Gas circuit breaker

Abstract

A gas circuit breaker according to an embodiment of the present invention comprises a tightly-sealed container, a first arc contact and a second arc contact, an operation mechanism, and a spraying part. The first arc contact and the second arc contact are separated from each other in an open-pole state. The operation mechanism separates the first arc contact and the second arc contact. The spraying part sprays a compressed arc-extinguishing gas onto an arc discharge arcing between the first arc contact and the second arc contact in the open-pole state after transitioning from a closed-pole state to the open-pole state. An exhaust flow path that causes a space between the first arc contact and the second arc contact to communicate with an exhaust port formed at a position separated from these contacts includes an acceleration taper in which a flow path cross-sectional area of the exhaust flow path expands in an inclined shape towards the exhaust port from a position at which the first arc contact and the second arc contact are in contact in the closed-pole state. A starting point corner and an ending point corner of a flow path formation surface forming the exhaust flow path are each rounded, the starting point corner and ending point corner being positioned respectively at a starting point and an ending point of the acceleration taper.

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a gas circuit breaker. [Background technology]

[0002] Gas circuit breakers, which switch current in power systems, interrupt the current by mechanically separating contacts. When the contacts are separated during the current interruption process, an arc discharge occurs between the contacts. Gas circuit breakers extinguish this arc discharge by spraying arc-extinguishing gas onto it.

[0003] A conventional gas circuit breaker will now be described with reference to Figures 1 and 2. Figure 1 is a diagram showing the closed state of the conventional gas circuit breaker. Figure 2 is a diagram showing the state of the conventional gas circuit breaker during current interruption operation. As shown in Figure 1, a gas circuit breaker 100 comprises a movable arcing contact 101 and a fixed arcing contact 102 arranged opposite to each other. The movable arcing contact 101 is hollow. A movable current contact 103 and a fixed current contact 104 are provided outside the movable arcing contact 101 and the fixed arcing contact 102. An insulating nozzle 105 is provided between the movable arcing contact 101 and the movable current contact 103.

[0004] The movable arcing contact 101, the movable current-carrying contact 103, and the insulating nozzle 105 are all fixed to a puffer cylinder 106. An operating rod 107 is connected to one end of the puffer cylinder 106. The operating rod 107 is hollow. The puffer cylinder 106 and the operating rod 107 are connected to an operating mechanism 109 via an insulating rod 108. A puffer piston 110 is slidably housed inside the puffer cylinder 106. The puffer piston 110 is supported by a piston support 111. The puffer cylinder 106, the operating rod 107, and the puffer piston 110 form a puffer chamber 112.

[0005] Between the insulating nozzle 105 and the movable arcing contact 101, an outflow path 113 is formed, through which the arc-extinguishing gas flowing out from the puffer chamber 112 flows. Furthermore, a first discharge flow path 114 is formed in the hollow portion between the movable arcing contact 101 and the operating rod 107. An exhaust port 115 is provided on the operating mechanism side of the operating rod 107, and the first discharge flow path 114 communicates with the interior of the piston support 111 via the exhaust port 115. As shown in FIG. 2, a second discharge flow path 116 is formed inside the insulating nozzle 105 in the gas circuit breaker 100 in the open state, and the outflow path 113 communicates with the first discharge flow path 114 and the second discharge flow path 116, respectively. The gas circuit breaker 100 in the closed state does not have the second discharge flow path 116.

[0006] In the gas circuit breaker 100 described above, the fixed arcing contact 102 and the fixed current-carrying contact 104 are fixed parts, and the other parts, such as the moving arcing contact 101, the moving current-carrying contact 103, the insulating nozzle 105, the puffer cylinder 106, and the operating rod 107 are movable parts. These members are housed in a sealed container (not shown) filled with an arc-extinguishing gas.

[0007] When an opening operation is started to interrupt the current from the closed state shown in Fig. 1, the movable part moves toward the operating mechanism 109 (not shown), i.e., in the direction of arrow Y1 shown in Fig. 1, resulting in the open state shown in Fig. 2. As the movable part moves, the puffer chamber 112 is compressed, increasing the gas pressure of the arc-extinguishing gas inside the puffer chamber 112. Furthermore, by absorbing the thermal energy generated by the arc discharge E, the arc-extinguishing gas inside the puffer chamber 112 becomes highly pressurized.

[0008] The arc-extinguishing gas that has become highly pressurized in the puffer chamber 112 is ejected into the outlet path 113. The ejected arc-extinguishing gas is blown through the outlet path 113 onto the arc discharge E generated between the movable arc contact 101 and the fixed arc contact 102. The arc-extinguishing gas that has been blown onto the arc discharge E is discharged in both directions, away from the first discharge path 114 and the second discharge path 116.

[0009] The arc-extinguishing gas that has passed through the first discharge flow path 114 flows out through the exhaust port 115, into the piston support 111, and into a tank space (not shown). The arc discharge E that has been sprayed with the arc-extinguishing gas is cooled by the arc-extinguishing gas and is extinguished. When the arc discharge E is extinguished, the current interruption is completed.

[0010] In the gas circuit breaker described above, it is important to sufficiently cool the arc discharge E during thermally demanding operations such as when interrupting a large current. However, although it is empirically known that performance improves by increasing the pressure in the puffer chamber 112 (hereinafter referred to as the puffer chamber pressure), the temperature of the arc-extinguishing gas blown onto the arc changes depending on how the thermal energy of the arc is absorbed. Therefore, there are cases where the puffer chamber pressure and the thermal interruption performance are not necessarily proportional. For this reason, in conventional gas circuit breakers, the thermal interruption performance has been ensured by increasing the puffer chamber pressure more than necessary.

