion is filled with the insulating gas having a low temperature, and the interruption is completed without causing another arc. In order to properly perform the shutoff in this way, the pressure in the puffer chamber 9 at the shutoff position is the predetermined pressure P corresponding to the shutoff capacity.
₁ is required.

[0006]

However, the arc 19 from the space between the insulating nozzle 13 and the fixed main contact 3 to the space between the fixed main contact 3 and the movable main contact 14 (hereinafter, this space is referred to as space S). Since the insulating gas heated by the gas flows out and flows into the cooling cylinder 21 and the drive rod 8 and does not flow into the space S, the density of the insulating gas in the space S decreases and the dielectric strength increases. Is reduced.

Further, it may be necessary to re-close or re-close immediately after the puffer type gas circuit breaker is cut off.
In such a case, if a low-density insulating gas remains between the fixed main contact and the movable main contact, the dielectric strength between the main contacts will decrease at the time of re-cutoff.

Therefore, an object of the present invention is to provide a puffer type gas circuit breaker which solves the above problems.

[0009]

The structure of the present invention for achieving the above object is to provide a tubular cooling tube to which one conductor is connected in a tank filled with an insulating gas, and to provide a cooling tube. A fixed main contact is provided on the inner peripheral surface on one end side of the above, and a fixed arcing contact is provided at a shaft center position inside the fixed main contact via a support portion, while a support conductor connected to the other conductor is provided via an insulating member. Fixed in the tank, and the fixed arcing contact is fitted with a driving rod with a movable arcing contact at the tip, which can be driven along the axis of the movable arcing contact and is slidable with respect to the support conductor. A puffer cylinder having a movable main contact that is inserted into and removed from the main contact is integrally provided at the tip of the drive rod so that the puffer cylinder and the drive rod can slide freely. An insulating nozzle is formed at the end of the puffer cylinder to fix the piston that forms the puffer chamber in the hollow cylinder to the support conductor, and to form a flow path outside the movable arcing contact that guides the insulating gas in the puffer chamber between both arcing contacts. In a puffer-type gas circuit breaker that is attached to the cooling section and has an insulating cylinder that extends over the cooling cylinder and the supporting conductor, when shutting off, insulation is provided between the fixed main contact and the movable main contact from the inside of the drive rod through the vicinity of the inner peripheral surface of the insulating cylinder. An on-off valve that forms a circulation flow path for guiding gas and that connects the inside of the drive rod and the inside of the insulating cylinder is provided inside the drive rod via a spring that urges the on-off valve in the closing direction. When the internal pressure becomes approximately the same as the pressure of the puffer etc. necessary to surely extinguish the arc, the spring is compressed and the opening and closing valve opens. Characterized in that the set.

[0010]

When the puffer type gas circuit breaker is shut off, the insulating gas whose temperature has dropped due to the inside of the drive rod flows into the space S, so that the density of the insulating gas in the space S does not decrease, and it is different from the conventional case. Dielectric strength does not decrease. Also, the on-off valve opens only when the pressure inside the drive rod reaches a predetermined value, and the insulating gas flows out of the puffer cylinder. Therefore, the pressure in the puffer chamber is maintained above the predetermined pressure.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. Since the present embodiment is an improvement of a part of the conventional puffer type gas circuit breaker, the same parts as those of the prior art are designated by the same reference numerals, and the description thereof will be omitted. Only different parts will be described.

An embodiment of the puffer type gas circuit breaker according to the present invention is shown in FIG. In the present invention, most of the insulating gas that has been conventionally discharged to the outside of the insulating cylinder 29 through the drive rod 8 at the time of interruption is guided to the space S along the inner peripheral surface of the insulating cylinder 29. . As shown in the figure, the communicating hole 17b is formed in order to guide the insulating gas from the inside of the piston 17 to the outside of the puffer cylinder 10 to form a circulation flow path.
Is formed at the base end of the. The right side of the inner peripheral surface of the communication hole 17b is formed in an arc shape so that the insulating gas can smoothly change its direction. This communication hole 17b is used for the piston 17
Are formed at equal intervals along the circumferential direction.

On the other hand, if the communication hole 8a is left open, the amount of the insulating gas discharged from the communication hole 8a increases and the pressure in the puffer chamber 9 communicating with the inside of the drive rod 8 reaches a predetermined pressure P ₁ . Will not reach. Therefore, it is configured as follows.

As shown in FIG. 1, an on-off valve 3 for opening and closing a communication hole 8a for communicating the inside and the outside of the drive rod 8.
0 is provided. That is, it is as follows. An accommodation chamber 31 for accommodating the on-off valve 30 is formed near the communication hole 8a of the drive rod 8, and the large-diameter portion 30a at the right end of the on-off valve 30 is slidably accommodated in the accommodation chamber 31. Then, in order to prevent the large diameter portion 30 a from protruding from the accommodation chamber 31, a stopper 32 as a small diameter portion is formed at the entrance of the accommodation chamber 31. A spring 33 for urging the opening / closing valve 30 to the left to close the communication hole 8a when no pressure is applied to the opening / closing valve 30 is housed in the housing chamber 31.

