Grounding switch

Abstract

The earthing switch (50) comprises a fixed contact (53) installed in a tank (51) filled with insulating gas, a movable contact (54) installed in the tank (51) so as to be movable between a closing position where it contacts the fixed contact (53) and a breaking position where there is a gap between the fixed contact (53) and the movable contact (54), and an operating device (55) installed outside the tank (51) for causing the movable contact (54) to perform closing and breaking operations, the fixed contact (53) comprises a fixed contactor (531) connected to the electrical circuit conductor (52), the movable contact (54) comprises a movable contactor (541) inserted into the fixed contactor (531) at the closing position and in contact with the fixed contactor (531), and the movable contactor (541) comprises a double cylindrical section (562) in which a first puffer chamber (571) and a second puffer chamber (572) are provided separately, for spraying gas toward the fixed contactor (531) during breaking operation.

Description

[Technical Field]

[0001] The present disclosure relates to a grounding switch incorporated in a gas-insulated switchgear. [Background technology]

[0002] The earthing switch incorporated in the gas-insulated switchgear is structured so that the breaking and making operations are performed by linearly or rotationally driving the moving contact within a tank filled with insulating gas. During the breaking operation, an arc is generated between the moving contact and the fixed contact, so the earthing switch is provided with a structure for extinguishing the arc. For example, the earthing switch employs a structure called a puffer system, in which the puffer chamber contracts during the breaking operation by linear driving, thereby blowing gas from the puffer chamber onto the arc, cooling it and extinguishing it.

[0003] Patent Document 1 discloses a switch in which gas in a puffer chamber is blown onto an arc generated between a fixed contact and a movable contact during an interruption operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-52761 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the arc-extinguishing performance of puffer-type earthing switches depends on the insulating properties of the gas in the tank, so there was a problem in that the arc-extinguishing performance was significantly reduced when using naturally occurring gases with low insulating properties, such as dry air.

[0006] The present disclosure has been made in consideration of the above, and aims to provide an earthing switch that can obtain high arc-extinguishing performance even when using a naturally occurring gas with low insulating properties, such as dry air. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the earthing switch according to the present disclosure includes a fixed contact installed in a tank filled with insulating gas, a movable contact installed in the tank so as to be movable between a make position where it contacts the fixed contact and a break position where there is a gap between the fixed contact and the movable contact, and an operating device installed outside the tank for causing the movable contact to perform a make operation and a break operation. The fixed contact includes a fixed contactor connected to an electric circuit conductor. The movable contact includes a movable contactor that is inserted into the fixed contactor and contacts the fixed contactor at the make position. The movable contactor includes a single-tube portion inserted into the fixed contactor, and a double-tube portion connected to the end of the single-tube portion farther from the fixed contact, the double-tube portion having first and second puffer chambers that spray gas toward the fixed contactor during a break operation. The double-tube portion includes an inner tube and an outer tube that surrounds the inner tube in a direction perpendicular to the movement direction of the movable contactor. The space inside the inner tube forms the first puffer chamber, and the space between the inner tube and the outer tube forms the second puffer chamber. The first puffer chamber and the second puffer chamber are separated. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to obtain an earthing switch that can achieve high arc-extinguishing performance even when using a naturally occurring gas with low insulating properties, such as dry air. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a gas-insulated switchgear incorporating a grounding switch according to a first embodiment. [Figure 2] 1 is a cross-sectional view taken along the central axis of a movable contact of a grounding switch according to a first embodiment; [Figure 3] 1 is a cross-sectional view taken along the central axis of a movable contact of a grounding switch according to a first embodiment; [Figure 4] Partial cross-sectional view of a grounding switch according to embodiment 1 [Figure 5]FIG. 1 is a diagram showing an interruption operation of a grounding switch according to the first embodiment. [Figure 6] 10 is a cross-sectional view taken along the central axis of a movable contact of a grounding switch according to a second embodiment. [Figure 7] 10 is a cross-sectional view taken along the central axis of a movable contact of a grounding switch according to a second embodiment. [Figure 8] FIG. 10 is a diagram showing the action of the magnet of the earthing switch according to the second embodiment. [Figure 9] FIG. 10 is a diagram showing the interruption operation of the earthing switch according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A grounding switch according to an embodiment will be described in detail below with reference to the drawings.

