Gas-insulated switchgear and cable withstand voltage test method for gas-insulated switchgear

Abstract

A gas-insulated switchgear (1) is provided, comprising: a disconnector (5) with a grounding switch and a circuit breaker (6) housed in a tank (2); and a power supply terminal (9) provided outside the tank (2), connected to the disconnector (5) with a grounding switch so as to ground the disconnector (5) with a grounding switch. One end of the circuit breaker (6) is electrically connected to a cable (8) outside the tank (2). The gas-insulated switchgear (1) has a grounding rod (10) with one end serving as a rotation axis and inserted horizontally into the power supply terminal (9). The power supply terminal (9) is grounded via a grounding conductor (11) connected to one side of the rotation axis. During a withstand voltage test of the cable (8), a test terminal (31) is connected to the power supply terminal (9), and a predetermined voltage is supplied from a test power supply (32).

Description

Technical Field

[0001] The present application relates to a gas-insulated switchgear and a cable withstand voltage test method for the gas-insulated switchgear. Background Art

[0002] Conventionally, gas-insulated switchgear has been equipped with a power supply terminal for purposes such as withstand voltage testing (see, for example, Patent Document 1). Patent Document 1 discloses a technique in which the power supply terminal provided on the gas-insulated switchgear is always used as a grounding terminal. During the withstand voltage test, insulating gas is sealed into a gas sealing chamber formed in a bushing, and a test bushing is installed to cover the power supply terminal.

[0003] However, when conducting a cable withstand voltage test on-site immediately after installing a gas-insulated switchgear, a structure is required to facilitate application of voltage to the cable. Therefore, the structure of Patent Document 1 requires complex on-site work such as gas handling, and also increases the cost of manufacturing the test bushing.

[0004] In contrast, Patent Document 2 discloses a technology for a gas-insulated switchgear in which a grounding switch is housed within a tank and a grounding circuit breaker is routed outside the tank. The technology includes an isolating switch connected between the grounding switch and the ground, and test terminals connected to terminals on the grounding switch side of the isolating switch. By turning the isolating switch on and off, the test terminals can be easily connected, making testing easier.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Utility Model Publication No. 3-63014

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 7-222315 Summary of the Invention

[0009] Technical problem to be solved by the invention

[0010] In Patent Document 2, the three-phase blades of the disconnector rotate about the shaft to move the disconnector upward and open it. However, the shaft remains near the terminal, so the insulation distance may be insufficient during a withstand voltage test.

[0011] The present application discloses a technology for solving the above-mentioned technical problems, and its purpose is to provide a gas-insulated switchgear that can connect test terminals with a simple structure and ensure insulation distance.

[0012] Technical solutions used to solve technical problems

[0013] The gas-insulated switchgear disclosed in the present invention includes: an isolating switch and a circuit breaker with a grounding switch, the isolating switch and the circuit breaker with the grounding switch being housed inside a tank; and a power supply terminal arranged outside the tank, the power supply terminal being connected to the isolating switch with the grounding switch so as to ground the isolating switch with the grounding switch. It is characterized in that one end of the circuit breaker is connected to a cable outside the tank in an electrically connectable state, and has a grounding rod, the grounding rod having one end as a rotating axis and being inserted into the power supply terminal in a horizontal direction and being connected, and the gas-insulated switchgear grounds the power supply terminal via a grounding conductor connected to one side of the rotating axis of the grounding rod.

[0014] The cable withstand voltage test method of the gas-insulated switchgear disclosed in the present invention is the cable withstand voltage test method of the above-mentioned gas-insulated switchgear, which is characterized in that it includes: a process of connecting the disconnector with the grounding switch to the power supply terminal to ground the power supply terminal; a process of connecting the circuit breaker to form a closed circuit to form a circuit from the power supply terminal to the cable; a process of rotating the grounding rod in the horizontal direction from the power supply terminal to disconnect it and retreating it from the power supply terminal; and a process of connecting a test instrument to the power supply terminal and performing a withstand voltage test on the cable.