[0011] Gas circuit breakers are becoming smaller in size to reduce installation space and costs. However, increasing the puffer chamber pressure requires an increase in the driving force of the operating mechanism and the weight of the components, which leads to larger equipment and higher costs, making it difficult to meet the social demand for such miniaturization. Furthermore, there is also the issue that, after multiple current interruptions, the insulating nozzle 105 wears out, increasing the flow rate of the second discharge flow path 116, making it impossible to obtain the desired puffer chamber pressure.

[0012] To address these issues, recent research has revealed that thermal blocking performance is significantly affected by the flow in the flow path provided inside the contact, i.e., the flow in the first discharge flow path 114 in Fig. 1, and that performance improves when the flow is as fast as possible. Therefore, a method has been proposed in which the shape of the moving arcing contact is made appropriate as a method for increasing the speed of the flow in the first discharge flow path 114 (see Patent Document 1).

[0013] Fig. 3 is a cross-sectional view of the main part of a conventional gas circuit breaker with an appropriate shape for the moving arc contact. In the gas circuit breaker 120 shown in Fig. 3, the distance L1 between the stagnation point 121 and the minimum cross-sectional area part 123 of the tulip contact 122 is shortened from 5 mm to 20 mm, which reduces pressure loss and forms a steep pressure distribution, thereby producing a high-speed flow.

[0014] Furthermore, it has been proposed that the slit width of the tulip contact 122 be set to 0.6 to 1.0 mm or less to minimize gas leakage from the tulip contact 122 and increase the speed of the flow in the inner flow path of the tulip contact 122. However, the above-mentioned Patent Document 1 does not mention the internal structure of the tulip contact 122, making it unclear.

[0015] For this reason, even if the pressure distribution between the stagnation point 121 and the minimum cross-sectional area portion 123 of the tulip contact 122 is made steeper or gas leakage from the tulip contact 122 is reduced, if the shape of the inside of the tulip contact 122 is not appropriate, shock waves and separation will occur, making it impossible to form a high-speed flow in the flow path inside the tulip contact 122. Therefore, it is difficult to improve the thermal insulation performance. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] European Patent Application Publication No. 3576125 Summary of the Invention [Problem to be solved by the invention]

[0017] The problem to be solved by the present invention is to provide a gas circuit breaker that achieves high thermal interruption performance. [Means for solving the problem]

[0018] A gas circuit breaker according to an embodiment includes a sealed container, a first arcing contact and a second arcing contact, an operating mechanism, and a spray unit. The sealed container is filled with an arc-extinguishing gas. The first arcing contact and the second arcing contact are provided within the sealed container so as to be movable toward and away from each other, and contact each other in a closed state and separate from each other in an open state. The operating mechanism separates the first arcing contact and the second arcing contact from the closed state to the open state. The spray unit sprays the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open state after transitioning from the closed state to the open state. An exhaust flow path is formed, communicating between the first arcing contact and the second arcing contact in the open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact. The exhaust flow path includes an acceleration taper in which a cross-sectional area of ​​the flow path increases in an inclined manner from a position where the first arcing contact and the second arcing contact are in contact toward the exhaust port in the closed state, and start and end corners of a flow path forming surface that forms the exhaust flow path, located at the start and end points of the acceleration taper, are rounded, respectively. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 10 is a cross-sectional view showing a conventional gas circuit breaker in a closed state. [Figure 2] FIG. 10 is a cross-sectional view showing a state during a current interruption operation of a conventional gas circuit breaker. [Figure 3] FIG. 10 is a cross-sectional view of a main part of another conventional gas circuit breaker. [Figure 4] 1 is a cross-sectional view of a gas circuit breaker 1 according to a first embodiment. [Figure 5] FIG. 2 is a cross-sectional view of the movable arcing contact 11 of the first embodiment. [Figure 6] FIG. 4 is a cross-sectional view of a movable arcing contact 50 according to a second embodiment. [Figure 7] FIG. 4 is a front view of a movable arcing contact 50 according to a second embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a movable arcing contact 60 according to a third embodiment. [Figure 9]FIG. 13 is a front view of a movable arcing contact 60 according to an eighth embodiment of the third embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a movable arcing contact 70 according to a fourth embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a movable arcing contact 80 according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a gas circuit breaker according to an embodiment will be described with reference to the drawings.

[0021] (First embodiment) First, a first embodiment will be described. Fig. 4 is a cross-sectional view of a gas circuit breaker 1 of the first embodiment. The gas circuit breaker 1 of the first embodiment includes, for example, a movable arcing contact 11, a fixed arcing contact 12, a movable current-carrying contact 13, a fixed current-carrying contact 14, an insulating nozzle 15, a puffer cylinder 16, an operating rod 17, an operating mechanism 19, a puffer piston 20, and a piston support 21. Each of these elements is housed in a sealed container 30 filled with an arc-extinguishing gas. Note that, for ease of explanation, the members housed in the sealed container 30 are depicted enlarged in Fig. 4.

[0022] The movable arc contact 11, the fixed arc contact 12, the movable current contact 13, the fixed current contact 14, the insulating nozzle 15, the puffer cylinder 16, the operating rod 17, the puffer piston 20, and the piston support 21 all have the shape of a rotating body rotated around the rotation axis X.

[0023] The movable arcing contact 11 is a hollow columnar body, and the fixed arcing contact 12 is a solid columnar body. The movable arcing contact 11 and the fixed arcing contact 12 are arranged coaxially. Both the movable arcing contact 11 and the fixed arcing contact 12 are conductors. In the following explanation, the side of the movable arcing contact 11 where the fixed arcing contact 12 is provided is referred to as the tip side, and the side opposite to the tip side is referred to as the rear side.

