JP2003308767A - Vacuum switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum switch capable of coordination of insulation of dielectric strength at a cut off or a block position. <P>SOLUTION: This vacuum switch is provided with a vacuum insulating vessel 21, a first fixed electrode 22 provided on one end of the vacuum insulating vessel 21, a first movable electrode 25 provided on another end of the vacuum insulating vessel 21, a second movable electrode 26 provided to surround a movable energizing shaft 23, a second fixed electrode 28 provided at a middle part of the vacuum insulating vessel 21, and an operating mechanism moving the movable energizing shaft 23 to optional three position including a on position and a ground position of the on position where the first movable electrode 25 and the first fixed electrode 22 keep contact, the cut off or the block position, and the ground position where the second movable electrode 26 and the second fixed electrode 28 keep contact. Strength of electric field between the electrode and the ground is lower than that between the electrodes at the cut off or the block position. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable vacuum switchgear having a higher dielectric strength between poles than the ground, which is suitable for use in, for example, a gas-insulated switchgear.

[0002]

2. Description of the Related Art Regarding conventional switchgear, 22 / 33k
The V-class power receiving and transforming equipment will be described as an example.

The switchgear of this class is required to be miniaturized and hermetically sealed due to problems such as dirt on the charging part, safety and noise as well as construction costs and soaring land, and a gas-insulated switchgear is adopted. Has been done.

FIG. 5 is a block diagram of a typical gas-insulated switchgear. In FIG. 5, the inside of the box 1 whose outer periphery is airtightly surrounded by a mild steel plate is sealed with SF6 gas having excellent dielectric strength, and is partitioned by a partition plate 2 into a circuit breaker chamber 1a and a power receiving chamber 1b. There is. The circuit breaker chamber 1a is provided with a vacuum switch 3 and its operating mechanism 3a, and the power receiving chamber 1b is provided with a power receiving cable head 4, disconnectors 5a and 5b, and a bus bar 7 fixed to the insulator 6. Are provided, and each is connected by the connection conductor 8.

A high vacuum vacuum valve 9 having excellent dielectric strength and arc extinguishing performance is provided at the opening / closing portion of the vacuum opening / closing device 3.
Is used.

In FIG. 6 showing the vacuum valve 9, a fixed-side sealing metal fitting 11 and a movable-side sealing metal fitting 12 are hermetically sealed at the openings at both ends of a cylindrical vacuum insulating container 10. Then, a fixed energizing shaft 13 which is one of electric paths that can be freely connected and detached is pierced through the fixed side sealing metal fitting 11 so as to be airtightly fixed, and a fixed electrode 14 is fixed to an inner end portion of the container of the fixed energizing shaft 13. Has been done.

On the other hand, the movable enclosing metal fitting 12 is penetrated by a movable energizing shaft 15 which is the other electric path connected to an operating mechanism (not shown), and is fixed by a bellows 16 so as to be movable back and forth and airtightly. The inside of the vacuum insulation container 10 is kept at a high vacuum with an internal pressure of 1 × 10 ⁻² Pa or less. A movable electrode 17, which is arranged to face the fixed electrode 14, is fixed to the inner end of the movable energizing shaft 15 inside the container. In addition, in the middle of the inner surface of the vacuum insulation container 10, the electrodes 14,
A cylindrical arc shield 18 is fixed so as to surround 17.

As described above, the entire shape of the vacuum valve 9 is a cylindrical high vacuum container and has a simple structure.

By the way, in the gas-insulated switchgear having such a structure, the disconnecting switches 5a and 5b in the power receiving chamber 1b are provided.
Are arranged in an SF6 gas atmosphere as an insulating / arc-extinguishing medium. It is known that this SF6 gas has excellent dielectric strength and arc extinguishing performance, and is a very stable gas under normal operating conditions.

However, when an arc discharge is generated in the SF6 gas, the SF6 gas reacts with the arc heat to generate a decomposition product or a decomposition gas composed of a fluorine compound.
Decomposition products of SF6 gas and decomposition gas lower the dielectric strength and arc extinguishing performance, and therefore, when the decomposed gas is collected, special treatment and management are required.

