WO2022070397A1

WO2022070397A1 - Gas circuit breaker

Info

Publication number: WO2022070397A1
Application number: PCT/JP2020/037505
Authority: WO
Inventors: 崇文飯島; 真一永田
Original assignee: 株式会社東芝; 東芝エネルギーシステムズ株式会社
Priority date: 2020-10-02
Filing date: 2020-10-02
Publication date: 2022-04-07

Abstract

A gas circuit breaker according to an embodiment has a fixed contactor, a movable contactor, an insulating nozzle, a pressure accumulation part, and a first cylindrical body. The movable contactor is displaced in a first direction from a closed pole state and spaced apart from the fixed contactor. The insulating nozzle has a nozzle opening section at an end section thereof in a second direction. The insulating nozzle surrounds an arc discharge which is generated between the fixed contactor and the movable contactor. The pressure accumulation part discharges an arc extinguishing gas into the insulating nozzle and blows the gas toward the arc discharge. The first cylindrical body surrounds the nozzle opening section in a fully closed pole state. The inner peripheral surface of the first cylindrical body has, in the fully open pole state, a diffuser part at a position further in the second direction than the nozzle opening section. The diffuser part expands in diameter in the second direction.

Description

Gas circuit breaker

The embodiment of the present invention relates to a gas circuit breaker.

A gas circuit breaker that switches currents in an electric power system mechanically disconnects contacts in a closed container filled with an arc-extinguishing gas during the disconnection process, and extinguishes the arc discharge between the contacts caused by the disconnection of the contacts. The arc is extinguished by spraying sex gas. The gas circuit breaker aims to restore the dielectric strength between the contacts by quickly removing the hot gas generated by the arc discharge from the contacts. The gas circuit breaker has an exhaust unit that forms a flow path for hot gas. The exhaust unit is required to cool the hot gas and then discharge it to the outside of the exhaust unit, and to suppress an increase in pressure inside the exhaust unit. If the hot gas is discharged from the exhaust gas at a high temperature, the insulation between the exhaust gas and the grounded closed container may be destroyed and a ground fault may occur. When the pressure in the exhaust section rises, the spraying of the arc-extinguishing gas weakens, the improvement of the dielectric strength becomes insufficient, and the current cutoff performance may deteriorate.

By the way, SF ₆ (sulfur hexafluoride), which has excellent arc extinguishing performance, is mainly used as the arc extinguishing gas. SF ₆ is a greenhouse gas, and it is required to reduce the amount used as an arc-extinguishing gas. Therefore, it is desired to develop a technique for reducing the volume of the closed container. However, as the size of the closed container becomes smaller, the distance between the exhaust part and the closed container becomes smaller, so it is necessary to review the method of exhausting the hot gas by the exhaust part in order to suppress the ground fault.

U.S. Patent Application Publication No. 2014/0251957 U.S. Patent Application Publication No. 2014/0209568

The problem to be solved by the present invention is to provide a miniaturized gas circuit breaker having excellent current breaking performance.

The gas circuit breaker of the embodiment has a fixed contact, a movable contact, an insulating nozzle, a pressure accumulator, and a first cylinder. The fixed contacts are fixedly arranged with respect to the closed container in a closed container filled with an arc-extinguishing gas. The movable contact is arranged in a closed container. The movable contact is in contact with the fixed contact in the closed pole state, and is displaced in the first direction from the closed pole state to be separated from the fixed contact. The insulating nozzle is formed in a tubular shape. The insulated nozzle has a nozzle opening at the end in the second direction opposite to the first direction. The insulating nozzle is displaced in conjunction with the movable contact. The insulating nozzle surrounds an arc discharge that ignites between the fixed and movable contacts. The pressure accumulator stores the arc-extinguishing gas. The pressure accumulator discharges the arc-extinguishing gas into the inside of the insulating nozzle and blows it against the arc discharge. The first cylinder surrounds the nozzle opening in a fully open state where the movable contact is farthest from the fixed contact. The inner peripheral surface of the first cylinder has a diffuser portion at a position in the second direction from the nozzle opening in a fully open state. The diameter of the diffuser portion increases toward the second direction.

Sectional drawing which shows the gas circuit breaker of embodiment. Sectional drawing which shows the gas circuit breaker of embodiment. Sectional drawing which shows the gas circuit breaker of embodiment. The graph which shows the characteristic of the gas circuit breaker which concerns on embodiment. The graph which shows the characteristic of the gas circuit breaker which concerns on embodiment.

