Switching device

Abstract

To enable the replacement of switches without causing a power outage. [Solution] The power supply line includes a first switch 1 and a commutator 3 connected in parallel to the first switch 1. The commutator 3 has a first fixed electrode 6 connected to ground or another phase, a second fixed electrode 5 to which a current limiting element 4 is connected, and a movable electrode 8 configured to be conductive to the first fixed electrode 6 or the second fixed electrode 5. The movable electrode 8, the second fixed electrode 5, and the current limiting element 4 are connected in parallel to the first switch 1.

Description

Technical Field

[0001] The present disclosure relates to an opening / closing device.

Background Art

[0002] In the replacement or maintenance of draw-out type switchgear, the draw-out type switchgear cannot be pulled out from the closed box in the live line state. Therefore, a power outage of the power supply line is required, and it is necessary to plan the power outage time in advance. Also, in important equipment, a power outage may not be possible. In addition, there is a problem that a power outage cost is incurred during a power outage.

[0003] Conventionally, there has been provided a current-limiting element provided in a power supply line from a predetermined power source to a load device, which exhibits a current-limiting effect when the current flowing through the power supply line exceeds a first current threshold value, a current-transfer path switch capable of switching on and off conduction in a current-transfer path connected in parallel to the power supply line, and a control device for controlling the on and off of the current-transfer path switch. When the control device detects that the current flowing through the current-limiting element has been current-limited to a second current threshold value after exceeding the first current threshold value, the control device switches the current-transfer path switch from off to on, and after a predetermined switch-on maintenance time has elapsed since the current-transfer path switch was turned on, switches the current-transfer path switch off again (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Traditionally, bypass switches have been used to replace and test switches without shutting off the load side. However, since replacing and testing switches is live-line work, there is a risk of internal arcing if an internal short circuit occurs, posing a challenge for workers. Furthermore, there were space limitations when installing bypass switches in enclosed boxes.

[0006] This disclosure provides technology to solve the above-mentioned problems, with the aim of replacing switches without causing a power outage. [Means for solving the problem]

[0007] The switchgear of this disclosure comprises a first switch installed in a power supply line and a commutator connected in parallel to the first switch. The commutator has a first fixed electrode connected to ground or another phase, a second fixed electrode to which a current limiting element is connected, and a movable electrode configured to be electrically conductive to the first fixed electrode or the second fixed electrode. The movable electrode, the second fixed electrode, and the current limiting element are connected in parallel to the first switch. [Effects of the Invention]

[0008] According to the switchgear of this disclosure, the switchgear can be replaced without causing a power outage. [Brief explanation of the drawing]

[0009] [Figure 1] This is a circuit diagram showing the power supply path in the switchgear according to Embodiment 1. [Figure 2] This is a cross-sectional view showing the structure of a commutator installed in the power supply path of a switchgear according to Embodiment 1. [Figure 3] This is a circuit diagram showing the power supply path under normal conditions. [Figure 4] This is a circuit diagram showing the power supply path when the circuit is bypassed. [Figure 5]This is a circuit diagram showing the power supply path when grounded. [Figure 6] This figure shows an example of the operation sequence in a commutator according to Embodiment 1. [Figure 7] This is a cross-sectional view showing the switch according to Embodiment 2 housed in a sealed box. [Figure 8] This is a detailed cross-sectional view showing the switch according to Embodiment 2 housed in a sealed box. [Modes for carrying out the invention]

[0010] Embodiment 1. This embodiment will be described below with reference to the drawings. This embodiment allows for the replacement of a switch without interrupting power supply by bypassing the main circuit current to the switching channel. Embodiment 1 will be described below. Figure 1 is a circuit diagram showing a power supply path in which a switch is installed. In this embodiment, a first switch 1 is provided in the power supply path, and a second switch 2 is connected in parallel to the supply path. The second switch 2 constitutes a commutator 3, and the commutator 3 is equipped with a current-limiting element 4 such as a current-limiting reactor.

[0011] Furthermore, in the commutator 3, a current-limiting element 4 is electrically connected to one fixed electrode (second fixed electrode) 5, and the other fixed electrode (first fixed electrode) 6 is connected to ground 7 or another phase. The movable electrode 8 and the current-limiting element 4 are connected in parallel to the first switch 1, and the movable electrode 8 is configured to be conductive to either the first fixed electrode 6 or the second fixed electrode 5.

[0012] Figure 2 is a cross-sectional view showing the commutator 3. The commutator 3 consists of an insulating container 9, a first fixed electrode 6, a second fixed electrode 5, a movable electrode 8, a drive device 10 for the movable electrode 8, and a current limiting element 4. The current limiting element 4 is electrically connected to the second fixed electrode 5, and the first fixed electrode 6 is connected to ground 7 or another phase.

[0013] The commutation device 3 shown in Fig. 2 has a structure in which an electromagnetic repulsion coil is used as the drive device 10 of the movable electrode 8 in order to ground it at high speed. Here, the structure using an electromagnetic repulsion coil is composed of a fixed coil and a movable coil. By flowing currents through the fixed coil and the movable coil, an electromagnetic repulsion force is generated between the coils, and the movable coil is driven. Then, by arranging the first fixed electrode 6 and the second fixed electrode 5 at both ends of the movable electrode 8, a bypass circuit can be formed at high speed, and furthermore, it can be grounded.