[0015] Effects of the Invention

[0016] According to the present disclosure, a gas-insulated switchgear and a cable withstand voltage test method for the gas-insulated switchgear can be provided, which can connect a test terminal with a simple structure and ensure an insulation distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a side view showing the structure of the gas insulated switchgear according to the first embodiment, and is a diagram showing a partial cross section.

[0018] Figure 2A This is a diagram showing the structure of the terminal chamber that houses the power supply terminals of the gas-insulated switchgear according to the first embodiment. Figure 1 Figure viewed from the AA direction.

[0019] Figure 2B It shows that Figure 2A A diagram showing the terminal room door being opened.

[0020] Figure 2C It will Figure 2B Figure 1 shows the state after the ground rod is disconnected.

[0021] Figure 3 This is a diagram showing the connection state between the power supply terminal and the grounding rod of the gas insulated switchgear of the first embodiment. Figure 2A Figure viewed from the BB direction.

[0022] Figure 4A It is a plan view showing the structure of the front end portion of the ground rod.

[0023] Figure 4B It is a side view showing the structure of the front end portion of the ground rod.

[0024] Figure 5A It is from Figure 2A A diagram viewed from the CC direction in FIG, which is a diagram showing the structure of the interlocking device.

[0025] Figure 5B It is from Figure 5A The diagram observed from the EE direction.

[0026] Figure 6 It is from Figure 2C A diagram viewed from the DD direction in FIG. 1 is a diagram showing the structure of the interlocking device.

[0027] Figure 7A This is a diagram for explaining the operation of the interlock device in the gas insulated switchgear according to the first embodiment.

[0028] Figure 7B This is a diagram for explaining the operation of the interlock device in the gas insulated switchgear according to the first embodiment.

[0029] Figure 7C This is a diagram for explaining the operation of the interlock device in the gas insulated switchgear according to the first embodiment.

[0030] Figure 7D This is a diagram for explaining the operation of the interlock device in the gas insulated switchgear according to the first embodiment.

[0031] Figure 8 These are diagrams for explaining the procedure of attaching the test terminal to the power feeding terminal of the gas insulated switchgear according to the first embodiment.

[0032] Figure 9A These are diagrams for explaining the procedure of attaching the test terminal to the power feeding terminal of the gas insulated switchgear according to the first embodiment.

[0033] Figure 9B It is from Figure 9A Cross-sectional view viewed from the FF direction.

[0034] Figure 10A This is a plan view showing the structure of a test terminal attached to a power feeding terminal of the gas insulated switchgear according to the first embodiment.

[0035] Figure 10B It is a side view showing the structure of the test terminal. DETAILED DESCRIPTION

[0036] Hereinafter, this embodiment will be described with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or corresponding parts.

[0037] Implementation Method 1

[0038] Hereinafter, the gas insulated switchgear according to the first embodiment will be described with reference to the drawings.

[0039] Figure 1 This is a right side view showing the structure of the gas-insulated switchgear of embodiment 1. In the figure, the gas-insulated switchgear 1 has a plurality of compartments inside the housing. The busbar 3 of the busbar chamber 3a is connected to the conductor inside the tank 2 via the busbar bushing 4. The tank 2 is enclosed with insulating gas, and includes a disconnector 5 with an earthing switch and a circuit breaker 6 connected to the disconnector 5 with an earthing switch. The circuit breaker 6 is connected to the cable 8 in the cable chamber 8a via the cable bushing 7, and power is supplied to the load from the cable 8. In addition, as long as the circuit breaker 6 is connected to the cable 8 in an electrically connectable state, a structure in which a disconnector is also connected between the circuit breaker 6 and the cable 8 is also possible.

[0040] The disconnector 5 with grounding switch is connected to the busbar 3 during operation of the gas-insulated switchgear 1 , but is disconnected from the busbar 3 when the circuit breaker 6 is grounded, connected to the power supply terminal 9 outside the tank 2 , and grounded via the grounding conductor 11 .

