JPH0556527A - Insulated bus line - Google Patents

Abstract

PURPOSE:To realize that an insulated bus line withstand voltage characteristics thereof can be sustained for a long term without increasing the profile thereof. CONSTITUTION:Insulating layers 3a of a T-type bushing 3 penetrating through the ceilings of juxtaposed cabinets 1A, 1B are connected through a coupling pipe 16. A bus 4 connecting the conductors 2 of T-type bushings 3 for the cabinets 1A, 1B is housed in the coupling pipe 16 and silicon gel is filled in the gap between the bus 4 and the coupling pipe 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated bus bar used in a gas-insulated switchgear.

[0002]

2. Description of the Related Art FIG. 3 shows an example in which a conventional gas-insulated bus bar is attached to a gas-insulated switchgear, and a partially enlarged detailed view of this FIG. 3 is shown in FIG. In FIG. 3 and FIG. 4, an electric device is housed inside, and an insulating gas (S
F ₆ gas) encapsulated right of the box 1A, the 1B ceiling plate, a circular through hole (not shown) provided in the ceiling plate is substantially T-shaped T-shaped bushing 3 lower penetrates inserted The T-shaped bushings 3 and 3 are connected by a bus bar 4 made of a copper rod.

This T-shaped bushing 3 is disclosed in Japanese Patent Laid-Open No. 2-262810.
As disclosed in the publication, an insulating layer 3 formed by casting with an epoxy resin around a tubular connecting conductor 2 and a lead-out rod 2c branched downward from the central portion of the connecting conductor 2 at a right angle.
a branch portion formed of a, a contactor 5 that is inserted into the holes 2a and 2b formed on the left and right of the connection conductor 2 of the insulating layer 3a and inserted inside, and that connects the end portion of the busbar 4 and the connection conductor 2; Layer 3
The gas pipe 6 is fixed to a and connects the T-shaped bushings 3 and 3.

An expandable and contractable stainless steel bellows 7 is connected to the gas pipe 6, and an insulating gas 8 is enclosed in the gas pipe 6 from a gas injection valve 9. Since the enclosed gas pressure is substantially atmospheric pressure as in the case bodies 1A and 1B,
As an insulating reinforcement, an insulating cylinder 10 is inserted around the bus bar 4 as shown in FIG. The end of the insulating cylinder 10 covers the expandable and contractible flat knitted conductor 11 connected to the bus bar 4, so that the electric fields of the flat knitted conductor 11 and the bus bar 4 are relaxed. This insulation tube 10
Is made of epoxy resin and has a dielectric constant of about 5. Further, the gas pipe 6 and the bellows 7 are fixed to the buried metal 12 embedded in the side surface of the insulating layer 3a by the bolt 14 via the O-ring 13 to keep airtightness.

At the lower end of the drawer bar 2c, the box 1
Connected to electrical equipment (not shown) housed in A and 1B,
When the box body is not adjacent to the right side of the box body 1B, the hole 2b of the T-shaped bushing 3 is sealed by the holding plate 15 via the O-ring 13, and the inside is filled with insulating gas.

[0006]

However, in the gas-insulated bus bar configured as described above, the electric field strength on the surface of the bus bar 4 is mitigated by the insulating cylinder 10, but on the other hand, the gas pipe 6 and the bus bar 4 are separated from each other. The insulation distance may be apparently shortened as described later, and the electric field strength on the surface of the insulating cylinder 10 may increase. this is,
This is because the insulating gas 8 has a dielectric constant of about 1, while the insulating cylinder 10 has a dielectric constant of about 5, so that most of the potential is shared by the insulating gas 8. Furthermore, since the surface of the expandable / contractible flat knitted conductor 11 for absorbing the manufacturing error of the width of the boxes 1A and 1B has fine irregularities, the insulation is broken when the electric field strength exceeds the dielectric strength of the insulating cylinder 10. ..

Therefore, it is necessary to increase the wall thickness of the insulating cylinder 10. When the thickness is increased, the insulation distance of the insulating gas 8 is shortened, so that the electric field strength is increased. Therefore, not only the gas pressure has to be increased, but also when the gas pressure is increased, the wall thickness of the gas pipe 6 must be increased so as to withstand the pressure, and the gas seal portion by the O-ring 13 is also pressurized. A leakproof structure is required. Therefore, an object of the first and second inventions is to provide a gas-insulated switchgear capable of suppressing a partial increase in electric field strength without increasing the outer shape and maintaining a withstand voltage characteristic for a long period of time. To get a gas insulated busbar.

[0008]

[Means and Action for Solving the Problems] The first invention is
In an insulating bus bar that connects between T-shaped bushings penetrating the outer wall of a box in which electrical equipment is housed and filled with insulating gas, a connecting pipe connected between the T-shaped bushings and a shaft of this connecting pipe By including the conductor that is housed in the core and that connects between the T-shaped bushings and the silicone gel that fills the connecting pipe, the conductor and the connecting pipe are insulated by the silicone gel with excellent insulation properties, and long-term equipment It is an insulating busbar that can maintain withstand voltage characteristics even during heat cycles during operation.