Since the accidental current is cut off by the vacuum switchgear 3 which is separated from the power receiving chamber 1b by the partition plate 2, no decomposition product or decomposition gas is generated, but the bus bar is switched in the substation. Is performed by the disconnectors 5a and 5b. Therefore, the disconnecting switches 5a and 5b are required to have a duty to interrupt the loop current close to the rated current.
Decomposition products and decomposition gas are generated at a and 5b. And
When recovering gas by shutting off with such a disconnector,
It is difficult to handle, such as collecting through an adsorbent.

Therefore, a vacuum disconnector in which the insulating medium of the disconnector is a vacuum is conceivable, but there is a problem that the price of the switchgear becomes high.

On the other hand, in order to solve such a problem,
For example, there is a technique described in JP-A-9-153320. In this structure, a fixed electrode and a ground electrode are provided at both ends of a cross-shaped vacuum valve, and a movable electrode having a fulcrum and a current-carrying shaft are provided at positions orthogonal to the fixed electrode and the ground electrode.

However, since the structure of the vacuum valve is complicated, the number of parts is increased and the cost is increased. Further, since the vacuum valve is not easy to assemble due to its complicated structure, it is difficult to obtain a highly reliable vacuum valve.

Further, there is a technique described in Japanese Patent Laid-Open No. 2000-164084. The vacuum valve used here is
A fixed electrode and a movable electrode are provided at both ends of a cylindrical insulating container, and a ground electrode fixed at an intermediate position of the insulating container is provided immediately below the movable electrode to simplify the structure of the vacuum valve.

However, since the movable electrode and the ground electrode are close to each other, when current is cut off between the fixed electrode and the movable electrode, the metal vapor diffuses and the withstand voltage performance of the ground electrode deteriorates. .

Furthermore, Japanese Patent Laid-Open No. 2001-210200
In the vacuum valve described in the publication, a fixed electrode is provided on one side of a cylindrical electrically conductive container and a fixed electrode is provided on the other side of the movable energizing shaft, and a first and a second movable electrode are provided at a fixed interval. , In addition,
Immediately below the second movable electrode, a ground electrode fixed at an intermediate position of the insulating container is provided. As a result, current is cut off between the fixed electrode and the first movable electrode, and
The movable electrode and the ground electrode are used to open and close the ground to suppress the effect of metal vapor on the ground electrode due to current interruption.

However, in the vacuum valve, the fixed electrode and the first movable electrode are provided with a cut position and a disconnection position, and each have a withstand voltage characteristic, but the withstand voltage from the ground to the pole is higher. There is a problem in terms of insulation coordination that improves the characteristics. That is, it is unclear in which portion dielectric breakdown occurs when an overvoltage that cannot be protected such as a direct lightning strike and has a withstand voltage characteristic or more is intruded, which is a problem from the viewpoint of preventing damage to electric equipment and accident spread.

[0019]

As described above, the conventional vacuum switchgear of this type has a complicated structure and is inferior in reliability, and has problems in insulation coordination.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum switchgear which has been made in view of the above problems and has a simple structure, high reliability, and insulation coordination.

[0021]

In order to achieve the above object, the vacuum switchgear according to the first invention (Claim 1) is hermetically sealed at both ends with sealing metal fittings. A cylindrical vacuum insulation container to which a vacuum insulation container is connected, a fixed current-carrying shaft that penetrates through the one sealing metal member and serves as one electric path fixed to the sealing metal member, and the vacuum of the fixed current-carrying shaft. A first fixed electrode provided at an inner end of the insulating container, a movable current-carrying shaft that penetrates the other sealing metal member and serves as the other electric path fixed to the sealing metal member via a bellows, A first movable electrode provided at an inner end portion of the movable energization shaft facing the first fixed electrode, and an intermediate portion in the vacuum insulation container in the axial direction of the movable energization shaft; And a second movable electrode provided so as to surround the movable energizing shaft, and the second movable electrode. A ring-shaped second fixed electrode, which is fixed to the connecting portion of the first and second vacuum insulating containers so as to face the electrode and is provided so as to penetrate the movable conducting shaft, and the movable conducting shaft. The first movable electrode and the first movable electrode
Of the contact position with which the fixed electrode is in contact, the disconnection position or the disconnection position, and the ground position with which the second movable electrode and the second fixed electrode are in contact, including the contact position and the ground position. An operating mechanism for moving to any three positions, and at the cut position or the disconnection position, compared with the electric field strength between the first fixed electrode and the first movable electrode, It is characterized in that the electric field strength between the second movable electrodes is increased.