Hereinafter, the gas circuit breaker 1 of the embodiment will be described with reference to the drawings. The gas circuit breaker 1 of the embodiment is a switchgear that opens and closes an electric circuit of an electric power system. In the following description, the same reference numerals are given to configurations having the same or similar functions. Then, the duplicate description of those configurations may be omitted.

1 to 3 are cross-sectional views showing the gas circuit breaker 1 of the embodiment. Note that FIG. 1 shows a state in which the gas circuit breaker 1 is turned on. FIG. 2 shows immediately before the opening of the gas circuit breaker 1 in the closed state. FIG. 3 shows a completely open state of the gas circuit breaker 1.

As shown in FIG. 1, the gas circuit breaker 1 includes a closed container (not shown) filled with an arc-extinguishing gas, and an opposed unit 3 and a movable unit 4 arranged in the closed container. The arc-extinguishing gas is a gas having excellent arc-extinguishing performance and insulating performance, and is, for example, sulfur hexafluoride (SF ₆ ) gas. The facing unit 3 and the movable unit 4 are housed in a closed container together with an arc-extinguishing gas. The closed container is made of a metal material. The closed container is grounded.

The facing unit 3 and the movable unit 4 form a part of an electric circuit. The facing unit 3 includes a facing contact portion 30. The facing contact portion 30 is conducting to a first conductor (not shown) drawn from the outside of the closed container to the inside. The movable unit 4 includes a movable contact portion 60. The movable contact portion 60 is electrically connected to a second conductor (not shown) drawn from the outside to the inside of the closed container. The gas circuit breaker 1 opens and closes an electric circuit and conducts or cuts off an electric current by contacting or separating the facing contact portion 30 and the movable contact portion 60 from each other. In the following description, the state in which the facing contact portion 30 and the movable contact portion 60 are in contact with each other is referred to as a closed pole state, and the state in which the facing contact portion 30 and the movable contact portion 60 are separated from each other is referred to as an open pole state. Further, among the closed pole states, the state applied when it is not necessary to shut off the electric circuit is particularly referred to as a closed state. Further, among the open pole states, the state in which the current cutoff operation is completed is particularly referred to as a completely open pole state. Further, the process of separating the facing contact portion 30 and the movable contact portion 60 from each other from the closed state to the completely open state is referred to as an open pole process.

As shown in FIG. 1, the facing unit 3 and the movable unit 4 are each formed of a plurality of cylindrical or columnar members. The cylindrical or columnar members are arranged so that their central axes coincide with each other. The facing unit 3 and the movable unit 4 are arranged so as to face each other in the axial direction of the central axis. In the following description, the axial direction of the central axis is simply referred to as an axial direction. Further, the direction that orbits around the central axis is referred to as a circumferential direction. Further, the direction orthogonal to the central axis is referred to as a radial direction. Further, in FIGS. 1 to 3, the first direction in the axial direction is indicated by an arrow A, and the second direction opposite to the first direction is indicated by an arrow B.

The facing unit 3 is fixedly arranged with respect to the closed container in a state of being spaced from the closed container. The facing unit 3 includes an exhaust chamber 10 and a facing contact portion 30.

The exhaust chamber 10 has an inner cylinder 11 (first cylinder) and an outer cylinder 21 (second cylinder). The inner cylinder 11 and the outer cylinder 21 are each formed in a cylindrical shape by a metal material. The inner cylinder 11 and the outer cylinder 21 are conductive to the first conductor described above.

The inner cylinder 11 is open on both sides in the axial direction. The inner cylinder 11 includes an upstream portion 12, a downstream portion 13, an intermediate portion 14, and a flange 15.

The upstream portion 12 extends in the second direction in the axial direction from the end portion in the first direction in the axial direction of the inner cylinder 11. The upstream portion 12 extends axially with a constant inner diameter and a constant outer diameter. The upstream portion 12 surrounds the nozzle opening 71 of the insulating nozzle 70, which will be described later, in a fully open state (see FIG. 3).

The downstream portion 13 is arranged in the second direction from the upstream portion 12. The downstream portion 13 extends in the first direction from the end portion of the inner cylinder 11 in the second direction. The downstream portion 13 is formed to have a larger diameter than the upstream portion 12. The downstream portion 13 extends axially with a constant inner diameter and a constant outer diameter. The inner diameter of the downstream portion 13 is larger than the inner diameter of the upstream portion 12.

