JP2013055738A - Switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environmentally-conscious switching device in a small size with high reliability and without making a high pressure container in a large size.SOLUTION: A switching device comprises: a vacuum circuit breaker 22 in a grounding closed container 1 having high pressure gas mixture mainly composed of Nand Otherein. The vacuum circuit breaker 22 includes: a vacuum valve 23 having a fixed electrode; a movable electrode which can be connected to/removable from the fixed electrode; an actuator 31 connected to the movable electrode; and a bellows allowing the movable electrode to move. The vacuum circuit breaker 22 further includes a pressure container 20 air-tightly connected to the bellows in the actuator 31 side in the vacuum valve 23; and an insulated pipe 21 connecting inside of the pressure container 20 and outside of the grounding closed container 1 in atmospheric pressure.

Description

  The present invention relates to a switchgear applied to a substation, switchgear, and the like.

A gas-insulated switchgear using SF ₆ which is an insulating gas having high insulating performance ensures high reliability and safety because of a sealed structure with a ground metal container, and is widely spread. Although SF ₆ gas is extremely chemically stable, it has a large amount of infrared absorption in the atmosphere and has a very large global warming potential GWP of 23900. Therefore, the SF ₆ gas has a large impact on the environment when released outside the gas-insulated switchgear. The impact is concerned.

Under such circumstances, a switchgear that combines a vacuum circuit breaker and dry air as an insulating gas has been proposed as a switchgear that does not use SF ₆ gas (see, for example, Patent Document 1).

JP 2005-94903 A

  When realizing a switchgear using high-pressure dry air as an insulating gas, insulation performance is ensured by supporting a vacuum circuit breaker to which a high voltage is applied inside a high-pressure vessel that is at ground potential with an insulating member. There is a need to.

  In addition, in the vacuum valve constituting the vacuum circuit breaker, in order to improve the mechanical durability of the bellows that keeps the vacuum state in the vacuum valve and allows the movable electrode to open and close, the outside of the bellows is low pressure or atmospheric pressure. There is known a method of providing a low pressure container adjacent to the bellows to reduce the pressure difference between the inside and outside of the bellows.

  In such a switchgear, a method in which the inside of the low-pressure vessel is brought to atmospheric pressure through the inside of the insulating support member of the vacuum circuit breaker is conceivable, but in this case, in order to ensure the insulation performance inside the insulating support member, a large amount can be considered. There is a need to increase the air creeping insulation distance in the atmospheric pressure region, which may increase the size of the switchgear.

  The present invention has been made based on the above-described matters, and an object of the present invention is to provide a small, highly reliable, and environmentally friendly switchgear without increasing the size of a high-pressure vessel.

In order to achieve the above object, the first invention provides a switchgear having a vacuum circuit breaker in a grounded sealed container in which a high-pressure mixed gas composed mainly of N ₂ and O ₂ is sealed. The vacuum circuit breaker includes a fixed electrode, a movable electrode that can be brought into contact with and separated from the fixed electrode, an operating device connected to the movable electrode, and a vacuum valve that allows operation of the movable electrode. It is assumed that a pressure vessel provided in an airtight manner on the operation unit side of the bellows and an insulating pipe that communicates the inside of the pressure vessel and the outside of the grounded sealed vessel at atmospheric pressure.

  Further, the second invention is the first invention, wherein the insulating pipe has one end connected to the pressure vessel, the other end connected to the grounded airtight vessel, and a connecting portion of the insulating pipe, A shield electrode is provided.

  Further, according to a third invention, in the first or second invention, the insulating pipe is formed by stacking a material satisfying pressure performance, a material satisfying airtightness performance, and a material satisfying moisture permeation suppression performance in multiple layers. It is characterized by being formed.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a filter that absorbs moisture in the atmosphere is disposed outside the connection portion of the insulating pipe in the grounded sealed container. Features.

  Furthermore, a fifth invention is characterized in that, in any one of the first to third inventions, a pressure regulating valve is disposed outside the connecting portion of the insulating pipe in the grounded airtight container.