[0024] An opening (hereinafter referred to as a tip opening) having substantially the same shape as the cross-sectional shape of the fixed arc contact 12 is formed at the end on the tip side of the movable arc contact 11. The movable arc contact 11 and the fixed arc contact 12 are provided so as to be able to come into contact with and separate from each other within the sealed container 30 when the movable arc contact 11 moves in a predetermined direction, for example, in the axial direction of the operating rod 17. The movable arc contact 11 and the fixed arc contact 12 come into contact with each other in a closed state and separate from each other in an open state. The movable arc contact 11 is an example of a first arc contact. The fixed arc contact 12 is an example of a second arc contact.

[0025] The movable current contactor 13 and the fixed current contactor 14 are both cylindrical conductors. The movable current contactor 13 is arranged so as to cover the periphery of the movable arc contactor 11. The fixed current contactor 14 is arranged so as to cover the periphery of the fixed arc contactor 12. The movable current contactor 13 is separated from the movable arc contactor 11, and a gap is formed between the movable arc contactor 11 and the movable current contactor 13. The outer diameter of the movable current contactor 13 is approximately the same as the inner diameter of the fixed current contactor 14. The movable current contactor 13 and the fixed current contactor 14 are arranged so as to be able to come into contact with and separate from each other within the sealed container 30 by movement of the movable current contactor 13 in a predetermined direction.

[0026] The insulating nozzle 15 is formed in a cylindrical shape. The insulating nozzle 15 covers the periphery of the tip end of the movable arcing contact 11 and further to the tip end thereof. The insulating nozzle 15 operates together with the movable arcing contact 11. The insulating nozzle 15 surrounds the arc discharge that occurs between the movable arcing contact 11 and the fixed arcing contact 12 in the open state (hereinafter referred to as the arc discharge generation position).

[0027] The puffer cylinder 16 is a cylindrical body with a larger diameter than the movable arcing contact 11. The puffer cylinder 16 is arranged on the rear end side of the movable arcing contact 11. A small diameter opening is formed on the front end side of the puffer cylinder 16, and a large diameter opening is formed on the rear end side. An insulating nozzle 15 is attached to the front end of the puffer cylinder 16.

[0028] The operating rod 17 is a conductor provided inside the puffer cylinder 16. The front part of the operating rod 17 is cylindrical and has approximately the same diameter as the movable arcing contact 11, and is connected to the rear end side of the movable arcing contact 11 coaxially with the movable arcing contact 11. The operating rod 17 is fixed to the puffer cylinder 16. A hole 18 is formed around the operating rod 17 at the front end of the puffer cylinder 16. The rear part of the operating rod 17 is plate-shaped. In FIG. 4, part of the rear part of the operating rod 17 is not shown.

[0029] The operating mechanism 19 includes, for example, a power source such as a motor and a link mechanism. The operating mechanism 19 is connected to the rear of the operating rod 17. The operating mechanism 19 operates the operating rod 17 in its axial direction. When the operating mechanism 19 operates the operating rod 17, the movable arcing contact 11, the puffer cylinder 16, the insulating nozzle 15, and the movable current-carrying contact 13 (hereinafter referred to as the movable part 40) move in the same direction. When the operating mechanism 19 operates the movable part 40, the operating mechanism 19 separates the movable arcing contact 11 and the fixed arcing contact 12 from a closed state to an open state.

[0030] The puffer piston 20 is a disk-shaped member with an opening formed in the center. The puffer piston 20 closes the rear end opening of the puffer cylinder 16. The diameter of the opening formed in the center of the puffer piston 20 is approximately the same as the outer diameter of the operating rod 17. The operating rod 17 moves in the axial direction through the opening formed in the puffer piston 20.

[0031] The piston support 21 is provided on the rear end side of the puffer piston 20. The piston support 21 supports the puffer piston 20. The puffer piston 20 is supported by the piston support 21 and thereby fixed.

[0032] A puffer chamber 22 is formed in an area surrounded by the puffer cylinder 16, the operating rod 17, and the puffer piston 20. Since the sealed container 30 is filled with an arc-extinguishing gas, the puffer chamber 22 is also filled with the arc-extinguishing gas. When the movable part 40 operates to separate the contacts from the closed state to the open state, the volume of the puffer chamber 22 decreases, and the arc-extinguishing gas in the puffer chamber 22 accumulates pressure.

[0033] A hole 18 formed in the puffer cylinder 16 communicates with the gap between the movable arcing contact 11 and the insulating nozzle 15. The gap between the movable arcing contact 11 and the insulating nozzle 15 serves as an outflow path 23 through which the arc-extinguishing gas in the puffer chamber 22 flows out when the volume of the puffer chamber 22 decreases.

[0034] The discharge portion of the arc-extinguishing gas in the outflow path 23 is located at the arc discharge generation position in the open-contact state. When the open-contact state is reached, the arc-extinguishing gas in the puffer chamber 22 is pressurized and discharged through the outlet of the outflow path 23. An arc discharge occurs at the arc discharge generation position when the open-contact state is reached. The outflow path 23 sprays the arc-extinguishing gas toward the arc discharge after the transition from the closed-contact state to the open-contact state. The puffer chamber 22 and the outflow path 23 are examples of a spray portion.

[0035] The hollow portions of the movable arcing contact 11 and operating rod 17 in the open state communicate with the tip opening of the movable arcing contact 11. The hollow portions of the movable arcing contact 11 and the front part of the operating rod 17 form a first exhaust flow path 24. An exhaust port 25 is provided at the rear end of the front part of the operating rod 17.

[0036] The first exhaust flow path 24 is a cylindrical flow path. The first exhaust flow path 24 communicates the arc discharge position in the open contact state with the exhaust port 25. Hot gas generated when the arc-extinguishing gas discharged from the outlet path 23 is blown onto the arc discharge flows through the first exhaust flow path 24. Due to the provision of the exhaust port 25, a portion of the generated hot gas flows into the first exhaust flow path 24 through the tip opening and is discharged from the exhaust port 25.