The intermediate portion 14 is arranged between the upstream portion 12 and the downstream portion 13. The intermediate portion 14 is connected to an end portion of the upstream portion 12 in the second direction and an end portion of the downstream portion 13 in the first direction. The inner peripheral surface of the intermediate portion 14 is connected to the inner peripheral surface of the upstream portion 12 at the end portion of the intermediate portion 14 in the first direction. The inner peripheral surface of the intermediate portion 14 gradually increases in diameter from the end portion of the intermediate portion 14 in the first direction toward the second direction. In other words, the inner diameter of the intermediate portion 14 gradually increases from the end portion of the intermediate portion 14 in the first direction toward the second direction. The inner peripheral surface of the intermediate portion 14 is connected to the inner peripheral surface of the downstream portion 13 at the end portion of the intermediate portion 14 in the second direction. The outer peripheral surface of the intermediate portion 14 is connected to the outer peripheral surface of the upstream portion 12 at the end portion of the intermediate portion 14 in the first direction. The outer peripheral surface of the intermediate portion 14 is connected to the outer peripheral surface of the downstream portion 13 at the end portion of the intermediate portion 14 in the second direction. The inner peripheral surface and the outer peripheral surface of the intermediate portion 14 each extend linearly in a vertical cross section along the central axis.

The flange 15 is provided at the end of the inner cylinder 11 in the first direction. The flange 15 protrudes radially outward from the end portion of the upstream portion 12 in the first direction, and extends in the circumferential direction over the entire circumference. The outer diameter of the flange 15 is larger than the outer diameter of the downstream portion 13.

The outer cylinder 21 is formed so as to surround the end portion of the inner cylinder 11 in the second direction. The outer cylinder 21 includes a peripheral wall portion 22 and a closing portion 23.

The peripheral wall portion 22 surrounds the inner cylinder 11 from the outside in the radial direction. The peripheral wall portion 22 extends in the axial direction with a constant inner diameter and a constant outer diameter. The inner diameter of the peripheral wall portion 22 is smaller than the outer diameter of the flange 15 of the inner cylinder 11. The end portion of the peripheral wall portion 22 in the first direction is located in the first direction with respect to the end portion of the downstream portion 13 of the inner cylinder 11 in the first direction. The end portion of the peripheral wall portion 22 in the first direction is spaced from the flange 15 of the inner cylinder 11 over the entire circumference in the circumferential direction. In the present embodiment, the end portion of the peripheral wall portion 22 in the first direction overlaps the upstream portion 12 of the inner cylinder 11 when viewed from the radial direction. The end portion of the peripheral wall portion 22 in the second direction is located in the second direction with respect to the end portion of the inner cylinder 11 in the second direction. The inner peripheral surface of the peripheral wall portion 22 is spaced from the outer peripheral surface of the downstream portion 13 of the inner cylinder 11 over the entire circumference in the circumferential direction.

The closed portion 23 closes the inside of the peripheral wall portion 22 in the second direction of the inner cylinder 11. The closed portion 23 projects inward in the radial direction from the end portion of the peripheral wall portion 22 in the second direction. The closing portion 23 is spaced from the end portion in the second direction of the inner cylinder 11 over the entire circumference in the circumferential direction.

The facing contactor portion 30 includes a facing energizing contact 31 and a facing arc contact 32 (fixed contact).

The opposed energizing contact 31 is formed in a cylindrical shape by a metal material. Both ends of the opposed energizing contact 31 are open in the axial direction. The opposed energizing contact 31 is coupled to the end of the inner cylinder 11 in the first direction. The opposed energizing contact 31 is conducting to the first conductor via the exhaust chamber 10.

The facing arc contactor 32 is formed in a columnar shape by a metal material. The facing arc contactor 32 is arranged inside the facing energizing contact 31. The facing arc contactor 32 is supported by the inner cylinder 11 via a support member (not shown). The facing arc contactor 32 projects in the first direction from the end portion of the inner cylinder 11 in the first direction. The facing arc contactor 32 is conducting to the first conductor via the support member and the exhaust chamber 10.

The movable unit 4 is arranged so as to be displaced in the axial direction with respect to the facing unit 3 except for the piston 50 described later. The movable unit 4 includes an operation rod 40, a cylinder 45, a piston 50, a movable contact portion 60, and an insulating nozzle 70.

The operation rod 40 is made of a metal material. The operation rod 40 is formed in a cylindrical shape. The operating rod 40 extends axially with a constant outer diameter. The operation rod 40 is connected to a drive device (both not shown) via an insulating rod at the end in the first direction, and is rotatable in the axial direction with respect to the closed container.

