JP2016225023A - Gas Circuit Breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas circuit breaker having an excellent current cutoff performance over a wide current region with a small control force even without downsizing a piston of a puffer chamber for reducing a reaction in the case of large current cutoff.SOLUTION: The gas circuit breaker comprises a puffer chamber 26 in which an arc-extinguishing gas is accumulated. In the puffer chamber 26, in addition to a communication port 26c that is connected with an insulation nozzle 27, an exhaust hole 26d is formed which is communicated to an external space such as an inner space of a piston support 44. The exhaust hole 26d is closed by a valve 26e. The valve 26e is configured to close the exhaust hole 26d with a predetermined operation pressure P1 that is lower than a pressure rise peak value that is generated in the puffer chamber 26 when cutting off a current corresponding to 90% of a rating cutoff current, and to open the exhaust hole 26d when the pressure rise in the puffer chamber 26 exceeds the predetermined operation pressure P1.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a gas circuit breaker that performs current interruption in a power system.

  In an electric power system, a gas circuit breaker is used for switching current when a current is interrupted. In the gas circuit breaker, the movable contact portion and the opposed contact portion are disposed to face each other in the sealed container, and the movable contact portion is mechanically separated from the opposed contact portion. In the interruption process, an arc is generated between the movable arc contact and the counter arc contact. The hermetic container is filled with an arc extinguishing gas, and the arc extinguishing gas is blown onto the arc by pressure accumulation in the puffer chamber, and the arc is extinguished at the current zero point. The arc extinguishing gas that has reached the arc is diverted to the movable contact portion side and the opposed contact portion side, and is diffused from the inside of the movable contact portion and the opposed contact portion to the outside.

  An operation mechanism such as a hydraulic type, a spring type, or an electric type is connected to the gas circuit breaker. The operating mechanism exerts an operating force, the operating force is transmitted to the movable contact portion, and the movable contact portion moves so as to be separated from the opposing contact portion. The puffer chamber accumulates arc-extinguishing gas by reducing the volume, and ejects high-pressure arc-extinguishing gas. This puffer chamber is generally composed of a piston and a cylinder, and uses the operating force of the operating mechanism to reduce the distance between the cylinder bottom surface and the piston.

  In other words, the puffer chamber and the operation mechanism are connected in the power transmission system of the operation force. The increase in the pressure in the puffer chamber generates a reaction force in the direction of increasing the distance between the cylinder bottom surface and the piston, and reduces the operation force of the operation mechanism. Therefore, the operation mechanism must generate an operation force in consideration of this reaction force. In particular, when the large current is interrupted, the gas pressure in the puffer chamber is significantly increased, and the reaction force is also increased. The operating mechanism must counteract this large reaction force and generate a large operating force that can quickly open the movable contact portion and the opposed contact portion.

  Therefore, in recent years, a gas circuit breaker has been proposed in which the puffer chamber is miniaturized with a small piston area and the reaction force is reduced. The arc generates a hot gas by heat energy and heats the surrounding arc extinguishing gas. In view of this, a gas circuit breaker using a so-called self-power effect in which hot gas or heated arc extinguishing gas is stored in the puffer chamber has been proposed.

Japanese Patent Laid-Open No. 11-67025 JP-A-10-149552

  However, if the self-power effect is used, there is a case where sufficient pressure accumulation in the puffer chamber cannot be obtained because the thermal energy of the arc is small when the medium and small currents are interrupted. Therefore, if a gas shut-off device with a small piston area is used, the mass of the arc extinguishing gas that can be blown onto the arc decreases, the gas density decreases, and the arc extinguishing gas exhausted downstream from the arc retains internal energy. There is a risk of temperature rise due to the amount.

  The gas circuit breaker according to this embodiment has an excellent current interruption performance in a wide current region with a small operating force without reducing the size of the piston of the puffer chamber in order to reduce the reaction force at the time of large current interruption. The purpose is to provide a vessel.

