Switchgear

Abstract

To provide a switch gear which makes a breaker as a movement object move only in a no-voltage state.SOLUTION: A switch gear includes: a main circuit structure 6 in which a current flows at the time of distributing and receiving a power; a breaker 8 that can be moved to a preset direction, and is a movement object which is detachably connected to the main circuit structure; and no-voltage means Mp (disconnection mechanism 14) that is provided to the main circuit structure, and is arranged on an upstream side from the breaker in a direction where the current flows. The no-voltage means can set the breaker to a no-voltage state so as to be electrically insulated to the main circuit structure, and the breaker can be moved to a predetermined direction so as to be separated from the main circuit structure when it becomes the no-voltage state by the no-voltage means.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a switchgear. [Background technology]

[0002] As a switching device for receiving and distributing electricity installed in a building or a large facility, for example, a switchgear equipped with a switch such as a circuit breaker or a disconnecting switch is known. A vacuum valve is applied to the switchgear as a component of the switch. The inside of the vacuum valve is maintained in a constant insulating state by an insulating container, and a pair of electrodes are housed inside the insulating container so as to be connectable and disconnectable. In this case, by connecting and disconnecting the pair of electrodes, a fault current is interrupted and a load current is opened and closed, and power is stably supplied from the switchgear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-45618 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, for example, during maintenance or inspection, it is conceivable that the circuit breaker may be pulled out from the switchgear and moved. In this case, the panel door (also called the front door) is kept closed for safety reasons, and the circuit breaker is operated to open the circuit to cut off the flow of current and create a currentless state, after which this current-free circuit breaker is separated from the main circuit structure through which current flows during power reception and distribution.

[0005] At this time, in order to safely disconnect the circuit breaker, which is the object to be moved, from the main circuit structure, it is required that the circuit breaker is electrically disconnected from the main circuit structure (in other words, in a no-voltage state where no voltage is applied) (i.e., the circuit breaker is de-voltaged).

[0006] In order to meet this demand, the present invention provides a switchgear that allows a circuit breaker, which is an object to be moved, to be moved only in a no-voltage state. [Means for solving the problem]

[0007] According to an embodiment, the system includes a main circuit structure through which current flows during power reception and distribution, a circuit breaker as a movable object that can move in a predetermined direction and is detachably connected to the main circuit structure, and a voltage-neutralizing means that is provided in the main circuit structure and arranged upstream of the circuit breaker in the direction of current flow, and the voltage-neutralizing means is capable of placing the circuit breaker in a voltage-neutral state in which it is electrically isolated from the main circuit structure, and when the circuit breaker is placed in the voltage-neutral state by the voltage-neutralizing means, it is detached from the main circuit structure and can move in the predetermined direction. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a side view showing the internal configuration of the switchgear according to the first embodiment. [Diagram 2] Operational flow diagram of the switchgear in Fig. 1. [Diagram 3] FIG. 11 is a front view showing an internal configuration of a switchgear according to a second embodiment. [Figure 4] Operational flow diagram of the switchgear in Figure 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] "First embodiment" 1 is a side view of the internal configuration of the switchgear 1. The switchgear 1 has a grounded metal housing 2 (also called a panel), and inside this housing 2, various electric devices (for example, switches such as a circuit breaker 8 and a disconnecting switch, a bus bar 7, and an instrument transformer equipped with various current transformers 12 and 13) described below are stored in multiple layers.

[0010] 1, as an example, the switchgear 1 has an opening on the front side 2p of the housing 2 and a panel door 3 (also called a front door) that releasably closes the opening 2p. The panel door 3 is configured to be unlockable when a circuit breaker 8, which will be described later, is moved in a preset direction.

[0011] The inside of the housing 2 is divided by a pair of partition frames (a first partition frame 4 and a second partition frame 5). These partition frames 4, 5 are arranged at an interval from the panel door 3 toward the rear of the housing 2. The panel door 3, the first partition frame 4, and the second partition frame 5 are aligned parallel to each other in this order.

