Gas-insulated switchgear

Abstract

A gas-insulated switchgear (50) comprises: a fixed-side electrode part (52) that has a fixed-side contactor (5b) installed inside a ground tank (1) in which an insulating gas is sealed; a movable-side electrode part (51) that has a puffer cylinder (92), a puffer piston (91) installed in the puffer cylinder (92), a conductor rod (14) fixed to the puffer piston (91), and a movable-side contactor (5a) fixed to the conductor rod (14), is installed inside the ground tank (1) in a movable manner, and sprays, in a blocking operation, the insulating gas inside a puffer chamber (32) toward the fixed-side contactor (5b); a cylindrical fixed-side frame (16) that supports the fixed-side electrode part (52); a fixed-side insulation support member (10) that supports the fixed-side frame (16); and an inner lid (39) that is attached to the fixed-side frame (16) and seals the opening of an end portion leading to the fixed-side insulating support member (10) of the fixed-side frame (16).

Description

Gas-insulated switchgear

[0001] The present disclosure relates to a gas-insulated switchgear that interrupts current in a grounded tank filled with insulating gas.

[0002] Conventionally, when interrupting high voltage current, a puffer-type gas-insulated switchgear is used, which interrupts the current in a cylindrical grounded tank filled with insulating gas. A puffer-type gas-insulated switchgear blows a gas flow onto the arc that occurs between the fixed contact and the moving contact when interrupting the current, thereby cooling and extinguishing the arc. In a puffer-type gas-insulated switchgear, a puffer cylinder is provided around the moving contact, and a puffer piston linked to the moving contact pushes the insulating gas from the puffer cylinder out of the puffer cylinder through a nozzle connected to the puffer cylinder during an interruption operation. The insulating gas pushed out of the puffer cylinder from the nozzle becomes a gas flow and is blown onto the arc that occurs between the fixed contact and the moving contact.

[0003] Inside the grounded tank, the fixed contact is supported by a cylindrical frame. The frame is fixed to a cylindrical insulating support member and supported inside the grounded tank so that the fixed contact is positioned on the central axis.

[0004] When current is interrupted, the gas flow blown onto the arc becomes hot as it absorbs heat from the arc. After absorbing the heat from the arc, the hot gas flow passes through the fixed contact, enters the inside of the frame, and is then blown onto the insulating support member. Because the insulating support member is made of plastic containing carbon, when the hot gas flow is blown onto it, the parts that are blown onto it carbonize, reducing its insulating performance.

[0005] Patent Document 1 discloses a gas-insulated switchgear in which the insulating support member is a solid cone shape and the frame is supported above the central axis of the grounding tank. In the gas-insulated switchgear disclosed in Patent Document 1, the insulating support member is not present in front of the nozzle that sprays the gas flow, so the gas flow is not blown onto the insulating support member.

[0006] Japanese Patent Application Laid-Open No. 2001-118476

[0007] However, in the gas-insulated switchgear disclosed in Patent Document 1, the gas flow that has absorbed the heat of the arc and become hot passes under the insulating support member, so the hot gas flow comes into contact with the insulating support member. Therefore, although carbonization of the insulating support member can be suppressed compared to when the hot gas flow is blown onto the insulating support member, there is a problem in that it cannot be prevented.

[0008] The present disclosure has been made in consideration of the above, and aims to provide a gas-insulated switchgear that prevents a high-temperature gas flow from coming into contact with an insulating support member to which a frame that supports a fixed contact is fixed.

[0009] In order to solve the above-mentioned problems and achieve the object, a gas-insulated switchgear according to the present disclosure includes: a grounded tank whose end is closed by a removable lid and filled with insulating gas; a fixed electrode unit having a fixed contactor installed inside the grounded tank; and a movable electrode unit having a puffer cylinder, a puffer piston installed in the puffer cylinder, a conductor rod fixed to the puffer piston, and a movable contactor fixed to the conductor rod, which is movably installed inside the grounded tank and which blows insulating gas from inside a puffer chamber, which is a space formed between the puffer cylinder and the puffer piston, toward the fixed contactor during a breaking operation in which the movable contactor transitions from a closed state in which it is in contact with the fixed contactor to an open state in which it is separated from the fixed contactor. The gas-insulated switchgear includes a cylindrical fixed frame supporting the fixed electrode unit, a fixed insulating support member supporting the fixed frame, and an inner lid attached to the fixed frame and closing an opening at an end of the fixed frame that leads to the fixed insulating support member.

