JPH10341518A - Gas insulating bus, and gas insulating switchgear using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove the inner short circuit, and reduce the loss of generated heat caused by an eddy current, by connecting circular conductors, which are made of the same conductors as low-resistance connecting conductors being arranged severally close to each three-phase conductor within conductive bellows, between the connecting conductors, and connecting conductive tanks and the connecting conductors through connections. SOLUTION: A three-phase conductor 1 made of aluminum material is accommodated and sealed together with incombustible gas at, for example, about 3-5 atmospheric pressures, within tanks 3 and 3' made of aluminum material and bellows 4 made of stainless material through an insulating spacer. A shield means 5 against an eddy current made of a low-resistance conductor is composed of a joint plate 5a and a joint ring 5b. The joint plates 5a are installed at three places in the positions each contiguous to a three-phase conductor 1, outside of the bellows 4, and both ends each of them are electrically connected with tanks 3 and 3'. Furthermore, these three sheets of joint plates 5a are connected with one another by the joint rings 5b in the vicinity of both ends, resulting or integral form.

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, and more particularly, to a gas-insulated bus that reduces heat generated by eddy currents generated in a bellows provided in a metal grounding container of a three-phase batch gas-insulated bus. The present invention relates to a gas insulated switchgear using the same.

[0002]

2. Description of the Related Art In recent years, due to an increase in power demand and a demand for miniaturization of power equipment, SFs having high insulation performance have been used in the backbone of power transmission systems.
There is a tendency to frequently use gas insulated equipment in which energized conductors and electrical devices are housed in a metal grounded container filled with _six gases.

[0003] A basic component of a gas-insulated device is a gas-insulated bus (GIB), and a current-carrying conductor is supported through an insulating spacer in a metal grounding vessel filled with SF ₆ gas. . Bellows are used in gas-insulated buses in various places in metal grounding vessels to absorb expansion and contraction of equipment due to temperature changes and vibrations.More recently, three-phase conductors have insulating spacers in the same grounding tank. There is a tendency to frequently use the three-phase collective type gas-insulated bus supported through the intermediary.

The three-phase batch type gas-insulated bus can reduce the number of gas sealing portions and the number of metal grounding vessels such as tanks and bellows to reduce the occupied volume. Since the generated magnetic field traverses the container wall, an induced electromotive force is generated in the metal grounded container, which causes a problem that an eddy current is generated.

This eddy current is small when the container is large and the metal grounding container wall is located sufficiently away from the current-carrying conductor, but increases as the container is reduced in size and the three-phase conductor comes close to the metal grounding container. become. For this reason, in recent years, heat generation loss due to eddy currents induced in high-resistance metal containers such as gas-insulated buses tends to increase with reduction in power transmission system and increase in capacity. To cope with this problem, aluminum tanks and the like have come to be used as tanks for large-capacity models as metal grounded containers. However, stainless steel is usually used for the bellows for reasons such as securing strength and easiness of processing.Because stainless steel has a higher resistance than aluminum tanks, heat loss due to eddy current is large, and Since the bellows needs to be reduced in thickness so as to be able to expand and contract freely, the cross-sectional area is small, the resistance is further increased, and there is a problem of a rise in temperature.

Conventionally, in order to reduce the heat loss, as a first prior art, a container of a gas insulated bus including a bellows is formed of a low-resistance conductor such as an aluminum material so that even if an eddy current is generated, heat is generated. Some things reduce the loss.

A second prior art is disclosed in Japanese Patent Application Laid-Open No. 58-9 / 1983.
As disclosed in Japanese Patent No. 3414, a magnetic shield formed of a low-resistance conductor such as aluminum or copper is provided inside a high-resistance metal grounding vessel such as a bellows to suppress eddy current generated in the metal grounding vessel.

A third prior art is disclosed in Japanese Patent Laid-Open No. 59-1
As shown in Japanese Patent No. 49706, a low-resistance conductive conductor (shunt plate) is used to connect between tanks made of aluminum before and after a bellows of a metal grounding container, and an eddy current generated in the tank is reduced. In some cases, the current flowing through the bellows suppresses the current passing through the bellows, thereby suppressing heat generation.

[0009]

However, the above-mentioned prior art has the following problems.