The vacuum switchgear according to the second aspect of the present invention (claim 3) is a cylindrical vacuum insulation device in which both ends are hermetically sealed with sealing metal fittings and the first and second vacuum insulation containers are connected. A container; a fixed current-carrying shaft that penetrates through the one sealing metal member and is fixed to the sealing metal member; a first fixed electrode provided at an inner end of the vacuum insulating container of the fixed current-carrying shaft; A movable current-carrying shaft that penetrates through the other sealing metal fitting and is fixed to the sealing metal fitting via a bellows and serves as one electric path, and the first fixing to the inner end of the vacuum insulating container of the movable current-carrying shaft. A first movable electrode provided to face the electrode, and a second movable electrode provided in the vacuum insulating container in an axially intermediate portion of the movable energizing shaft so as to surround the movable energizing shaft. An electrode and a connection between the first and second vacuum insulating containers facing the second movable electrode. A ring-shaped second fixed electrode which is fixedly attached to the movable energizing shaft and serves as the other electric path provided so as to penetrate the movable energizing shaft, and the movable energizing shaft, the second movable electrode and the second fixed electrode. The entry position where the electrode is in contact,
An operation mechanism for moving to any three positions including an on-position and a grounding position among a cutting position or a disconnecting position and a grounding position where the first movable electrode and the first fixed electrode are in contact with each other. , The electric field strength between the first fixed electrode and the first movable electrode is higher than the electric field strength between the second fixed electrode and the second movable electrode at the cut position or the disconnection position. It is characterized in that

According to the first and second aspects of the invention, since the electrodes of the disconnecting switch are housed in the vacuum insulating container, even if the current close to the rated current is cut off, the SF
Since 6 gases are not used, no decomposition product or decomposition gas is generated.

Further, since the dielectric strength between the cut position and the disconnection position is between the ground and the pole, insulation coordination is achieved when an unprotected overvoltage such as direct lightning strikes. It is possible to prevent damage to the power supply, and to prevent accidents on the power supply side.

Further, since the electrodes of the circuit breaker, the disconnecting switch and the grounding switch are housed in the same cylindrical vacuum insulation container, the number of parts can be reduced, so that the vacuum switchgear can be downsized and the cost can be reduced. be able to.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the first embodiment of the present invention
A vacuum switchgear according to the embodiment will be described with reference to FIG. FIG. 1 is a vertical cross-sectional view showing the structure of a vacuum valve used in the vacuum switchgear according to the present embodiment.

As shown in FIG. 1, first and second cylindrical vacuum insulating containers 21 made of ceramic and connected to each other.
A fixed-side sealing metal fitting 11 and a movable-side sealing metal fitting 12 are hermetically sealed to the opening portions at both ends of the vacuum insulating container 21 constituted by a and 21b. A fixed energizing shaft 13 serving as one of the electric paths is penetrated and airtightly fixed to the fixed-side sealing metal fitting 11, and a first fixed electrode 22 is fixed to an inner end portion of the container of the fixed energizing shaft 13. ing.

On the other hand, a movable energizing shaft 23, which is the other electric path connected to an operating mechanism (not shown), penetrates through the movable side sealing member 12, and is fixed in an airtight manner by a bellows 24 so as to be movable back and forth. The inside of the vacuum insulation container 21 is maintained at a high vacuum with an internal pressure of 1 × 10 ⁻² Pa or less.
The fixed electrode 22 is attached to the inner end of the container of the movable energizing shaft 23.
A first movable electrode 25, which is arranged so as to face and is detachable, is fixed.