  According to the present invention, since the atmospheric pressure pressure vessel provided in an airtight connection with the bellows of the vacuum valve is connected to the atmosphere outside the switchgear by the insulating piping, the atmospheric pressure can be reduced without increasing the size of the high pressure vessel. Sufficient creepage distance in the area can be secured. As a result, it is possible to provide a small and reliable switchgear that is environmentally friendly.

It is a schematic side view which shows the structure of 1st Embodiment of the switchgear of this invention. It is a schematic side view which shows the vacuum circuit breaker which comprises 1st Embodiment of the switchgear of this invention. It is a longitudinal cross-sectional view which expands and shows the vacuum circuit breaker which comprises 1st Embodiment of the switchgear of this invention. It is a characteristic view which shows the relationship between the dielectric breakdown voltage by the gas pressure and piping length in the insulation piping which comprises 1st Embodiment of the switchgear of this invention. It is a side view which shows one shape of the insulation piping which comprises 1st Embodiment of the switchgear of this invention. It is a side view which shows the other shape of the insulation piping which comprises 1st Embodiment of the switchgear of this invention. It is a longitudinal section showing insulation piping which constitutes a 1st embodiment of a switchgear of the present invention. It is a characteristic view which shows the relationship between the presence or absence of dew condensation in the insulation piping which comprises 2nd Embodiment of the switchgear of this invention, and the dielectric breakdown voltage by piping length. It is a side view which shows the piping exterior of the insulated piping which comprises 2nd Embodiment of the switchgear of this invention. It is a side view which shows the piping exterior of the insulated piping which comprises 3rd Embodiment of the switchgear of this invention. It is a side view which shows the piping exterior of the insulated piping which comprises 4th Embodiment of the switchgear of this invention.

Hereinafter, embodiments of the switchgear according to the present invention will be described with reference to the drawings.
1 to 7 show a first embodiment of the switchgear according to the present invention. FIG. 1 is a schematic side view showing the configuration of the switchgear according to the first embodiment of the present invention. FIG. FIG. 3 is a schematic side view showing a vacuum circuit breaker constituting the first embodiment of the switchgear of the invention, and FIG. 3 is an enlarged longitudinal sectional view showing the vacuum circuit breaker constituting the first embodiment of the switchgear of the present invention. FIG.

In FIG. 1, the switchgear is arranged in a ground metal first high-pressure vessel 1 filled with an insulating gas and a rear upper portion of the first high-pressure vessel 1, and is made of a ground metal made of filled with an insulating gas. The second high-pressure vessel 2A, the third high-pressure vessel 2B made of ground metal, which is disposed in the lower rear part of the first high-pressure vessel 1 and encloses the insulating gas, and the front of the first high-pressure vessel 1 are arranged. And an operation box 3 made of a ground metal, in which each switch for operating a disconnector, a ground switch, and a vacuum circuit breaker, which will be described later, is housed. In the first high-pressure vessel 1, the second high-pressure vessel 2A, and the third high-pressure vessel 2B, a mixed gas consisting mainly of N ₂ and O ₂ as a main component typified by dry air is enclosed as an insulating gas. ing.

  The first high-pressure vessel 1 houses a vacuum circuit breaker 22 and constitutes a circuit breaker unit. The second high-pressure vessel 2A accommodates the bus-side disconnector 5a and constitutes a bus-side disconnector unit. Further, the third high-pressure vessel 2B houses the line-side disconnector 5b and constitutes a line-side disconnector unit. A bus unit having a bus 7 is connected to the bus-side disconnector unit. Also. A cable 10 is connected to the line-side disconnector unit via a cable head 9.

  The above-described busbar unit includes a three-phase main busbar 7 conductor supported by an insulating support member. The bus-side disconnector unit described above includes a bus-side disconnector 5a in which the movable element of the bus-side disconnector 5a is integrated with the movable element 6a of the grounding switch, and the disconnector and the grounding switch are combined, and an insulating spacer. And a conductor 15a connected to the conductor 12a of the circuit breaker unit via a central conductor 4a.