[0010] In the first prior art, aluminum has a lower strength than stainless steel or the like. Therefore, there is a problem that the strength deteriorates after repeated expansion and contraction for a long time, and it becomes difficult to secure the strength of the bellows for a long time. .

In the second prior art, since the shield is installed in the bellows, the distance between the shield and the three-phase conductor is short, which is not only disadvantageous in terms of withstand voltage, but also the bolts and the like are loosened and dropped by the vibration electromagnetic force. there is a possibility. Further, since the shield is located inside the bellows, there is a problem that a sufficient cooling effect cannot be obtained. Further, when the shield is installed in the bellows, there is a problem that foreign matter is generated or assembly is troublesome.

In the third prior art, the shunt plate connecting the aluminum tanks before and after the bellows does not take into account the function as a magnetic shield, as will be described later. However, there is a problem that a sufficient reduction effect cannot be expected with respect to the eddy current loss.

In view of the above-mentioned problems of the prior art, the present invention uses a low-resistance material such as aluminum which is expensive and difficult to process in a high-resistance metal grounding container such as a bellows in a gas-insulated bus. To provide a gas-insulated bus and a gas-insulated switchgear using the same, which have a simple structure that is easy to assemble without danger of a short circuit inside, and that can reliably reduce heat loss due to eddy current. is there.

[0014]

The present invention employs the following means in order to solve the above-mentioned problems.

A gas having a plurality of conductive tanks and a conductive bellows connecting the conductive tanks, wherein a non-combustible gas is sealed in the conductive tank and the conductive bellows, and a three-phase conductor is inserted through the gas. A plurality of connection conductors, each of which is formed of a conductor having a lower resistance than the conductive tank and the conductive bellows, and is disposed in close proximity to each of the three-phase conductors in the conductive bellows; A plurality of annular conductors formed of the same conductor as the connection conductors and installed so as to connect the plurality of connection conductors to each other; and provided at ends of the plurality of connection conductors and connected to the conductive tank. And a shield unit comprising a connection unit.

[0016] Also, a plurality of conductive tanks and a conductive bellows for connecting the conductive tanks are provided, and a non-combustible gas is sealed in the conductive tank and the conductive bellows, and a three-phase conductor is inserted. A plurality of connection conductors formed of a conductor having a lower resistance than the conductive tank and the conductive bellows, and disposed in close proximity to each of the three-phase conductors in the conductive bellows; A connection unit provided at an end of the plurality of connection conductors and connected to the conductive tank, the connection unit collecting eddy current generated in the conductive tank. It is characterized by having a contact area sufficient for the contact.

[0017] In addition, a plurality of conductive tanks and a conductive bellows for connecting the conductive tanks are provided, and a non-combustible gas is sealed in the conductive tank and the conductive bellows to insert a three-phase conductor. A plurality of connection conductors formed of a conductor having a lower resistance than the conductive tank and the conductive bellows, and disposed in close proximity to each of the three-phase conductors in the conductive bellows; A connection part provided at an end of the plurality of connection conductors and connected to the conductive tank, wherein each of the plurality of connection conductors is a three-phase conductor in the conductive bellows. Are disposed so as to be close to each other. Further, the plurality of connection conductors have a width at least as large as the width of the three-phase conductor.

Further, the conductive tank has a flange connected to the conductive bellows, and the connecting portion is connected to the flange.

The connecting portion is connected to a surface of the flange on the side of the conductive bellows.

Further, the flange is constituted by an annular body, and the connecting portion is constituted by an annular flat body so as to be in contact with the flange surface.

Further, the shield means is characterized in that the conductive bellows has a mirror surface and a position and a shape so as to be a mirror surface of the three-phase conductor.

Further, the conductive tank is formed of a material mainly composed of aluminum, and the conductive bellows is
The shield means is made of a material mainly made of an aluminum material or a copper material.

Further, the gas-insulated bus according to any one of claims 1 to 9 is used for a gas-insulated switchgear.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of a three-phase collective gas-insulated bus according to the present embodiment.

In the drawing, reference numeral 1 denotes a three-phase conductor made of aluminum material. The three-phase conductor 1 is made of a tank 3, 3 'made of aluminum material and a stainless steel material via an insulating spacer (not shown). 3 to 3 inside the formed bellows 4
It is hermetically stored together with non-flammable SF ₆ gas of about 5 atm.