Further, the movable energizing shaft 23 is surrounded by an intermediate portion in the axial direction of the vacuum insulating container 21 so as to surround the movable energizing shaft 23 and keep a constant distance from the first movable electrode 25. The second movable electrode 26 is fixed.
In addition, the first and second constituents of the vacuum insulation container 21.
A ring-shaped fixed energizing plate 27 is fixed to the connecting portion of the vacuum insulating containers 21a and 21b, a part of which protrudes outside the vacuum insulating container 21 in an airtight manner. In addition, an end portion of the fixed energizing plate 27 located inside the vacuum insulating container 21 faces a peripheral portion of a surface of the second movable electrode 26 facing the bellows 24, and has a ring-shaped second portion. The fixed electrode 28 of is fixed. The fixed energization plate 27 is set to the ground potential with a ground wire (not shown).

Inside the first vacuum insulating container 21a, the first fixed electrode 22 and the first movable electrode 25 are provided.
A cylindrical arc shield 29 is provided so as to surround and.

Here, a position where the first fixed electrode 22 and the first movable electrode 25 are in contact with each other is defined as an entry position, and the first movable electrode 25 is linearly moved by an operation mechanism (not shown), The gap length between these electrodes 22 and 25 is d1
The position at the time of is the cut position. Then, the first movable electrode 25 further linearly moves, and between the electrodes 22 and 25.
The position when the gap length between them is d2 is the disconnection position. At this disconnection position, the second movable electrode 26 and the second fixed electrode 28 are separated from each other with a gap length d5. Further, the first movable electrode 25 linearly moves to move the second movable electrode 26 and the second fixed electrode 28.
The position where and are in contact is the grounding position. The total gap length that moves linearly is d2 + d5, and the gap lengths d5 and d1 have almost the same gap length.

At the four positions thus moved, the second movable electrode is compared with the electric field strength between the first fixed electrode 22 and the first movable electrode 25 at the cut position and the disconnection position. The electric field strength between 26 and the second fixed electrode 28 is increased.

The reason for this will be described with reference to FIG. Figure 2
, The vertical axis represents the electric field strength at the outer peripheral end of the electrode contact surface between the first fixed electrode 22 and the first movable electrode 25 and between the second movable electrode 26 and the second fixed electrode 28. Is. Then, the first fixed electrode 22 and the first
The electric field strength characteristic between the movable electrodes 25 is E1, and the electric field strength characteristic between the second movable electrode 26 and the second fixed electrode 28 is E1.
It is 2. The horizontal axis represents the first fixed electrode 22 and the first fixed electrode 22.
It is a gap length between the movable electrodes 25 of 1, which is a disconnection position at d1 and a disconnection position at d2.

As shown in FIG. 2, the gap lengths d1 and d2
In the above, all have a relation of E1 <E2. this is,
Between the first fixed electrode 22 and the first movable electrode 25,
Since each of the electrodes has a disk shape and an appropriate curvature is formed at the ends and the intervals of equipotential lines become uniform, the gap length d1
This is because the electric field strength characteristic E1 is lower than E2 at d2 and d2. Further, between the second movable electrode 26 and the second fixed electrode 28, the electrode shape is a disc shape and a ring shape,
Particularly in the ring shape, it is difficult to form an appropriate curvature and the intervals of the equipotential lines become non-uniform, so that the electric field strength characteristic E2 becomes higher than E1.

From the relationship of the electric field strength characteristic E1 <E2,
Since the second fixed electrode 28 is at the ground potential, the dielectric strength between the second movable electrode 26 and the second fixed electrode 28, which is between the ground, is low, and the first fixed electrode 28 is between the electrodes. The dielectric strength between the fixed electrode 22 and the first movable electrode 25 increases. That is, it is possible to achieve insulation cooperation in the relationship between the ground and the pole.