  The circuit breaker unit in which the vacuum circuit breaker 22 is arranged includes a vacuum circuit breaker 22, insulating support members 11 a and 11 b that fix and support the vacuum circuit breaker 22 to the ground metal plate 32 that covers the side surface of the first high-pressure vessel 1, and an insulating spacer. A conductor 12a connected to the conductor 15a of the bus-side disconnector unit via the central conductor of 4a, a conductor 12b connected to the conductor 15b of the line-side disconnector unit via the central conductor of the insulating spacer 4b, An insulating rod 33 for transmitting the operation to the movable electrode and an insulating pipe 21 to be described later are provided.

  The line-side disconnector unit in which the line-side disconnector 5b and the earthing switch are arranged is the circuit breaker unit through the disconnector having the same structure as the busbar-side disconnector 5a of the busbar-side disconnector unit and the central conductor of the insulating spacer 4b. A conductor 15b connected to the other conductor 12b, an arrester 8 and the like.

  The cable unit has a cable 10 led out from the line-side disconnector unit via the cable head 9, and this cable 10 is connected to a load.

In the first to third high-pressure vessels 1, 2A, 2B, a mixed gas composed mainly of N ₂ and O ₂ , represented by dry air sealed as an insulating gas, is mixed with insulating spacers 4a, 4b and a ground metal plate. The airtightness against high pressure is secured at 32, but the dry air has an insulation performance of about 1/3 compared with the SF ₆ gas, and the dry air is made into an insulating gas by the same size switchgear. Therefore, it is necessary to use it under a higher pressure than SF ₆ gas. If the operating gas pressure is increased in order to ensure the same size and the same insulating performance as SF ₆ , it is necessary to increase the thickness of the high-pressure vessel and insulating spacer, leading to an increase in manufacturing cost. Here, in consideration of ensuring the insulation performance of the switchgear and reducing the size and cost, the appropriate pressure of the mixed gas is 0.2 to 0.8 MPa.

Next, the circuit breaker unit and the vacuum circuit breaker 22 will be described in detail with reference to FIGS. 2 and 3, the same reference numerals as those shown in FIG. 1 denote the same parts.
The vacuum circuit breaker 22 includes a vacuum valve 23 having a fixed side end plate 23B and a movable side end plate 23C provided at the upper and lower ends of the insulating cylinder 23A and the insulating cylinder 23A, and a fixed side end plate 23B above the vacuum valve 23, respectively. A fixed shield electrode 13 a connected to the metal, a low pressure vessel 20 made of metal connected to the movable end plate 23 C below the vacuum valve 23, and a movable shield electrode 13 b connected to the bottom of the low pressure vessel 20. ing.

  A fixed electrode 24 is attached to a fixed conductor 24A fixed to the fixed side end plate 23B of the vacuum valve 23. One end of a bellows-shaped bellows 26 is connected to the movable side end plate 23C of the vacuum valve 23 in an airtight manner, and the other end of the bellows 26 is connected to the movable rod 25A in an airtight manner. A movable electrode 25 facing the fixed electrode 24 is attached to the movable rod 25A.

  The upper part of the metal low-pressure vessel 20 is hermetically connected to the lower part of the movable side end plate 23C, for example, by welding or the like, and the movable rod 25A is lowered from the lower part of the low-pressure vessel 20 via the seal member 28. It is slidably led out into the lower movable shield electrode 13b while maintaining airtightness with the pressure vessel 20. The lower end of the movable rod 25 </ b> A is connected to the mechanism portion of the operating device 31 via the link 34 and the insulating rod 33.

  The insulating support member 11a made of an insulating material such as an epoxy resin disposed above the vacuum valve 23 insulates and supports the fixed-side shield electrode 13a with respect to the ground metal plate 32, and the fixed-side shield electrode 13a is interposed through the fixed-side shield electrode 13a. The upper part of the vacuum valve 23 is supported. The fixed electrode 24 is electrically connected to the fixed conductor 24A, the fixed shield electrode 13a, and the conductor 12a connected to the conductor 15a of the busbar side disconnector unit via the contact 14a.