[0037] A gap is formed between the fixed arcing contact 12 in the open state and the insulating nozzle 15. The gap between the fixed arcing contact 12 and the insulating nozzle 15 serves as a second exhaust flow path. The side of the second exhaust flow path opposite to the movable arcing contact 11 side is open. Therefore, part of the hot gas generated at the arc discharge position in the open state flows into the second exhaust flow path and is exhausted from the side of the second exhaust flow path opposite to the movable arcing contact 11 side.

[0038] Next, the movable arcing contact 11 will be described in detail. Fig. 5 is a cross-sectional view of the movable arcing contact 11 of the first embodiment. The inner wall surface of the movable arcing contact 11 includes a front straight portion 41, a tapered portion 42, and a rear straight portion 43. A first curved portion 44 is formed between the front straight portion 41 and the tapered portion 42, and a second curved portion 45 is formed between the tapered portion 42 and the rear straight portion 43.

[0039] The front straight portion 41 and the rear straight portion 43 are both formed parallel to the rotation axis X of the movable arcing contact 11. The tapered portion 42 is formed as an acceleration taper 24T with a slope such that the portion of the first discharge flow path 24 surrounded by the tapered portion 42 has a flow path cross-sectional area that increases in an inclined manner from the position where the movable arcing contact 11 and the fixed arcing contact 12 contact each other toward the exhaust port 25 in a closed state. In other words, the acceleration taper 24T has a shape that increases in an inclined manner from upstream to downstream. The inner wall surface of the movable arcing contact 11 is an example of a flow path forming surface.

[0040] The first curved portion 44 is located at the start point of the acceleration taper 24T, and the second curved portion 45 is located at the end point of the acceleration taper 24T. The first curved portion 44 is an example of a start point corner. The second curved portion 45 is an example of an end point corner. Both the first curved portion 44 and the second curved portion 45 are rounded by being curved. Only one of the first curved portion 44 and the second curved portion 45 may be provided.

[0041] The cross-sectional area of ​​the movable arc contact 11 at a position corresponding to the front straight portion 41 (hereinafter referred to as the first cross-sectional area) is the minimum cross-sectional area of ​​the first discharge flow path 24. The first cross-sectional area D* and the cross-sectional area of ​​the rear straight portion 43 (hereinafter referred to as the second cross-sectional area) De are in a relationship that satisfies the following formula (1). Note that the cross section at the position corresponding to the rear straight portion 43 and the cross section of the operating rod 17 have the same shape, and therefore the second cross-sectional area De and the cross-sectional area of ​​the operating rod 17 are the same. De / D*<13.2 (1)

[0042] The divergence angle α of the tapered portion 42 satisfies the following formula (2). α<34.4° (2) The divergence angle α of the tapered portion 42 is expressed as the angle formed between the tapered portion 42 and the rotation axis X, for example.

[0043] Furthermore, the first curvature radius R1 of the first curved portion 44 satisfies the following formula (3), and the second curvature radius R2 of the second curved portion 45 satisfies the following formula (4). R1>(D* / π) 1 / 2 ···(3) R2>R1 (4)

[0044] Next, the operation of the gas circuit breaker 1 of the first embodiment will be described, focusing on the operation of the movable arcing contact 11. When there is a sufficient difference between the pressure in the puffer chamber 22 and the filling pressure in the sealed container 30, the arc discharge chokes at the minimum cross-sectional area portion of the first discharge flow path 24. In a typical gas circuit breaker, the pressure ratio between the pressure in the puffer chamber 22 and the filling pressure in the sealed container 30 when interrupting a large current is approximately 10. This pressure ratio is sufficient to choke the arc discharge. Therefore, by providing the acceleration taper 24T surrounded by the tapered portion 42 in the first discharge flow path 24, the portion downstream of the minimum cross-sectional area portion of the first discharge flow path 24 becomes a supersonic flow, and a high-speed flow can be formed.

[0045] However, if the acceleration taper 24T is not configured appropriately, there is a concern that the flow velocity may rapidly decrease due to the generation of normal shock waves due to over-expansion in the first exhaust flow path 24, or the generation of oblique shock waves due to flow separation or changes in the cross-sectional area of ​​the flow path. Therefore, in order to prevent the generation of normal shock waves due to over-expansion, for example, the following configuration may be adopted.

[0046] In the acceleration of a supersonic flow by expansion using a pressure difference and the acceleration taper 24T as in the first embodiment, a normal shock wave occurs if the relationship between the pressure ratio and the flow path cross-sectional area ratio is not appropriate. Generally, the relationship of the following equation (5) holds between the pressure Pw at the position where the normal shock wave occurs and the pressure P0 in the puffer chamber, and between the flow path cross-sectional area Dw at the position where the normal shock wave occurs and the first cross-sectional area (=minimum cross-sectional area) D* of the first discharge flow path 24.

number

[0047] From the above formula (5), it can be seen that for general gases (specific heat ratios of 1.0 to 1.7), when the flow path cross-sectional area ratio Dw / D* is approximately 1.2 or more, the pressure ratio Pw / P0 monotonically decreases with the flow path cross-sectional area ratio Dw / D*. Therefore, in the gas circuit breaker 1 of the first embodiment, the flow path cross-sectional area ratio Dw / D* is set so that the pressure ratio Pw / P0 does not fall below the ratio of the filling pressure of the sealed container 30 to the pressure P0 of the puffer chamber 22.