[0012] Between the partition frames 4, 5, there are provided a main circuit structure 6 through which current flows during power reception and distribution, a bus bar 7 for connecting an electric path to an adjacent panel to pass current through the main circuit structure 6, and a housing section 9 for housing a circuit breaker 8. The circuit breaker 8 includes a pair of electrodes E1, E2, a plurality of rollers 10, a gripping section 11, and a pair of circuit breaker side connecting sections 8a, 8b. The housing section 9 includes a guide 9g and a pair of main circuit side connecting sections 9a, 9b.

[0013] The pair of electrodes E1, E2 are housed in a vacuum valve (not shown) constituting the circuit breaker 8, and are configured to be relatively connectable and disconnectable by a control unit 17, which will be described later. In this case, the vacuum valve is opened by separating the pair of electrodes E1, E2 from each other, and at this time, the flow of current is stopped by the circuit breaker 8. On the other hand, the vacuum valve is closed by bringing the pair of electrodes E1, E2 into contact with each other, and at this time, the flow of current is maintained by the circuit breaker 8.

[0014] 1, the guide 9g of the accommodation section 9 extends straight from the accommodation section 9, across the first partition frame 4, to just before the panel door 3. The roller 10 of the circuit breaker 8 is configured to be able to roll along the guide 9g. In this configuration, the roller 10 rolls along the guide 9g, thereby allowing the circuit breaker 8 to move in a preset direction.

[0015] For example, after unlocking the panel door 3, the grip portion 11 of the circuit breaker 8 is gripped and pulled (hereinafter referred to as the pulling operation). At this time, the rollers 10 roll along the guides 9g. This allows the circuit breaker 8 to be moved toward the front side (opening) 2p of the housing 2. On the other hand, after the circuit breaker 8 has been moved to the front side (opening) 2p of the housing 2, the grip portion 11 is gripped and pushed in (hereinafter referred to as the pushing operation). At this time, the rollers 10 roll along the guides 9g. This allows the circuit breaker 8 to be moved toward the back of the housing 2.

[0016] The circuit breaker 8 is configured as a movable object that is connected to the main circuit structure 6 in a detachable manner by such pulling and pushing operations. That is, a pair of circuit breaker side connection parts (a first circuit breaker side connection part 8a, a second circuit breaker side connection part 8b) are attached to the circuit breaker 8 so as to be movable together with the circuit breaker 8. These circuit breaker side connection parts 8a, 8b extend toward the back of the housing 2. Meanwhile, a pair of main circuit side connection parts (a first main circuit side connection part 9a, a second main circuit side connection part 9b) are fixed to the housing part 9. These main circuit side connection parts 9a, 9b extend toward the pair of circuit breaker side connection parts 8a, 8b while being electrically connected to the main circuit structure 6.

[0017] In this case, the first circuit breaker side connection portion 8a and the second circuit breaker side connection portion 8b extend in parallel with each other over the same overall length. The first main circuit side connection portion 9a and the second main circuit side connection portion 9b extend in parallel with each other over the same overall length. The first circuit breaker side connection portion 8a and the first main circuit side connection portion 9a are aligned straight and facing each other. The second circuit breaker side connection portion 8b and the second main circuit side connection portion 9b are aligned straight and facing each other. This allows the pair of circuit breaker side connection portions 8a, 8b and the pair of main circuit side connection portions 9a, 9b to be simultaneously separated from or connected to each other.

[0018] For example, after unlocking the panel door 3, the circuit breaker 8 is pulled. This allows the pair of circuit breaker side connection parts 8a, 8b to be simultaneously separated from the pair of main circuit side connection parts 9a, 9b. Meanwhile, the circuit breaker 8 is pushed in. This allows the pair of circuit breaker side connection parts 8a, 8b to be simultaneously connected to the pair of main circuit side connection parts 9a, 9b. In this way, by connecting and disconnecting the pair of circuit breaker side connection parts 8a, 8b and the pair of main circuit side connection parts 9a, 9b from each other, the circuit breaker 8 can be detachably connected to the main circuit structure 6.