  In order to achieve the above object, the gas circuit breaker of the present embodiment is a gas circuit breaker that mechanically switches between interruption and injection of current, and includes a sealed container filled with an arc-extinguishing gas, and the sealed container The first contact portion and the second contact portion that are disposed opposite to each other and are relatively close to and away from each other, the first contact portion and the second contact portion are provided separately from each other, facing each other, Accompanying the opening of the first contact part and the second contact part, the first arc contactor and the second arc contactor that generate an arc between both ends, and the arc extinguishing gas are accumulated. A puffer chamber, a communication port formed in the puffer chamber, an exhaust hole formed in the puffer chamber, and an arc extinguishing gas ejected from the puffer chamber and directed to the arc. The insulating nozzle that rectifies and the valve has an electric power equivalent to 90% of the rated breaking current. The exhaust hole is closed with a predetermined operating pressure lower than the pressure increase peak value generated in the puffer chamber when the valve is shut off, and the exhaust hole is opened when the pressure increase in the puffer chamber exceeds the predetermined operating pressure. And a valve.

It is sectional drawing which shows the whole structure of the gas circuit breaker which concerns on this embodiment. It is sectional drawing which shows the detailed structure of the gas circuit breaker which concerns on embodiment. The gas circuit breaker which concerns on embodiment relates to the gas circuit breaker, and shows the state in the middle of interruption when the interruption current exceeds 90% of the rated interruption current.

  Hereinafter, the gas circuit breaker according to the present embodiment will be described in detail with reference to the drawings.

(Constitution)
As shown in FIGS. 1 and 2, the gas circuit breaker is provided with a conductor 7a and a conductor 7b drawn into the hermetic container 5 from the outside, and a counter contact portion 1 and a movable contact portion 2 are disposed between the conductor 7a and the conductor 7b. . The sealed container 5 is filled with an arc extinguishing gas. The arc extinguishing gas is excellent in insulation performance and arc extinguishing performance, for example, sulfur hexafluoride gas (SF ₆ gas). In the sealed container 5, the opposite side support portion 3 is fixed. The conductor 7 a is connected to the opposite side support portion 3. The opposing contact portion 1 is fixed to the opposing side support portion 3 connected to the conductor 7a. A movable support 4 is fixed in the sealed container 5. The conductor 7b is connected to the movable support 4. The movable contact portion 2 is fitted in the movable side support portion 4 connected to the conductor 7b, and is slidable in a direction in which the movable contact portion 2 contacts and separates from the opposing contact portion 1.

  In the gas circuit breaker, the conductor 7a, the opposed side support portion 3 and the opposed contact portion 1 are connected in series to form a one-side electric circuit, and the conductor 7b, the movable side support portion 4 and the movable contact portion 2 are connected in series. The other electric circuit is formed. The gas circuit breaker opens and closes the electric paths on the conductor 7a side and the conductor 7b side by bringing the movable contact portion 2 into contact with and away from the opposing contact portion 1, and mechanically conducts and interrupts the current. The movable contact portion 2 is connected to the insulating rod 25 via the connecting rod 24. The insulating rod 25 is connected to an operating mechanism 8 that is a power source such as a spring type or a hydraulic type. The movable contact portion 2 is brought into contact with and separated from the opposing contact portion 1 through the connecting rod 24 by following the pushing and pulling of the insulating rod 25 by the operation mechanism 8.

  In the current interruption process, an arc 9 is generated between the opposed contact portion 1 and the movable contact portion 2. The movable contact portion 2 is provided with a puffer chamber 26 that reduces the volume in conjunction with the separation from the opposed contact portion 1 as a pressure accumulating means. An insulating nozzle 27 that surrounds the space where the arc 9 is generated extends from the puffer chamber 26. The puffer chamber 26 and the insulating nozzle 27 serve as blowing means for blowing the arc extinguishing gas onto the arc 9.

  That is, the puffer chamber 26 first mechanically accumulates the arc extinguishing gas by reducing the volume. Second, the puffer chamber 26 accumulates pressure due to the inflow of the hot gas generated from the arc 9 and the arc extinguishing gas heated by the arc 9 due to the thermal energy of the arc 9. The puffer chamber 26 accumulates the arc-extinguishing gas inside due to the mechanical and thermal energy action. The insulating nozzle 27 rectifies and guides the arc extinguishing gas ejected from the puffer chamber 26 toward the arc 9, and blows the arc extinguishing gas to the arc 9 to extinguish the arc at the current zero point.