[0048] As described above, the ratio of the pressure in the puffer chamber 22 to the filling pressure in the sealed container 30 when a large current is interrupted is approximately 10. In addition, the specific heat ratio of the arc-extinguishing gas generally used in gas circuit breakers is 1.4. Under these conditions, the generation of normal shock waves can be prevented by setting the ratio De / D* of the first cross-sectional area D* to the second cross-sectional area De to be less than 13.2.

[0049] Next, we will explain the configuration for preventing flow separation. Flow separation is a phenomenon in which, when a flow expands, it cannot resist the pressure difference between the pressure drop due to expansion and the filling pressure, causing a backflow in the slow-flowing portion. Here, when accelerating expansion using the acceleration taper 24T, if the divergence angle of the acceleration taper 24T is too large, the hot gas will not be able to expand completely, resulting in a region where no flow occurs near the wall. Therefore, by limiting the divergence angle of the acceleration taper 24T, the generation of a region where no hot gas flows near the wall, which causes separation, is suppressed.

[0050] In general, the relationship between the maximum allowable nozzle divergence angle αmax and the Mach number after divergence can be expressed by the following equation (6) using the Prandtl-Meyer function ν.

number

[0051] Equation (6) above shows that as the Mach number increases, the maximum allowable divergence angle also increases. If the flow passage cross-sectional area ratio Dw / D* is set to 13.2 as mentioned above, the specific heat ratio is 1.4, the Mach number is 4.24, and the Prandtl-Meyer function ν is 68.8°. Therefore, the maximum allowable divergence angle αmax of the nozzle is 34.4°. Therefore, by setting the divergence angle α of the acceleration taper 24T to less than 34.4°, separation can be prevented.

[0052] Furthermore, if the flow path is widened without providing a curvature at the start point of the acceleration taper 24T, a boundary layer rapidly develops along the inner wall surface, making flow separation more likely to occur. To address this separation, in the gas circuit breaker 1 of the first embodiment, as shown in the above formula (3), the first radius of curvature R1 of the first curved portion 44 located at the start point of the acceleration taper 24T on the inner wall surface of the moving arcing contact 11 is made to exceed the radius of the minimum cross-sectional area of ​​the first discharge flow path 24. Making the first radius of curvature R1 exceed the radius of the minimum cross-sectional area of ​​the first discharge flow path 24 contributes to suppressing this type of flow separation.

[0053] At the start and end points of the acceleration taper 24T in the movable arcing contact 11, i.e., at the first curved portion 44 and the second curved portion 45, the flow direction changes, generating an expansion wave and a compression wave, respectively. Of these, the compression waves generated at the second curved portion 45 overlap each other to generate an oblique shock wave, which reduces the velocity of the hot gas in the first discharge flow path 24.

[0054] To cope with such a decrease in velocity of the hot gas, in the gas circuit breaker 1 of the first embodiment, the second curvature radius R2 is made larger than the first curvature radius R1 as shown in the above formula (4). The reason why the second curvature radius R2 is made larger than the first curvature radius R1 will be explained below.

[0055] The compression wave generated at the end of the acceleration taper 24T can be canceled out by appropriately utilizing the expansion wave generated at the start of the acceleration taper 24T. To utilize the expansion wave generated at the start of the acceleration taper 24T, the deflection angle of the flow when the expansion wave is generated must be the same as the deflection angle of the wall at the end of the acceleration taper 24T where the expansion wave arrives.

[0056] By setting the deflection angle of the flow when the expansion wave is generated to be the same as the deflection angle of the wall at the end of the acceleration taper 24T where the expansion wave arrives, the compression wave generated at the end of the acceleration taper 24T and the expansion wave that arrives cancel each other out, resulting in a flow where no compression wave is generated from the end. Also, due to interference between the expansion waves, the expansion wave generated at the start of the acceleration taper 24T enters the wall at the end of the acceleration taper 24T at a shallower angle than when it was generated.

[0057] For this reason, the deflection angle of the wall surface at the end point of the acceleration taper 24T needs to be gentler than that at the start point of the acceleration taper 24T. Therefore, as shown in the above formula (3), the second radius of curvature R2 located at the end point of the acceleration taper 24T is made larger than the first radius of curvature R1 located at the start point of the acceleration taper 24T.

[0058] In the movable arcing contact 11 of the gas circuit breaker 1 of the first embodiment, the tip straight portion 41 is provided and a portion where the minimum cross-sectional area D* is constant is set, but the tip straight portion 41 does not have to be provided. Also, in the movable arcing contact 11, the acceleration taper 24T is provided only in the portion of the movable arcing contact 11, but the acceleration taper 24T may reach the portion of the operating rod 17.

[0059] According to the gas circuit breaker 1 of the first embodiment, a high-speed flow can be realized without normal shock waves, separation, or oblique shock waves throughout the entire first discharge flow path 24. Therefore, it is possible to provide a gas circuit breaker having high thermal insulation performance without increasing the pressure in the puffer chamber 22 more than necessary.

[0060] (Second embodiment) Next, a second embodiment will be described. Gas circuit breakers of the second to fifth embodiments described below differ from the gas circuit breaker 1 of the first embodiment mainly in the configuration of the movable arc contactor, and other configurations are similar to the gas circuit breaker 1 of the first embodiment. In the following explanation of the second to fifth embodiments, the gas circuit breaker of the second embodiment will be described, focusing on the differences from the first embodiment.

[0061] Fig. 6 is a cross-sectional view of a movable arcing contactor 50 of the second embodiment. Fig. 7 is a front view of the movable arcing contactor 50 of the second embodiment. Like the movable arcing contactor 11 of the first embodiment, the movable arcing contactor 50 of the second embodiment comprises a front straight portion 51, a tapered portion 52, a rear straight portion 53, a first curved portion 54, and a second curved portion 55. The movable arcing contactor 50 of the second embodiment further comprises a plurality of, for example, four, protrusions 56. The protrusions 56 are an example of concave and convex portions.