[0019] Here, in a state where the pair of circuit breaker side connecting parts 8a, 8b and the pair of main circuit side connecting parts 9a, 9b are connected to each other and the circuit breaker 8 is electrically connected to the main circuit structure 6, a vacuum valve constituting the circuit breaker 8 is closed by a control part 17 described later, and the pair of electrodes E1, E2 are brought into contact with each other. At this time, for example, a current that has flowed into the main circuit structure 6 via the busbar 7 flows from the first main circuit side connecting part 9a through the first circuit breaker side connecting part 8a to the circuit breaker 8 (electrodes E1, E2), and then flows from the second circuit breaker side connecting part 8b through the second main circuit side connecting part 9b to the instrument transformer (current transformer 12, zero-phase current transformer 13, etc.).

[0020] Meanwhile, for example, during maintenance or inspection, it is assumed that the circuit breaker 8 will be pulled out from the switchgear 1 and moved. At this time, in order to safely disconnect the circuit breaker 8 to be moved from the main circuit structure 6, it is required that the circuit breaker 8 is in a state in which it is electrically disconnected from the main circuit structure 6 (in other words, in a no-voltage state in which no voltage is applied) (i.e., the circuit breaker 8 is in a no-voltage state).

[0021] In order to meet this demand, the switchgear 1 has a voltage-relieving means Mp that can bring the circuit breaker 8 into a voltage-relieved state in which the circuit breaker 8 is electrically insulated from the main circuit structure 6. The voltage-relieving means Mp is provided in the main circuit structure 6 upstream of the circuit breaker 8 in the direction of current flow from the busbar 7 to the circuit breaker 8. In FIG. 1 , as an example, the voltage-relieving means Mp is disposed in the main circuit structure 6 between the circuit breaker 8 and the busbar 7.

[0022] 1, the voltage-relieving means Mp includes a disconnecting mechanism 14 that puts the circuit breaker 8 into a voltage-relieving state. The disconnecting mechanism 14 puts the circuit breaker 8 into a voltage-relieving state by preventing a potential difference from occurring between the pair of circuit breaker side connecting parts 8a, 8b (in other words, by making the pair of circuit breaker side connecting parts 8a, 8b have the same potential).

[0023] As a method for preventing a potential difference from occurring between the pair of circuit breaker side connection parts 8a, 8b, for example, the disconnecting mechanism 14 stops the flow of current between the busbar 7 and the circuit breaker 8 (specifically, the first main circuit side connection part 9a).

[0024] As a method for stopping the flow of current, for example, a case is assumed in which the main circuit structure 6 includes a conductor (not shown) through which current flows during power reception and distribution. In this case, the disconnecting mechanism 14 disconnects a part of the conductor that constitutes the main circuit structure 6 and that extends between the busbar 7 and the circuit breaker 8 (first main circuit side connection portion 9a).

[0025] As a method for partially disconnecting the conductor, for example, a conductor that is divided into two is set in advance in the disconnecting mechanism 14. During power reception and distribution, the two divided conductors are brought into contact with each other to allow a current to flow between the busbar 7 and the circuit breaker 8 (first main circuit side connection portion 9a). Then, when the disconnecting mechanism 14 is activated, the two conductors are separated from each other and disconnected.

[0026] In a specific example of the disconnecting mechanism 14, one of the two separated conductors is fixed and the other is movable. In this configuration, when receiving and distributing electricity, the other conductor is brought close to one of the conductors to make contact with it. When the disconnecting mechanism 14 is activated, the other conductor is moved away from the one of the conductors to form a spatial gap between the conductors, thereby disconnecting the conductors.

[0027] Another specific example of the disconnecting mechanism 14 is one in which the base end of a switch lever (not shown) is connected to one of two divided conductors, and the other conductor is provided with a contact that the tip of the switch lever can contact. In this configuration, when receiving and distributing electricity, the tip of the switch lever is brought into contact with the contact of the other conductor. Then, when the disconnecting mechanism 14 is activated, the tip of the switch lever is moved away from the contact of the other conductor, thereby forming a spatial gap between the conductors and disconnecting the conductor.

[0028] This allows the circuit breaker 8 to be in a voltage-free state. At this time, the circuit breaker 8 is in a state equivalent to a state in which it is not in electrical contact with the main circuit structure 6, that is, in a state in which no voltage is applied. In this state, the circuit breaker 8 is safely separated from the main circuit structure 6 and becomes movable in the above-mentioned preset direction.