  This gas circuit breaker is assembled by members mainly composed of a cylinder, and each member is disposed in the sealed container 5 with the central axes thereof aligned. Hereinafter, in order to explain the positional relationship and direction of each member, the direction toward the movable contact portion 2 in each member of the opposed contact portion 1 and the opposed side support portion 3 is referred to as a movable side, and the opposite is referred to as an anti-movable side. In each member of the movable contact portion 2 and the movable side support portion 4, the direction toward the opposed contact portion 1 is referred to as an opposite side, and the opposite is referred to as an opposite side.

  The opposite side support portion 3 that fixes the opposite contact portion 1 is a hollow cylindrical conductor having both ends opened. A support plate 31, which is a rod-like or plate-like member, is fixed to the inner wall surface of the opposing support portion 3 so as to protrude toward the central axis. The opposed contact portion 1 includes an opposed energized contact 11 and an opposed arc contact 12. The opposed energizing contact 11 is a conductor having a cylindrical shape with openings at both ends, and is erected on the movable side end face of the opposed side support 3 to extend the cylinder to the movable side. The counter energizing contact 11 has an opening edge on the movable side bulging inside. The counter arc contact 12 is a solid cylindrical conductor whose one end is rounded. The counter arc contact 12 is connected to a support plate 31 and extends on the central axis with one rounded end facing the movable side.

  The movable side support portion 4 through which the movable contact portion 2 is inserted is formed as one cylinder by connecting the cover 41, the base 42 and the insulating cylinder 43 having the same diameter in the axial direction from the opposite side to the opposite side. The conductor 7b is connected to the base 42. The movable contact portion 2 is fitted from the cover 41 side and protrudes from the cover 41 to the opposite side. The cover 41 has an opposite end bulged inward, and the bulged portion supports the movable contact portion 2. The cover 41 and the base 42 are conductors and are electrically connected to the movable contact portion 2 and the conductor 7b. The cover 41 is formed with an opening 41a that communicates inside and outside.

  The movable contact portion 2 is arranged with the operation rod 23 as a core on the central axis. A connecting rod 24 having the same diameter as that of the operating rod 23 is coaxially connected to the opposite side of the operating rod 23. A long insulating rod 25 that transmits the power of the operation mechanism 8 is connected to the opposite side of the connecting rod 24 via a link 24b. The insulating rod 25 is coaxially arranged with a slightly smaller diameter than the operation rod 23 and the connecting rod 24. The operation rod 23, the connecting rod 24, and the insulating rod 25 extend along the axis inside the movable support 4.

  The movable contact portion 2 includes a puffer chamber 26 that is a Baumkuchen-like space around the circumference of the operation rod 23. A movable arc contact 22 is provided on the opposite end face of the operation rod 23. An insulating nozzle 27 is provided extending from the opposite end face of the puffer chamber 26 toward the opposite side so as to surround the movable arc contact 22. Furthermore, a movable energizing contact 21 that extends from the opposite end face of the puffer chamber 26 toward the opposite side is provided around the circumference of the insulating nozzle 27.

  The operation rod 23 that is the core of the movable contact portion 2 is a hollow cylinder that opens on the opposite side. The opposite end of the operation rod 23 is closed by a solid connecting rod 24. On the peripheral surface of the operation rod 23, a through-hole 23a that connects the inside and the outside of the operation rod 23 is formed. The through hole 23 a is formed at the boundary between the operation rod 23 and the connecting rod 24. The movable arc contact 22 that continues from the opposite end of the operation rod 23 is a conductor having a cylindrical shape that is open at both ends. The opposed opening edge of the movable arc contact 22 bulges inside, and the inner diameter of the bulging position coincides with the outer diameter of the opposed arc contact 12.