[0010] According to the present disclosure, it is possible to obtain an advantageous effect of a gas-insulated switchgear in which a high-temperature gas flow is prevented from coming into contact with an insulating support member to which a frame supporting a fixed contact is fixed.

[0011] FIG. 1 is a cross-sectional view of the gas-insulated switchgear according to the first embodiment in a closed state; FIG. 1 is a cross-sectional view of the gas-insulated switchgear according to the first embodiment in an open state; FIG. 2 is an enlarged view of a fixed portion between a fixed-side frame and an inner cover of the gas-insulated switchgear according to the first embodiment; FIG. 3 is a view showing an example of a gas flow blown out from a nozzle in the gas-insulated switchgear according to the first embodiment;

[0012] Gas-insulated switchgear according to embodiments will be described in detail below with reference to the drawings.

[0013] Embodiment 1. Fig. 1 is a cross-sectional view of a gas-insulated switchgear according to embodiment 1 in a closed state. Fig. 2 is a cross-sectional view of the gas-insulated switchgear according to embodiment 1 in an open state. A gas-insulated switchgear 50 according to embodiment 1 includes a cylindrical grounded tank 1, a switching unit 4 having a movable electrode portion 51 and a fixed electrode portion 52, and a movable outer conductor 34 and a fixed outer conductor 36 disposed within a pair of bushings 22 extending above the grounded tank 1. In the gas-insulated switchgear 50 according to embodiment 1, the grounded tank 1 and the bushings 22 are integrally formed to form a sealed container in which insulating gas is sealed. The grounded tank 1 is, for example, cylindrical, but the cross-sectional shape of the grounded tank 1 is not limited to being perfectly circular.

[0014] A lid 3a is detachably attached to the movable end of the grounded tank 1, and a lid 3b is detachably attached to the fixed end of the grounded tank 1. The lid 3a is disk-shaped with a hole in the center. The lid 3b is disk-shaped without a hole. In the arrangement direction of the movable-side electrode portion 51 and the fixed-side electrode portion 52, the direction from the fixed-side electrode portion 52 to the movable-side electrode portion 51 is referred to as the "movable side," and the direction from the movable-side electrode portion 51 to the fixed-side electrode portion 52 is referred to as the "fixed side." In Figures 1 and 2, the movable-side electrode portion 51 and the fixed-side electrode portion 52 are aligned in the left-right direction on the paper, so the left side of the paper is the movable side and the right side is the fixed side.

[0015] The gas-insulated switchgear 50 has a cylindrical movable-side frame 8 connected to the lower end of the movable-side outer conductor 34, and a cylindrical fixed-side frame 16 connected to the lower end of the fixed-side outer conductor 36. The movable-side frame 8 and the fixed-side frame 16 are formed of a conductive material. The movable-side frame 8 and the fixed-side frame 16 are, for example, cylindrical, but the cross-sectional shapes of the movable-side frame 8 and the fixed-side frame 16 are not limited to being perfect circles.

[0016] The movable frame 8 is supported inside the grounded tank 1 by a cylindrical movable insulating support member 17. The fixed frame 16 is supported inside the grounded tank 1 by a cylindrical fixed insulating support member 10. The movable insulating support member 17 and the fixed insulating support member 10 are, for example, cylindrical, but the cross-sectional shapes of the movable insulating support member 17 and the fixed insulating support member 10 are not limited to being perfect circles. The movable insulating support member 17 and the fixed insulating support member 10 do not have to be cylindrical and may be, for example, rod-shaped, as long as they can support the movable frame 8 and the fixed frame 16 inside the grounded tank 1.