[0062] All four protrusions 56 are arranged at positions spanning between the second curved portion 55 and the rear end straight portion 53. All four protrusions 56 are arranged evenly in the circumferential direction of the movable arcing contact 50 at a common cross-sectional portion of the movable arcing contact 50 that is at the same position relative to the flow direction of the hot gas.

[0063] The four protrusions 56 have the same shape. In the movable arcing contact 50, the portion surrounded by the tapered portion 52 excluding the protrusions 56 is formed as the acceleration taper 24T. Therefore, the protrusions 56 are formed so as to protrude from the inner wall surface of the movable arcing contact 50 toward the acceleration taper 24T. There are.

[0064] Next, the operation of the gas circuit breaker of the second embodiment will be described, focusing on the operation of the movable arcing contact 50. Flow separation is thought to be a factor that causes a decrease in flow velocity in the first discharge flow path 24. Flow separation occurs because the viscosity of the gas reduces the flow velocity in the immediate vicinity of the wall surface. Therefore, separation can be suppressed by maintaining the flow velocity by making the flow in the vicinity of the wall surface turbulent.

[0065] The protrusions 56 provided on the movable arcing contact 50 can intentionally disturb the flow of hot gas near the inner wall surface of the first exhaust flow path 24, creating a turbulent flow. Creating a turbulent flow in the first exhaust flow path 24 can suppress flow separation, contributing to the formation of a high-speed flow without flow separation throughout the entire first exhaust flow path 24.

[0066] The above effects are the same as those of the first embodiment, but in the second embodiment, by making the flow near the inner wall surface of the movable arc contact 50 a turbulent flow, even if a region with a slow flow velocity occurs locally near the wall surface in the first discharge flow path 24 due to some factor, a flow without separation can be formed throughout the first discharge flow path 24, thereby achieving even greater effects.

[0067] In the second embodiment, the movable arcing contact 50 has four protrusions 56 evenly spaced in the circumferential direction. However, the number and arrangement of the protrusions 56 are not limited as long as they are effective in suppressing flow separation. In the second embodiment, the movable arcing contact 50 has four protrusions 56 arranged in a single row at the same position relative to the flow direction of the hot gas. However, the protrusions 56 may be arranged in different positions relative to the flow direction of the hot gas, or in multiple rows, as long as they are effective in suppressing flow separation. The shape of the protrusions 56 may be any shape that is effective in suppressing flow separation. The protrusions 56 may be located in a position other than a position straddling the second curved portion 55 and the rear straight portion 53. For example, the protrusions 56 may be located in either the second curved portion 55 or the rear straight portion 53, or in any one of the front straight portion 51, the tapered portion 52, and the first curved portion 54, or in a position straddling these.

[0068] (Third embodiment) Next, a third embodiment will be described. Fig. 8 is a cross-sectional view of a movable arcing contactor 60 of the third embodiment. Fig. 9 is a front view of a movable arcing contactor 60 of an eighth embodiment of the third embodiment. The movable arcing contactor 60 of the third embodiment has a leading straight portion 61, a tapered portion 62, a trailing straight portion 63, a first curved portion 64, and a second curved portion 65, similar to the movable arcing contactor 11 of the first embodiment. In the movable arcing contactor 60 of the third embodiment, a plurality of, for example, four recesses 66 are further formed on the inner wall surface of the movable arcing contactor 50. The recesses 66 are an example of irregularities.

[0069] All four recesses 66 are formed in the second curved portion 65. All four recesses 66 are arranged evenly in the circumferential direction of the movable arcing contact 60 in a common cross-sectional portion of the movable arcing contact 60 (the same position in the direction of hot gas flow). All four recesses 66 have the same shape. In the movable arcing contact 60, the portion surrounded by the tapered section 52 in which no recesses 66 are formed is formed as the acceleration taper 24T. Therefore, the recesses 66 are formed so as to be recessed from the acceleration taper 24T into the inner wall surface of the movable arcing contact 60. There are.

[0070] Next, the operation of the gas circuit breaker of the third embodiment will be described, focusing on the operation of the movable arcing contact 60. As with the gas circuit breaker of the second embodiment, the gas circuit breaker of the third embodiment can suppress separation by making the flow in the vicinity of the wall surface of the movable arcing contact 60 a turbulent flow and maintaining the flow velocity.

[0071] In the gas circuit breaker of the third embodiment, the recess 66 provided in the movable arcing contact 60 is formed, and therefore, the same effects as those of the second embodiment can be obtained.

[0072] In the third embodiment, the movable arcing contact 60 has four dimples 66 evenly arranged in the circumferential direction. However, the number and arrangement of the dimples 66 are not limited as long as they are effective in suppressing flow separation. In the third embodiment, the movable arcing contact 60 has four dimples 66 arranged in a single row at the same position relative to the flow direction of the hot gas. However, as long as they are effective in suppressing flow separation, they may be arranged in different positions relative to the flow direction of the hot gas, or in multiple rows. The dimples 66 may have any shape as long as they are effective in suppressing flow separation. The dimples 66 may be formed in a position other than the second curved portion 65. For example, the dimples may be formed in the leading straight portion 61, the tapered portion 62, the trailing straight portion 63, or the first curved portion 64, or in a position spanning these.

[0073] (Fourth embodiment) Next, a fourth embodiment will be described. 10 is a cross-sectional view of a movable arcing contactor 70 of the fourth embodiment. The movable arcing contactor 70 of the fourth embodiment has a leading straight portion 71 and a trailing straight portion 73, similar to the movable arcing contactor 11 of the first embodiment. The movable arcing contactor 70 of the fourth embodiment has a stepped widening portion 72 instead of the tapered portion 42 of the movable arcing contactor 11 of the first embodiment.

