JP4334852B2 - Gas insulated switchgear - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the structure of a gas-insulated switchgear.
[0002]
[Prior art]
In a conventional gas insulated switchgear, a tank is provided on a base via a mount. The tank has a shape in which a lower part on the front side is cut out, and an opening is formed on the front side of the tank, and the opening is closed by a mounting plate. The inside of the tank is hermetically sealed and filled with insulating gas. One end of an insulating frame having a substantially U-shaped cross section made of a solid insulator is attached inside the mounting plate, and a vacuum circuit breaker is attached as a switch inside the insulating frame. Further, a disconnecting switch with a ground switch as a switch is provided above the insulating frame. And the operation part which operates a vacuum circuit breaker and the operation part which operates a disconnecting switch with a ground switch are provided in the outer side of the attachment plate.
[0003]
The bus bar is disposed above the tank. An opening is formed on the upper surface of the tank, and a three-phase insulating spacer is provided as an insulating member that hermetically closes the opening. This three-phase insulating spacer is a three-phase inner conductor molded with a solid insulator. The upper end of the inner conductor is connected to the bus bar, and the lower part is connected to a disconnecting switch with a ground switch.
At the bottom of the tank, a composite type bushing in which an internal conductor and a current transformer are embedded in a bushing that is a solid insulator is provided for three phases. This bushing is airtightly attached from the inside to the opening of the tank via an O-ring. A cable head is attached to the bushing from the front side of the gas-insulated switchgear. The vacuum circuit breaker and the internal conductor of the bushing are connected via a conductor, and a power cable is connected to the cable head. (For example, see Patent Document 1)
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-185577
[Problems to be solved by the invention]
The conventional gas-insulated switchgear requires reinforcement measures such as increasing the wall thickness at the end because the cross-section of the insulating frame that supports the vacuum circuit breaker is U-shaped. There was a problem that heat was difficult to dissipate.
[0006]
In addition, because the main circuit part of each phase of the disconnecting switch with earthing switch was placed in the depth direction in the vicinity of the circuit breaker, it was used as a circuit breaker between the vacuum switches of the electromagnetic field that accompanies fault current conduction for each phase. Due to different influences, there was a problem that the breaking performance of the vacuum circuit breaker varies depending on each phase.
[0007]
In addition, the three-phase insulating spacer attached to the upper surface of the tank has a poor manufacturing yield due to its complicated shape, and since the flange surface is wide, in order to maintain airtightness, the tank side has a wide flatness. It was expensive because it had to be secured.
[0008]
In addition, the bushing provided in the lower part of the tank is complicated and large in size because a current transformer is embedded, so that the production yield is poor and the workability is also poor. In addition, it was necessary to cope with the specifications of current transformers that varied from customer to customer, which was the cause of hindering bushing standardization and production efficiency.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, according to the gas-insulated switchgear of the present invention, a metal container filled with an insulating gas, a bus-side bushing supported by the metal container and connected to an external circuit, and a metal container An insulating frame supported at one end on the container wall, a movable terminal connected to an insulating rod supported by the insulating frame and extending through one end of the insulating frame, and a fixed supported at the other end of the insulating cylinder A vacuum circuit breaker having a side terminal, a rotatable blade provided on an insulating frame, a disconnector connected between the bus-side bushing and the vacuum circuit breaker, and an electric power connected to the vacuum circuit breaker A gas-insulated switchgear having a cable head that can be connected to a cable and a current transformer that measures a current flowing through the cable head, wherein the insulating frame is a tube whose cross section is perpendicular to the axial direction. A body, a gas insulated switchgear, characterized in that with an opening for connecting the movable terminal of the vacuum circuit breaker to the disconnector is obtained.
[0010]
In addition, even if a flexible conductor that penetrates the insulating cylinder and connects the movable terminal to the blade is provided, the main circuit conductor including the bus-side bushing and disconnector is substantially vertical including the axis of the vacuum circuit breaker. Assuming that the bus-side bushings are offset from each other in the depth and width directions of the gas-insulated switchgear, or that the current transformer is a separate component from the cable head Also good.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
As shown in FIG. 1, in the gas insulated switchgear of the present invention, a tank 3 is provided on a gantry 2 made of a thin metal plate. The front surface of the tank 3 is cut out. An opening is formed in the front surface of the tank 3, the opening is closed by the mounting plate 4, the inside of the tank 3 is configured to be airtight, and is filled with an insulating gas.
[0012]
Inside the mounting plate 4, one side of an insulating cylinder 18 made of a solid insulator is attached so as to have a gap of 5 mm or more with the main circuit portion of the circuit breaker 6. Inside the insulating cylinder 18, a vacuum valve 19 and a vacuum are provided. A circuit breaker main circuit section such as a flexible conductor 23 that connects the movable shaft 20 of the valve 19 and the blade support terminal 21 for the disconnecting switch with grounding switch so as not to impair the operation of the movable shaft 20, and the vacuum valve 19 Mechanical parts such as an insulating rod 23 that insulates the movable shaft 20 and the circuit breaker operating unit 8 and an adapter 24 that connects the insulating rod 23 and the movable shaft 20 of the vacuum valve 19 are housed. Further, a disconnecting switch 7 with a ground switch is provided on the insulating cylinder 18. On the outside of the mounting plate 4, a circuit breaker operating section 8 and a grounding switch-equipped disconnecting switch operating section 9 are provided as in the conventional case.