The cylinder 45 is formed in a cylindrical shape by a metal material. The cylinder 45 includes a peripheral wall 46 extending in the axial direction and a bottom wall 47 connected to the end of the peripheral wall 46 in the second direction. The peripheral wall 46 extends with a constant inner diameter. The inner diameter of the peripheral wall 46 is larger than the outer diameter of the operation rod 40. The peripheral wall 46 surrounds the operation rod 40 from the outside in the radial direction. The bottom wall 47 projects radially inward from the end of the peripheral wall 46 in the second direction. A circular through hole 47a is formed in the center of the bottom wall 47. That is, the bottom wall 47 is formed in the shape of an annular plate. An operation rod 40 is inserted through the through hole 47a. The cylinder 45 is fixedly arranged with respect to the operation rod 40, and is displaced in the axial direction in conjunction with the operation rod 40.

The piston 50 is arranged between the operation rod 40 and the peripheral wall 46 of the cylinder 45. The piston 50 is formed in the shape of an annulus plate extending in both the radial and circumferential directions. The inner diameter of the piston 50 coincides with the outer diameter of the operating rod 40. The outer diameter of the piston 50 coincides with the inner diameter of the peripheral wall 46 of the cylinder 45. The piston 50 is fixedly arranged with respect to the closed container.

The cylinder 45, the piston 50, and the operation rod 40 define a puffer chamber 55 (accumulation unit) for accumulating arc-extinguishing gas. The volume of the puffer chamber 55 is variable in conjunction with the displacement of the operation rod 40. The volume of the puffer chamber 55 decreases with the displacement of the cylinder 45 and the operating rod 40 in the first direction, so that the internal arc-extinguishing gas is boosted. The puffer chamber 55 discharges the extinguished gas boosted in the puffer chamber 55 from the puffer chamber 55 through the gap between the bottom wall 47 of the cylinder 45 and the operation rod 40.

The movable contact portion 60 includes a movable arc contact 61 (movable contact) and a movable energizing contact 62.

The movable arc contactor 61 is formed in a cylindrical shape by a metal material. Both ends of the movable arc contactor 61 are open in the axial direction. The movable arc contact 61 is coupled to the end portion of the operation rod 40 in the second direction and extends in the second direction from the end portion of the operation rod 40 in the second direction. The movable arc contactor 61 is conducting to the operation rod 40. The end portion 61a of the movable arc contactor 61 in the second direction bulges inward in the radial direction. The inner diameter of the end portion 61a in the second direction of the movable arc contactor 61 is equal to or smaller than the outer diameter of the opposed arc contactor 32.

The movable arc contactor 61 is displaced in the axial direction in conjunction with the operation rod 40. The facing arc contactor 32 and the movable arc contactor 61 are provided so as to be able to come into contact with each other in the axial direction as the operation rod 40 is displaced. The opposed arc contactor 32 and the movable arc contactor 61 are in contact with each other in the closed pole state and separated from each other in the open pole state. The facing arc contactor 32 and the movable arc contactor 61 come into contact with each other and become conductive when the facing arc contactor 32 is inserted into the opening of the movable arc contactor 61.

The movable energizing contact 62 is formed in a cylindrical shape by a metal material. The movable energizing contact 62 is arranged so as to surround the movable arc contact 61. The movable energizing contact 62 extends in the second direction from the bottom wall 47 of the cylinder 45. The movable energizing contactor 62 is conducting to the cylinder 45. The end of the movable energizing contact 62 in the second direction is open in the second direction.

The movable energizing contact 62 is relatively fixed to the operation rod 40 via the cylinder 45. The movable energizing contact 62 is displaced in the axial direction in conjunction with the operation rod 40. The opposed energizing contact 31 and the movable energizing contact 62 are provided so as to be detachable from each other in the axial direction as the operation rod 40 is displaced. The opposed energizing contact 31 and the movable energizing contact 62 are in contact with each other in the closed state and separated from each other in the open pole state. The opposed energized contact 31 and the movable energized contact 62 are separated from each other earlier than the opposed arc contact 32 and the movable arc contact 61 in the opening process (see FIG. 2). The counter-energized contact 31 and the movable energized contact 62 are in contact with each other to conduct conduction by inserting the movable energized contact 62 into the opening in the first direction of the opposed energized contact 31.

The insulating nozzle 70 is formed in a cylindrical shape by the insulating material. The insulating nozzle 70 projects from between the movable arc contact 61 and the movable energizing contact 62 in the second direction from the movable arc contact 61 and the movable energizing contact 62. The insulating nozzle 70 is fixed to the inner peripheral surface of the movable energizing contact 62. The insulating nozzles 70 are provided at intervals in the radial direction with respect to the movable arc contactor 61. The insulating nozzle 70 includes a nozzle opening 71 at the end in the second direction. The nozzle opening 71 is open inside the exhaust chamber 10.