[0029] Here, an interlock is provided for the operation timing of the disconnecting mechanism 14 described above, i.e., the timing at which the disconnecting mechanism 14 de-energizes the circuit breaker 8. In Fig. 1, as an example, an interlock is set between the circuit breaker 8 and the disconnecting mechanism 14. As a result, the disconnecting mechanism 14 de-energizes the circuit breaker 8 when the circuit breaker 8 is operated to cut off the flow of current and enters a no-current state, i.e., when a vacuum valve constituting the circuit breaker 8 is opened by the control unit 17 described later and the pair of electrodes E1, E2 are separated from each other.

[0030] Furthermore, the panel door 3 is configured to be unlocked when the circuit breaker 8 is moved in a preset direction. The panel door 3 is provided with a locking unit 15, and the panel door 3 can be unlocked or locked by operating the locking unit 15. In this case, an interlock is provided for the timing of unlocking the panel door 3 (locking unit 15). As an example, in FIG. 1, an interlock is set between the circuit breaker 8, the disconnecting mechanism 14, and the panel door 3 (locking unit 15). As a result, the panel door 3 (locking unit 15) is unlocked when the circuit breaker 8, which has been set to a no-current state, is set to a no-voltage state by the disconnecting mechanism 14.

[0031] In addition, the switchgear 1 has a control system for executing the above-mentioned interlock. In Fig. 1, as an example, the control system includes a multi-relay 16 and a control unit 17 electrically connected to the multi-relay 16. The multi-relay 16 and the control unit 17 are provided on the panel door 3. A control program for executing the interlock is stored in advance in the control unit 17.

[0032] The multi-relay 16 integrates, for example, the measurement function of the instrument transformers (current transformer 12, zero-phase current transformer 13), the control function of the circuit breaker 8 and the voltage-relieving means Mp (disconnection mechanism 14) and the lock unit 15, and the remote operation function for the circuit breaker 8 and the voltage-relieving means Mp (disconnection mechanism 14) and the lock unit 15.

[0033] The multi-relay 16 is electrically connected to the circuit breaker 8, the voltage dissipation means Mp (disconnection mechanism 14), and the lock unit 15, and operates the circuit breaker 8 and activates the voltage dissipation means Mp (disconnection mechanism 14) and the lock unit 15 in accordance with a control program stored in the control unit 17.

[0034] 2 is an operation flow diagram of the interlock set between the circuit breaker 8, the disconnecting mechanism 14, and the panel door 3 (lock unit 15). This interlock operation is performed by a CPU (not shown) in the control unit 17, where a control program stored in a ROM (not shown) is executed using a RAM (not shown) as a working area.

[0035] As shown in FIG. 2, when the circuit breaker 8 as the moving object is opened (i.e., the pair of electrodes E1, E2 are separated) (S1), thereby interrupting the electric circuit of the circuit breaker 8 (S2), the circuit breaker 8 is made currentless and enters a currentless state in which the flow of current is interrupted in the main circuit structure 6 (S3).

[0036] Next, when the interlock of the disconnecting mechanism 14 is released (S4), the disconnecting mechanism 14 is activated (S5), thereby stopping the flow of current between the busbar 7 and the circuit breaker 8 (first main circuit side connection portion 9a). As a result, the circuit breaker 8 is de-energized and is electrically isolated from the main circuit structure 6 (in other words, is in a no-voltage state where no voltage is applied) (S6).

[0037] Next, when the interlock of the panel door 3 (lock unit 15) is released (S7), the lock unit 15 is activated (S8), whereby the circuit breaker 8 is disconnected from the main circuit structure 6 and becomes movable in the predetermined direction described above (S9).

[0038] As described above, according to this embodiment, the circuit breaker 8 as the object to be moved can be moved only in a no-voltage state. This causes the circuit breaker 8 to be in a no-voltage state, being electrically disconnected from the main circuit structure 6 (in other words, in a no-voltage state where no voltage is applied). As a result, the circuit breaker 8 can be safely disconnected from the main circuit structure 6.

[0039] According to this embodiment, the multi-relay 16 has a remote control function for the circuit breaker 8, the voltage neutralization means Mp, and the lock unit 15. This makes it possible to perform the above-mentioned interlock control by remotely controlling the multi-relay 16. As a result, the circuit breaker 8 can be separated from the main circuit structure 6 more safely.