The electric field strength characteristic E1 is sloping down to the right and the electric field strength characteristic E2 is sloping up to the right, which is caused by the shape of the electrodes. That is, since the equipotential lines are evenly spaced between the first fixed electrode 22 and the first movable electrode 25, the electric field strength characteristic E1 is proportional to the gap length if the gap length is increased. It drops and falls to the right. In addition, the second movable electrode 26 and the second fixed electrode 2
Since the interval between the equipotential lines is nonuniform between 8 and 8, if the gap length is increased, the nonuniformity of the interval between the equipotential lines is further increased and the electric field strength characteristic E2 is proportional to the gap length. It goes up and goes up to the right.

According to the vacuum switchgear of the first embodiment, the first fixed electrode 22 and the first movable electrode are operated by the operating mechanism in response to a circuit breaker opening command from a control circuit (not shown). The first movable electrode 25 moves linearly from the entry position (FIG. 3a) where 25 is in contact with the first fixed electrode 22, and the cut position (FIG. 3b) at the position of the gap length d1. Become. Next, in response to the disconnection command from the disconnection position, the first movable electrode 25 further linearly moves to the disconnection position (FIG. 3c) at the position of the gap length d2. Then, from the state of the disconnection position, by the ground contact command, the second
The movable electrode 26 moves along the gap length d5 and comes into contact with the second fixed electrode 28 to reach the ground position (FIG. 3d).

However, since the electrode of the disconnector is housed in the vacuum container, even if the current close to the rated current such as the loop current is cut off, SF6 gas is not used, so that decomposition products and decomposition gas are generated. There is nothing to do.

Further, since the dielectric strength is between the ground and the pole between the cut position (FIG. 3b) and the disconnection position (FIG. 3c), when the unprotected overvoltage such as direct lightning strikes, the second Movable electrode 26 and second fixed electrode 28 of
Dielectric breakdown will occur between the ground and the ground. This means that insulation coordination is achieved between the load side and the power source side of the circuit breaker in the disconnection position (FIG. 3b) or the disconnection position (FIG. 3c). That is, on the load side, an overvoltage does not enter an electric device in a non-voltage state, and damage due to dielectric breakdown can be prevented. Further, on the power supply side, the ground fault is prioritized, so that the short-circuit current is smaller than that in the inter-phase short circuit, and it is possible to prevent the accident ripple.

Further, since the electrodes constituting the circuit breaker, the disconnecting switch and the grounding switch are housed in the same vacuum insulating container 21 and the number of parts can be reduced, high reliability can be obtained and the vacuum switching device can be obtained. It is possible to achieve downsizing and low price.

(Second Embodiment) Next, the second embodiment of the present invention will be described.
The vacuum switchgear according to the embodiment will be described with reference to FIG. FIG. 4 is a vertical cross-sectional view showing the structure of the vacuum valve used in the vacuum switchgear according to the present embodiment. In addition,
In FIG. 4, the same components as those of the first embodiment are
The same reference numerals are given and detailed description is omitted.

As shown in FIG. 4, first and second cylindrical vacuum insulating containers 21 made of ceramic and connected to each other.
A fixed-side sealing metal fitting 11 and a movable-side sealing metal fitting 12 are hermetically sealed to the opening portions at both ends of the vacuum insulating container 21 constituted by a and 21b. The fixed energizing shaft 13 is penetrated and airtightly fixed to the fixed-side sealing metal fitting 11, and the first fixed electrode 22 is fixed to the inner end portion of the container of the fixed energizing shaft 13. The fixed energizing shaft 13 is set to the ground potential by a ground wire (not shown).

On the other hand, a movable energizing shaft 23, which is one electric path connected to an operating mechanism (not shown), penetrates through the movable side sealing member 12 and is fixed by a bellows 24 so as to be movable back and forth. At the inner end of the container of the movable energizing shaft 23,
A first movable electrode 25 arranged to face the fixed electrode 22.
Is stuck.

Further, a second movable electrode 26 is fixed to the axially intermediate portion of the movable energizing shaft 23 so as to surround the movable energizing shaft 23. In addition, a ring-shaped fixed current-carrying plate 27, which partially protrudes to the outside of the vacuum insulating container 21 and serves as the other electric path, is airtightly provided at the connecting portion between the first and second vacuum insulating containers 21a and 21b. At the end of the fixed current-carrying plate 27, which is fixed and is located inside the vacuum insulating container 21, a ring-shaped member is disposed so as to face the outer peripheral portion of the surface of the second movable electrode 26 that faces the bellows 24. The second fixed electrode 28 of is fixed.