[0017] The movable electrode unit 51 includes a cylindrical puffer cylinder 92, a puffer piston 91 installed in the puffer cylinder 92, a conductor rod 14 smaller in diameter than the puffer cylinder 92 and fixed to the puffer piston 91, a movable contact 5a fixed to the conductor rod 14, a cylindrical movable shield 35 surrounding the movable contact 5a from the outer periphery of the grounded tank 1, and a nozzle 11 arranged around the movable contact 5a. The conductor rod 14 is connected to an insulating rod 12 connected to a shaft 6 of an operating device (not shown) installed outside the grounded tank 1 to operate the movable contact 5a. The puffer cylinder 92 is fixed to the conductor rod 14. The movable shield 35 is installed at the end of the puffer cylinder 92. The puffer piston 91 is fixed to the movable frame 8. The puffer piston 91 surrounds the conductor rod 14 from the outer periphery of the grounded tank 1, closing the gap between the conductor rod 14 and the puffer cylinder 92.

[0018] A contact 33 is formed inside the cylinder of the movable-side frame 8. A hole is formed in the contact 33, and the inner peripheral surface of the hole is in contact with the conductor rod 14. The conductor rod 14 passes through the hole formed in the contact 33 and is connected to the insulating rod 12. Therefore, the movable-side outer conductor 34 is electrically connected to the conductor rod 14 via the movable-side frame 8.

[0019] The fixed electrode portion 52 has a fixed contactor 5b and a cylindrical fixed shield 15 that surrounds the fixed contactor 5b from the outer periphery of the grounded tank 1. The fixed contactor 5b and the fixed shield 15 are supported by a fixed frame 16.

[0020] The movable electrode portion 51 is installed inside the grounded tank 1 so as to be movable in the axial direction of the grounded tank 1. In the first embodiment, a state in which the movable contactor 5a and the fixed contactor 5b are in contact with each other is called a "closed state," and a state in which the movable contactor 5a is separated from the fixed contactor 5b is called an "open state." An operation of transitioning from the closed state to the open state is called a "breaking operation," and an operation of transitioning from the open state to the closed state is called a "closing operation." The gas-insulated switchgear 50 switches between the open state and the closed state when the movable electrode portion 51 moves, causing the movable contactor 5a to come into contact with the fixed contactor 5b or when the movable contactor 5a, which was in contact with the fixed contactor 5b, separates from the fixed contactor 5b.

[0021] In a closed state where the movable contact 5 a and the fixed contact 5 b are in contact with each other, the movable shield 35 comes into contact with the fixed shield 15 .

[0022] The space surrounded by the puffer cylinder 92 and the puffer piston 91 forms a puffer chamber 32 connected to the nozzle 11. During an interruption operation in which a contact is switched from a closed state to an open state, the amount of protrusion of the puffer cylinder 92 from the movable frame 8 decreases, thereby reducing the volume of the puffer chamber 32 and allowing insulating gas to be sprayed from the nozzle 11. That is, during an interruption operation in which a contact is switched from a closed state in which the movable contact 5a is in contact with the fixed contact 5b to an open state in which the movable contact 5a is separated from the fixed contact 5b, the movable electrode portion 51 blows insulating gas from the inside of the puffer chamber 32, which is the space formed between the puffer cylinder 92 and the puffer piston 91, toward the fixed contact 5b. An arc formed between the movable contact 5a and the fixed contact 5b during an open operation is cooled and extinguished by the insulating gas blown from the nozzle 11.