[0041] Furthermore, the control equipment room 5b in front of the housing of the tank 2 houses a controller 5a for controlling the disconnector 5 with a grounding switch, and a controller 6a for controlling the circuit breaker 6. The door 9a of the terminal room 9b, which houses the power supply terminals 9 and serves as a compartment, is opened to connect test equipment such as the test terminals and test power supply described later. Door 9a also serves as the front door of the housing of the gas-insulated switchgear 1.

[0042] Figure 2A 、 Figure 2B 、 Figure 2C This is a diagram showing the structure of the terminal chamber 9b that houses the power supply terminal 9. Figure 1 Figure viewed from the AA direction. Figure 2B It shows that Figure 2A The diagram of the state in which the door 9a is opened, Figure 2C It shows Figure 2B The ground rod 10 is disconnected. Figure 2Ashows a state where a grounding rod 10 is connected to the three-phase power supply terminals 9. One end of the grounding rod 10 is rotatably mounted on a grounding rod support 12 and connected to the power supply terminals 9, while the other end is engaged within an interlocking device 13. Furthermore, a grounding conductor 11 is mounted on the grounding rod support 12, and the grounding rod 10 is grounded via the grounding conductor 11.

[0043] Figure 3 It is from Figure 2A The connection portion 91 of the power feeding terminal 9 has a connection portion structure, and the grounding rod 10 is connected by being sandwiched between the connection portion structure from a horizontal direction.

[0044] Normally, all three phases of the power supply terminal 9 are short-circuited to ground via a grounding rod 10, serving as the grounding terminal for the disconnector with a grounding switch. During a withstand voltage test of the cable 8, after the disconnector with a grounding switch 5 is connected to the power supply terminal 9 and the circuit breaker 6 is turned on (closed), the grounding rod 10 is disconnected to connect the power supply terminal 9 to the test equipment. Figure 2B This is the state after the wall switch 5 with the grounding switch is connected to the power supply terminal 9 side, the circuit breaker 6 is turned on (the circuit breaker is closed), and the door 9a is opened. Figure 2C In the process, the interlocking device 13 of the grounding rod 10 is released, and the grounding rod 10 is rotated in the horizontal direction about the grounding rod support 12 as an axis, and the grounding rod 10 is disconnected from the power supply terminal 9.

[0045] Figure 4A is a top view showing the structure of the front end portion of the ground rod 10, Figure 4B This is a side view showing the structure of the front end of the ground rod. As shown in the figure, the front end of the ground rod 10 is attached with an upwardly protruding L-shaped metal fitting 10a and a hook-shaped engaging metal fitting 10b. The front end of the engaging metal fitting 10b is engaged within the interlocking device 13.

[0046] Next, the structure of the interlocking device 13 will be described. Figure 5A is a diagram showing the structure of the interlocking device 13, which is Figure 2A Figure viewed from the CC direction. Figure 5B It is from Figure 5A In addition, Figure 6 It is from Figure 2CThe D-D view in FIG. 1 shows the grounding rod 10 disconnected. As shown in the figure, when the grounding rod 10 is connected to the power supply terminal 9, the L-shaped metal fitting 10a of the grounding rod 10 abuts the frame of the interlocking device 13 as the grounding rod 10 rotates horizontally, acting as a stopper. Furthermore, the actuator of the microswitch 13a protrudes from the surface of the interlocking device 13 frame that the L-shaped metal fitting 10a abuts, acting as a sensor that detects the insertion, connection, and disconnection of the grounding rod 10 into the power supply terminal 9. The detected signal is output as an interlock signal to the controller 5a that controls the disconnector 5 with the grounding switch and the controller 6a that controls the circuit breaker 9.

