JPH0731039A - Gas insulated bus - Google Patents

Abstract

PURPOSE:To reduce the size while enhancing the reliability by setting the ratio between the diameter of a high voltage conductor and the inner diameter of a metal enclosure larger than a specific value, setting the ratio between the diameter at a joint and the inner diameter of the metal enclosure within a specific range, and coating the bottom of the metal enclosure with a dielectric material in the vicinity of an insulating spacer. CONSTITUTION:A high voltage conductor 5 is made thin such that the ratio D/d1 between the diameter d1 thereof and the inner diameter D of a metal tank 1 is larger than 3.0. The inner diameter d2 at a joint 3 is determined such that the ratio D/d2 between the diameter d2 at the joint 3 and the inner diameter D of the metal tank 1 is in the range of 2.7-3.0. Furthermore, the bottom of the metal tank 1 is coated with a viscous substance 7 in the vicinity of an insulating spacer 4. This structure lowers the electric field on the inner face of the tank while preventing the concentration of the field on the high voltage conductor side without enlarging the metal enclosure thus lowering the electric field at the joint. Consequently, a metallic foreign matter is prevented from adhering to the insulating spacer or shifting to the high voltage conductor side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated busbar which is a busbar portion of a gas-insulated switchgear (hereinafter referred to as GIS).

[0002]

2. Description of the Related Art A conventional gas-insulated bus bar will be described with reference to FIGS. As shown in FIG. 6, the metal tank 1
The superior SF ₆ gas 2 while pressure sealed about 3~6kg / cm ² of insulation performance, co with a metallic connection part 3 - down type insulating space - arranged a support 4, connected The high-voltage conductor 5 is connected to the portion 3 to insulate and support the high-voltage conductor 5 in the center of the metal tank 1. The insulating spacer 4 supports and fixes the high-voltage conductor 5 and constitutes an SF ₆ gas section.

In designing such a gas-insulated bus bar, a metal tank 1 and a connection are mainly provided so as to ensure a required insulation performance and to keep the temperature rise of each part below a specified value when a rated current is applied. The dimensions of the part 3 and the high-voltage conductor 5 are selected. With the recent increase in voltage and capacity, transmission voltage is 550K
As V and 1100KV become extremely high, the insulation performance becomes the dominant factor in determining the dimensions.

In order to ensure the insulation performance of the gas-insulated busbar, the electric field on the surface of the high-voltage conductor 5 must be below a value that does not impair the insulation performance of the SF ₆ gas 2, and the inner surface of the metal tank 1 It is necessary to control the electric field (hereinafter referred to as the tank inner surface electric field) to a predetermined value or less. The control of the electric field on the inner surface of the tank will be described with reference to FIG. When a metal foreign matter 6 of about several mm is mixed in the gas-insulated bus bar at the time of assembly, etc., the metal foreign matter 6 is not contained in the metal tank 1 when no voltage is applied, as shown in the state A of FIG. Lying on the bottom of. However, when a voltage is applied to the high-voltage conductor 5 and the tank inner surface electric field E ₂ rises, the metallic foreign matter 6 stands up as shown in state B of FIG. 7, and when the tank inner surface electric field E ₂ further rises, state C of FIG. As shown in S
It comes to float in F ₆ gas. The flying height increases as the electric field E _{2 on the} inner surface of the tank increases, and the insulation performance of the SF ₆ gas 2 may be significantly reduced. Therefore, to determine the dimensions of the gas-insulated busbar, the high-voltage conductor 5
Not the surface electric field E ₁ only, it is necessary to consider the value of the tank inner surface electric field E _2.

Next, the magnitude of the tank inner surface electric field E ₂ will be described with reference to FIG. As shown in FIG. 8, a portion other than the vicinity of the insulating spacer 4 having the connecting portion 3 is defined as a region X, and a portion near the insulating spacer 4 is defined as a region Y. In the region X, the magnitude of the electric field on the tank inner surface is determined by the coaxial shape of the high-voltage conductor 5 having the diameter d ₁ and the metal tank 1 having the inner diameter D ₁ , and this magnitude is referred to as the tank inner surface electric field E ₂₀ . On the other hand, in the area Y near the insulating spacer 4, the magnitude of the electric field on the inner surface of the tank is different from the value in the area X because of the existence of the connecting portion 3 for electrically connecting the high-voltage conductor 5.
That is, the diameter d ₂ of the connecting portion 3 is equal to the diameter d _{1 of the} high-voltage conductor 5.
Since it is larger, the tank inner surface electric field E ₂₁ in the region Y becomes larger than the tank inner surface electric field E ₂₀ in the region X.