  The movable arc contact 22 moves toward the opposed arc contact 12 by moving toward the opposite side along the central axis of the operating rod 23, and the opposed arc contact 12 is inserted into the opening of the movable arc contact 22. Thus, they are in contact with each other and become conductive. Further, the movable arc contact 22 moves in a direction away from the opposed arc contact 12 by the movement toward the opposite side along the central axis of the operation rod 23, and the opposed arc contact 12 is moved from the movable arc contact 22. They are separated from each other by being pulled out. The arc 9 is generated by the separation.

  The tip of the movable arc contact 22 may be divided in the circumferential direction to form a finger electrode. In this case, the movable arc contact 22 has flexibility, and the inner diameter of the opening edge of the movable arc contact 22 is slightly smaller than the outer diameter of the opposed arc contact 12 and is reduced. The opposing arc contact 12 is inserted into the opening of the movable arc contact 22 so that they come into contact with each other and can be conducted.

  The puffer chamber 26 located around the operation rod 23 is composed of a cylinder 26a that is interlocked with the operation rod 23 and a piston 26b that does not move. The cylinder 26a is a conductor having a cup shape with a hole and a bottom, and has a bottomed end face directed to the opposite side and a side surface extending to the opposite side along the central axis so as to surround the operation rod 23. The cylinder 26a is coupled so that the hole and the operation rod 23 are coaxial, and is flush with the opposite end surface of the operation rod 23. The hole in the bottomed end surface of the cylinder 26 a is slightly larger than the operation rod 23. That is, a communication port 26 c that connects the inside and outside of the cylinder 26 a is formed around the operation rod 23.

  The piston 26b is a donut-shaped disk whose center is open. A piston support 44 extends from the inner surface of the movable support 4, and the position of the piston 26 b is fixed by the piston support 44. The piston 26b is disposed facing the bottom end face of the cylinder 26a away from the opposite side. The operation rod 23 is inserted through the opening, thereby having a plane perpendicular to the central axis. The outer diameter of the piston 26b substantially matches the inner diameter of the cylinder 26a, and the piston 26b is fitted into the cylinder 26a. The piston 26b is fixed to the opposite side with respect to the position of the through hole 23a when the operating rod 23 moves most to the opposite side.

  The piston support 44 is a cylinder having a larger diameter than the operation rod 23, the connecting rod 24, and the insulating rod 25, and a smaller diameter than the cylinder 26a. The piston support 44 is fixed to the cover 41 with a skirt extending on the opposite side and extending outward from the cylinder. A tube opening 44a is formed on the opposite side. The cylinder opening 44 a is formed near the opening 41 a of the cover 41.

  The puffer chamber 26 is defined by the outer peripheral surface of the operating rod 23, the inner peripheral surface of the cylinder 26a, and the piston 26b. The cylinder 26a moves so that the bottomed end surface approaches the piston 26b in conjunction with the movement of the operating rod 23 toward the opposite side, and eventually the arc-extinguishing gas is ejected from the communication port 26c toward the arc 9.

  The piston 26b is formed with an exhaust hole 26d penetrating the disk so as to connect the two table surfaces. The exhaust hole 26 d connects the inner space of the piston support 44 and the puffer chamber 26. A valve 26e is inserted into the exhaust hole 26d and plugged. The valve 26 e is a so-called pressure control valve, for example, a wedge-shaped member, and is inserted into the exhaust hole 26 d from the inner space side of the piston support 44.

  The valve 26e is pressed from the inner space side of the piston support 44 to the exhaust hole 26d with the operating pressure P1, and is movable so as to open the exhaust hole 26d with a pressure exceeding the operating pressure P1. That is, the valve 26e is urged at the operating pressure P1 by the compression spring 26f so as to press the valve 26e from the inner space side of the piston support 44 toward the piston 26b. The compression spring 26f is an example of an elastic body that applies a biasing pressure to the valve 26e.

  On the piston support 44, a spring seat surface 26g is erected toward the internal space of the piston support 44. The compression spring 26f is installed on the piston 26b side with the spring seat surface 26g as a seat surface, and the valve 26e is fixed to the end portion of the compression spring 26f on the piston 26b side, and the pointed portion projects into the exhaust hole 26d.