Reference numeral 5 denotes eddy current shielding means formed of a low-resistance conductor, and includes a shunt plate 5a and a shunt ring 5b.
It is composed of The shunt plates 5a are provided outside the bellows 4 at three positions close to the three-phase conductor 1, respectively, and both ends thereof are electrically connected to the tanks 3, 3 '. Further, these three shunt plates 5a are connected by shunt rings 5b near both ends of the bellows 4 to form an integrated structure.

6 is an eddy current flowing in the tanks 3 and 3 ', 2
a represents a current flowing through the shunt plate 5a, and 2b represents a current flowing through the shunt ring 5b.

Next, the operation principle of this embodiment will be described with reference to FIGS.

FIG. 2 is an enlarged sectional view of the three-phase conductor 1 and the bellows 4 shown in FIG. 1. When an alternating current flows in one of the three-phase conductors 1 in the direction shown in FIG. Occur. The magnetic flux 7 generates magnetic fields 71 and 72 interlinking with the bellows 4, and an induced electromotive force is generated in the bellows 4. However, since the thickness of the bellows 4 is very thin compared to the radius of the bellows, mainly the bellows 4 of the magnetic fields 71 and 72 are used.
The eddy currents 8, 9 are generated in the bellows 4 in the direction shown in the figure by the vertical components 73, 74 with respect to

FIG. 3 is an enlarged sectional view of the three-phase conductor 1, the bellows 4, and the shunt plate 5a shown in FIG. 1. The eddy current 6 generated in the tank 3 is transferred to the shunt plate 5a provided outside the bellows 4. Power is supplied in the direction shown. Magnetic fields 101, 1 generated by current 2a passing through shunt plate 5a
The vertical components 103, 104 of the three-phase conductor 1 are the vertical components 73, 74 of the magnetic fields 71, 72 with respect to the bellows 4.
Work in the direction of offsetting. As a result, the magnetic flux linked to the bellows 4 can be reduced without providing a shield means inside the bellows 4, and the heat loss of the bellows 4 due to the eddy currents 8, 9 can be reduced.

FIG. 4 is an enlarged sectional view of the entire three phases of the three-phase conductor 1, the bellows 4 and the shunt plate 5a shown in FIG. 1. On the bellows 4, a shunt plate 5a is provided on each of the three-phase conductors 1. It is installed at the position facing. Tank 3,
At 3 ', an eddy current having a magnitude corresponding to the current flowing through the three-phase conductor 1 is generated at a position close to the three-phase conductor 1, and this eddy current is passed through the shunt plate 5a. Of the current 2a flowing through the three-phase conductor 1 also corresponds to the current flowing through each three-phase conductor 1.

Here, the current 2a flowing through the shunt plate 5a
Is most effective as a shield when the current flowing through the three-phase conductor 1 and the bellows 4 have a relationship between the position of the mirror image and the strength. In that case, ideally, the eddy current generated in the bellows 4 can be reduced to zero. However, if only the shunt plate 5a is provided as in the third related art, the shunt plate 5a is a theoretical mirror image. And the current 2a flowing through the shunt plate 5a does not have the strength of the mirror image current.

FIG. 5 is a view for explaining the role of the shunt ring 2b shown in FIG.

As described above, the residual eddy current 11 is generated in the bellows 4 as shown in the drawing, irrespective of the theoretical mirror image only with the shunt plate 5a of the third prior art.

For this reason, in the present embodiment, as shown, the shunt ring 5 b
And a conduction path is provided. As a result, in the current 2b flowing through the shunt ring 5b, an image electromotive force that cancels the residual eddy current of the bellows 4 is generated on the bellows 4, and heat generation in the bellows 4 can be further reduced.

As described above, according to the present embodiment, the shunt plate 5a is provided on the bellows 4 as the shielding means 5 so that the current flowing through the three-phase conductor 1 and the bellows 4 have a relationship between the position of the mirror image and the strength. By arranging the shunt ring 5b, heat generation in the bellows 4 can be reduced, and the size and capacity of the device can be reduced.

Next, a gas-insulated bus according to a second embodiment of the present invention will be described with reference to FIG.