Further, one end peripheral portion of a cylindrical arc shield 30 is fixed to the fixed current-carrying plate 27 located inside the vacuum insulating container 21, and the other end extends toward the second movable electrode 26, It is provided so as to surround the second fixed electrode 28 and the second movable electrode 26.

Here, a position where the second fixed electrode 28 and the second movable electrode 26 are in contact with each other is defined as an entry position, and the second movable electrode 26 is linearly moved by an operating mechanism (not shown), The gap length between these electrodes 26 and 28 is d3
The position at the time of is the cut position. Then, the second movable electrode 26 further linearly moves, and the position when the gap length between these electrodes 26 and 28 is d4 is taken as the disconnection position. Further, the second movable electrode 26 linearly moves to move the first movable electrode 26 to the first movable electrode 26.
The position where the movable electrode 25 and the first fixed electrode 22 are in contact with each other is referred to as a ground position. In addition, the total gap length that moves linearly is d4 + d5, and the gap length d5 is set to a gap length substantially the same as d3.

At the four positions thus moved, the first fixed electrode is compared with the electric field intensity between the second movable electrode 26 and the second fixed electrode 28 at the cut position and the disconnection position. The electric field strength between 22 and the first movable electrode 25 is increased.

The reason for this will be described again with reference to FIG.
In FIG. 2, the vertical axis represents the first fixed electrode 22 and the first fixed electrode 22.
Between the movable electrodes 25 and between the second movable electrode 26 and the second fixed electrode 28 at the outer peripheral end of the electrode contact surface. The electric field strength characteristic between the first fixed electrode 22 and the first movable electrode 25 is E1,
The electric field strength characteristic between the movable electrode 26 and the second fixed electrode 28 is E2. The horizontal axis represents the second movable electrode 26.
Is the gap length between the second fixed electrode 28 and the second fixed electrode 28. The cut position is d3 and the disconnection position is d4.

As shown in FIG. 2, the gap lengths d3 and d4
In a region narrower than the gap lengths d1 and d2 of the first embodiment, both have a relationship of E2 <E1. This is because if the gap length between the second movable electrode 26 and the second fixed electrode 28 is narrowed, the curvature of the outer peripheral end of the second fixed electrode 28 is apparently increased. . Then, the nonuniformity of the interval between equipotential lines is improved, and the electric field strength characteristic E2 becomes lower than E1. Further, since the gap length d5 between the first fixed electrode 22 and the first movable electrode 25 is narrower than d3 and d4, the electric field strength characteristic E1 is E.
Higher than 2.

From the relationship of the electric field strength characteristic E2 <E1,
Since the first fixed electrode 22 is at the ground potential, the dielectric strength between the first fixed electrode 22 and the first movable electrode 25, which is between the ground, is low, and the second fixed electrode 22 is between the electrodes. The dielectric strength between the movable electrode 26 and the second fixed electrode 28 increases. That is, it is possible to achieve insulation cooperation in the relationship between the ground and the pole.

Incidentally, the electric field strength characteristic E1 is sloping down to the right and the electric field strength characteristic E2 is sloping up to the right.
This is caused by the electrode shape as described in the above embodiment.

According to the vacuum switchgear of the second embodiment, the circuit breaker from the control circuit (not shown) from the state where the second fixed electrode 28 and the second movable electrode 26 are in contact with each other. In response to the contact opening command, the second movable electrode 26 linearly moves and separates from the first fixed electrode 28, and becomes the cut position of the gap length d3. Next, in response to the disconnection command from the cut position, the second movable electrode 26 further linearly moves to the disconnection position of the gap length d4. And
In response to a grounding command from the state of the disconnection position, the first movable electrode 25 moves in the gap d5, and the first movable electrode 25 and the first fixed electrode 22 come into contact with each other to reach the grounded position.