A second aspect of the present invention is a T which is penetrated through an outer wall of a box in which electric equipment is housed and which is filled with an insulating gas.
In an insulating bus bar connecting between the B-shaped bushings, a connecting pipe connected between the T-shaped bushings, a conductor housed in the axial center of the connecting pipe and connecting the T-shaped bushings with an insulating jacket, and a connecting pipe By having the insulating gas sealed in
It is an insulating busbar capable of suppressing the increase of the electric field strength of the gas insulating portion and maintaining the withstand voltage characteristics for a long period of time.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the insulating bus bar of the present invention will be described below with reference to the drawings. However, the same parts as those in FIG. 3 and FIG. FIG. 1 is a longitudinal sectional view showing a state in which an insulating bus bar of the first invention is connected to a T-shaped bushing, and is a view corresponding to FIG.

In FIG. 1, a T-shaped bushing 3 is airtightly attached to the ceiling portion of the box 1B via an O-ring 13 as in FIGS. 2 and 3, and is connected to the connecting conductor 2 of the T-shaped bushing 3. Pull-out bar 2 branched from this connecting conductor 2 at a right angle
An insulating layer 3a cast with epoxy resin is formed around c, and holes 2a and 2b are formed in the insulating conductor 3a around the connecting conductor 2 in the axis of the connecting conductor 2. Of these, a plurality of contacts 5 attached to the outer circumference of the end of the bus bar 4 are fitted in the left hole 2a, and the contacts 5 come into contact with the inner circumference of the connection conductor 2 at a predetermined contact pressure. is doing.

Here, a connecting pipe is provided between the T-shaped bushing 3 and the T-shaped bushing attached to an unillustrated adjacent box body.
16 is fixed to the embedded metal 12 embedded in the insulating layer 3a with bolts 14, and between the bus bar 4 and the connecting pipe 16, silicone oil 17 and a curing agent are mixed and the silicone gel 17 cured into a gel is defoamed. Is filled. This silicone gel 17 is filled with the liquid gel immediately after mixing the silicone oil and the curing agent from the inlet 16a attached to the connecting pipe 16 after assembling the busbar 4 and the connecting pipe 16, and then at room temperature. It is held for several hours to cure into a gel. In addition, on the left side surface of the connecting conductor 2, an insulating plate previously inserted into the bus bar 4 is provided.
18 is in contact with the silicone gel 17 so that the silicone gel 17 does not flow into the inside of the connecting conductor 2 and enter the contact portion between the contact 5 and the inner periphery of the connecting conductor 2.

On the other hand, the T on the right side where the bus bar 4 is not attached
In the hole 2b of the shaped bushing 3, a holding plate 19 is fixed to the embedded metal 12 embedded in the insulating layer 3a with a bolt 14, and the connecting conductor 2
Silicone gel 17 is filled in the spaces and via an insulating plate 18. The silicone gel 17 is injected through the injection port 19a.
There are methods such as atmospheric pressure injection, vacuum, pressurization, etc., but if vacuum injection is selected, the hole 2b of the T-shaped bushing 3 is already in a vacuum state. The injection port 19a may be located at any position as long as the injection port 19a has an exhaust valve and an injection valve (not shown).

In the insulated bus bar thus constructed,
Since the silicone gel 17 is hardened into a gel and filled between the bus bar 4, the connecting pipe 16, the connecting conductor 2 and the holding plate 19, the silicone gel 17 forms the main insulation. Silicone gel 17 is a mixture of silicone oil and a curing agent. In one example in which the dielectric strength was examined, silicone gel and a curing agent were mixed at a ratio of 1: 1 and gelled,
Although the breakdown voltage is inferior to that of epoxy resin, it is superior to silicone oil by about 30% and AC of about 45 kV / mm. Further, if the gel is formed after the vacuum degassing, no voids are generated and no corona discharge is generated. Comparing the dielectric strength with SF ₆ gas, the breakdown voltage is 8.9kV at atmospheric pressure.
/ Mm, the silicone gel 17 has about 5 times the dielectric strength.

Since the silicone gel 17 is gel-like as compared with an insulating material such as an epoxy resin, there is no residual stress at the time of curing, and even after curing, the stress of expansion and contraction due to temperature change is caused. Since it is absorbed, no crack is generated and excellent dielectric strength can be maintained. However, since the thermal expansion coefficient is large and the volume increases when the temperature rises, this increase is absorbed by the injection ports 16a and 19a. Therefore,
This insulating busbar does not need to have an airtight structure because the main insulating portion can be downsized and no gas seal is required.
The structure is simple enough that the silicone gel does not leak, the number of parts can be reduced, and maintenance is easy.

Next, FIG. 2 shows that the insulating bus bar of the second invention is T
FIG. 5 is a vertical cross-sectional view showing a state in which the bushing is connected to the shape bushing, and is also a view corresponding to FIG. 4. In FIG. 2, in the hole 2a on the left side of the connection conductor 2, a cable 20 having a plurality of contacts 5 attached to the outer periphery of the core wire 21 at the end is attached to
The gas pipe 6 and the bellows 7 similar to those in FIGS. Further, as in FIG. 4, the expandable and contractible bellows 7 is sealed in the gas pipe 6 by welding, and the insulating gas 8 is filled from the gas injection valve 9.