[0074] The stepped widening portion 72 has a structure in which the tapered portion 42 in the first embodiment is widened in a stepped manner. More specifically, the stepped widening portion 72 is formed as an acceleration widening portion 24H in which the portion of the first discharge flow path 24 surrounded by the stepped widening portion 72 has a flow path cross-sectional area that widens in a stepped manner from the position where the movable arc contact 11 and the fixed arc contact 12 contact each other in the closed state toward the exhaust port 25. In other words, the acceleration widening portion 24H has a shape in which the acceleration taper 24T in the first embodiment is widened in a stepped manner, and widens in a stepped manner from upstream to downstream.

[0075] Next, the operation of the gas circuit breaker of the fourth embodiment will be described, focusing on the operation of the movable arc contact 70. The gas circuit breaker of the fourth embodiment is formed with an acceleration widening portion 24H, which is a stepped widening of the acceleration taper 24T of the first embodiment. By forming the acceleration widening portion 24H, it is possible to intentionally generate a weak oblique shock wave in the first discharge flow path 24. As a result, it is possible to suppress a significant decrease in the flow velocity of the hot gas due to flow separation.

[0076] In the gas circuit breaker of the fourth embodiment, the acceleration widening portion 24H is formed, thereby realizing a high-speed flow without a significant decrease in flow velocity due to separation in the first discharge flow path 24. Therefore, the gas circuit breaker of the fourth embodiment can contribute to improving the thermal breaking performance.

[0077] In the gas circuit breaker of the fourth embodiment, the stepped widening portion 72 has a plurality of steps, but the number and arrangement of the steps are not limited as long as they are effective in generating weak oblique shock waves. Furthermore, the height of the steps in the stepped widening portion 72 is also not limited as long as they are effective in generating weak oblique shock waves. Furthermore, the leading end and the trailing end of the stepped widening portion 72 may be provided with a first curved portion and a second curved portion similar to those in the first embodiment, or only one of these may be provided.

[0078] (Fifth embodiment) Next, a fifth embodiment will be described. FIG. 11 is a cross-sectional view of a movable arcing contact 80 of the fifth embodiment. Similar to the movable arcing contactor 11 of the first embodiment, the movable arcing contactor 80 of the fifth embodiment includes a front straight portion 81, a tapered portion 82, a rear straight portion 83, a first curved portion 84, and a second curved portion 85. The movable arcing contactor 80 of the fifth embodiment further includes an insulating member 86. The insulating member 86 is a cylindrical member made of an insulator.

[0079] The insulating member 86 is arranged on at least a part of the inner wall surface of the movable arcing contact 80 closer to the exhaust port 25 than between the movable arcing contact 11 and the fixed arcing contact 12 in the open state, and in the fifth embodiment, from the second curved portion 85 of the movable arcing contact 80 to the operating rod 17. Compared to the gas circuit breaker 1 of the first embodiment, recesses for fitting the insulating member 86 are formed on the inner wall surfaces of the movable arcing contact 80 and the operating rod 17. In the gas circuit breaker of the fifth embodiment, the insulating member 86 and the inner wall surfaces of the movable arcing contact 80 and the operating rod 17 are formed flush with each other.

[0080] Next, the operation of the gas circuit breaker of the fifth embodiment will be described, focusing on the operation of the movable arc contact 80. When the flow of arc-extinguishing gas in the first discharge flow path 24 pushes the portion of the arc discharge E that is attached to the contact (movable arc contact 80) downstream of the first discharge flow path 24, the arc discharge E may reach an area where the flow velocity is reduced. In this case, the arc-extinguishing gas cannot be blown at the arc discharge E at high speed, which may result in a decrease in interruption performance. In this regard, the gas circuit breaker of the fifth embodiment is provided with an insulating member 86. The portion of the arc discharge E that is attached to the contact cannot proceed downstream from the position where the flow path surface becomes an insulator, so the provision of the insulating member 86 makes it possible to blow the arc-extinguishing gas at high speed at the arc discharge E.

[0081] In the gas circuit breaker of the fifth embodiment, the insulating member 86 is provided on the inner wall surface of the movable arcing contact 80, which makes it possible to spray high-speed gas onto the arc discharge E. Therefore, the gas circuit breaker of the fifth embodiment can further improve the thermal interruption performance.

[0082] In the gas circuit breaker of the fifth embodiment, the insulating member 86 is disposed at the end point of the acceleration taper 24T, i.e., at the second curved portion 85, but the position of the insulating member 86 is not limited as long as it is possible to spray high-velocity gas to the arc discharge E. Furthermore, the insulating member 86 may be provided only on the movable arc contact 80 or only on the operating rod 17.

[0083] In the above embodiment, the first arcing contact is the movable arcing contact 11 and the second arcing contact is the fixed arcing contact 12, but the first arcing contact may be the fixed arcing contact 12 and the second arcing contact may be the movable arcing contact 11. In this case, for example, the shapes of the movable arcing contact 11 and the fixed arcing contact 12 may be interchanged so that the exhaust port 25 is formed at the front end of the fixed arcing contact 12.

[0084] According to at least one embodiment described above, a gas circuit breaker is provided, which includes: a sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be able to come into contact with each other and to be separated from each other in an open state; an operation mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; and a blowing unit that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open state after transitioning from the closed state to the open state. In the device, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open contact state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact, and the exhaust flow path includes an acceleration taper in which the cross-sectional area of ​​the flow path increases in an inclined manner from the position where the first arcing contact and the second arcing contact come into contact in the closed contact state toward the exhaust port, and the start point corners and end point corners of the flow path forming surface that form the exhaust flow path, located at the start point and end point of the acceleration taper, are rounded, thereby achieving high thermal insulation performance.