  The operating pressure P1 accompanying opening of the valve 26e is set to be higher than the pressure rise peak value P90 of the puffer chamber 26 due to the thermal energy of the arc 9 that is generated when the current of 90% of the rated breaking current is cut off. ing. On the other hand, the operating pressure P1 accompanying opening of the valve 26e is set to be lower than the pressure rise peak value P100 of the puffer chamber 26 due to the thermal energy of the arc 9 that is generated when the rated breaking current is cut off. That is, P90 <P1 <P100.

  Further, the pressure P2 in the puffer chamber 26 for returning the valve 26e once to open and close the exhaust hole 26d again causes the arc 9 to be generated when the current of 90% of the rated breaking current is cut off. The compression spring 26f is adjusted so as to be 60% of the pressure rise peak value P90 of the puffer chamber 26 due to the thermal energy. That is, P2> 0.6 × P90.

  The insulating nozzle 27 covering the movable arc contact 22 is erected so as to extend the cylinder from the outer periphery of the communication port 26c of the cylinder 26a to the opposite side. The insulating nozzle 27 extends to the opposite side until the counter arc contact 12 is inserted and at least the tip of the counter arc contact 12 is included. The insulating nozzle 27 has an internal space where U-shaped and V-shaped bent portions are overlapped with each other, and is a Laval nozzle in which a convergent nozzle and a divergent nozzle are combined.

  The movable energizing contact 21 around the circumference of the insulating nozzle 27 is a cylindrical conductor having an open end. The movable energizing contact 21 is erected from the bottomed end surface of the cylinder 26a toward the opposite side. The movable energizing contact 21 is opposed to the opposing energizing contact 11. The outer diameter of the movable energizing contact 21 coincides with the inner diameter of the opening edge portion that bulges inside the opposing energizing contact 11. When the movable energizing contact 21 is inserted into the opening of the opposed energizing contact 11, the inner surface of the opposed energizing contact 11 and the outer surface of the movable energizing contact 21 are brought into contact with each other and become electrically conductive. When the movable energizing contact 21 is pulled out from the opening of the opposing energizing contact 11, the opposing energizing contact 11 and the movable energizing contact 21 are separated.

  The opposed arc contact 12 and the movable arc contact 22 are inserted deeper than the opposed energized contact 11 and the movable energized contact 21, and the opposed energized contact 11 and the movable energized contact 21 are separated first. As a result, the arc 9 is ignited between the opposed arc contact 12 and the movable arc contact 22, and the arc extinguishing gas is blown to extinguish the arc at the current zero point, thereby interrupting the current.

(Function)
The operation and action of this gas circuit breaker are as follows. First, in the energized state, the opposing energizing contact 11 and the movable energizing contact 21, and the opposing arc contact 12 and the movable arc contact 22 are in contact with each other, so that the conductor 7 a, the opposing support 3 and the opposing contact are provided. The electric circuit formed by the part 1 and the electric circuit formed by the movable contact point part 2, the movable support part 4, and the conductor 7b are connected.

  In response to an opening command to the gas circuit breaker at the time of interruption of medium and large currents such as ground faults of lines and short circuit faults of lines, and at the time of advanced small current interruptions, the gas circuit breaker is connected to the opposed contact part 1 and the movable contact part 2 Is opened and current interruption starts. Specifically, the insulating rod 25 is pulled to the opposite side along the central axis by driving the operation mechanism 8.

  The operating rod 23 of the movable contact portion 2 is pulled away from the opposed contact portion 1 following the pulling of the insulating rod 25 via the connecting rod 24. The movable contact portion 2 having the operation rod 23 as a core is also interlocked and separated from the opposed contact portion 1, and the opposed energized contact 11 and the movable energized contact 21 are separated. When the interruption operation further proceeds and the opposed arc contact 12 and the movable arc contact 22 are separated, an arc 9 is generated between the opposed arc contact 12 and the movable arc contact 22.