  An insulating support member 11 b made of an insulating material such as an epoxy resin disposed below the vacuum valve 23 insulates and supports the low pressure vessel 20 with respect to the ground metal plate 32, and the vacuum valve is interposed via the low pressure vessel 20. The lower part of 23 is supported. The movable electrode 25 is electrically connected to the conductor 12b connected to the conductor 15b of the line side disconnector unit via the contact rod 14b and the movable rod 25A and the low pressure vessel 20.

  The vacuum circuit breaker 22 is supported on the ground metal plate 32 by insulating support members 11a and 11b, and is detachable at the conductors 12a and 12b and the contacts 14a and 14b. As a result, the vacuum circuit breaker 22 can be integrally removed by removing the ground metal plate 32 from the first high-pressure vessel 1. The ground metal plate 32 is provided with a hole 32a communicating with the outside and a connection portion 32b to which the insulating pipe 21 is connected.

  The low pressure vessel 20 has a movable rod 25A vertically extending therethrough. The upper penetrating portion is formed by a bellows 26 in the vacuum valve 23, and the lower penetrating portion is formed by a sealing member 28 such as an O-ring. Each of them has a linear seal structure that can be linearly driven and maintains hermetic performance. In addition, a hole 20 a and a connecting portion 20 b for communicating with the atmosphere outside the switch via the insulating pipe 21 are provided in the lower portion of the low pressure vessel 20. Since the low pressure vessel 20 communicates with the outside via the insulating pipe 21, the pressure in the low pressure vessel 20 is atmospheric pressure. The inside of the vacuum valve 23 is a high vacuum, and the differential pressure applied to the inside and outside of the bellows 26 is 1 atm (0.1 MPa).

  In order to ensure highly reliable airtightness in the connector section, both ends of the insulating pipe 21 are provided with metal connection connectors 27, 27, each of which is connected to the connection section 20b of the low pressure vessel 20 and the ground. It is connected to the connection part 32 b of the metal plate 32. In order to reduce the electric field of the connection connectors 27, 27, a shield electrode 35 is provided on the ground metal plate 32 so as to cover the connection portion 32 b with the ground metal plate 32. On the lower surface side of the low pressure vessel 20, a movable shield electrode 13 b is provided so as to cover the connection portion 20 b with the low pressure vessel 20. As shown in FIG. 3, it is desirable that the shield electrodes 35 and 13b and the insulating pipe 21 are not in direct contact with each other. This is because when the shield electrodes 35 and 13b and the insulating pipe 21 are in contact with each other, a triple junction of gas, solid, and insulator is formed, so that the electric field of the triple junction increases and can be the starting point of discharge.

  Next, the configuration of the insulating pipe 21 will be described in detail with reference to FIGS. FIG. 4 is a characteristic diagram showing the relationship between the gas pressure in the insulating pipe constituting the first embodiment of the switchgear of the present invention and the breakdown voltage depending on the pipe length, and FIG. 5 is the first embodiment of the switchgear of the present invention. FIG. 6 is a side view showing another shape of the insulating pipe constituting the first embodiment of the switchgear of the present invention, and FIG. 7 is a side view showing the shape of the insulating pipe constituting the form of the present invention. It is a longitudinal section showing insulating piping which constitutes a 1st embodiment of a switchgear. 4 to 7, the same reference numerals as those shown in FIGS. 1 to 3 are the same parts, and the detailed description thereof is omitted.

  As shown in FIG. 4, if the length of the insulating pipe 21 is long and the gas pressure in the atmosphere is high, the dielectric breakdown voltage becomes high. That is, in the present embodiment, since the high-pressure dry air is the atmosphere outside the insulating pipe 21 arranged in the first high-pressure vessel 1, the breakdown voltage is high, but the inside of the insulating pipe 21 is Due to the atmospheric pressure, the breakdown voltage is low. For this reason, dielectric breakdown is likely to occur inside the insulating pipe 21.

  That is, since the insulating support members 11a and 11b and the insulating spacers 4a and 4b are used in the high pressure portion in the first high-pressure vessel 1, the insulating performance can be sufficiently ensured even if the insulating distance is short. . On the other hand, since the inside of the insulating pipe 21 is at atmospheric pressure and the dielectric breakdown voltage is low, it is necessary to increase the creeping distance (pipe length) in order to ensure sufficient insulation performance.