[0011] Embodiment 1 FIG. 1 is a diagram showing the configuration of a gas-insulated switchgear incorporating a grounding switch according to a first embodiment. The gas-insulated switchgear 100 includes an electric circuit 10, a disconnecting switch 20, a circuit breaker 30, a lightning arrester 40, and a grounding switch 50, all of which are installed on the electric circuit 10. When the disconnecting switch 20 and the circuit breaker 30 are closed, they each constitute part of the electric circuit 10. The circuit breaker 30 has an interrupting function for interrupting current during normal operation and fault current. When interrupting the current flowing through the electric circuit 10, the circuit breaker 30 is first set to an interrupted state, and then the disconnecting switch 20 is set to an interrupted state. When a voltage exceeding a preset protection voltage is applied to the electric circuit 10, the lightning arrester 40 releases the charge of the electric circuit 10 to earth, thereby protecting the electric circuit 10 and each device installed on the electric circuit 10.

[0012] 2 and 3 are cross-sectional views taken along the central axis of the movable contact of the earthing switch according to the first embodiment. FIG. 2 shows the earthing switch 50 in a closed state in which the movable contact 54 and the fixed contact 53 are in contact, and FIG. 3 shows the earthing switch 50 in a disconnected state in which the movable contact 54 and the fixed contact 53 are not in contact. The earthing switch 50 includes a tank 51 filled with insulating gas, a fixed contact 53 installed in the tank 51 and installed on an electric circuit conductor 52 that forms part of the electric circuit 10, a movable contact 54 installed in the tank 51 so as to be movable between a closed position in which the movable contact 54 is in contact with the fixed contact 53 and a disconnected position in which a gap exists between the movable contact 54 and the fixed contact 53, and an operating device 55 installed outside the tank 51 for causing the movable contact 54 to perform a closing operation and a disconnecting operation. Note that only a portion of the tank 51 is shown in the figure.

[0013] The fixed contact 53 includes a cylindrical fixed contact element 531 and a shield 532 surrounding the fixed contact element 531. The fixed contact element 531 is not limited to a particular shape as long as it has a shape that allows the movable contact element 541 to be inserted when the movable contact 54 is in the closed position. For example, the fixed contact element 531 may be cylindrical as shown in Figures 2 and 3, or may be configured by arranging thin plates with a width of about 4.5 mm in an annular shape.

[0014] The movable contact 54 includes a movable contact element 541 that is linearly driven during closing and opening operations, a support part 542 connected to the movable contact element 541, and a nozzle 543. When the movable contact element 541 is inserted into the fixed contact element 531, the earthing switch 50 is in a closing state in which the movable contact 54 and the fixed contact 53 are in contact. When the movable contact element 541 is pulled out of the fixed contact element 531, the earthing switch 50 is in a breaking state in which a gap is formed between the movable contact 54 and the fixed contact 53 and the movable contact 54 and the fixed contact 53 are not in contact with each other.

[0015] The movable contact 541 has a single cylindrical portion 561 arranged on the side that contacts the fixed contact 531, and a double cylindrical portion 562 arranged on the side that connects to the support portion 542. The double cylindrical portion 562 is connected to the end of the single cylindrical portion 561 that is farther from the fixed contact 53. The double cylindrical portion 562 is composed of an inner cylindrical portion 562a and an outer cylindrical portion 562b arranged with a gap therebetween. The outer cylindrical portion 562b surrounds the inner cylindrical portion 562a in a direction perpendicular to the moving direction of the movable contact 541. The end of the single cylindrical portion 561 is a ring portion 561a. The ring portion 561a is made of a material with a high melting point, such as tungsten. The movable contact 541 has a structure in which the single cylindrical portion 561 and the double cylindrical portion 562 are connected in the axial direction via a connecting portion 565. Therefore, the end of the single cylinder portion 561 farther from the double cylinder portion 562 becomes one end portion 541a of the movable contactor 541, and the end portion 562d of the double cylinder portion 562 farther from the single cylinder portion 561 becomes the other end portion 541b of the movable contactor 541.