FIG. 6 is a sectional view of the gas-insulated bus bar to which the shield means 5 is attached.

In the figure, 12 is a bolt for attaching the shielding means 5 to the tank 3, and 31 is a tank 3, 3 '.
Reference numeral 41 indicates a bellows flange, and reference numeral 51 indicates a portion for attaching the shielding means 5 to the tanks 3 and 3 '. Other configurations are the same as those shown in FIG.

As a material of the shield means 5, a low-resistance conductor such as copper or aluminum can be considered. In this embodiment, an inexpensive and low-resistance copper plate is used. The shield means 5 may be attached and fixed by providing a pedestal on the surface of the tank 3, 3 ′, but as shown, a flange 31 is provided at the end of the tank 3, 3 ′, and Press and fix. Furthermore, the connection is made such that the paint on the conductor surface is peeled off and the contact resistance is reduced electrically.

The shape of the shield means 5 is not a simple flat plate, but a shape considering the expansion and contraction of the bellows 4. Further, the shunt plate 5a is bent on the bellows 4 so as to approach the center. Has become. By bringing the shunt plate 5a closer to the bellows as described above, the shielding effect can be enhanced even when the intensity of the mirror image current is weak. That is, the shielding effect of the shield means 5 can be adjusted depending on the positions of the bellows 4 and the shield means 5. In order to further enhance the shielding effect, the shielding means 5 may have a waveform conforming to the shape of the bellows 4.

Next, a shield means according to a third embodiment of the present invention will be described with reference to FIG.

FIG. 7 is a perspective view of the shield means 5 attached to the gas-insulated bus.

As shown in the figure, in the present embodiment, the size of the mounting portion 51 of the shielding means 5 to the flange 31 of the tank 3, 3 'is increased. The shielding effect of the shield means 5 largely depends on the installation position of the shield means 5 on the tanks 3 and 3 ′, the area of the mounting portion 51, and the shape of the shield means 5 on the bellows 4. The inventors performed a three-dimensional numerical analysis, and found that most of the eddy current generated in the tanks 3 and 3 ′ was flanged at the ends of the tanks 3 and 3 ′.
It was found that the vehicle turns in the circumferential direction at 1. Therefore, by increasing the mounting portion 51 of the shield means 5,
The eddy current generated in the tanks 3 and 3 'can be effectively collected, and the current 2a flowing through the shield means 5 can be increased.

The most effective demagnetizing field for canceling the magnetic field generated by the three-phase conductor 1 on the bellows 4 is a magnetic field having the same magnitude as the magnetic field generated by the three-phase conductor 1 with respect to the surface of the bellows 4 and having the opposite direction. It is. In order to generate such a magnetic field, it is desirable that the shape of the shielding means 5 be such that the three-phase conductor 1 is in a mirror image relationship with the bellows 4. For this reason, in the present embodiment, in the shielding means 5, the tank 3,
The width of the portion attached to the flange 31 of 3 ′ is widened to effectively collect the current, and the width of the shunt plate 5a that brings a demagnetizing field to the bellows 4 is set to about the width of the three-phase conductor 1. Improved the effect of the magnetic field.

Next, a shield means according to a fourth embodiment of the present invention will be described with reference to FIG.

FIG. 8 is a perspective view of the shield means 5 attached to the gas-insulated bus.

In the present embodiment, the mounting portion 51 for mounting the shield means 5 to the flange 31 of the tank 3, 3 'is formed of an annular flat plate made of copper. With this configuration, the contact resistance with the tanks 3 and 3 ′ can be reduced, and more eddy current can flow through the shield means 5.
Further, according to the present embodiment, since the mounting portion 51 of the shield means 5 is integrally formed, it is possible to prevent uneven current flowing through the shunt plate 5a of each phase due to a difference in mounting state.

Next, shield means according to the fifth and sixth embodiments of the present invention will be described with reference to FIGS.

FIGS. 9 and 10 are perspective views of the shield means 5 attached to the gas-insulated bus according to the fifth and sixth embodiments, respectively.

The shield means 5 shown in FIG. 9 is a third embodiment in which a shunt ring 5b is added to the shield means 5 shown in FIG. 7, and the shield means 5 shown in FIG. It is obtained by adding a shunt ring 5b to the shield means 5 shown in FIG.