  When the arc 9 is ignited, a hot gas or a heated arc extinguishing gas is generated, and a part of the gas is divided into an opposing side and a movable side and exhausted. On the opposite side, air is exhausted through the inside of the opposite side support portion 3. On the movable side, it flows through the movable arc contact 22, flows through the operation rod 23, enters the space inside the piston support 44 through the through hole 23 a, and communicates with the communication port 26 d of the piston support 44 and the opening 41 a of the cover 41. It passes through the movable contact portion 2 and passes through.

  Further, a part of the hot gas and the heated arc extinguishing gas also flow into the puffer chamber 26. Therefore, the puffer chamber 26 accumulates the arc extinguishing gas by the thermal energy of the arc 9. The bottom of the cylinder 26a connected to the operation rod 23 approaches the fixed piston 26b. The volume of the puffer chamber 26 is reduced, and the arc extinguishing gas in the puffer chamber 26 is also accumulated by mechanical action.

  Here, when the breaking current is 90% or less of the rated breaking current, the peak pressure Pr of the puffer chamber 26 caused by the thermal energy of the arc 9 with respect to the operating pressure P1 of the valve 26e is P1> P90. ≧ Pr. For this reason, the valve 26e does not operate with the exhaust hole 26d closed. Therefore, the puffer chamber 26 and the internal space of the piston support 44 are not in communication, and no pressure is released from the puffer chamber 26.

  In the latter half of the interruption process, the arc 9 attenuates toward the current zero point, and the pressure in the space around the arc 9 decreases. When the interrupting current is 90% or less of the rated interrupting current, the arc extinguishing gas having a high pressure while the exhaust hole 26d is not in communication is ejected from the puffer chamber 26. The arc-extinguishing gas that has become a jet is guided toward the arc 9 using the gas supply path between the insulating nozzle 27 and the movable arc contact 22 and is strongly blown onto the arc 9. When the arc 9 reaches the current zero point, the arc 9 is extinguished in combination with the blowing of a strong arc extinguishing gas, and the current interruption of 90% or less of the rated interruption current is completed.

  In the case of short-distance line fault interruption, since the voltage increase rate immediately after the current zero point is extremely steep, it is necessary to supply a high-density arc extinguishing gas to the arc 9 with a strong pressure. This gas circuit breaker supplies high-density arc extinguishing gas at a strong pressure to the arc 9 because the valve 26e does not operate when the short-distance line fault current is cut off, which is 60% to 90% of the rated breaking current. To do.

  On the other hand, as shown in FIG. 3, when the breaking current is close to 100% of the rated breaking current, the pressure rise peak value of the puffer chamber 26 due to the thermal energy of the arc 9 with respect to the operating pressure P1 of the valve 26e. Pr is P1 <Pr ≦ P100. Therefore, the valve 26e moves away from the exhaust hole 26d and opens the exhaust hole 26d. The puffer chamber 26 and the internal space of the piston support 44 communicate with each other, and pressure is released from the puffer chamber 26.

  Then, when the breaking current is close to 100% of the rated breaking current, the pressure increase in the puffer chamber 26 is suppressed to a certain limit. In other words, excessive pressure is released, and a sufficient pressure is generated in the puffer chamber 26 to extinguish the arc 9 due to the breaking current close to 100% of the rated breaking current. Accordingly, the reaction force to the cylinder 26a due to the pressure increase in the puffer chamber 26 is also suppressed to a certain limit, so that opening can be realized with a small driving force by the operation mechanism 8, and the breaking performance against a breaking current close to 100% of the rated breaking current. Can also be obtained.

  In the case of a terminal short-circuit failure, good shut-off performance can be obtained even if the gas density of the arc-extinguishing gas is somewhat reduced, and the puffer chamber 26 and the inner space of the piston support 44 can communicate with each other even when a small and medium current is cut off. Therefore, since the arc extinguishing gas having a sufficient density for arc extinguishing is supplied, a good shut-off performance can be obtained, and the influence of the valve 26e is small.