[0040] According to this embodiment, the panel door 3 (lock section 15) is unlocked when the circuit breaker 8 that has been put into a no-current state is put into a no-voltage state by the voltage-relief means Mp. This allows the panel door 3 (lock section 15) to be unlocked and the circuit breaker 8 to be moved only when the circuit breaker 8 to be moved is in a no-current and no-voltage state. In other words, when the circuit breaker 8 to be moved is not in a voltage-relief state, the panel door 3 (lock section 15) cannot be unlocked. As a result, the safety of the worker who moves the circuit breaker 8 can be ensured.

[0041] "Second embodiment" 3 is a front view of the internal configuration of the switchgear 1. In describing this embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0042] 3, as an example, the inside of the housing 2 is divided into two areas by a partition wall 18 provided in the center when viewed from the front. In such a housing 2, a circuit breaker 19 is housed on one side of the partition wall 18, and a circuit breaker 8 as an object to be moved and a disconnecting mechanism 14 (voltage neutralization means Mp) are housed on the other side of the partition wall 18, similarly to the first embodiment described above.

[0043] As shown in Fig. 3, a busbar 7 is provided in the partition wall 18. The main circuit structure 6 of the first embodiment described above is extended from one side of the housing 2 to the other side via the busbar 7. In this case, the circuit breaker 19, the busbar 7, the disconnecting mechanism 14, and the circuit breaker 8 are arranged in this order in the main circuit structure 6 from the upstream side to the downstream side in the direction in which the current flows from one side of the housing 2 to the other side via the busbar 7. That is, the disconnecting mechanism 14 is arranged upstream of the circuit breaker 8, as in the first embodiment described above. The circuit breaker 19 is arranged upstream of the disconnecting mechanism 14 and the circuit breaker 8.

[0044] Here, focusing on the two circuit breakers 8 and 19, in the direction of current flow, circuit breaker 8 as the object to be moved is defined as the lower circuit breaker 8 located downstream of circuit breaker 19, and circuit breaker 19 is defined as the upper circuit breaker 19 located upstream of the lower circuit breaker 8.

[0045] In Fig. 3, as an example, the upper circuit breaker 19 is applied as a voltage-relieving means Mp that brings the lower circuit breaker 8 into a voltage-relieving state in which it is electrically insulated from the main circuit structure 6. The upper circuit breaker 19 as the voltage-relieving means Mp brings the lower circuit breaker 8 into a voltage-relieving state when a current-relieving state is achieved in which the flow of current to the lower circuit breaker 8 is interrupted by operation of the upper circuit breaker 19.

[0046] The upper circuit breaker 19 has a pair of electrodes E1, E2 that can be relatively connected and separated. The pair of electrodes E1, E2 are housed in a vacuum valve (not shown) that constitutes the upper circuit breaker 19, and are configured to be relatively connected and separated by a control unit 17 described later. In this case, the vacuum valve is closed by bringing the pair of electrodes E1, E2 into contact with each other, and the flow of current is maintained by the upper circuit breaker 19.

[0047] In response to this, the pair of electrodes E1, E2 are separated from each other to open the vacuum valve. In this state, the upper circuit breaker 19 stops the flow of current toward the lower circuit breaker 8. This allows the lower circuit breaker 8 to be in a voltage-free state. At this time, the lower circuit breaker 8 is in a state equivalent to a state in which it is not in electrical contact with the main circuit structure 6, that is, in a state in which no voltage is applied. In this state, the lower circuit breaker 8 is safely separated from the main circuit structure 6 and becomes movable in the above-mentioned preset direction.

[0048] Here, an interlock is provided for the operation timing of the upper circuit breaker 19, i.e., the timing at which the upper circuit breaker 19 de-energizes the lower circuit breaker 8. In Fig. 3, as an example, an interlock is set between the lower circuit breaker 8 and the upper circuit breaker 19. As a result, the upper circuit breaker 19 de-energizes the lower circuit breaker 8 when the flow of current is interrupted by the operation of the lower circuit breaker 8, i.e., when the vacuum valve constituting the lower circuit breaker 8 is opened by the control unit 17 described later and the pair of electrodes E1, E2 are separated from each other.