The magnitude of the spring constant of the spring 33 is such that the spring 33 is compressed and the communication hole 8a is opened when the pressure inside the drive rod 8 becomes P ₁ or more when the puffer type gas circuit breaker is shut off. Is set. A predetermined value P ₁ as the pressure in the puffer chamber 9 that communicates with the inside of the drive rod 8 when shutting off
This is to ensure that

Next, the operation of the puffer type gas circuit breaker will be described. When the drive rod 8 is moved to the right as shown in FIG. 2 when the puffer type gas circuit breaker is shut off, an arc 19 is generated between the fixed arcing contact 4 and the movable arcing contact 7. When the insulating gas is heated by the arc 19, the heated insulating gas expands and flows into the puffer chamber 9 and the drive rod 8. When the pressure inside the drive rod 8 becomes larger than P _{1, the} on-off valve 30 is pushed rightward in FIG. 2 against the biasing force of the spring 33, and the communication hole 8a opens. Then, the insulating gas that has passed through the communication hole 8 a flows between the insulating cylinder 29 and the cylinder 10. As a result, the non-heated insulating gas between the insulating cylinder 29 and the cylinder 10 is pushed and flows into the space S between the fixed main contact 3 and the movable main contact 14, and the insertion hole 11 of the insulating nozzle 13 is inserted. By preventing the high-temperature insulating gas discharged from the chamber from flowing toward the space S, the temperature increase and the density decrease in the space S are prevented, and the breakdown voltage between the main contacts is maintained.

On the other hand, the inside of the puffer chamber 9 communicating with the inside of the drive rod 8 opens only when the opening / closing valve 30 inside the drive rod 8 reaches the pressure P ₁ , so that the pressure value is maintained at P ₁ or more. To be done. Therefore, in the shutoff position shown in FIG.
Insulating gas is blown toward the arc 9 from the high-pressure puffer chamber 9 whose pressure value is maintained at P ₁ or higher.

As described above, the cylinder 10 and the insulating cylinder 29
The non-heated insulating gas existing between and flows into the space P between the main contacts to prevent a decrease in density due to a temperature increase in the space P to prevent a decrease in dielectric strength, while at the arc generating portion. The high-pressure insulating gas from the puffer chamber 9 surely blows off the arc to surely interrupt the current.

[0019]

As can be seen from the above description, according to the puffer type gas circuit breaker of the present invention, insulating gas is supplied between the fixed main contact and the movable main contact (space S) at the time of interruption.
Since the circulation flow path leading to the space S is formed, a decrease in the density of the insulating gas in the space S is prevented and a decrease in the dielectric strength is prevented.

Therefore, the gap between the fixed unit and the movable unit can be reduced by the amount that the dielectric strength is improved as compared with the conventional case, and the puffer type gas circuit breaker can be downsized. Further, the cost reduction of the drive device can be achieved by the downsizing, and the cost of the puffer type gas circuit breaker can be reduced.

Further, since the on-off valve that allows the insulating gas to flow from the inside of the drive rod to the outside of the puffer cylinder only when the pressure inside the drive rod becomes larger than a predetermined value, the inside of the puffer chamber is provided. The pressure can be maintained above a predetermined pressure, and the shutoff can be performed reliably.

[Brief description of drawings]

FIG. 1 is a sectional view showing a closed state of a puffer type gas circuit breaker according to the present invention.

FIG. 2 is a cross-sectional view showing a state of the puffer type gas circuit breaker according to the present invention immediately after opening the electrodes.

FIG. 3 is a cross-sectional view showing a state of a conventional puffer type gas circuit breaker in a blocking position.

FIG. 4 is a sectional view of a conventional puffer type gas circuit breaker.

[Explanation of symbols]

 3 ... Fixed main contact 4 ... Fixed arcing contact 7 ... Movable arcing contact 8 ... Driving rod 8a, 17a, 17b ... Communication hole 9 ... Puffer chamber 10 ... Puffer cylinder 11 ... Insertion hole 12 ... Flow path 13 ... Insulation nozzle 14 ... Movable Main contact 17 ... Piston 20, 23 ... Conductor 21 ... Cooling cylinder 22 ... Support conductor 30 ... Open / close valve 33 ... Spring

Claims (1)

[Claims] 1. A tank filled with insulating gas is provided with a tubular cooling tube to which one conductor is connected, and a fixed main contact is provided on the inner peripheral surface on one end side of the cooling tube. A fixed arcing contact is provided at the inner shaft center position via a support part, while the supporting conductor connected to the other conductor is fixed in the tank via an insulating member, so that the fixed arcing contact can be inserted and removed freely. A drive rod having a tip is provided so that it can be driven along the axis of the movable arc contact and is slidable with respect to the support conductor, and a puffer cylinder having a movable main contact that is inserted into and removed from the fixed main contact is provided in the drive rod. A piston that is integrally provided at the tip and is slidable between the puffer cylinder and the drive rod to form a puffer chamber in the puffer cylinder. Fixed, fitted with the insulating nozzle for forming a flow path for guiding the insulating gas puffer chamber to between both arcing contacts on the outside of the movable arcing contact to the end portion of the puffer cylinder,
In a puffer type gas circuit breaker in which an insulating cylinder is provided between the cooling cylinder and the supporting conductor, a circulation of insulating gas from the inside of the drive rod between the fixed main contact and the movable main contact through the vicinity of the inner peripheral surface of the insulating cylinder when shutting off. An on-off valve that forms a flow path and connects the inside of the drive rod and the inside of the insulating cylinder is provided inside the drive rod via a spring that urges the on-off valve in the closing direction. A puffer-type gas circuit breaker characterized in that when the pressure in the puffer chamber is about the same as that required to reliably extinguish the arc, the spring is compressed and the on-off valve is opened to set the spring constant.