[0047] When the grounding rod 10 is inserted into the power supply terminal 9, the L-shaped metal fitting 10a contacts the frame of the interlocking device 13, pressing the actuator of the microswitch 13a protruding from the contact surface. Furthermore, the front end of the engaging metal fitting 10b engages with the solenoid's movable iron core 13b1 below the solenoid 13b. The solenoid 13b of the interlocking device 13 receives an interlock signal from the controller 5a, which controls the disconnector 5 with the grounding switch, and the controller 6a, which controls the circuit breaker 6. It is energized, causing the solenoid's movable iron core 13b1 to rise, only when the circuit breaker 6 is on (circuit breaker closed) and the disconnector 5 with the grounding switch is grounded. When the solenoid's movable iron core 13b1 rises, the front end of the engaging metal fitting 10b is disengaged, allowing the grounding rod 10 to be disconnected from the power supply terminal 9. In any state other than the state in which the circuit breaker 6 is on (circuit breaker closed) and the disconnector 5 with the grounding switch is grounded, the solenoid 13b is de-energized, and the solenoid movable core 13b1 remains engaged with the front end of the engaging metal member 10b, thereby preventing the grounding rod 10 from being disconnected.

[0048] use 7A to 7D , the operation of the interlocking device 13 is described in detail.

[0049] 7A to 7D 1 is a diagram showing the relationship between the interlock device 13 having a micro switch 13a and a solenoid 13b and the ground rod. Figure 7A Figure 2 shows the grounding rod's engaging metal fitting 10b engaged with the solenoid's movable core 131b. This shows that during normal operation, such as when the gas-insulated switchgear 1 is in operation, the grounding rod 10 is inserted into the power supply terminal 9, grounding the power supply terminal 9. When the circuit breaker 6 is closed and the disconnector 5 with a grounding switch is connected to the busbar 3, the solenoid 13b is not energized, preventing the grounding rod 10 from being disconnected. This prevents the grounding of the power supply terminal 9 from being accidentally disconnected.

[0050] Figure 7BThe figure shows the state during a cable withstand voltage test. During this test, circuit breaker 6 is turned on (closed), and disconnector 5 with a grounding switch is connected to power supply terminal 9, forming a circuit from power supply terminal 9 to cable 8. At this point, solenoid 13b receives interlock signals from controllers 5a and 6a and is energized, causing the solenoid's movable core 13b1 to rise, thereby disconnecting grounding rod 10.

[0051] When the grounding rod 10 is disconnected, Figure 7C As shown, the microswitch 13a detects the disconnection of the grounding rod 10 and outputs an interlock signal indicating the grounding is released to the controllers 5a and 6a. When the grounding rod 10 is disconnected and the power supply terminal 9 is not grounded, the disconnector 5 with a grounding switch and the circuit breaker 6 cannot be operated by the controllers 5a and 6b. This prevents inadvertent operation of the disconnector 5 with a grounding switch and the circuit breaker 6 until the grounding rod 10 is reinserted.

[0052] In the state where the grounding rod 10 is disconnected, for example, when the cable withstand voltage test is completed and the circuit breaker 6 is disconnected by manual operation, as shown in FIG. Figure 7D As shown, solenoid 13b is de-energized, and solenoid movable core 13b1 descends. Consequently, the tip of engaging metal fitting 10b cannot be inserted into engagement with solenoid movable core 13b1, rendering grounding rod 10 inoperable. Unless circuit breaker 6 is re-energized (closed) and disconnector 5 with a grounding switch is connected to power supply terminal 9 to energize solenoid 13b, power supply terminal 9 cannot be grounded.