(effect)
As described above, in the gas circuit breaker, the opposed contact portion 1 and the movable contact portion 2 are arranged to face each other in the sealed container 5 filled with the arc extinguishing gas. The opposing contact portion 1 and the movable contact portion 2 include a conductor and can be contacted and separated relatively. The opposed contact portion 1 and the movable contact portion 2 are opposed to each other, and the opposed arc contact 12 and the movable arc are generated in which an arc 9 is generated between both ends as the opposed contact portion 1 and the movable contact portion 2 are separated. A contact 22 is provided. The gas circuit breaker further includes a puffer chamber 26 for accumulating arc-extinguishing gas, and an insulating nozzle 27 for rectifying the arc-extinguishing gas ejected from the puffer chamber toward the arc 9.

  The puffer chamber 26 is formed with an exhaust hole 26 d communicating with an external space such as an inner space of the piston support 44 in addition to a communication port 26 c connected to the insulating nozzle 27. The exhaust hole 26d is closed by a valve 26e, and the valve 26e is exhausted at a predetermined operating pressure P1 lower than the peak pressure rise value generated in the puffer chamber 26 when a current corresponding to 90% of the rated cutoff current is cut off. When the pressure increase in the puffer chamber 26 exceeds a predetermined operating pressure P1, the exhaust hole 26d is opened.

  As a result, the gas circuit breaker can achieve an excellent current interrupting performance in a wide current region with a small driving force without reducing the size of the piston 26b in order to reduce the driving reaction force at the time of interrupting a large current.

(Other embodiments)
In the present specification, a plurality of embodiments according to the present invention have been described. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The embodiments and the modifications thereof are included in the scope of the invention and the scope of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Opposed contact part 11 Opposite energizing contact 12 Opposed arc contact 2 Movable contact part 21 Movable energizing contact 22 Movable arc contact 23 Operation rod 23a Through-hole 24 Connecting rod 24b Link 25 Insulating rod 26 Puffer chamber 26a Cylinder 26b Piston 26c Communication port 26d Exhaust hole 26e Valve 26f Compression spring 26g Spring seat surface 27 Insulating nozzle 3 Opposing side support portion 31 Support plate 4 Movable side support portion 41 Cover 41a Opening 42 Base 43 Insulating cylinder 44 Piston support 44a Tube opening 5 Sealed container 7a Conductor 7b Conductor 8 Operating mechanism 9 Arc

Claims (4)

A gas circuit breaker that mechanically switches between cutting off and turning on current,
A sealed container filled with arc-extinguishing gas;
A first contact portion and a second contact portion which are disposed opposite to each other in the sealed container and are relatively close to and away from each other;
The first contact portion and the second contact portion are provided separately from each other, opposed to each other, and an arc is generated between both ends as the first contact portion and the second contact portion are separated. A first arc contact and a second arc contact that ignite,
A puffer chamber for accumulating the arc extinguishing gas;
A communication port formed in the puffer chamber;
An exhaust hole formed in the puffer chamber;
An insulating nozzle connected to the communication port and rectifying the arc extinguishing gas ejected by the puffer chamber toward the arc;
The valve closes the exhaust hole at a predetermined operating pressure lower than a pressure increase peak value generated in the puffer chamber when a current corresponding to 90% of the rated cutoff current is cut off, and the pressure increase in the puffer chamber is the predetermined pressure. A movable valve that opens the exhaust hole when the operating pressure is exceeded;
Providing
A gas circuit breaker characterized by The valve closes the exhaust hole with a pressure exceeding 60% of a peak value of pressure rise generated in the puffer chamber when a current corresponding to 90% of a rated breaking current is cut off;
The gas circuit breaker according to claim 1. An elastic body for urging the valve to be inserted into the exhaust hole from the outside of the puffer chamber;
The elastic body is
Energizing the valve with an energizing pressure lower than a pressure increase peak value generated in the puffer chamber when the current corresponding to 90% of the rated breaking current is interrupted;
The gas circuit breaker according to claim 1 or 2. The elastic body is
Energizing the exhaust hole with an energizing pressure exceeding 60% of a peak value of the pressure rise generated in the puffer chamber when the current corresponding to 90% of the rated breaking current is interrupted;
The gas circuit breaker according to claim 3.

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