[0013]
On the opposite side of the mounting plate 4 of the insulating cylinder 18, a fixed terminal 25 of the vacuum valve is mounted via a fixed terminal 26. The insulating cylinder 18 on the upper side protrudes upward and is an input terminal of a disconnecting switch with a ground switch. 27 is attached above the vacuum valve movable shaft 20 of the insulating cylinder 18, and a blade support terminal 21 of a disconnecting switch with a ground switch is attached that protrudes smaller than the protruding portion. An opening 28 is provided on the mounting plate 4 side of the small protrusion so as to penetrate the insulating cylinder 18, and the movable shaft 20 of the vacuum valve is grounded by a flexible conductor 22 that penetrates the opening 28. It is connected to the blade support terminal 21 of the disconnector with switch.
[0014]
Above the insulating cylinder 18 of the mounting plate 4, openings are formed at the same pitch as the insulating cylinder 18 for each phase, and a test terminal and ground terminal 29 is provided as an insulating member that hermetically closes the opening. Yes. The test terminal and ground terminal 29 has an inner conductor 29a embedded in the center, and a mounting bracket 30 for tank mounting is embedded on the circumference centered on the inner conductor 29a. A recess 31 for attaching a packing for airtight mounting to the tank is provided around the inner conductor 29a. A tank inner end of the internal conductor 29a is connected to a ground side terminal 32 of a disconnecting switch with a ground switch, and a tank outer end is connected to a ground terminal. Around the opening above the insulating cylinder 18 of the mounting plate 4, there is a small hole for mounting the test terminal and ground terminal 29 on the circumference having the same center as the center of the opening. The cum-grounding terminal 29 is inserted into the opening from the inside of the tank, and a bolt 33 penetrating the mounting hole from the outside of the tank is inserted into the mounting bracket 30 and fastened.
[0015]
On the upper surface of the tank 3, openings are formed above the insulating cylinder 18 for each phase at a position that is the same pitch as the insulating cylinder 18 and is slightly larger than the outer diameter of the bus bar 10 and shifted in the front-rear direction. A bus single-phase bushing 34 is provided as an insulating member that hermetically closes the opening. The single-phase bushing 34 is embedded in the center of the inner conductor 34a, and a mounting bracket 35 for the tank 3 is embedded on the circumference centering on the inner conductor 34a. A concave portion 36 for attaching a packing for airtight attachment is provided around the inner conductor 34a. The inner conductor 34 a has an inner end connected to the inlet terminal 27 of the disconnecting switch with a ground switch via a connection conductor 38, and an outer end connected to the bus 10. Around the opening on the upper surface of the tank, there is a small hole for mounting the single-phase bushing 34 on the circumference having the same center as the center of the opening, and the single-phase bushing 34 extends from the inside of the tank to the opening. The bolt 37 inserted through the mounting hole from the outside of the tank is inserted into the mounting bracket and fastened.
[0016]
In the lower part of the front surface of the tank 3, openings are formed at the same pitch as the insulating cylinders 18 below the insulating cylinders 18 for each phase, and a single-phase bushing for cable connection as an insulating member that hermetically closes the openings. 39 is provided. The single-phase bushing 39 is embedded in the center of the inner conductor 39a, and a mounting bracket 40 for the tank 3 is embedded on the circumference centering on the inner conductor 39a. A recess 41 for attaching a packing for airtight attachment is provided around the inner conductor 39. The inner conductor 39 is connected to the tank inner end of the internal conductor 39 via the connection conductor 42, and the tank outer end is connected to the power cable 17 via the cable head 15. Around the opening at the lower front of the tank 3, there is a small hole for mounting the single-phase bushing 39 on the circumference having the same center as the center of the opening. A bolt 42 inserted into the opening and penetrating the mounting hole from the outside of the tank is inserted into the mounting bracket and fastened.
[0017]
In the gas-insulated switchgear of this embodiment, the insulating frame that supports the vacuum circuit breaker is a cylindrical body and has an opening, so that reinforcement such as increasing the wall thickness of the end as in the prior art is performed. No countermeasure is required, and heat generated in the vacuum circuit breaker can be efficiently dissipated. Further, since the main circuit conductor including the bus-side bushing and the disconnecting device is in a substantially vertical plane including the axis of the vacuum circuit breaker, the breaking performance of the vacuum circuit breaker for each phase becomes equal. In addition, since the bus-side bushings are shifted from each other in the depth direction and width direction of the gas insulation switch gear, the shape of the insulation spacer attached to the upper surface of the tank can be simplified, and the manufacturing yield and airtight performance can be maintained. Easy to do. Furthermore, since the current transformer is a separate part from the cable head, the manufacturing yield is good, the workability is good, and the specifications of the current transformer that changes from customer to customer can be easily accommodated. it can.