The inner peripheral surface of the insulating nozzle 70 is provided with a throat portion 72. The throat portion 72 is a portion of the insulating nozzle 70 having the smallest inner diameter. The throat portion 72 is provided at an intermediate portion in the axial direction of the insulating nozzle 70. The throat portion 72 is provided in a second direction with respect to the movable arc contactor 61. The insulating nozzle 70 surrounds an arc discharge described later in the open pole state. The inside of the insulating nozzle 70 forms a flow path for the arc-extinguishing gas discharged from the puffer chamber 55. The insulating nozzle 70 guides the arc-extinguishing gas discharged from the puffer chamber 55 to the arc discharge.

As shown in FIG. 3, the nozzle opening 71 of the insulating nozzle 70 is opened inside the inner cylinder 11 in a completely open state. The inner peripheral surface 16 of the inner cylinder 11 forms a flow path for the arc-extinguishing gas discharged from the nozzle opening 71. The inner peripheral surface 16 of the inner cylinder 11 includes an upstream guide portion 17, a diffuser portion 18, and a downstream guide portion 19 as a portion forming a flow path. The upstream guide portion 17 is at least a part of the inner peripheral surface of the upstream portion 12. The upstream guide portion 17 extends axially from the position of the nozzle opening 71 in the axial direction with a constant inner diameter in the second direction. The diffuser portion 18 is an inner peripheral surface of the intermediate portion 14. The diffuser portion 18 is connected to the upstream guide portion 17 at the end portion of the diffuser portion 18 in the first direction. The diameter of the diffuser portion 18 is gradually increased from the upstream guide portion 17 toward the second direction. The downstream guide portion 19 is an inner peripheral surface of the downstream portion 13. The downstream guide portion 19 is connected to the diffuser portion 18 at the end of the downstream guide portion 19 in the first direction. The downstream guide portion 19 extends in the axial direction with a constant inner diameter. The inner diameter of the downstream guide portion 19 is larger than the inner diameter of the upstream guide portion 17.

Subsequently, the circuit breaker operation of the gas circuit breaker 1 will be described.
As shown in FIG. 1, in the loaded state, the movable contact portion 60 is located at the end portion in the movable range in the second direction. In the turned-on state, the movable energizing contact 62 is inserted inside the opposed energizing contact 31 to make contact, and the opposed arc contact 32 is inserted inside the movable arc contact 61 to make contact. As a result, the facing unit 3 and the movable unit 4 become conductive.

When the current is cut off, the gas circuit breaker 1 displaces the operation rod 40 in the first direction and separates the opposed contact portion 30 and the movable contact portion 60 from each other. When the operating rod 40 is displaced in the first direction, the movable arc contact 61, the movable energizing contact 62, the insulating nozzle 70, and the cylinder 45 are displaced in the first direction in conjunction with the operating rod 40. When the cylinder 45 is displaced in the first direction, the volume of the puffer chamber 55 is reduced, and the arc-extinguishing gas inside the puffer chamber 55 is boosted.

As shown in FIG. 2, when the operating rod 40 is displaced in the first direction from the closed state, the opposed energizing contact 31 and the movable energizing contact 62 are separated from each other. In this state, the facing arc contactor 32 and the movable arc contactor 61 are in contact with each other, so that the facing unit 3 and the movable unit 4 are conducting with each other.

When the operating rod 40 is further displaced in the second direction, the opposed arc contactor 32 and the movable arc contactor 61 are separated from each other, and the state shifts from the closed pole state to the open pole state. When the facing arc contactor 32 and the movable arc contactor 61 are separated from each other, an arc discharge is generated between the facing arc contactor 32 and the movable arc contactor 61. When the arc discharge is triggered, the surrounding arc-extinguishing gas is heated to become a high-temperature hot gas and expands. A part of the expanded arc-extinguishing gas flows into the puffer chamber 55. As a result, the extinguishing gas inside the puffer chamber 55 is further boosted.

As shown in FIG. 3, as the breaking operation progresses, the distance between the opposed arc contactor 32 and the movable arc contactor 61 increases, the current decreases toward the current zero point, and the arc discharge decreases. When the arc discharge becomes small, the inflow of the arc-extinguishing gas into the puffer chamber 55 is stopped, and the high-pressure arc-extinguishing gas is discharged from the puffer chamber 55. The arc-extinguishing gas discharged from the puffer chamber 55 passes between the insulating nozzle 70 and the movable arc contactor 61 and is blown to the arc discharge. As a result, the arc discharge is extinguished and the current is cut off. Then, the movable contact portion 60 reaches the fully open state at the position farthest from the facing contact portion 30, and the shutoff operation is completed. The position of the operation rod 40 in the fully open state is a position where the operation rod 40 is completely displaced in the first direction by a drive device (not shown) connected to the operation rod 40.