[0023] An inner lid 39 is attached to the fixed-side frame 16. The inner lid 39 has a shape that closes the end of the fixed-side frame 16 and has the same cross-sectional shape as the fixed-side frame 16, for example. For example, if the cross-sectional shape of the fixed-side frame 16 is a perfect circle, the inner lid 39 is disk-shaped. FIG. 3 is an enlarged view of a fixed portion between the fixed-side frame and the inner lid of the gas-insulated switchgear according to the first embodiment. The fixed-side frame 16 is provided with a fixing rib 16a. The fixing rib 16a is formed on the inner peripheral surface of the fixed-side frame 16 so as to be connected without gaps around the entire circumference. The fixed-side frame 16 does not have holes formed on its side surface. The inner lid 39 is attached to the fixed-side frame 16 and closes the opening at the end of the fixed-side frame 16 that leads to the fixed-side insulating support member 10. The inner lid 39 abuts against the fixing rib 16a from the fixed side and is fixed to the fixing rib 16a by fixing members 38 such as bolts. The maximum width of the inner lid 39 is smaller than the inner diameter of the fixed-side insulating support member 10 and larger than the inner diameter of the fixing rib 16a of the fixed-side frame 16. When the inner lid 39 is disk-shaped, the diameter of the inner lid 39 is the maximum width of the inner lid 39. When the inner lid 39 is elliptical, the major axis of the inner lid 39 is the maximum width of the inner lid 39.

[0024] FIG. 4 is a diagram illustrating an example of a gas flow ejected from a nozzle in the gas-insulated switchgear according to the first embodiment. In FIG. 4 , solid arrows indicate the gas flow ejected from the nozzle 11, and dashed arrows indicate the flow of insulating gas pushed out from the fixed frame 16. Because no holes are formed in the side surface of the fixed frame 16, the gas flow that flows into the fixed frame 16 from the end of the movable side hits the inner cover 39 and turns back. The insulating gas originally inside the fixed frame 16 is pushed out by the gas flow and flows out of the fixed frame 16. During the breaking and making operations, metal powder is generated by the sliding of the moving contact 5a and the fixed contact 5b. Therefore, the gas flow ejected from the nozzle 11 and passing through the fixed contact 5b during the breaking operation contains metal powder. In the gas-insulated switchgear 50 according to the first embodiment, the insulating gas in the fixed-side frame 16 is pushed out and flows out of the fixed-side frame 16 by the gas flow that hits the inner lid 39 and turns back toward the end of the movable side, so that the metal powder tends to remain in the fixed-side frame 16. Therefore, in the gas-insulated switchgear 50 according to the first embodiment, it is possible to prevent the metal powder scattered inside the grounded tank 1 from adhering to the movable-side insulating support member 17 and the fixed-side insulating support member 10 and thereby reducing the insulation performance.

[0025] 5 is a diagram showing an example of a gas flow blown out from a nozzle in a gas-insulated switchgear according to a modification of Embodiment 1. In a gas-insulated switchgear 50 according to the modification, a hole 16b is provided in a side surface of the fixed-side frame 16. The gas flow that flows into the interior of the fixed-side frame 16 from the end of the movable side flows out of the fixed-side frame 16 through the hole 16b. Therefore, the gas flow can pass smoothly through the interior of the fixed-side frame 16, making it difficult for the gas flow to decelerate, and the arc can be quickly cooled and extinguished.

[0026] 6 is a diagram showing the gas-insulated switchgear according to the first embodiment with the fixed-side lid removed. By removing the lid 3b, the fixed member 38 and the inner lid 39 can be removed through the interior of the fixed-side insulating support member 10. Because the maximum width of the inner lid 39 is smaller than the inner diameter of the fixed-side insulating support member 10, the inner lid 39 removed from the fixed-side frame 16 can be taken out to the outside of the grounded tank 1 through the interior of the fixed-side insulating support member 10. By taking the inner lid 39 out of the grounded tank 1, maintenance and replacement of the fixed-side contactor 5b can be performed through the interior of the fixed-side insulating support member 10 and the fixed-side frame 16. Therefore, the gas-insulated switchgear 50 according to the first embodiment allows maintenance and replacement of the fixed-side contactor 5b without providing a maintenance opening in the side surface of the grounded tank 1.