[0018]
Embodiment 2. FIG.
Next, the second embodiment will be described with reference to FIG. As can be seen from a comparison between FIG. 2 and FIG. 1, there is no circuit breaker inside the insulating cylinder, and the shorting conductor 45 connects the blade support terminal 21 and the fixed terminal 26 of the disconnecting switch with a ground switch without going through the switch. ing.
[0019]
Embodiment 3 FIG.
Next, Embodiment 3 will be described with reference to FIG. As can be seen by comparing FIG. 3 and FIG. 2, the positions of the insulating cylinder 18 and the disconnecting switch with grounding switch 7 are turned upside down without changing the mutual positional relationship, and the fixed terminal 26 of the circuit breaker is The connection terminal 46 is connected to the single-phase bushing 34 on the upper surface of the tank via the connection conductor 46, and the input terminal 27 of the disconnecting switch with ground switch is connected to the single-phase bushing 39 on the lower front surface of the tank via the connection conductor 47. In addition, although the power transformer 17 is connected to the single-phase bushing 39 at the lower front of the tank instead of the power cable 17, a power cable, a lightning arrester, and the like can be connected in a similar structure.
[0020]
Embodiment 4 FIG.
Next, a fourth embodiment will be described with reference to the drawings. As can be seen by comparing FIG. 4 and FIG. 1, the single-phase bushing 39 at the bottom of the tank is attached to the back side, and the power cable 17 is connected to the single-phase bushing 39 from the back side of the gas-insulated switchgear. In the figure, the power cable 17 is drawn from above the gas-insulated switchgear, but it can be connected even when the power cable 17 is drawn from below.
[0021]
As described above, according to the gas-insulated switchgear of the present invention, the insulator in which the main circuit part of the circuit breaker is housed is made circular or oval to disperse the stress in the insulator, and the insulator thin wall Can be realized. In addition, by providing protrusions on the insulator, it is possible to reduce assembly time without requiring extra metal fittings for mounting each terminal of the disconnecting switch with grounding switch, and through holes in some of the insulating cylinders By providing, heat generated in the insulating cylinder can be easily dissipated outside the insulating cylinder, and a large current can be passed even with the same conductor size.
[0022]
【The invention's effect】
The gas-insulated switchgear according to the present invention is a cylindrical body having an annular cross-section in a plane perpendicular to the axial direction of the insulating frame, and includes an opening for connecting the movable side terminal of the vacuum circuit breaker to the disconnector. Therefore, the stress in the insulating frame can be dispersed to reduce the thickness of the insulating frame, a disconnect switch with a ground switch can be attached to the insulating frame, and a through hole is provided in a part of the insulating frame. Thus, the heat generated in the insulating frame can be easily dissipated to the outside, and a large current can be applied even with the same conductor size.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a first embodiment of a gas-insulated switchgear according to the present invention.
FIG. 2 is a side sectional view showing a second embodiment of the gas-insulated switchgear of the present invention.
FIG. 3 is a side sectional view showing a third embodiment of the gas-insulated switchgear of the present invention.
FIG. 4 is a side sectional view showing a fourth embodiment of the gas-insulated switchgear of the present invention.
[Explanation of symbols]
3 Metal container (tank), 7 Disconnector, 15 Cable head, 17 Power cable, 18 Insulating frame, 19 Vacuum circuit breaker (vacuum valve), 20 Movable terminal, 22 Flexible conductor, 23 Insulating rod, 25 Fixed terminal , 28 Opening, 34 Busbar side bushing, 48 Current transformer.

Claims (4)

A metal container filled with an insulating gas;
A bus-side bushing supported by the metal container and to be connected to an external circuit;
An insulating frame supported at one end on the container wall in the metal container;
A vacuum circuit breaker having a movable side terminal supported by the insulating frame and connected to an insulating rod extending through the one end of the insulating frame and a fixed side terminal supported by the other end of the insulating frame;
A disconnector having a rotatable blade provided on the insulating frame and connected between the bus-side bushing and the vacuum circuit breaker;
A cable head connected to the vacuum circuit breaker and connectable to a power cable;
In a gas insulated switchgear comprising a current transformer for measuring the current flowing through the cable head,
The insulating frame is a cylindrical body having a ring-shaped cross section perpendicular to the axial direction, and has an opening that penetrates the insulating frame in the radial direction to open the internal space of the insulating frame,
A gas-insulated switchgear comprising a flexible conductor that passes through the opening and connects the movable terminal of the vacuum circuit breaker to the disconnector. In the gas insulated switchgear according to claim 1, the gas insulated switchgear in which the flexible conductor is characterized in that it connects the movable terminal in the blade.   3. The gas insulated switchgear according to claim 1, wherein the main circuit conductor including the bus-side bushing and the disconnector is in a substantially vertical plane including the axis of the vacuum circuit breaker. Gas insulation switchgear.   The gas insulated switchgear according to any one of claims 1 to 3, wherein the bus-side bushings are shifted from each other in the depth direction and the width direction of the gas insulated switchgear. Gas insulation switchgear.

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