[0014] The commutation device 3 shown in Fig. 2 has a structure in which an electromagnetic repulsion coil is used as the drive device 10 of the movable electrode 8, so that the number of components can be reduced. Furthermore, the reliability can be improved and the cost can be reduced. Also, the size of the drive device 10 can be reduced.

[0015] Fig. 3 is a circuit diagram showing the normal power supply path, Fig. 4 is a circuit diagram showing the power supply path during bypass, and Fig. 5 is a circuit diagram showing the power supply path during grounding. As shown in Fig. 3, during normal operation, the upper system and the lower system are connected using the first switch 1. The first switch 1 needs to be replaced during regular equipment inspection work and when its expected life has passed. In that case, the work is carried out after disconnecting it from the power supply path. In the present embodiment, during such work, as shown in Fig. 4, by bypassing to the second switch 2 arranged in parallel with the first switch 1, the work can be carried out without power interruption. And during the work, the power supply path bypassed by the second switch 2 is in a live state, and the operator has to perform live work. If an internal short circuit occurs in the bypassed power supply path, by quickly switching to the grounding circuit shown in Fig. 5, the occurrence of an accident due to an internal arc can be prevented.

[0016] FIG. 6 is a diagram showing an operation sequence by the current transformer 3. In the figure, a shows the operation (opening / closing) of the current transformer 3 on the ground side, b shows the operation (opening / closing) of the current transformer 3 on the current limiting element side, and c shows the operation (opening / closing) of the first switch 1. During normal operation (when replacing the current transformer) at A, the first switch 1 is closed and the current transformer 3 is open, and the current flows through the first switch 1 (see FIG. 3). When replacing the first switch 1 at B, by closing the current transformer 3 on the current limiting element side (see FIG. 4), and flowing the current through the current transformer 3, the current flowing through the first switch 1 is bypassed. Thereby, the first switch 1 can be replaced without powering off the power supply line.

[0017] When an internal arc accident due to an internal short circuit occurs during the replacement of the first switch 1 (period C in FIG. 6), the ground circuit of the current transformer 3 is closed to form a ground circuit (see FIG. 5). Thereby, the internal arc accident can be suppressed. Also, when an internal arc accident occurs during normal operation (period D in FIG. 6), the internal arc accident can be suppressed by closing the ground circuit of the current transformer 3. Further, at the time of a power outage at E, by opening the first switch 1 and closing the ground circuit of the current transformer 3, it is also possible to form a ground circuit. Thus, by closing the ground circuit of the current transformer 3 at the time of a power outage to form a ground circuit, the adverse effects caused by an accident can be prevented.

[0018] Furthermore, during high current conduction at F, it is also possible to conduct electricity in the first switch 1 or the current limiting element 4 incorporated in the current transformer 3. Thus, by conducting electricity in the first switch 1 or the current limiting element 4 incorporated in the current transformer 3 for high current, it is possible to expect prevention of adverse effects caused by an accident in any circuit during an accident, so a higher effect can be expected for accident prevention.

[0019] According to this embodiment, by bypassing the main circuit current through the current transformer 3, the switch can be replaced without powering off. Further, in live working during replacement, the occurrence of an internal arc accident due to an internal short circuit can be suppressed.

[0020] Embodiment 2. Figure 7 is a cross-sectional view showing the first switch 1 housed in a closed box, and Figure 8 is a detailed cross-sectional view thereof. The first switch 1 is a pull-out device that allows the first switch 1 to be pulled out from the closed box 11 for maintenance and inspection. The first switch 1 is housed in a fixed frame 100 that houses switches. The commutator 3 is located within the fixed frame 100 of the pull-out switch. The movable electrode 8 is connected to the higher-level system, the first fixed electrode 6 is connected to the grounding circuit, and the second fixed electrode 5 is connected to the lower-level system via a current-limiting element 4. The commutator 3 is made of an integrally molded insulating container 9 and can be housed within the fixed frame 100. The commutator 3 is formed to be an integral structure with the unit that houses the pull-out switch, which is the fixed frame 100, and the commutator 3 can be attached to a structure called a bushing 12 that holds and insulates the conductor 13 within the fixed frame 100. By forming the commutator 3 as an integral structure with a unit called the fixed frame 100, which houses a draw-out type switch, the commutator 3 can be compactly arranged inside the enclosed box 11.

[0021] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed in this specification. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments. [Explanation of symbols]

[0022] 1 1st switch, 2 2nd switch, 3 Commutator, 4 Current limiting element, 5 2nd fixed electrode, 6 First fixed electrode, 8 Movable electrode, 100 Fixed frame, 11 Enclosure box, 12 Bushing, 13 Conductor.

Claims

1. The power supply line includes a first switch and a commutator connected in parallel to the first switch. The commutator has a first fixed electrode connected to ground or another phase, a second fixed electrode to which a current limiting element is connected, and a movable electrode configured to be electrically conductive to the first fixed electrode or the second fixed electrode. A switching device in which the movable electrode, the second fixed electrode, and the current limiting element are connected in parallel to the first switch.

2. The switching device according to claim 1, wherein the commutator is formed to be an integral structure with the fixed frame of the draw-out type switch housing the first switch, and the commutator is attachable to a bushing that holds and insulates a conductor in the fixed frame.

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