JPS596568B2 - 3-phase gas insulated busbar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides three-phase conductors arranged in a metal container.
Concerning a circular gas insulated busbar.

A three-phase, circular gas insulated bus is constructed by housing three-phase bus conductors arranged at each vertex of an isosceles triangle in a metal container filled with an insulating gas such as SF6 gas.

In such a gas-insulated bus, when current flows through the bus conductor, eddy current flows through the metal container due to the influence of the magnetic field induced from the bus conductor.

This eddy current causes local heating of the metal container.

For example, in conventional gas-insulated busbars, the metal container is partially made of non-magnetic material so as not to form one turn, thereby coping with this temperature rise.

However, if a three-phase coiled gas insulated bus for a large current such as a rated current of 8000 A is produced as an extension of such technology, the diameter will be extremely large.

Furthermore, although the use of SF6 gas, which has excellent insulating properties, has the advantage of reducing the insulation distance, the problem of having to determine the diameter of the metal container from the perspective of temperature rise has become a new problem when used for carrying large currents. It occurred in

The present inventor investigated a new cause of local temperature rise in a metal container.

3-phase AC current Iu, I to 3-phase conductor 2U, 2V, 2W
When vtIw flows, this current generates a magnetic field H around each conductor as shown in FIG.

Since the three-phase conductors are arranged at each vertex of an approximately isosceles triangle, this magnetic field H has a vertical component H8 with respect to the metal container 1.
and horizontal component H1.

Due to the existence of the vertical component H8, a current 2 is generated in the metal container 1, which cancels the vertical component H8, as shown in FIG.

As shown in FIG. 3, in the metal container 1 as a whole, since the directions of the currents in adjacent parts are opposite, they are canceled and an eddy current IE flows as a whole.

This eddy current IE causes local heating in a portion of the metal container 1 where the vertical component H6 is large.

This is a phenomenon that has not been observed in gas-insulated busbars with a phase-separated structure, which cannot be solved even if the metal container is partially made of non-magnetic material.

This is a phenomenon that occurs in three-phase, circular gas-insulated busbars whose diameter has been reduced due to the passage of large currents.

That is, the present inventor attempted to make the container diameter so small that such a new problem would arise.

As a method of preventing this local temperature rise in the metal container, it may be possible to manufacture the metal container from a good conductor such as aluminum, but this would result in a very expensive gas insulated bus bar.

Another method of prevention could be to increase the diameter of the metal container, but this would increase the site area and weight, and the use of insulating gas to greatly reduce the insulation distance could be useful. It will no longer be done.

An object of the present invention is to provide a gas insulated bus bar whose diameter is reduced while suppressing a local temperature rise in a metal container.

The present invention provides a highly conductive current-carrying part that allows eddy current to flow inside a metal container where a magnetic field with a vertical component exists, and prevents a local temperature rise in the metal container by shunting the eddy current to this current-carrying part. It is.

The present invention will be explained below using a gas insulated bus shown in the drawings as an example.

FIG. 4 shows an example of a three-phase, continuous gas insulated bus.

The three-phase conductors 2U, 2V, and 2W are each supported and fixed in the metal container 1 by insulating supports, such as a plurality of supporting insulators 3, and each conductor is arranged at each vertex of an approximately isosceles triangle.

Such a gas insulated bus bar is, for example, a conductor 4U in a phase-separated branch pipe 5U, 5V, 5W at its end.

Connect conductors 2U, 2V, and 2W to 4V and 4W, respectively.

Other units are configured with branch pipes.

FIG. 5 shows the main component, the eddy current carrying conductor 6, which is made of a good electrical conductor, for example copper or aluminum.

The current-carrying conductor 6 in this example has a saddle shape.

As shown in FIGS. 6 and 7, the current-carrying conductors 6 are attached to the generation part of a magnetic field that is induced by the current flowing through the three-phase conductor and has a component perpendicular to the metal container 1. 8, which is an enlarged view of part A in Figure 6.
As shown in the figure, it is fixed near the inner wall of the metal container 1.

That is, a plurality of seats 7 are formed on the inner wall of the metal container 1 by welding or the like, and a current-carrying conductor 6 is sandwiched between the seats 7 and a presser foot 90 and tightened with bolts 8.