However, since the electrode of the disconnector is housed in the vacuum container, even if the current close to the rated current such as loop current is cut off, SF6 gas is not used. It never happens.

Further, since the dielectric strength between the cut position and the disconnection position is between the ground and the pole, the first fixed electrode 22 and the first fixed electrode 22 and the first Dielectric breakdown occurs between the movable electrodes 25 and the ground. This means that insulation coordination is achieved between the load side and the power source side of the circuit breaker in the off position or the disconnecting position. That is, on the load side, an overvoltage does not enter an electric device in a non-voltage state, and damage due to dielectric breakdown can be prevented. Further, on the power supply side, the ground fault is prioritized, so that the short-circuit current is smaller than that in the inter-phase short circuit, and it is possible to prevent the accident ripple.

Further, since the electrodes constituting the circuit breaker, the disconnecting switch and the grounding switch are housed in the same vacuum insulating container 21 and the number of parts can be reduced, high reliability can be obtained and the vacuum switching device can be obtained. It is possible to achieve downsizing and low price.

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways without departing from the scope of the invention. In the first embodiment and the second embodiment, the movable energizing shaft is linearly moved to form the four positions of the on-position, the off-position, the disconnection position and the ground contact position. It may be set at three positions, or three positions of an on position, a disconnection position and a ground contact position.

Even in this case, at the disconnection position or the disconnection position, the insulation cooperation of the relation between the ground and the pole is achieved, so that the overload voltage does not enter the electric equipment in the non-voltage state on the load side. It is possible to prevent damage due to dielectric breakdown. Also, on the power supply side, the ground fault has priority, so
Compared with inter-phase short circuit, the short circuit current becomes smaller and accident ripple can be prevented.

Further, since the number of operations of the operating mechanism can be reduced, the number of parts of the operating mechanism can be simplified, and the vacuum switchgear can be downsized and the cost can be reduced.

In the first embodiment, the first fixed electrode 22 is used as one electric path, and the first movable electrode 25 is used.
The second movable electrode 26 and the second movable electrode 26 are used as the other electric path, and the second fixed electrode 28 is grounded.
And the second movable electrode 26 as a common electric path, the first fixed electrode 22 as one electric path, and the second fixed electrode 28 as the other electric path, two electric paths are formed. can do.

[0061]

As described above, according to the vacuum switchgear of the present invention, since the electrode of the disconnector is housed in the vacuum valve, an insulating medium such as SF6 gas is not used. Does not generate decomposition products or decomposition gas. And, in the vacuum valve, the dielectric strength is set between the ground and the pole, and the insulation coordination is achieved. Therefore, the load side of the circuit breaker can prevent the damage of the electric equipment in the no-voltage state,
Also, on the power supply side, the ground fault is prioritized to prevent the spread of accidents. Furthermore, since a simple vacuum valve with a reduced number of parts is housed, the vacuum switchgear can be downsized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vacuum valve in a vacuum switchgear according to a first embodiment of the present invention.

FIG. 2 is an electric field characteristic diagram showing the electric field strength inside the vacuum valve according to the first and second embodiments of the present invention.

FIG. 3 is a vertical sectional view showing the operation of the vacuum valve in the vacuum switchgear according to the first embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of a vacuum valve in a vacuum switchgear according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a vacuum valve in a conventional vacuum switching device.

FIG. 6 is a configuration diagram of a switchgear.

[Explanation of symbols]

1 box 1a Circuit breaker room 1b Power receiving room 2 partition boards 3 vacuum switchgear 3a Operating mechanism 4 cable head 5a, 5b disconnector 6 insulator 7 bus 8 connection conductors 9 Vacuum valve 10, 21, 21a, 21b Vacuum insulation container 11 Fixed side fitting 12 Movable side metal fittings 13 Fixed energizing shaft 14 fixed electrode 15, 23 movable energizing shaft 16,24 Bellows 17 movable electrode 18, 29, 30 Arc shield 22 First fixed electrode 25 First movable electrode 26 Second movable electrode 27 Fixed energizing plate 28 Second fixed electrode