  In the case of the insulating pipe 21 as in the present embodiment, the creepage distance can be increased by utilizing the space in the first high-pressure vessel 1. For example, in FIG. 3, when considering the creepage distance between the first high-pressure vessel 1 that is a ground potential and the vacuum circuit breaker 22 that is a high voltage, the insulating support members 11a and 11b generate a creepage distance corresponding to the length. In contrast, the insulating pipe 21 is connected to the connecting part 32b of the ground metal plate 32 having the ground potential to the connecting part 20b of the low-pressure vessel 20 having the high voltage (the insulating pipe 21 is connected via the internal atmosphere). It is possible to generate a creepage distance. That is, if the insulating pipe 21 is arranged in the space inside the first high-pressure vessel 1, a creepage distance corresponding to the length of the pipe can be secured.

  As a raw material of the insulating pipe 21, an insulating material such as tetrafluoroethylene resin or nylon is preferable, and if it is a flexible material, the degree of freedom of the pipe shape can be increased. In general, even if it is a flexible pipe, if it is for high pressure, it has a structure in which a reinforcing material of insulating fiber is contained inside, and the shape can be maintained without being crushed even if the outside is at high pressure.

  In FIG. 3, the insulating pipe 21 is L-shaped and pulled out from the low-pressure vessel 20 to the ground metal plate 32. However, in order to increase the creepage length using more space, FIG. 5 and FIG. A configuration as shown in FIG. In FIG. 5, one end of the insulating pipe 21 is connected to the low pressure vessel 20, and the creeping length is increased as a form in which it is once bent in the direction opposite to the direction in which the other end of the insulating pipe 21 is connected. In FIG. 6, the creeping length is increased by rotating the insulating pipe 21 once in the middle. In order to further increase the creepage length, it is possible to make a number of turns in the form of FIG.

  FIG. 7 shows an example of an insulating pipe 21 having a composite function. For example, an airtight layer 21A made of nylon is formed on the innermost side of the pipe, a pressure-resistant layer 21B made of, for example, a fiber reinforcement, and made of polyurethane on the outermost side. The insulating piping 21 of the composite material provided with the multilayer structure which arrange | positions 21 C of moisture permeation suppression layers is shown.

  In the present embodiment, since the inside of the insulating pipe 21 is at atmospheric pressure, if moisture contained in the atmosphere permeates, moisture may enter the first high-pressure vessel 1 and the insulation performance may be reduced. . For this reason, the insulating pipe 21 needs to ensure moisture permeability in addition to ensuring pressure performance, airtight performance, and insulation performance. Conventional resin materials such as tetrafluoroethylene resin and nylon are considered to be difficult to pass moisture. However, when long-term use is considered, it is better to use an insulating pipe 21 having a material capable of suppressing moisture permeation. . Considering the cost, there is almost no material that satisfies all the performance with a single material, and therefore the composite insulating pipe 21 that satisfies the functions of pressure, airtightness, and moisture permeation suppression with a plurality of layers is desirable.

  According to the first embodiment of the switchgear of the present invention described above, the atmospheric pressure low pressure vessel 20 provided in an airtight connection with the bellows 26 of the vacuum valve 23 is connected to the atmosphere outside the switchgear and the insulating pipe 21. Since they are connected, the air creeping distance in the atmospheric pressure region can be sufficiently secured without increasing the size of the first high-pressure vessel 1. As a result, it is possible to provide a small and reliable switchgear that is environmentally friendly.

  Further, according to the first embodiment of the switchgear of the present invention described above, the atmospheric pressure outside the low pressure container 20 and the switchgear is provided with the low-pressure container 20 at atmospheric pressure on the bellows 26 of the vacuum valve 23 in an airtight manner. Are connected by the insulating pipe 21, the pressure in the low pressure vessel 20 can be maintained at atmospheric pressure over a long period of time. As a result, even if a slow leak over a long period of time occurs in the low pressure vessel 20, it is possible to prevent a pressure increase in the low pressure vessel 20 and to reduce the pressure difference related to the bellows 26.