[0053] Next, the cable withstand voltage test will be described using the drawings. Figure 8 It shows that Figure 2C FIG. 1 is a diagram showing a structure in which a base 30 made of an insulating member is arranged in front of and on the front side of the power feeding terminal 9 in a state in which the grounding rod 10 is disconnected. Figure 9A The test terminals 31 corresponding to each are arranged in Figure 8 The test terminal 31 is inserted into the connection portion of the connection portion 91 of the power supply terminal 9 on the base 30 shown in FIG. Figure 9B Shown from Figure 9A The cross-sectional view of the F-F direction. Figure 8 、 Figure 9A The ground conductor 11 is omitted. Figure 10A 3 is a top view showing the structure of the test terminal 31, Figure 10B31 is a side view showing the structure of the test terminal 31. The test terminal 31 is made of a conductive material and has a plug portion 31b made of a plate-like member and a power supply connection portion 31a made of a plate-like member. Figure 9A 、 Figure 9B As shown, the plug portion 31b of the test terminal 31 is inserted into the connection portion of the connection portion 91 of the power supply terminal 9, and the power supply connection portion 31a fixed to the base 30 is connected to the test power supply 32 outside the frame. At this time, the distance between the phases connected to the test terminal 31 and between the terminals of each phase and the grounding rod 10, the frame, and other grounding metals must ensure an insulation distance that can withstand the test voltage. A specified voltage (DC voltage) is applied to the cable from the test power supply 32, and a withstand voltage test is performed. When the cable withstand voltage test is completed, the test power supply 32 is removed from the test terminal 31, and the plug portion 31b of the test terminal 31 is pulled out from the connection portion 91 of the power supply terminal 9. The base 30 arranged in front of the power supply terminal 9 is removed, and preparations for connecting the grounding rod 10 are made.

[0054] In this embodiment, after the grounding rod 10 for grounding the power supply terminal 9 is rotated in the horizontal direction and retracted from the power supply terminal 9, the test terminal 31 is connected to the power supply terminal 9 and the cable withstand voltage test is performed. Therefore, the insulation distance between each phase of the test terminal 31 and the grounding rod can be ensured. Figure 2C 、 Figure 9A 、 Figure 9B By fastening the rotating shaft of the grounding rod 10 to the grounding rod support 12 so that the grounding rod 10 can be removed from the grounding rod support 12, the insulation distance can be effectively ensured, and the withstand voltage test can be facilitated. Alternatively, a rail can be provided inside the grounding rod support 12 to allow the grounding rod 10 to be stored along the grounding rod support 12.

[0055] Furthermore, this embodiment includes an interlock device 13 that restricts the grounding and disconnecting of the grounding rod 10. Therefore, the grounding and disconnecting states of the grounding rod 10 are linked to the controllers 5 a and 6 a of the disconnector 5 with a grounding switch and the circuit breaker 6, respectively, to restrict the operation of the grounding rod 10 or the disconnector 5 with a grounding switch and the circuit breaker 6. Consequently, a gas-insulated switchgear can be provided that prevents inadvertent operation and circuit-breaking accidents, thereby providing high reliability.

[0056] In the above description, the interlocking device 13 includes the solenoid 13b, and the tip of the grounding rod 10 engages with the hook-shaped engaging member 10b and the solenoid movable core 13b1. However, this is not limiting. The tip of the engaging member 10b need not be hook-shaped, but may be a hole-shaped member that is engaged and disengaged by the raising and lowering of the solenoid movable core 13b1.

[0057] In the gas-insulated switchgear 1 of the present embodiment, as a method for conducting a withstand voltage test on the cable 8, for the disconnector 5 with an earthing switch and the circuit breaker 6 located between the busbar 3 and the cable 8, first, the busbar is disconnected from the disconnector 5 with an earthing switch and grounded via the power supply terminal 9, and the circuit breaker 6 is turned on (closed) to form a circuit from the power supply terminal 9 through the disconnector 5 with an earthing switch and the circuit breaker 6 toward the cable 8. Subsequently, the grounding rod used to ground the power supply terminal 9 is rotated horizontally from the power supply terminal 9 in the terminal chamber to retract it, and then the test instrument is connected to the power supply terminal 9. Therefore, it is possible to easily switch to the withstand voltage test mode, and a structure can be formed in which the insulation distance from the power supply terminal 9 of each phase is ensured in the terminal chamber 9b, so that the withstand voltage test of the cable 8 can be easily carried out. Furthermore, since the controller 5a of the disconnector 5 with a grounding switch and the controller 6a of the circuit breaker 6 are linked via an interlock signal based on the on / off status of the grounding rod 10, operation of the grounding rod 10, the disconnector 5 with a grounding switch, and the circuit breaker 6 are restricted. This provides a method for conducting a withstand voltage test on the cable 8 of a gas-insulated switchgear, which can prevent inadvertent operation during the withstand voltage test and short-circuit accidents, thereby providing high reliability.