[0016] Fig. 4 is a partial cross-sectional view of the earthing switch according to the first embodiment. Fig. 4 corresponds to a cross-sectional view taken along line IV-IV in Fig. 3. Nozzle 543 is provided at one end 541a of movable contactor 541. As shown in Fig. 4, nozzle 543 has a plurality of ventilation holes 543a formed therein. The plurality of ventilation holes 543a extend radially from central axis AX of movable contactor 541.

[0017] The space inside the inner cylinder 562a is connected to the space inside the single cylinder portion 561 to form a first puffer chamber 571. The support portion 542 has a cylindrical piston portion 542a and a cylindrical cylinder portion 542b that surrounds the piston portion 542a from the outer diameter direction.

[0018] The cylinder portion 542b is disposed between the inner cylinder 562a and the outer cylinder 562b, and the inner cylinder 562a is disposed between the piston portion 542a and the cylinder portion 542b, thereby connecting the movable contact 541 and the support portion 542 in an expandable and contractible manner. The cylinder portion 542b has a head portion 542c formed at the end inserted between the inner cylinder 562a and the outer cylinder 562b. The cylinder portion 542b is thickened only at the head portion 542c, and the head portion 542c contacts both the inner cylinder 562a and the outer cylinder 562b. The portion of the cylinder portion 542b other than the head portion 542c is not in contact with the inner cylinder 562a and the outer cylinder 562b. As a result, the portion of the cylinder portion 542b other than the head portion 542c does not generate friction with the inner cylinder 562a and the outer cylinder 562b, and resistance when the movable contact 541 and the support portion 542 are expanded or contracted is kept low. The portion of the cylinder portion 542b other than the head portion 542c may be in contact with at least one of the inner cylinder 562a and the outer cylinder 562b.

[0019] The space between inner cylinder 562a and outer cylinder 562b and closer to one end 541a than head portion 542c forms a second puffer chamber 572. A ventilation hole 567 is formed in connecting portion 565. The inside and outside of second puffer chamber 572 are connected via ventilation hole 567.

[0020] A flange portion 562c is provided on the outer cylinder 562b. A flange 59 is connected to the flange portion 562c. A rod 551 that transmits a driving force generated by the operating device 55 is connected to the flange 59. The driving force generated by the operating device 55 is transmitted to the outer cylinder 562b via the rod 551 and the flange 59, causing the movable contact 541 to move between a break position where it is out of contact with the fixed contact 531 and a close position where it is in contact with the fixed contact 531. A guide rod 552 extending along the axial direction of the rod 551 is installed in the tank 51. The guide rod 552 passes through the flange portion 562c and the flange 59, and the outer cylinder 562b is movable along the axial direction of the rod 551 without rotating around the axis of the rod 551.

[0021] As described above, the earthing switch 50 according to the first embodiment has a gas-immersed disconnecting section made up of the fixed contact 53 and the movable contact 54, and has a linear drive structure in which the movable contact 54 is provided with the first puffer chamber 571 and the second puffer chamber 572 to interrupt current. The first puffer chamber 571 and the second puffer chamber 572 are separated and isolated by the inner cylinder 562a. Therefore, the structure is such that gas does not directly flow in or out between the first puffer chamber 571 and the second puffer chamber 572.

[0022] FIG. 5 is a diagram illustrating the interruption operation of the earthing switch according to the first embodiment. In FIG. 5, the solid arrow indicates the movement direction of the movable contact 541, and the open arrow indicates the flow of gas blown out from the first puffer chamber 571 and the second puffer chamber 572. In the interruption operation, the movable contact 541 moves in a direction to be pulled out from the fixed contact 531. When the movable contact 541 separates from the fixed contact 531, an arc 60 is generated between the ring portion 561a and the fixed contact 531. Furthermore, as the movable contact 541 moves in a direction to be pulled out from the fixed contact 531, the volumes of the first puffer chamber 571 and the second puffer chamber 572 decrease. As the volume of the first puffer chamber 571 decreases, the gas in the first puffer chamber 571 is blown out from the nozzle 543 through the vent hole 543a. Furthermore, the gas in the second puffer chamber 572 is blown out through the vent hole 567. The gas blown out from the ventilation holes 543a and 567 is blown onto the arc 60. The gas blown onto the arc 60 stretches the arc 60 and cools it.