By combining the shunt ring 5b in this way, not only the eddy current generated in the tanks 3 and 3 'can be effectively reduced, but also the accuracy of the mounting position of the shielding means 5 can be improved, and the shielding effect can be improved. Can be made uniform.

Next, a gas-insulated bus according to a seventh embodiment of the present invention will be described with reference to FIG.

FIG. 11 is a sectional view of the gas-insulated bus bar to which the shield means 5 is attached.

In the figure, reference numeral 13 denotes an insulating spacer interposed between the flange 41 of the bellows 4 and the mounting portion 51 of the shield means 5, and the mounting portion 51 is formed of the insulating spacer 13 and the bellows of the flange 31 of the tank 3, 3 '. It is installed between the sides and the other configuration is the same as that shown in FIG.

Normally, eddy currents generated in the tanks 3, 3 'mainly flow through the inner walls of the tanks 3, 3' due to the skin effect. Therefore, by connecting the mounting portion 51 to the surface of the flange 31 following the inner wall of the tank 3, 3 ′, the current from the tank 3, 3 ′ can flow to the shielding means 5 efficiently. As a result, compared to the skin depth, tank 3, 3 '
Even when the flange 31 is thick, a large eddy current can flow through the shield means 5.

In each of the first, second, third, fourth, fifth, and sixth embodiments, similarly to this embodiment, the mounting portion 51 of the shielding means 5 is attached to the tank 3, 3 '. It may be sandwiched between the flange 31 and the bellows flange 41.

In the third prior art, a shunt plate is provided so that eddy current generated in the tank does not pass through the bellows. In this case, if an insulating spacer or the like is inserted between the aluminum material tank and the SUS bellows, the eddy current is cut off, and it is considered that a shunt plate is not necessary, but as described above. Actually, the eddy current generated on the bellows is also a major factor of the temperature rise. Therefore, in each of the above-described embodiments including this embodiment, the eddy current generated in the tanks 3, 3 ′ does not pass through the bellows 4 by insulating the tanks 3, 3 ′ and the bellows 4 with the spacer 13 or the like. By providing the shielding means 5 in this manner, the eddy current generated in the tanks 3 and 3 'is prevented from flowing into the bellows 4 and the eddy current generated on the bellows 4 is suppressed. Therefore, heat generation in the bellows 4 can be further reduced. As described above, according to each of the above embodiments, a shield means formed of a low-resistance conductor is installed outside a bellows using a high-resistance conductor such as stainless steel, and a three-phase conductor is used. An eddy current that generates a demagnetizing field with respect to a magnetic field that causes the generation of an eddy current is generated in the bellows, thereby suppressing the generation of the eddy current in the bellows and suppressing the heat generation in the bellows.

Further, according to each of the above-described embodiments, an effect superior to the related art in which a shield is provided inside the bellows can be obtained.

Further, according to the above embodiments,
Equipment that is easy to assemble because the internal structure of the tank or bellows can be simplified, is excellent in maintainability, and because the shielding means is outside, it is unlikely to cause a short circuit accident and has excellent cooling performance. It is possible to reduce the size and increase the capacity.

[0062]

As described above, according to the present invention, a plurality of connection conductors each formed of a conductor having a lower resistance than the conductive tank and the conductive bellows, each of which is close to the three-phase conductor in the conductive bellows, Shielding means composed of a plurality of annular conductors connecting the plurality of connection conductors to each other is provided and connected to the conductive tank, so that generation of eddy current in the conductive bellows can be suppressed, and It is possible to effectively suppress the heat generated by the conductive bellows.

[Brief description of the drawings]

FIG. 1 is a perspective view of a three-phase batch-type insulated bus according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the three-phase conductor 1 and the bellows 4 shown in FIG.

FIG. 3 is an enlarged cross-sectional view of the three-phase conductor 1, the bellows 4, and the shunt plate 5a shown in FIG.

FIG. 4 is an enlarged cross-sectional view of the entire three phases of the three-phase conductor 1, the bellows 4, and the shunt plate 5a shown in FIG.

FIG. 5 is a diagram illustrating a role of a shunt ring 2b shown in FIG.