[0058] The present disclosure describes various exemplary embodiments and examples, but the features, modes, and functions described in one or more embodiments are not limited to application to specific embodiments and can be applied to the embodiments alone or in various combinations.

[0059] Therefore, numerous modifications not shown are contemplated within the technical scope disclosed in this specification. For example, these include modifying, adding, or omitting at least one component, and also include extracting at least one component and combining it with components from other embodiments.

[0060] (Explanation of Symbols)

[0061] 1. Gas-insulated switchgear; 2. Tank; 3. Busbar; 3a. Busbar compartment; 4. Busbar bushing; 5. Disconnector with earthing switch; 5a. Controller; 5b. Control equipment compartment; 6. Circuit breaker; 6a. Controller; 7. Cable bushing; 8. Cable; 8a. Cable compartment; 9. Power supply terminal; 9a. Door; 9b. Terminal compartment; 10. Grounding rod; 10a. L-shaped metal fitting; 10b. Clamping metal fitting; 11. Grounding conductor; 12. Grounding rod support; 13. Interlocking device; 13a. Micro switch; 13b. Solenoid; 13b. Movable iron core; 30. Base; 31. Test terminal; 32. Test power supply; 91. Connector.

Claims

1. A gas-insulated switchgear, comprising: A disconnector and a circuit breaker with an earthing switch, the disconnector and the circuit breaker with an earthing switch being housed inside the tank; as well as A power supply terminal is provided outside the tank, the power supply terminal is connected to the disconnector with a grounding switch so as to ground the disconnector with a grounding switch. It is characterized by: One end of the circuit breaker is connected to a cable outside the tank in an electrically connectable state. A grounding rod is provided, one end of which serves as a rotation axis and is horizontally inserted into the power feeding terminal for connection. The gas insulated switchgear grounds the power feeding terminal via a grounding conductor connected to one side of the rotation axis of the grounding rod.

2. The gas-insulated switchgear according to claim 1, wherein: A locking metal piece is provided at the other end of the grounding rod, and the gas-insulated switchgear includes an interlocking device for engaging the locking metal piece when the grounding rod is connected to the power feeding terminal.

3. The gas-insulated switchgear according to claim 2, wherein: The interlocking device includes a sensor, and the sensor detects whether the grounding rod and the power supply terminal are in a connected state or a disconnected state.

4. The gas-insulated switchgear according to claim 3, wherein: The interlocking device transmits the state of the grounding rod detected by the sensor to the controller of the disconnector with grounding switch and the controller of the circuit breaker, and releases the engagement of the engaging metal member according to the signals from the controllers.

5. The gas-insulated switchgear according to claim 4, wherein: The interlocking device releases the engagement of the engaging metal member when the disconnector with the earthing switch is connected to the power feeding terminal and the circuit breaker is in a closed circuit.

6. The gas-insulated switchgear according to any one of claims 1 to 5, characterized in that: The power supply terminal has three phases.

7. The gas-insulated switchgear according to any one of claims 1 to 5, wherein: The test terminal can be connected to the power supply terminal in a state where the grounding rod is disconnected.

8. The gas-insulated switchgear according to claim 6, wherein: The test terminal can be connected to the power supply terminal in a state where the grounding rod is disconnected.

9. A method for testing cable withstand voltage of a gas-insulated switchgear according to any one of claims 1 to 6, characterized in that: include: connecting the isolating switch with a grounding switch to the power supply terminal to ground the power supply terminal; a step of turning on the circuit breaker to close the circuit and thereby forming a circuit from the power feeding terminal to the cable; The step of rotating the grounding rod in a horizontal direction to disconnect it from the power feeding terminal and retracting it from the power feeding terminal; as well as A step of connecting a test device to the power supply terminal to perform a withstand voltage test on the cable.

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