  Furthermore, according to the first embodiment of the switchgear of the present invention described above, the vacuum circuit breaker 22 is supported on the ground metal plate 32 by the insulating support members 11a and 11b, and the conductors 12a and 12b and the contact 14a. 14b, the vacuum circuit breaker 22 can be integrally removed by removing the ground metal plate 32 from the first high-pressure vessel 1. As a result, it is possible to provide an opening / closing device with good workability during assembly and maintenance.

  8 and 9 show a second embodiment of the switchgear according to the present invention, and FIG. 8 shows the presence or absence of dew condensation and piping in the insulating pipe constituting the second embodiment of the switchgear according to the present invention. FIG. 9 is a side view showing the outside of the insulating pipe constituting the second embodiment of the switchgear according to the present invention. 8 and 9, the same reference numerals as those shown in FIGS. 1 to 7 are the same or corresponding parts, and the description thereof is omitted.

  Condensation generated due to the influence of temperature and humidity is a factor that lowers the insulating performance of the insulating pipe 21. As shown in FIG. 8, even if condensation occurs, it is possible to prevent dielectric breakdown by increasing the length of the insulating pipe 21, but it is better to apply a method for preventing the occurrence of condensation. This is preferable from the viewpoint of miniaturization of the switchgear. As a general method for preventing condensation, there is a method of increasing the ambient temperature by using a heater so that condensation does not occur. However, in the case of the switchgear according to the present invention, the insulating piping 21 and the entire low-pressure vessel 20 where condensation can occur are arranged in the high voltage part itself or in the vicinity of the high voltage part. It is difficult to dispose a heater for heating, and it is difficult to prevent the occurrence of condensation by a general method.

  For this reason, as an example, as shown in FIG. 9, the connection part 32b to which the connector 27 of the insulating pipe 21 is connected, the shield electrode 35 covering the connection part 32b, and the outside of the connection part 32b are provided. A ground metal plate 32 provided with a filter 40 can be used. According to this example, the provision of the filter 40 at the outlet of the insulating pipe 21 can prevent the occurrence of condensation in the insulating pipe.

  Here, the filter 40 is a dry filter made of, for example, silica gel, and has a function of removing moisture from the passing air. As a result, since the outside air with a large amount of moisture is not sucked into the insulating pipe 21 and the outside air from which moisture has been removed is sucked, the possibility of dew condensation is reduced even if the internal temperature is low.

  According to the second embodiment of the switchgear of the present invention, the same effects as those of the first embodiment described above can be obtained. Further, since the filter 40 is provided at the outlet of the insulating pipe 21, it is possible to prevent the dew condensation in the insulating pipe 21 and provide a highly reliable switching device.

  FIG. 10 shows a third embodiment of the switchgear according to the present invention, and is a side view showing the outside of the insulated piping constituting the third embodiment of the switchgear according to the present invention. In FIG. 10, the same reference numerals as those shown in FIGS. 1 to 9 are the same or corresponding parts, and the description thereof is omitted.

  In this embodiment, as shown in FIG. 10, the connection part 32b to which the connector 27 of the insulating pipe 21 is connected, the shield electrode 35 covering the connection part 32b, and the outside of the connection part 32b are provided. This is composed of a ground metal plate 32 provided with a pressure control valve 41. According to this example, the pressure control valve 41 is provided at the outlet of the insulating pipe 21, and the pressure control valve 41 suppresses the entry of external moisture into the insulating pipe 21 to prevent the occurrence of condensation. be able to.

  Here, as an example of the pressure control valve 41, there is a check valve with a pressure control function. By setting so that air can pass only from the inside of the insulating pipe 21 to the outside, the air is released to the outside only when the internal pressure of the insulating pipe 21 rises. As a result, the intrusion of air containing external moisture into the insulating pipe 21 is prevented. As another example of the pressure control valve, there is a pressure control valve that opens when a set pressure represented by a safety valve is reached. When the internal pressure of the insulating pipe 21 becomes a set pressure (for example, 0.12 MPa) or more, the valve is opened, and the internal air is released to the outside.