[0027] Although the structure in which the inner lid 39 is fixed to the fixed-side frame 16 using the fixing member 38 has been exemplified here, the inner lid 39 may be fixed to the fixed-side frame 16 without using the fixing member 38. For example, the inner lid 39 may be fixed by adhesive to the fixing rib 16a, and when performing maintenance or replacement of the fixed-side contactor 5b, the adhesive may be removed using a solvent or the like before the inner lid 39 is removed from the fixed-side frame 16. Furthermore, a female thread may be formed on the fixed-side end of the inner peripheral surface of the fixed-side frame 16, and a male thread may be formed on the outer peripheral surface of the inner lid 39, and the female thread of the fixed-side frame 16 may be engaged with the male thread of the inner lid 39 to fix the inner lid 39 to the fixed-side frame 16.

[0028] In the gas-insulated switchgear 50 according to the first embodiment, the fixed-side frame 16 and the fixed-side insulating support member 10 are separated by the inner cover 39 attached to the fixed-side frame 16, so that the gas flow that is blown out through the nozzle 11 during an interruption operation and passes through the fixed-side contactor 5b and enters the fixed-side frame 16 does not come into contact with the fixed-side insulating support member 10. Therefore, the gas-insulated switchgear 50 according to the first embodiment can prevent the fixed-side insulating support member 10 from being carbonized.

[0029] Furthermore, in the gas-insulated switchgear 50 according to embodiment 1, by removing the fixed side cover 3b, the fixed member 38 and the inner cover 39 can be taken out of the grounded tank 1 through the inside of the fixed side insulating support member 10, and maintenance and replacement of the fixed side contactor 5b can be performed, so there is no need to provide a maintenance opening on the side of the grounded tank 1.

[0030] The configurations shown in the above embodiments are merely examples of the content, and may be combined with other known technologies, or parts of the configurations may be omitted or modified without departing from the spirit of the invention.

[0031] REFERENCE SIGNS LIST 1 Grounded tank, 3a, 3b Lid, 4 Opening / closing portion, 5a Movable side contactor, 5b Fixed side contactor, 6 Shaft, 8 Movable side frame, 10 Fixed side insulating support member, 11 Nozzle, 12 Insulating rod, 14 Conductor rod, 15 Fixed side shield, 16 Fixed side frame, 16a Fixing rib, 16b Hole, 17 Movable side insulating support member, 22 Bushing, 32 Puffer chamber, 33 Contact, 34 Movable side outer conductor, 35 Movable side shield, 36 Fixed side outer conductor, 38 Fixed member, 39 Inner lid, 50 Gas insulated switchgear, 51 Movable side electrode portion, 52 Fixed side electrode portion, 91 Puffer piston, 92 Puffer cylinder.

Claims

1. A gas-insulated switchgear comprising: a grounded tank whose end is closed by a removable lid and filled with insulating gas; a fixed electrode unit having a fixed contactor installed inside the grounded tank; a movable electrode unit having a puffer cylinder, a puffer piston installed inside the puffer cylinder, a conductor rod fixed to the puffer piston, and a movable contactor fixed to the conductor rod, the movable electrode unit being movably installed inside the grounded tank, the movable electrode unit blowing insulating gas from inside a puffer chamber, which is a space formed between the puffer cylinder and the puffer piston, toward the fixed contactor during an interruption operation in which the movable contactor transitions from a closed state in which it is in contact with the fixed contactor to an open state in which it is separated from the fixed contactor; a cylindrical fixed frame supporting the fixed electrode unit; a fixed insulating support member supporting the fixed frame; and an inner lid attached to the fixed frame and closing an opening at the end of the fixed frame that leads to the fixed insulating support member.

2. The gas-insulated switchgear according to claim 1, characterized in that the fixed-side insulating support member is cylindrical, the inner lid is detachably attached to the fixed-side frame, and the maximum width of the inner lid is smaller than the inner diameter of the fixed-side insulating support member.

3. A gas-insulated switchgear according to claim 1 or 2, characterized in that no holes are formed on the side surface of the fixed frame.

Images