[0023] In the closing operation, the movable contact 541 moves in the direction of insertion into the fixed contact 531. As the movable contact 541 moves in the direction of insertion into the fixed contact 531, the volumes of the first puffer chamber 571 and the second puffer chamber 572 increase. As the volume of the first puffer chamber 571 increases, gas is drawn into the first puffer chamber 571 through the ventilation hole 543a. Also, gas is drawn into the second puffer chamber 572 through the ventilation hole 567. The gas drawn into the first puffer chamber 571 and the second puffer chamber 572 is blown out from the first puffer chamber 571 and the second puffer chamber 572 during the next breaking operation, and is blown onto the arc 60.

[0024] As described above, in the earthing switch 50 according to the first embodiment, in a cross section perpendicular to the moving direction of the movable contactor 541, the distance between the vent hole 543a, which is the gas outlet of the first puffer chamber 571, and the center of the cross section perpendicular to the moving direction of the movable contactor 541 is smaller than the distance between the vent hole 567, which is the gas outlet of the second puffer chamber 572, and the center of the cross section perpendicular to the moving direction of the movable contactor 541. Furthermore, in the earthing switch 50 according to the first embodiment, during an interruption operation, the arc 60 generated between the fixed contactor 531 and the movable contactor 541 is sandwiched between the gas blown out from the first puffer chamber 571 and the gas blown out from the second puffer chamber 572.

[0025] Even in a configuration with multiple vent holes serving as gas outlets, such as the switch disclosed in Patent Document 1, if the puffer chamber is shared, the gas in the puffer chamber will concentrate in a path with low flow resistance and will not flow easily in a path with high flow resistance. Therefore, in a configuration with multiple vent holes for one puffer chamber, such as the switch disclosed in Patent Document 1, it is not possible to spray gas so as to reliably sandwich the arc. In contrast, in the earthing switch 50 according to the first embodiment, the first puffer chamber 571 and the second puffer chamber 572 are isolated and independent and not connected to each other. Therefore, during an interruption operation, gas is injected from both the first puffer chamber 571 and the second puffer chamber 572, regardless of the respective flow resistances of the vent holes 543a and 567. Therefore, the earthing switch 50 according to the first embodiment can reliably sandwich the arc 60 between the gas injected from the first puffer chamber 571 and the gas injected from the second puffer chamber 572, thereby quickly cooling and extinguishing the arc 60. Therefore, the earthing switch 50 according to the first embodiment can obtain high arc-extinguishing performance even when a gas with low insulating properties is used.

[0026] Embodiment 2 6 and 7 are cross-sectional views taken along the central axis of the movable contact of the earthing switch according to embodiment 2. Fig. 6 shows the earthing switch 50 in a closed state in which the movable contact 54 and the fixed contact 53 are in contact, and Fig. 7 shows the earthing switch 50 in a cut-off state in which the movable contact 54 and the fixed contact 53 are not in contact.

[0027] In the earthing switch 50 according to the second embodiment, the movable contact 54 has a magnet 58 that is grounded in the space inside the single cylindrical portion 561. The magnet 58 is installed inside the movable contact 541 with its magnetic poles oriented along the direction of movement of the movable contactor 541. Other than this, it is the same as the earthing switch 50 according to the first embodiment.

[0028] The magnet 58 is supported by support legs 561c formed on the single cylindrical portion 561. A gap is formed between the magnet 58 and the single cylindrical portion 561 except for the portion of the support legs 561c. The magnet 58 is installed with an orientation such that one end 541a of the movable contact 541 is the north pole and the other end 541b is the south pole. Alternatively, the magnet 58 may be installed with an orientation such that one end 541a of the movable contact 541 is the south pole and the other end 541b is the north pole.