The arc-extinguishing gas sprayed on the arc discharge is discharged separately from the flow path on the facing unit 3 side and the flow path on the movable unit 4 side together with the heat gas generated by the arc discharge. The arc-extinguishing gas that has flowed into the flow path on the facing unit 3 side passes through the inside of the throat portion 72 of the insulating nozzle 70 and is discharged from the nozzle opening 71. The arc-extinguishing gas discharged from the nozzle opening 71 passes through the flow path formed on the inner peripheral surface 16 of the inner cylinder 11, passes between the inner cylinder 11 and the outer cylinder 21, and reaches the inside of the closed container. The flow path on the movable unit 4 side reaches the inside of the closed container from the opening of the movable arc contact 61 in the first direction through the inside of the movable arc contact 61 and the inside of the operation rod 40.

As described above, in the present embodiment, the configuration in which the inner peripheral surface 16 of the inner cylinder 11 of the exhaust chamber 10 has the diffuser portion 18 is adopted. The diffuser portion 18 is provided at a position in the second direction from the nozzle opening 71 in a fully open state, and its diameter increases toward the second direction.
According to this configuration, the heat gas generated by the arc discharge inside the insulating nozzle 70 is pushed out to the arc-extinguishing gas discharged from the puffer chamber 55 in the second direction from the nozzle opening 71 of the insulating nozzle 70. Is discharged to. The hot gas discharged from the nozzle opening 71 flows in the second direction inside the inner cylinder 11 and is agitated with the low-temperature arc-extinguishing gas existing inside the inner cylinder 11. Here, the heat gas passes through the inside of the diffuser portion 18 in the process of flowing inside the inner cylinder 11 in the second direction. The heat gas is boosted by passing through the inside of the diffuser portion 18. Therefore, stirring between the hot gas and the low-temperature arc-extinguishing gas existing inside the inner cylinder 11 is promoted by the pressure difference between the hot gas and the low-temperature arc-extinguishing gas. As a result, the inner cylinder 11 can cool the heat gas and then discharge it. Therefore, it is possible to suppress dielectric breakdown between the exhaust chamber 10 and the closed container while reducing the size of the closed container.
By the way, the low-temperature arc-extinguishing gas has a higher specific density than the hot gas. Therefore, if the hot gas is not agitated with the low-temperature arc-extinguishing gas inside the inner cylinder 11, the flow of the hot gas is hindered by the low-temperature arc-extinguishing gas, and the hot gas moves with the facing arc contactor 32. It becomes difficult to come off from between the arc contactor 61. According to the present embodiment, the hot gas is agitated with the low-temperature arc-extinguishing gas inside the inner cylinder 11, so that the opposed arc contactor 32 and the movable arc contactor are compared with the case where the hot gas is not agitated. It is possible to promote the discharge of hot gas from between 61. As a result, the pressure between the opposed arc contactor 32 and the movable arc contactor 61 can be made sufficiently smaller than the pressure in the puffer chamber 55. Therefore, it is possible to suppress the weakening of the spraying of the arc-extinguishing gas and improve the dielectric strength between the opposed arc contactor 32 and the movable arc contactor 61.
As described above, it is possible to provide a miniaturized gas circuit breaker 1 having excellent current breaking performance.

Further, in the present embodiment, the exhaust chamber 10 has an outer cylinder 21. The outer cylinder 21 has a peripheral wall portion 22 that surrounds the inner cylinder 11 and a closing portion 23 that closes the inside of the peripheral wall portion 22 in the second direction of the inner cylinder 11. According to this configuration, the heat gas discharged from the end portion of the inner cylinder 11 in the second direction passes between the inner cylinder 11 and the outer cylinder 21 and is discharged to the outside of the exhaust chamber 10. Therefore, the flow path length of the hot gas in the exhaust chamber can be lengthened as compared with the configuration in which the exhaust chamber has only the inner cylinder. Therefore, the exhaust chamber 10 can cool the heat gas more sufficiently before discharging it.