[0049] Furthermore, the housing 2 is provided with a panel door 3 (also called a front door) that closes the front side (opening) 2p in an openable manner, as in the first embodiment described above. An interlock is provided for the timing of unlocking the panel door 3 (lock section 15). As an example in FIG. 3, an interlock is set between the lower circuit breaker 8, the upper circuit breaker 19, and the panel door 3 (lock section 15). As a result, the panel door 3 (lock section 15) is unlocked when the lower circuit breaker 8, which has been set to a no-current state, is set to a no-voltage state by the upper circuit breaker 19.

[0050] As in the first embodiment described above, the panel door 3 is provided with a multi-relay 16 constituting a control system, a control unit 17 electrically connected to the multi-relay 16, and a lock unit 15. In addition to the functions of the first embodiment described above, the multi-relay 16 also has a control function for the voltage-relief means Mp (upper circuit breaker 19) and a remote control function for the voltage-relief means Mp (upper circuit breaker 19).

[0051] 3, a relay unit 20 is provided on the partition wall 18. The multi-relay 16 is electrically connected to the lower circuit breaker 8, the voltage relief means Mp (upper circuit breaker 19, disconnection mechanism 14), and the lock unit 15 via the relay unit 20. This enables the multi-relay 16 to operate the lower circuit breaker 8 and activate the voltage relief means Mp (upper circuit breaker 19, disconnection mechanism 14) and the lock unit 15 in accordance with a control program stored in the control unit 17.

[0052] 4 is an operation flow diagram of the interlock set between the lower circuit breaker 8, the upper circuit breaker 19, and the panel door 3 (lock unit 15). This interlock operation is performed by a CPU (not shown) in the control unit 17, where a control program stored in a ROM (not shown) is executed using a RAM (not shown) as a working area.

[0053] As shown in Figure 4, the presence of the lower circuit breaker 8 as the object to be moved is confirmed (T1), and when the presence of the upper circuit breaker 19 upstream of it is confirmed (T2), the lower circuit breaker 8 is opened (i.e., the pair of electrodes E1, E2 are separated) (T3). As a result, when the electric circuit of the lower circuit breaker 8 is interrupted (T4), the lower circuit breaker 8 is made currentless and enters a currentless state in which the flow of current is interrupted in the main circuit structure 6 (T5).

[0054] Next, when the interlock of the upper circuit breaker 19 is released (T6), the upper circuit breaker 19 is opened (i.e., the pair of electrodes E1, E2 are separated) (T7), whereby the electric path of the upper circuit breaker 19 is interrupted (T8), and the upper circuit breaker 19 is put into a currentless state. At this time, in the main circuit structure 6, a currentless state is entered in which the flow of current from the upper circuit breaker 19 to the lower circuit breaker 8 is interrupted. As a result, the lower circuit breaker 8 is put into a voltageless state and is electrically isolated from the main circuit structure 6 (in other words, a voltageless state where no voltage is applied) (T9).

[0055] Next, when the interlock of the panel door 3 (lock unit 15) is released (T10), the lock unit 15 is activated (T11), whereby the lower circuit breaker 8 is disconnected from the main circuit structure 6 and becomes movable in the predetermined direction described above (T12).

[0056] As described above, according to this embodiment, when the upper circuit breaker 19 is present upstream of the lower circuit breaker 8 to be moved, the upper circuit breaker 19 is used as the voltage neutralization means Mp. In this case, the upper circuit breaker 19 is opened to cut off the flow of current to the lower circuit breaker 8 without operating the disconnecting mechanism 14, resulting in a no-current state. This causes the lower circuit breaker 8 to be voltage neutralized and electrically isolated from the main circuit structure 6 (in other words, a no-voltage state where no voltage is applied). As a result, the circuit breaker 8 can be safely isolated from the main circuit structure 6. The other configurations and effects are similar to those of the first embodiment described above, and therefore will not be described further.