If only the tank inner surface electric field E ₂₀ formed by the high-voltage conductor 5 and the metal tank 1 is taken into consideration, the inner diameter D ₁ of the metal tank ₁ is the diameter d _{1 of the} high-voltage conductor 5.
The inner diameter of the metal tank 1 is D
It can be D ₂ less than ₁ . However,
If the inner diameter of the metal tank 1 is D ₂ , the insulating spacer 4
Since the connecting portion 3 having a diameter d ₂ larger than the diameter d ₁ of the high-voltage conductor 5 is arranged in the region Y which is in the vicinity of, the tank inner surface electric field in the region Y has a large value of 1.2 to 1.5 times E _21. And there is a problem in insulation performance.

Therefore, in the conventional gas-insulated bus bar, the inner diameter of the metal tank is determined according to the electric field on the inner surface of the tank in the vicinity of the insulation spacer, which has the strictest insulation condition. Therefore GI
As the whole S becomes larger and the installation area increases,
Since the insulation spacer also becomes larger, the quality of the insulation spacer,
There is a problem that a more advanced resin casting manufacturing technique is required to maintain reliability.

[0008]

As described above, in the conventional gas-insulated busbar, the diameter of the metal tank is determined according to the vicinity of the insulating spacer where the electric field on the inner surface of the tank is locally increased. There was a problem that it was difficult to miniaturize the gas-insulated busbar because the ratio of the diameter of the high-voltage conductor to the diameter of the metal tank could not be optimized except in the vicinity of the spacer. Therefore, an object of the present invention is to provide a gas-insulated bus bar that is small in size and has improved reliability.

[0009]

In order to achieve the above object, in the present invention, as a first invention, an insulating spacer is arranged in a metal container filled with an insulating gas, and the insulating space is provided.
In a gas-insulated busbar in which a metal connecting portion is arranged in the substantially central portion of the chamber, a high-voltage conductor is connected to this connecting portion, and the high-voltage conductor is insulated and supported by the metal container, the diameter d _{1 of the} high-voltage conductor is wherein the ratio D / d ₁ of the inner diameter D of the metal container is larger than 3.0, the ratio D / d ₂ of the inner diameter D of the metal container and the diameter d ₂ of the connecting portion is 2.7 to 3.0, the insulation Coat the bottom of the metal container near the spacer with an insulating material.
Provided is a gas-insulated bus bar, which is characterized by being coated. In addition, as a second invention, there is provided a gas-insulated busbar, characterized in that a recess is formed on the inner surface of the metal container instead of the coating.

[0010]

[Function] By thinning the high-voltage conductor so that the ratio D / d ₁ of the diameter d _{1 of the} high-voltage conductor to the inner diameter D of the metal container is larger than 3.0, the electric field is concentrated on the high-voltage conductor side, and the metal container is large. It is possible to control the electric field on the inner surface of the tank to be low without changing the temperature.

Further, by determining the diameter of the connecting portion such that the ratio D / d ₂ of the diameter d _{2 of the} connecting portion and the inner diameter D of the metal container is 2.7 or more and 3.0 or less, the surface electric field of the connecting portion is lowered. Can be controlled. In this case, the electric field on the inner surface of the tank increases, but the movement of the metallic foreign matter can be suppressed by coating the bottom of the metal container with an insulating material or forming a recess. Therefore, it is possible to prevent foreign metal particles from adhering to the insulating spacer and to move to the high-voltage conductor side, and it is possible to downsize the metal container.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. It should be noted that the same parts as the conventional ones are given the same numbers and their explanations are omitted. As shown in FIG. 1, an insulating spacer 4 is arranged in a metal tank 1 in which SF ₆ gas 2 is sealed, and a connecting portion 3 having a diameter d ₂ is arranged substantially in the center of the insulating spacer 4. . A high-voltage conductor 5 having a diameter d ₁ is connected to the connecting portion 3 to insulate and support the high-voltage conductor 5 in the metal tank 1. An adhesive substance 7 made of an insulating material is coated in the vicinity of the insulating spacer 4 of the metal tank 1.