Therefore, this current-carrying conductor 6 is at the same potential as the metal container 1.

According to this structure, the weak current {circle around (2)}E shown in FIG. 3 is shunted to the highly conductive current-carrying conductor 6, and the amount of heat generated can be suppressed.

Moreover, since this current-carrying conductor 6 does not constitute a pressure vessel, even if it is made of aluminum, it can be made thin and lightweight, and it is cheaper to use gas than when the metal vessel 1 is made entirely of aluminum. It can be an insulated bus bar.

In a preferred embodiment, the metal container 1 can be made of iron.

9 and 10 show different mounting structures for the current-carrying conductor 6. FIG.

FIG. 9 shows a current-carrying conductor 6 attached to the inner surface of the metal container 1 by direct welding.

The shape of the current-carrying conductor 6 is not limited to a saddle shape, but may be a plate shape.

In addition, as shown in FIG. 10, the current-carrying conductor 6 is made into a roughly cylindrical shape with at least a split portion at the portion opposite to the base of the isosceles triangle formed by the center conductor, as shown in FIG. 6, and directly welded to the inner surface of the metal container 1. You may do so.

In still another example, each of the above-described current-carrying conductors 6 may be divided in the axial direction and fixed to the inner surface of the metal container 1 at predetermined intervals.

As described above, the current-carrying conductor 6 may have a plate shape, a saddle shape, or a shape divided into these shapes, as long as the shape allows the loop-shaped conduction of the eddy current IE shown in FIG. It can be fixed to the inner surface of the metal container 1.

In addition, considering the material of the current-carrying conductor 6 and the branch pipe 4 shown in FIG. 4, it is necessary to install it only in the part of the magnetic field that is perpendicular to the metal container 1, as shown in FIGS. 5 to 9. is desirable.

Particularly, in such a configuration, a divided portion is formed at least in the circumferential direction of the current-carrying conductor 6 in the portion facing the base of the isosceles triangle formed by the center conductor.

Therefore, when the branch pipe 4 is formed in the metal container 1 as shown in FIG. 4 and FIG.
Expansion due to temperature rise of the current-carrying conductor 6 can be escaped through the divided portion.

FIG. 11 shows an embodiment in which the mounting of the current-carrying conductor 6 has a different structure.

This example has a 3-phase conductor of 2U. The support insulator 3 for supporting and fixing 2V and 2W is attached by fixing the current-carrying conductor 6 to the inner surface of the metal container 1 using a section.

In other words, the opposite side of the seat 70 for attaching the supporting insulator fixed to the inner surface of the metal container 1 is made longer than the conventional one, and the current-carrying conductor 6 is sandwiched between this facing part and the presser foot 9 and is tightened by the port 8. There is.

With this structure, there is no need to provide a new seat for fixing the current-carrying conductor 6.

Since most of the generation part of the magnetic field having a vertical component with respect to the metal container 1 corresponds to between the seats 7 of the support insulator 30, the use of the seats 7 can be said to be extremely effective.

In each embodiment, when the current-carrying conductor 6 is constructed of a material other than a cylinder, depending on the allowable temperature of the metal container 1, the current-carrying conductor 6 may not be provided in all the parts where a magnetic field having a vertical component with respect to the metal container 1 is generated.

Since the distance between conductors 2U and 2W is large, conductors 2U and 2V
It is preferable to first provide a current-carrying conductor 6 between the conductors 2 and 2W.

In other words, it is preferable to provide the current-carrying conductors 6 on both sides of the conductor 2V placed at the apex of the isosceles triangle with respect to its base.

The feature of the embodiment in which a conductor other than a cylinder is adopted as the current-carrying conductor 6 through which the eddy current IE flows is that the magnetic field generating part having a vertical component with respect to the metal container 1 is formed near the inner surface of the metal container 1 between any two phases. This is what I chose.

This selection makes it easy to attach the current-carrying conductor 6, and as shown in FIG. 11, it becomes possible to fix the current-carrying conductor 6 by using the monthly production 7 to attach columnar insulators such as the support insulator 3. .

The current-carrying conductor 6 may be fixed between adjacent seats 7, or the current-carrying conductor 6 may be fixed on both sides of one seat 7, as shown in FIG.