FIG. 6 is a cross-sectional view of a gas-insulated bus bar equipped with a shield means according to a second embodiment of the present invention.

FIG. 7 is a perspective view of a shield means attached to a gas-insulated bus according to a third embodiment of the present invention.

FIG. 8 is a perspective view of a shield means attached to a gas-insulated bus according to a fourth embodiment of the present invention.

FIG. 9 is a perspective view of a shield means attached to a gas-insulated bus according to a fifth embodiment of the present invention.

FIG. 10 is a perspective view of a shield means attached to a gas-insulated bus according to a sixth embodiment of the present invention.

FIG. 11 is a perspective view of a shield means attached to a gas-insulated bus according to a seventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 3 phase conductor 2a Current which flows through a shunt plate 2b Current which flows through a shunt ring 3,3 'Tank 31 Flange 4 Bellows 41 Flange 5 Shielding means 5a Shunt plate 5b Shunt ring 51 Mounting part 6 Eddy current

Claims (10)

[Claims] 1. A conductive tank comprising: a plurality of conductive tanks; and a conductive bellows connecting the conductive tanks, wherein a non-combustible gas is sealed in the conductive tank and the conductive bellows, and a three-phase conductor is provided. In the inserted gas-insulated bus, a plurality of connection conductors formed of a conductor having a lower resistance than the conductive tank and the conductive bellows, and arranged in close proximity to each of the three-phase conductors in the conductive bellows A plurality of annular conductors formed of the same conductor as the connection conductors and installed so as to connect the plurality of connection conductors to each other; and the conductive tank provided at an end of the plurality of connection conductors. A gas-insulated bus, comprising: a shield unit configured to include a connection unit that connects to the bus. 2. A fuel cell comprising: a plurality of conductive tanks; and a conductive bellows connecting the conductive tanks, wherein a non-combustible gas is sealed in the conductive tank and the conductive bellows, and a three-phase conductor is provided. In the inserted gas-insulated bus, a plurality of connection conductors formed of a conductor having a lower resistance than the conductive tank and the conductive bellows, each of which is disposed in close proximity to each of the three-phase conductors in the conductive bellows And a connection part provided at an end of the plurality of connection conductors and connected to the conductive tank. The connection part captures an eddy current generated in the conductive tank. A gas-insulated bus bar having a contact area sufficient to collect. 3. A conductive tank comprising: a plurality of conductive tanks; and a conductive bellows connecting the conductive tanks, wherein a non-flammable gas is sealed in the conductive tank and the conductive bellows, and a three-phase conductor is provided. In the inserted gas-insulated bus, a plurality of connection conductors formed of a conductor having a lower resistance than the conductive tank and the conductive bellows, each of which is disposed in close proximity to each of the three-phase conductors in the conductive bellows And a connection part provided at an end of the plurality of connection conductors and connected to the conductive tank. Each of the plurality of connection conductors is provided with a three-phase connection in the conductive bellows. A gas-insulated bus bar, which is bent and disposed so as to be close to a conductor. 4. The method according to claim 1, wherein
The gas-insulated bus according to any one of claims 1 to 3, wherein each of the plurality of connection conductors has a width at least as large as a width of the three-phase conductor. 5. The method according to claim 1, wherein
The gas-insulated bus according to any one of claims 1 to 3, wherein the conductive tank includes a flange connected to the conductive bellows, and the connection portion is connected to the flange. 6. The gas-insulated bus according to claim 5, wherein the connecting portion is connected to a surface of the flange on the side of the conductive bellows. 7. The method according to claim 5, wherein
The gas-insulated busbar according to one of the claims, wherein the flange is formed of an annular body, and the connecting portion is formed of an annular flat body so as to contact the flange surface. 8. The method according to claim 1, wherein
The gas-insulated bus according to any one of claims 1 to 3, wherein the shielding means has a position and a shape such that the conductive bellows is a mirror surface of the three-phase conductor. 9. The method according to claim 1, wherein
In one claim, the conductive tank is formed of a material mainly composed of an aluminum material, the conductive bellows is formed of a material mainly composed of a stainless steel material, and the shielding means is an aluminum material or a copper material. A gas-insulated bus bar formed of a material mainly composed of: 10. A gas-insulated switchgear using the gas-insulated bus according to any one of claims 1 to 9.