In order that the ratio D / d ₁ between the diameter d ₁ of the high-voltage conductor 5 and the inner diameter D of the metal tank 1 becomes larger than 3.0,
The high-voltage conductor 5 is thin. Further, the ratio D / d ₂ of the diameter d ₂ of the connecting portion 3 and the inner diameter D of the metal tank 1 is 2.7.
The connecting portion 3 is configured to be 18.

Next, the operation will be described. In the present embodiment, the high-voltage conductor 5 is thin so that the ratio D / d ₁ between the diameter d ₁ of the high-voltage conductor 5 and the inner diameter D of the metal tank 1 is larger than 3.0. Therefore, the electric field is concentrated on the high-voltage conductor 5 side, and the electric field on the tank inner surface can be controlled to be low without increasing the size of the metal tank 1.

On the other hand, the connecting portion 3 is arranged substantially in the center of the insulating spacer 4 and is arranged coaxially with the metal tank 1. Therefore, the electric field formed by the connecting portion 3 and the metal tank 1 can be regarded as the electric field formed by the coaxial cylindrical gap. The maximum potential gradient E ₀ of the coaxial cylindrical gap is

[0016]

[Equation 1] Here, the _{r = d 2/2, R} = D / 2. When the radius r of the connecting portion 3 is extremely small, the curvature is large, so that E ₀ is large, and when r is extremely close to R, the gap length is small, so that E ₀ is large. , in the meantime shows that E ₀ is small.

When 1 / E ₀ is differentiated by r and zero is calculated, R / r = e. That is, R / r is about 2.7
It can be seen that E ₀ is minimum when it is 18. By setting R / r, that is, D / d ₂ to 2.178,
The surface creeping electric field of the insulating spacer 4 can be minimized. However, by setting D / d ₂ to 2.718, the electric field on the tank inner surface in the region Y near the insulating spacer 4 is set to the region Y.
It becomes higher than the tank inner surface electric field in the region X which is a portion other than. Therefore, in order to ensure insulation when the foreign metal 6 is mixed in the region Y where the electric field is high, an adhesive substance 7 is coated on the bottom of the metal tank 1 near the insulating spacer 4.

When the metal foreign matter 6 is mixed into the metal tank 1 during the assembly of the gas-insulated bus bar of this embodiment, the metal foreign matter 6
Fall to the bottom of the metal tank 1. Since the adhesive substance 7 is coated in the area Y near the insulating spacer 4, the metallic foreign matter 6 is captured by the adhesive substance 7. On the other hand, when the foreign metal 6 drops in the region X, when a voltage is applied to the high-voltage conductor 5, the electric field in the region Y is higher than in the region X, so the foreign metal 6 moves toward the region Y.
The metallic foreign matter 6 that has entered the region Y is captured by the adhesive substance 7.

As described above, according to this embodiment, the high voltage conductor 5
The ratio D / d ₁ of the diameter d ₁ to the inner diameter D of the metal tank ₁ is
The high-voltage conductor 5 is made thin so as to be larger than 3.0, and the ratio D / d of the diameter d ₂ of the connecting portion 3 and the inner diameter D of the metal tank 1 is D / d.
_The connecting portion 3 is constructed so that ₂ becomes 2.718, and the adhesive tank 7 is coated on the bottom of the metal tank 1 near the insulating spacer 4. Therefore, the surface creeping electric field of the insulating spacer 4 is minimized, the ratio of the diameter of the high-voltage conductor 5 and the inner diameter of the metal tank 1 can be optimized, and the metal foreign matter 6 moves in the metal tank 1. Can be suppressed,
It is possible to provide a gas-insulated bus bar that is small and has improved reliability.

In this embodiment, the insulating spacer 4
It is not limited to the adhesive substance 7 to be provided at the bottom of the metal tank 1 in the vicinity, and an insulating material such as paint may be used. In this case, since the floating electric field of the metallic foreign matter 6 is improved, the metallic foreign matter 6 that has entered the region Y does not stand up and float again, and the same effect can be obtained.

A second embodiment of the present invention will be described with reference to FIG. It should be noted that the same parts as the conventional ones are given the same numbers and their explanations are omitted. As shown in FIG. 2, the present embodiment is characterized in that instead of coating the adhesive substance 7, a recess 8 is formed in the bottom of the metal tank 1 near the insulating spacer 4. The other points are the same as those in the first embodiment.

In this embodiment, the metallic foreign matter 6 that has moved to the area Y falls into the recess 8. Since the electric field on the inner surface of the tank in the concave portion 8 is lower than that in the surrounding area, the metallic foreign matter 6 does not fly out of the concave portion 8 again and the metallic foreign matter 6 can be captured.