[0029] FIG. 8 is a diagram illustrating the action of the magnet of the earthing switch according to the second embodiment. In FIG. 8, the open arrows indicate the flow of gas blown out from the first puffer chamber 571 and the second puffer chamber 572. The arc 60 generated between the fixed contact 531 and the ring portion 561a is initially generated along the shortest straight path connecting the fixed contact 531 and the ring portion 561a. The magnetic field 71 generated by the magnet 58 is generally perpendicular to the shortest straight path connecting the fixed contact 531 and the ring portion 561a, so that a Lorentz force 72 acts on the arc 60, moving the arc 60 in a direction perpendicular to both the arc 60 and the magnetic field 71. In the example shown in FIG. 8, the arc 60 moves toward the front of the page due to the influence of the Lorentz force 72 from the magnetic field 71 generated by the magnet 58. As the arc 60 moves, the direction of the current flowing along the arc 60 changes, and therefore the direction perpendicular to both the arc 60 and the magnetic field 71 also changes with the movement of the arc 60. In other words, as the arc 60 moves, the direction of the Lorentz force 72 acting on the arc 60 changes, and the arc 60 is stretched in a spiral shape between the fixed contact 531 and the ring portion 561a.

[0030] Fig. 9 is a diagram showing the interruption operation of the earthing switch according to embodiment 2. In Fig. 9, the solid arrow indicates the moving direction of the movable contactor 541, and the open arrow indicates the flow of gas blown out from the first puffer chamber 571 and the second puffer chamber 572. By stretching the arc 60 in a spiral shape, the gas blown out from the ventilation holes 543a and 567 is more likely to blow onto the arc 60, and the arc 60 is extinguished more quickly than in the earthing switch 50 according to embodiment 1.

[0031] The configurations shown in the above embodiments are merely examples of the content, and may be combined with other known technologies, and parts of the configurations may be omitted or modified as long as they do not deviate from the gist of the invention. [Explanation of symbols]

[0032] 10 electric circuit, 20 disconnecting switch, 30 circuit breaker, 40 lightning arrester, 50 earthing switch, 51 tank, 52 electric circuit conductor, 53 fixed contact, 54 moving contact, 55 operating device, 58 magnet, 59 flange, 60 arc, 71 magnetic field, 72 Lorentz force, 100 gas-insulated switchgear, 531 fixed contact, 532 shield, 541 moving contact, 541a one end, 541b other end, 542 support part, 542a piston part, 542b cylinder part, 542c head part, 543 nozzle, 543a, 567 ventilation hole, 561 single cylinder part, 551 rod, 552 guide rod, 561a ring part, 562a inner cylinder, 562b outer cylinder, 562c flange part, 562d End portion, 561c support leg, 562 double cylinder portion, 565 connection portion, 571 first puffer chamber, 572 second puffer chamber.

Claims

1. a fixed contact installed in a tank filled with insulating gas; a movable contact disposed in the tank so as to be movable between a closing position where the movable contact comes into contact with the fixed contact and a closing position where a gap exists between the movable contact and the fixed contact; an operating device that is installed outside the tank and causes the movable contact to perform a closing operation and a breaking operation, The fixed contact includes a fixed contact piece connected to an electrical path conductor; the movable contact includes a movable contact inserted into the fixed contact at the closing position and in contact with the fixed contact; the movable contactor includes a single cylindrical portion inserted into the fixed contactor, and a double cylindrical portion provided with a first puffer chamber and a second puffer chamber for ejecting the gas toward the fixed contactor during the breaking operation, the double cylindrical portion being connected to an end of the single cylindrical portion farther from the fixed contactor, The double-tube portion comprises an inner tube and an outer tube that surrounds the inner tube from a direction perpendicular to the direction of movement of the movable contact and is structurally connected to the inner tube, the space inside the inner tube forms the first puffer chamber, and the space between the inner tube and the outer tube forms the second puffer chamber, and the first puffer chamber and the second puffer chamber are isolated from each other.

2. In a cross section perpendicular to the moving direction of the movable contact, the distance between the gas outlet of the first puffer chamber and the center of the cross section perpendicular to the moving direction of the movable contact is: the distance is smaller than the distance between the gas outlet of the second puffer chamber and the center of a cross section perpendicular to the moving direction of the movable contact, 2. The earthing switch according to claim 1, wherein, during the breaking operation, the arc generated between the fixed contact and the movable contact is sandwiched between the gas blown out from the first puffer chamber and the gas blown out from the second puffer chamber.

3. 3. The earthing switch according to claim 1, wherein the movable contact comprises a magnet installed inside the movable contact in a direction in which the magnetic poles are arranged along the direction of movement of the movable contactor.

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