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akira Sato             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office (72) Inventor Tetsuo Yoshida             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office (72) Inventor Masaru Miyagawa             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office (72) Inventor Mitsutaka Honma             No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation             Fuchu Office F-term (reference) 5G026 CB01 VA01

Claims (4)

[Claims] 1. Both ends are airtightly sealed by sealing metal fittings,
And a cylindrical vacuum insulation container to which the second vacuum insulation container is connected, a fixed current-carrying shaft that penetrates through the one sealing metal member and is fixed to the sealing metal member and serves as one electric path, and the fixed energization current. Movable energization that serves as the other electric path that penetrates the first fixed electrode provided at the inner end of the vacuum insulating container of the shaft and the other sealing metal fitting and is fixed to the sealing metal fitting via the bellows. A shaft, a first movable electrode provided at an inner end portion of the movable energizing shaft in the vacuum insulating container so as to face the first fixed electrode, and a shaft of the movable energizing shaft in the vacuum insulating container. A second movable electrode provided so as to surround the movable current-carrying shaft in an intermediate portion of the direction, and fixed to a connecting portion of the first and second vacuum insulating containers facing the second movable electrode. And a ring-shaped second fixing provided so that the movable energizing shaft penetrates The pole and the movable energizing shaft are connected to the first movable electrode and the first fixed electrode in the contact position, the cut position or the disconnection position, and the second movable electrode and the second fixed electrode. An operating mechanism for moving to any three positions including an on position and a ground position among ground positions where the electrodes are in contact with each other, and the first fixed electrode and the first electrode at the cut position or disconnection position. The electric field strength between the second fixed electrode and the second movable electrode is made higher than the electric field strength between the movable electrodes. 2. The movable current-carrying shaft is provided with an entry position, a cut position, a disconnection position where the first movable electrode and the first fixed electrode are in contact with each other, and the second movable electrode and the second electrode. And an operating mechanism for moving the fixed electrode to four positions which are in contact with the fixed electrode.
The electric field strength between the second fixed electrode and the second movable electrode is higher than the electric field strength between the first fixed electrode and the first movable electrode. Item 1
Vacuum switchgear according to. 3. Both ends are airtightly sealed by sealing metal fittings,
And a cylindrical vacuum insulation container to which a second vacuum insulation container is connected, a fixed current-carrying shaft fixed to the sealing metal fitting through the one sealing metal fitting, and the vacuum insulation of the fixed current-carrying shaft. The first fixed electrode provided at the inner end of the container and the movable energizing shaft that penetrates through the other sealing metal member and serves as one electric path fixed to the sealing metal member via the bellows, A first movable electrode provided to face the first fixed electrode at an inner end portion of the current-carrying shaft in the vacuum insulating container; and an intermediate portion in the vacuum insulating container in an axial direction of the movable current-carrying shaft. ,
A second movable electrode provided so as to surround the movable energization shaft, and a second movable electrode facing the second movable electrode, fixed to a connecting portion of the first and second vacuum insulating containers, and having the movable energization. The ring-shaped second fixed electrode serving as the other electric path provided so that the shaft penetrates and the movable energizing shaft are connected to the second electric field.
Of the entry position, the cutting position or the disconnection position where the movable electrode and the second fixed electrode are in contact with each other, and the ground position where the first movable electrode and the first fixed electrode are in contact with each other, An operating mechanism for moving to any three positions including an entry position and a ground position, and in the cutting position or the disconnecting position, in comparison with the electric field strength between the second fixed electrode and the second movable electrode, A vacuum switching device, wherein the electric field strength between the first fixed electrode and the first movable electrode is increased. 4. The movable energizing shaft is provided with an input position, a cut position, a disconnection position where the second movable electrode and the second fixed electrode are in contact with each other, and the first movable electrode and the first movable electrode. And an operating mechanism for moving the fixed electrode to four positions which are in contact with the fixed electrode.
The electric field strength between the first fixed electrode and the first movable electrode is made higher than the electric field strength between the second fixed electrode and the second movable electrode. Item 3
Vacuum switchgear according to.