[0085] Although several 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 forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0086] 1...gas circuit breaker, 11, 50, 60, 70, 80...movable arc contact, 12...fixed arc contact, 13...movable current-carrying contact, 14...fixed current-carrying contact, 15...insulating nozzle, 16...puffer cylinder, 17...operating rod, 18...hole portion, 19...operating mechanism, 20...puffer piston, 22...puffer chamber, 23...outflow path, 24...first discharge path, 24H...accelerated expansion Width portion, 24T...acceleration taper, 25...exhaust port, 30...sealed container, 40...movable portion, 41,51,61,71,81...front straight portion, 42,52,62,82...tapered portion, 43,53,63,73,83...rear straight portion, 44,54,64,84...first curved portion, 45,55,65,85...second curved portion, 56...projection, 72...step-like widening portion, 86...insulating member

Claims

1. a sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be capable of coming into contact with each other and being separated from each other in an open-contact state; an operating mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; a blowing section that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open contact state after transition from the closed contact state to the open contact state, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact; the exhaust flow path includes an acceleration taper whose flow path cross-sectional area increases in an inclined manner from a position where the first arcing contact and the second arcing contact are in contact with each other in the closed state toward the exhaust port, a start point corner and an end point corner of a flow path forming surface that forms the exhaust flow path and are located at a start point and an end point of the acceleration taper are rounded, respectively; The radius of curvature of the starting corner is larger than the radius of the smallest cross-sectional area portion of the exhaust flow path, and the radius of curvature of the ending corner is larger than the radius of curvature of the starting corner. Gas circuit breaker.

2. A sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be capable of coming into contact with each other and being separated from each other in an open-contact state; an operating mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; a blowing section that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open contact state after transition from the closed contact state to the open contact state, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact; the exhaust flow path includes an acceleration taper whose flow path cross-sectional area increases in an inclined manner from a position where the first arcing contact and the second arcing contact are in contact with each other in the closed state toward the exhaust port, a start point corner and an end point corner of a flow path forming surface that forms the exhaust flow path and are located at a start point and an end point of the acceleration taper are rounded, respectively; The cross-sectional area ratio of the start point corner portion to the end point corner portion is less than 13.

2. Gas circuit breaker.

3. A sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be capable of coming into contact with each other and being separated from each other in an open-contact state; an operating mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; a blowing section that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open contact state after transition from the closed contact state to the open contact state, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact; the exhaust flow path includes an acceleration taper whose flow path cross-sectional area increases in an inclined manner from a position where the first arcing contact and the second arcing contact are in contact with each other in the closed state toward the exhaust port, a start point corner and an end point corner of a flow path forming surface that forms the exhaust flow path and are located at a start point and an end point of the acceleration taper are rounded, respectively; The divergence angle of the acceleration taper is less than 34.4°. Gas circuit breaker.

4. A sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be capable of coming into contact with each other and being separated from each other in an open-contact state; an operating mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; a blowing section that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open contact state after transition from the closed contact state to the open contact state, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact; the exhaust flow path includes an acceleration taper whose flow path cross-sectional area increases in an inclined manner from a position where the first arcing contact and the second arcing contact are in contact with each other in the closed state toward the exhaust port, a start point corner and an end point corner of a flow path forming surface that forms the exhaust flow path and are located at a start point and an end point of the acceleration taper are rounded, respectively; The flow path forming surface is formed with irregularities. Gas circuit breaker.

5. A sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be capable of coming into contact with each other and being separated from each other in an open-contact state; an operating mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; a blowing section that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open contact state after transition from the closed contact state to the open contact state, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact; the exhaust flow path includes an acceleration taper whose flow path cross-sectional area increases in an inclined manner from a position where the first arcing contact and the second arcing contact are in contact with each other in the closed state toward the exhaust port, a start point corner and an end point corner of a flow path forming surface that forms the exhaust flow path and are located at a start point and an end point of the acceleration taper are rounded, respectively; an insulating member is disposed on at least a portion of a flow path forming surface that forms the exhaust flow path, on the exhaust port side, relative to a portion between the first arcing contact and the second arcing contact in an open state; Gas circuit breaker.

6. a sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be capable of coming into contact with each other and being separated from each other in an open-contact state; an operating mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; a blowing section that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open contact state after transition from the closed contact state to the open contact state, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact; the exhaust flow path includes an acceleration widening section in which a flow path cross-sectional area expands in a stepped manner with a plurality of successive steps from a position where the first arcing contact and the second arcing contact are in contact with each other toward the exhaust port in the closed state of the exhaust flow path. Gas circuit breaker.

7. A sealed container filled with an arc-extinguishing gas; a first arcing contact and a second arcing contact that are provided in the sealed container so as to be capable of coming into contact with each other and being separated from each other in an open-contact state; an operating mechanism that separates the first arcing contact and the second arcing contact from the closed state to the open state; a blowing section that blows the stored arc-extinguishing gas against an arc discharge occurring between the first arcing contact and the second arcing contact in the open contact state after transition from the closed contact state to the open contact state, an exhaust flow path is formed that communicates between the first arcing contact and the second arcing contact in an open state and an exhaust port formed at a position away from the gap between the first arcing contact and the second arcing contact; the exhaust flow path includes an acceleration widening portion in which a flow path cross-sectional area increases stepwise from a position where the first arcing contact and the second arcing contact are in contact with each other toward the exhaust port in the closed state, an insulating member is disposed on at least a portion of a flow path forming surface that forms the exhaust flow path, on the exhaust port side, relative to a portion between the first arcing contact and the second arcing contact in an open state; Gas circuit breaker.

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