According to the configuration shown in FIG. 12', a divided opposing portion is formed between the current-carrying conductors 6 between adjacent seats 7, but three-phase conductors 2
Support units of the same structure can be used as support units for U, 2V, and 2W.

According to the present invention described above, since the current-carrying conductor 6 with good conductivity is provided, the temperature rise of the metal container 1 due to the eddy current IE can be suppressed to an allowable range, and the metal container 1 is formed of cheap iron. make it possible to

Furthermore, because the current-carrying conductor was set at the same potential as the metal container and placed near its inner wall, corona was generated, causing gas contamination and decomposition, as when the current-carrying conductor was fixed to the metal container with an insulator and set to an intermediate potential. There is no generation of products or deterioration of the insulating material, and stable insulation properties can be maintained.

In this way, the diameter of the metal container 1 can be made close to the dimension determined mainly by electrical insulation, and the gas insulated bus bar can be made smaller.

For example, at a rated current of 8000 A, it can be manufactured with an outer diameter that is 2/3 that of the conventional one.

Further, in the present invention, since the current-carrying conductor 6 is at least divided at the portion facing the base of the isosceles triangle, even if the branch conductor 5 is provided as shown in FIG.
It is possible to avoid a decrease in the strength of the insulating part due to electric field concentration between the two parts, and the heat and expansion of the current-carrying conductor can be absorbed by the divided part.

In addition, the present invention uses columnar insulators such as support insulators 3 to support the three-phase busbar conductors, and since the columnar insulators are attached by fixing the current-carrying conductor 6 to the monthly generator 7, the conventional configuration is almost completely changed. The current-carrying conductor 6 can be fixed with a simple structure without any modification.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams showing the reasons why eddy currents occur, and FIG. 4 is a front view of a gas-insulated bus bar according to an embodiment of the present invention.
FIG. 5 is a perspective view showing an example of a current-carrying conductor which is a main part of the present invention, FIG. 6 is a sectional view of a gas insulated bus bar according to an embodiment of the present invention, and FIG. 7 is a side view of FIG. 8 to 12 are sectional views of essential parts showing other different embodiments of the present invention. 1...Metal container, 2U, 2V, 2W...Bus conductor,
3... Support insulator, 6... Eddy current carrying conductor, 7...
·seat.

Claims (1)

[Scope of Claims] 1. In a cylindrical metal container filled with an insulating gas, three-phase busbar conductors located at each vertex of an isosceles triangle are provided, at least the base of the isosceles triangle. A highly conductive current-carrying conductor is divided in the circumferential direction at a portion facing the bus conductor, and is induced by a current flowing through the bus conductor, and carries an eddy current flowing due to a magnetic field having a component perpendicular to the metal container. A three-phase circular gas insulated bus bar, characterized in that it is fixed near the inner wall at the same potential as the metal container. 2. Under claim 1, the eddy current carrying conductor is a three-phase conductor fixed near the inner wall of the metal container located between any two phases of the bus conductor.
Convex gas insulated busbar. 3. A three-phase, circular gas insulated bus bar according to claim 1, in which the eddy current carrying conductor is welded to the metal container. 4. In the device described in claim 1 above, the three-phase bus conductors are arranged at each vertex of an isosceles triangle with the base facing upward, and the metal container is placed between the two-phase bus conductors arranged at the base. A three-phase, circular gas-insulated bus bar having two of the above-mentioned current-carrying conductors divided in the circumferential direction. 5 A three-phase busbar conductor located at each vertex of an isosceles triangle is installed in a cylindrical metal container filled with insulating gas,
This bus conductor is supported and fixed by a columnar insulator attached to a seat fixed to the metal container, and the bus conductor is divided in the circumferential direction at least at a portion facing the base of the isosceles triangle, and the current flowing through the bus conductor is A highly conductive current-carrying conductor through which an eddy current is induced and flows by a magnetic field with a component perpendicular to the metal container is provided near the inner wall of the metal container between the bus conductors of any two phases, and the eddy current-carrying conductor is fixed to the dust to have the same potential as the metal container. 6. A three-phase circular gas insulated bus bar in which the eddy current carrying conductor is fixed between seats of the two-phase bus conductor. 7. The three-phase coiled gas insulated bus bar according to claim 4, wherein the eddy current carrying conductor is fixed to each phase seat on both sides of each floor in the opposite direction.