[0057] "Modification of the second embodiment" In the above-mentioned second embodiment, a technique for setting an interlock between the lower circuit breaker 8 and the upper circuit breaker 19 has been assumed, but instead, a case in which no interlock is set between the lower circuit breaker 8 and the upper circuit breaker 19 is also included in the technical scope of the present invention. In this case, even if the lower circuit breaker 8 is not placed in a no-current state, the flow of current from the upper circuit breaker 19 to the lower circuit breaker 8 is interrupted by opening the upper circuit breaker 19, and the lower circuit breaker 8 can be placed in a no-current state, and no voltage is applied to the lower circuit breaker 8. Note that other configurations and effects are similar to those of the above-mentioned second embodiment, and therefore description thereof will be omitted.

[0058] Although some embodiments and modifications of the present invention have been described above, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. These embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0059] 1...switchgear, 2...housing, 3...panel door (front door), 4...first partition frame, 5...second partition frame, 6...main circuit structure, 7...busbar, 8...circuit breaker, 9...accommodation section, 10...roller, 11...gripping section, 12...current transformer, 13...zero-phase current transformer, 14...disconnecting mechanism, 15...lock section, 16...multi-relay, 17...control section, 18...partition wall, 19...upper circuit breaker, 20...relay section.

Claims

1. A main circuit structure through which current flows during power reception and distribution; a breaker as a movable object that is movable in a preset direction and is detachably connected to the main circuit structure; a voltage neutralization means provided in the main circuit structure and arranged upstream of the breaker in a current flow direction, the voltage neutralization means is capable of bringing the breaker into a voltage neutral state in which the breaker is electrically insulated from the main circuit structure, The circuit breaker is a switchgear that, when the voltage-dissipating means brings the circuit breaker into the voltage-dissipating state, is separated from the main circuit structure and becomes movable in the preset direction.

2. The switchgear according to claim 1 , wherein the no-voltage state includes a state in which no voltage is applied to the circuit breaker by making the circuit breaker electrically non-contact with the main circuit structure.

3. An interlock is provided between the circuit breaker and the voltage neutralizing means, The switchgear according to claim 1 , wherein the voltage-relieving means brings the circuit breaker into the voltage-relieving state when a current-relieving state is achieved in which a flow of current is interrupted by operation of the circuit breaker.

4. a panel door that can be unlocked when the circuit breaker is moved in the preset direction; An interlock is provided between the circuit breaker, the voltage dissipation means, and the panel door, The switchgear according to claim 3 , wherein the panel door is unlocked when the circuit breaker is brought into the voltage-free state by the voltage-free means.

5. The circuit breaker includes a pair of connection parts that are detachably connected to the main circuit structure, The switchgear according to claim 1 , wherein the voltage-relieving means includes a disconnecting mechanism that brings the circuit breaker into the voltage-relieving state by preventing a potential difference from occurring between the pair of connecting portions.

6. The switchgear according to claim 5 , wherein the disconnecting mechanism stops a flow of current toward the circuit breaker.

7. The main circuit structure includes a conductor through which a current flows during power reception and distribution, The switchgear according to claim 6, wherein the disconnecting mechanism stops a flow of current toward the circuit breaker by partially disconnecting the conductor that extends from the disconnecting mechanism toward the circuit breaker, among the conductors that constitute the main circuit structure.

8. In the main circuit structure, an upper circuit breaker is provided upstream of the circuit breaker in the direction of current flow, 2. The switchgear according to claim 1, wherein the upper circuit breaker is used as the voltage-neutralizing means, so that the upper circuit breaker puts the circuit breaker into the voltage-neutralizing state when a current flow is interrupted by operation of the upper circuit breaker, thereby putting the circuit breaker into the voltage-neutralizing state.

9. a panel door that can be unlocked when the circuit breaker is moved in the preset direction; An interlock is provided between the upper circuit breaker and the panel door, The switchgear according to claim 8 , wherein the panel door is unlocked when the circuit breaker is brought into the no-voltage state by the higher-level circuit breaker.

10. The switchgear according to claim 8 , wherein the upper circuit breaker stops a flow of current toward the circuit breaker.

11. The upper circuit breaker includes a pair of electrodes that can be relatively connected and disconnected, The switchgear according to claim 10 , wherein the upper circuit breaker stops a flow of current toward the circuit breaker by separating the pair of electrodes from each other.

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