  According to the third embodiment of the switchgear of the present invention, the same effects as those of the first embodiment described above can be obtained. Further, since the pressure control valve 41 is provided at the outlet of the insulating pipe 21, it is possible to prevent moisture containing air from entering the insulating pipe 21 and to provide a highly reliable switching device.

  FIG. 11 shows a fourth embodiment of the switchgear according to the present invention, and is a side view showing the outside of the insulated pipe constituting the fourth embodiment of the switchgear according to the present invention. In FIG. 11, the same reference numerals as those shown in FIGS. 1 to 10 are the same or corresponding parts, and the description of those parts is omitted.

  In this embodiment, as shown in FIG. 11, the connecting portion 32b to which the connector 27 of the insulating pipe 21 is connected, the shield electrode 35 covering the connecting portion 32b, and the pressure provided outside the connecting portion 32b. This is composed of a ground metal plate 32 provided with a control valve 41. According to this example, an electromagnetic valve 42 is provided at the outlet of the insulating pipe 21, and air containing moisture from outside is prevented from entering the insulating pipe 21 as much as possible by the electromagnetic valve 42, thereby preventing the occurrence of condensation. be able to.

  Here, the electromagnetic valve 42 can be opened and closed at an arbitrary timing by controlling an electric signal, and has a function of opening and closing in accordance with, for example, the operation of the vacuum circuit breaker 22. Since the electromagnetic valve 42 opens and closes only when the vacuum circuit breaker 22 operates, the inside of the insulating pipe 21 is opened to the atmosphere for a very short time. As a result, the amount of air entering the insulating pipe 21 is reduced, and the amount of moisture in the air can be reduced as much as possible.

  According to the fourth embodiment of the switchgear of the present invention, the same effects as those of the first embodiment described above can be obtained. In addition, since the solenoid valve 42 is provided at the outlet of the insulating pipe 21, it is possible to reduce the intrusion of moisture-containing air into the insulating pipe 21 as much as possible, and to provide a highly reliable switchgear. Can do.

DESCRIPTION OF SYMBOLS 1 1st high pressure vessel 2A 2nd high pressure vessel 2B 3rd high pressure vessel 3 Operation boxes 4a and 4b Insulating spacer 5 Disconnector 6 Movable element 7 Main bus 11 Insulating support member 13a Fixed side shield electrode 13b Movable side shield electrode 20 Low pressure vessel 21 Insulating piping 22 Vacuum circuit breaker 23 Vacuum valve 24 Fixed electrode 25 Movable electrode 26 Bellows 27 Connection connector 28 Seal member 31 Operating device 32 Ground metal plate 33 Insulating rod 35 Shield electrode 40 Filter 41 Pressure control valve 42 Solenoid valve

Claims (5)

In a switchgear provided with a vacuum circuit breaker in a grounded airtight container in which a high-pressure mixed gas composed of N ₂ and O _{2 as a} main component is enclosed,
The vacuum circuit breaker includes a fixed electrode, a movable electrode that can be brought into contact with and separated from the fixed electrode, an operating device connected to the movable electrode, and a vacuum valve that allows operation of the movable electrode,
A pressure vessel provided in an airtight connection to the operating side of the bellows in the vacuum valve;
An opening / closing device comprising: an insulating pipe communicating between the inside of the pressure vessel and the outside of the grounded sealed vessel at atmospheric pressure. The switchgear according to claim 1,
The insulating pipe has one end connected to the pressure vessel and the other end connected to the grounded sealed vessel,
A switchgear characterized in that a shield electrode is provided at each connection portion of the insulating pipe. The switchgear according to claim 1 or 2,
The insulating pipe is formed by stacking a material satisfying pressure performance, a material satisfying air tightness performance, and a material satisfying moisture permeation suppression performance in a multilayer manner. The switchgear according to any one of claims 1 to 3,
A switch that absorbs moisture in the atmosphere is disposed outside the connection portion of the insulated pipe in the grounded airtight container. The switchgear according to any one of claims 1 to 3,
An opening / closing device, wherein a pressure regulating valve is disposed outside the connecting portion of the insulated pipe in the grounded airtight container.

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