The inner peripheral surface 16 of the inner cylinder 11 has an upstream guide portion 17. The upstream guide portion 17 extends from the nozzle opening 71 in the second direction with a constant inner diameter in a fully open state, and is connected to the diffuser portion 18. Here, when the inner diameter of the upstream guide portion 17 is r1 and the axial length of the upstream guide portion 17 is x1, the step between the inner peripheral surface of the insulating nozzle 70 and the diffuser portion 18 becomes small. As a result, it is possible to alleviate the decrease in the flow velocity when the hot gas passes through the inside of the upstream guide portion 17, and to generate a negative pressure behind the hot gas due to the inertia of the hot gas. Therefore, it is possible to promote the discharge of heat gas from between the opposed arc contactor 32 and the movable arc contactor 61. The length of the upstream guide portion 17 in the axial direction is the distance from the nozzle opening 71 to the end portion of the upstream portion 12 in the second direction in the axial direction.

FIG. 4 is a graph showing the characteristics of the gas circuit breaker according to the embodiment.
FIG. 4 shows a simulation result of an embodiment in which the frequency of the alternating current is 50 Hz, the frequency of the alternating current is set to 50 Hz, the above x1 is constant, and r1 is changed in the gas circuit breaker 1 according to the embodiment. In FIG. 4, the horizontal axis indicates the elapsed time in the shutoff operation. The vertical axis shows the ratio (boosting ratio) of the pressure increased inside the upstream guide portion 17 to the pressure inside the closed container in the steady state. In the simulation result shown in FIG. 4, the gas circuit breaker opens at the timing of the elapsed time of −20 msec, and the alternating current reaches the zero point at the timing of 0 msec. That is, the simulation result shown in FIG. 4 is an evaluation result for a maximum arc time of 20 msec, assuming a short-distance line failure.

As shown in FIG. 4, when r1 / x1 is 0.9 or less, the pressure inside the upstream guide portion 17 continues to increase toward the timing when the alternating current reaches the zero point. On the other hand, when r1 / x1 is larger than 0.9, the increase in pressure inside the upstream guide portion 17 is suppressed until the AC current reaches the zero point. As a result, the puffer chamber 55 continues to blow the arc-extinguishing gas between the opposed arc contactor 32 and the movable arc contactor 61 toward the timing when the alternating current reaches the zero point, so that the recurrence of the arc discharge is suppressed. Will be done. Therefore, by setting r1 / x1 to be larger than 0.9, the dielectric strength can be improved and the current cutoff performance of the gas circuit breaker 1 can be improved.

Further, when the inner diameter of the end portion of the inner cylinder 11 in the second direction is r2, the heat gas can flow inside the inner cylinder 11 without delay as r2 / r1 becomes larger. As a result, it is possible to alleviate the decrease in the flow velocity when the hot gas passes through the inside of the upstream guide portion 17, and to generate a negative pressure behind the hot gas due to the inertia of the hot gas. Therefore, it is possible to promote the discharge of heat gas from between the opposed arc contactor 32 and the movable arc contactor 61. In this embodiment, the inner diameter of the end portion of the inner cylinder 11 in the second direction is the inner diameter of the downstream guide portion 19.

FIG. 5 is a graph showing the characteristics of the gas circuit breaker according to the embodiment.
FIG. 5 shows the simulation results of an embodiment in which the frequency of the alternating current is 50 Hz, the frequency of the alternating current is set to 50 Hz, the r2 is constant, and r1 is changed in the gas circuit breaker 1 according to the embodiment. In FIG. 5, the horizontal axis indicates the elapsed time in the shutoff operation. The vertical axis shows the ratio (boosting ratio) of the pressure increased inside the upstream guide portion 17 to the pressure inside the closed container in the steady state. In the simulation result shown in FIG. 5, the gas circuit breaker opens at the timing of the elapsed time of −20 msec, and the alternating current reaches the zero point at the timing of 0 msec. That is, the simulation result shown in FIG. 5 is an evaluation result for a maximum arc time of 20 msec, assuming a short-distance line failure, similar to the simulation result shown in FIG.

As shown in FIG. 5, when r2 / r1 is 1.5, the pressure inside the upstream guide portion 17 continues to increase toward the timing when the alternating current reaches the zero point. On the other hand, when r2 / r1 is larger than 1.5, the increase in pressure inside the upstream guide portion 17 is suppressed toward the timing when the alternating current reaches the zero point. As a result, the puffer chamber 55 continues to blow the arc-extinguishing gas between the opposed arc contactor 32 and the movable arc contactor 61 toward the timing when the alternating current reaches the zero point, so that the recurrence of the arc discharge is suppressed. Will be done. Therefore, by setting r2 / r1 to be larger than 1.5, the dielectric strength can be improved and the current breaking performance of the gas circuit breaker 1 can be improved.