Here, an insulating material having a low dielectric constant is integrally formed around the stranded wire 21. For example, an insulating bus bar may be used in which the ground layer of the jacket is peeled off with a cable material made of cross-linked polyethylene having a dielectric constant of about 2.3. In addition, the insulating gas 8 is sealed in the hole 2b on the right side through which the insulating busbar does not penetrate by the holding plate 15 as in the case of FIG.

In the insulated bus bar thus constructed,
The permittivity of the jacket of the cable 20 is the same as that of the conventional insulating cylinder shown in FIG.
Since it is smaller than 10, the sharing voltage of the insulation distance of the gas space is lowered, and the electric field strength is reduced accordingly. Also stranded
The electric field strength of the surface of 21 is also reduced because it is covered with the jacket. Therefore, it is not necessary to increase the gas pressure to increase the dielectric strength, and good insulation performance can be maintained at a low gas pressure. Therefore, the gas pressure can be made equal to the gas pressure of the box body 1B, the gas seal article can be shared, and the reliability is improved. Furthermore, when the dielectric strength has a margin, the diameter of the entire gas-insulated bus bar can be reduced.

Next, a stranded wire 21 is used as a conductor for conducting electricity.
In addition, the outer cover is made of a cross-linked polyethylene cable material. Since the outer cover is stretchable and flexible, the box 1A,
Since it is possible to absorb the manufacturing error of 1B and the dimensional difference due to the temperature change caused by the operation stop of the equipment with the outside air, the parts of the flat knitted conductor of the conventional method can be omitted. For this reason,
Insulation bus bar is easy to manufacture.

In the above embodiment, the case where the cross-linked polyethylene is used as the jacket of the stranded wire 21 is explained. However, even if an insulating gas is sealed by wrapping a paper tape having a low dielectric constant, etc. The strength can be suppressed and the dielectric strength can be improved.

[0021]

As described above, according to the first aspect of the present invention, in the insulating bus bar that connects the T-shaped bushings penetrating the outer wall of the box in which the electric equipment is housed and the insulating gas is sealed,
By providing a connecting pipe connected between the T-shaped bushings, a conductor housed in the axial center of the connecting pipe and connecting the T-shaped bushings, and a silicone gel filled in the connecting pipe, excellent insulation characteristics can be obtained. Since the conductor and the connecting pipe are insulated with the silicone gel, it is possible to obtain an insulating bus bar capable of maintaining the withstand voltage characteristic even with respect to the heat cycle due to the operation of the equipment for a long period of time.

According to the second aspect of the invention, in the insulating bus bar connecting the T-shaped bushings penetrating the outer wall of the box in which the electric equipment is housed and the insulating gas is sealed,
By including a connecting pipe connected between the B-shaped bushings, a conductor housed in the axial center of the connecting pipe and connecting the T-shaped bushings with an insulating jacket, and an insulating gas sealed in the connecting pipe. Since the increase in the electric field strength of the gas insulating portion is suppressed, it is possible to obtain an insulating bus bar that can maintain the withstand voltage characteristics for a long period of time.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an insulating bus bar of the first invention.

FIG. 2 is a longitudinal sectional view showing an embodiment of an insulating bus bar of the second invention.

FIG. 3 is a view showing a state in which a conventional insulated bus bar is attached to a gas insulated switchgear.

FIG. 4 is a vertical sectional view of a conventional insulating bus bar.

[Explanation of symbols]

1A, 1B ... Box body, 2 ... Connection conductor, 3 ... T-shaped bushing, 4 ... Busbar, 5 ... Contact, 6 ... Gas pipe, 7 ... Bellows, 8
... Insulating gas, 9 ... Gas injection valve, 10 ... Insulating cylinder, 11 ... Flat knitted conductor, 12 ... Fill metal, 13 ... O-ring, 14 ... Bolt, 15, 19 ... Holding plate, 16 ... Connecting pipe, 17 ... Silicone Gel, 18 ... insulation board,
20 ... cable.

Claims (2)

[Claims] 1. An insulating bus bar connecting between T-shaped bushings penetrating the outer wall of a box in which an electric device is housed and in which an insulating gas is sealed, and a connecting pipe connected between the T-shaped bushings. An insulating bus bar, comprising: a conductor housed in the axis of the connecting pipe to connect between the T-shaped bushings; and a silicone gel filled in the connecting pipe. 2. An insulating bus bar connecting between T-shaped bushings penetrating the outer wall of a box in which an electric device is housed and in which an insulating gas is sealed, and a connecting pipe connected between the T-shaped bushings. An insulating busbar, comprising: a conductor housed in the axis of the connecting pipe, connected between the T-shaped bushings, and having an insulating jacket; and an insulating gas sealed in the connecting pipe.