As described above, this embodiment also has the same effect as that of the first embodiment. If the inner surface of the recess is coated with an adhesive material or an insulating material such as paint, the foreign metal can be more reliably captured.

Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the high voltage conductor 5 in the region X
The structure is similar to that of the first embodiment except that the opening 9 is formed on the lower side and the adhesive substance 10 is applied to the periphery of the opening 9.

In the present embodiment, the diameter d ₁ of the high voltage conductor 5
As for the diameter D of the metal tank 1, D / d ₁ is larger than 3.0, the electric field on the inner surface of the tank is controlled to be low. On the other hand, even if the metallic foreign matter moves in the region X, the opening 9 is formed in the high-voltage conductor 5, so that the metallic foreign matter is located around the opening 9 having a higher electric field than the other portions. Collected and captured by the sticky substance 10 applied around the opening 9.

As described above, in this embodiment, the trap portion for the metallic foreign matter is formed also in the high-voltage conductor 5, so that the same effects as those of the above-described first and second embodiments can be obtained.
Further, there is an effect that the insulation performance is improved and the reliability is increased.

A fourth embodiment will be described with reference to FIG.
In this embodiment, instead of the opening of the third embodiment,
A feature is that a groove 11 is formed around the high-voltage conductor 5 and an adhesive substance 12 is applied to the periphery of the groove 11.

Similarly to the opening, the electric field of the groove 11 is higher than that of the other portions. Therefore, metal foreign matter is positively collected in the groove 11,
By capturing the metallic foreign matter with the adhesive substance 12, the same effect as that of the third embodiment is obtained.

A fifth embodiment will be described with reference to FIG.
In place of the opening and the groove, the convex portion 13 is formed on the high-voltage conductor 5,
Even if the adhesive material 14 is applied to the convex portion 13, the same effects as those of the third and fourth embodiments can be obtained.

Incidentally, in the third, fourth and fifth embodiments, a coating material may be coated instead of the adhesive substances 10, 12 and 14, and the adhesive material is adhered to the bottom of the metal tank 1 in the region Y. Of course, the same effect can be obtained even if the concave portion 8 is formed instead of coating the sexual substance 7.

[0031]

As described above, according to the present invention, the ratio D / d ₁ between the diameter d _{1 of the} high-voltage conductor and the inner diameter D of the metal container is set to be larger than 3.0, and the diameter d _{2 of the} connecting portion and the metal container are set. The ratio of the inner diameter D to D / d ₂ is 2.7 or more and 3.0 or less, and the bottom of the metal container near the insulation spacer is coated with an insulating material or a recess is formed to make it small and reliable. It is possible to provide a gas-insulated bus bar having improved properties.

[Brief description of drawings]

FIG. 1 is a sectional view of a gas-insulated bus bar showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a gas-insulated bus bar showing a second embodiment of the present invention.

FIG. 3 is a sectional view of a gas insulated bus bar showing a third embodiment of the present invention.

FIG. 4 is a sectional view of a gas insulated bus bar showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a gas-insulated bus bar showing a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a conventional gas-insulated bus bar.

FIG. 7 is an explanatory diagram showing the behavior of a metallic foreign matter.

FIG. 8 is an explanatory diagram of an electric field on the tank inner surface of the gas insulated busbar.

[Explanation of symbols]

1 ... Metal tank, 2 ... SF ₆ gas, 3 ... Connection part, 4 ...
Insulation spacer, 5 ... High voltage conductor, 7 ... Adhesive substance, 8 ... Recess

Claims (2)

[Claims] 1. An insulating spacer is provided in a metal container filled with an insulating gas, a metal connecting portion is provided at substantially the center of the insulating spacer, and a high-voltage conductor is connected to this connecting portion. Then, in the gas-insulated busbar in which the high-voltage conductor is insulated and supported in the metal container, the ratio D / d ₁ between the diameter d ₁ of the high-voltage conductor and the inner diameter D of the metal container is larger than 3.0, and Diameter d ₂
And the ratio D / d ₂ of the inner diameter D of the metal container is 2.7 or more 3.0
The gas-insulated bus bar is characterized in that the bottom part of the metal container near the insulating spacer is coated with an insulating material. 2. A recess is formed on the inner surface of the metal container instead of the coating.
Gas-insulated bus bar as described.