The relationship between the inner diameter r1 of the upstream guide portion 17 and the axial length x1 of the upstream guide portion 17 is not particularly limited. Even if r1 / x1 is 0.9 or less, heat gas can be discharged from between the opposed arc contactor 32 and the movable arc contactor 61. Therefore, it is possible to suppress the weakening of the spraying of the arc-extinguishing gas and improve the dielectric strength between the opposed arc contactor 32 and the movable arc contactor 61. However, as described above, by setting r1 / x1 to be larger than 0.9, a larger effect can be obtained.

Further, the relationship between the inner diameter r1 of the upstream guide portion 17 and the inner diameter r2 of the end portion of the inner cylinder 11 in the second direction is not particularly limited. Even if r2 / r1 is 1.5 or less, heat gas can be discharged from between the opposed arc contactor 32 and the movable arc contactor 61. Therefore, it is possible to suppress the weakening of the spraying of the arc-extinguishing gas and improve the dielectric strength between the opposed arc contactor 32 and the movable arc contactor 61. However, as described above, by setting r2 / r1 to be larger than 1.5, a larger effect can be obtained.

Further, in the above embodiment, the exhaust chamber 10 has an inner cylinder 11 and an outer cylinder 21. However, the exhaust chamber does not have to have the outer cylinder 21. Even with this configuration, the hot gas can be cooled and discharged from the exhaust chamber by the above-mentioned action. Therefore, it is possible to suppress the dielectric breakdown between the exhaust chamber and the closed container while reducing the size of the closed container.

Also, the arc-extinguishing gas is not limited to sulfur hexafluoride gas. According to the above embodiment, the dielectric breakdown between the exhaust chamber 10 and the closed container can be suppressed, so that even if air, carbon dioxide, oxygen, nitrogen and a mixed gas thereof are applied as the arc extinguishing gas, for example. good.

According to at least one embodiment described above, the diffuser portion on the inner peripheral surface of the inner cylinder is provided at a position in the second direction from the nozzle opening in the fully open state, and the diameter increases toward the second direction. are doing. As a result, the inner cylinder can be discharged after cooling the heat gas. Therefore, it is possible to suppress the dielectric breakdown between the exhaust chamber and the closed container while reducing the size of the closed container. Further, it is possible to promote the discharge of hot gas from between the opposed arc contactor and the movable arc contactor. Therefore, it is possible to suppress the weakening of the spraying of the arc-extinguishing gas and improve the dielectric strength between the opposed arc contactor and the movable arc contactor. As described above, it is possible to provide a miniaturized gas circuit breaker 1 having excellent current breaking performance.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

Claims

A fixed contact that is fixedly arranged with respect to the closed container in a closed container filled with an arc-extinguishing gas.
A movable contact that is arranged in the closed container and is in contact with the fixed contact in the closed pole state and is displaced in the first direction from the closed pole state to be separated from the fixed contact.
It is formed in a cylindrical shape and has a nozzle opening at the end in the second direction opposite to the first direction, and is displaced in conjunction with the movable contact, and the fixed contact and the movable contact are provided. An insulating nozzle that surrounds the arc discharge that ignites between and
A pressure accumulating portion that accumulates the arc-extinguishing gas and discharges the arc-extinguishing gas into the inside of the insulating nozzle to blow against the arc discharge.
The movable contactor surrounds the nozzle opening in a fully open state farthest from the fixed contact, and in the fully open state, the inner peripheral surface is located at a position in the second direction with respect to the nozzle opening. A first cylinder having a diffuser portion whose diameter increases in two directions, and
A gas circuit breaker equipped with.
A second cylinder having a peripheral wall portion surrounding the first cylinder and a closing portion for closing the inside of the peripheral wall portion in the second direction of the first cylinder is further provided.
The gas circuit breaker according to claim 1.
The inner peripheral surface has a guide portion extending from the nozzle opening in the second direction with a constant inner diameter in the fully open state and connecting to the diffuser portion.
The inner diameter of the guide portion is r1, and the guide portion is set to r1.
When the length of the guide portion in the second direction is x1
r1 / x1 is greater than 0.9,
The gas circuit breaker according to claim 1 or 2.
The end of the first cylinder in the second direction is formed in a cylindrical shape.
The inner peripheral surface has a guide portion extending from the nozzle opening in the second direction with a constant inner diameter in the fully open state and connecting to the diffuser portion.
The inner diameter of the guide portion is r1, and the guide portion is set to r1.
When the inner diameter of the end of the first cylinder in the second direction is r2,
r2 / r1 is greater than 1.5,
The gas circuit breaker according to any one of claims 1 to 3.