JPH05151849A - Bushing - Google Patents

Abstract

PURPOSE:To provide an excellent bushing which enables a rise in temperature of a hollow conductor to be effectively decreased to contribute to enhancing the cooling efficiency, by increasing the circulating efficiency of a fluid such as gas in the bushing without making the bushing large in size. CONSTITUTION:A bushing comprises a bushing pipe 1, a hollow conductor 4 received in the bushing pipe 1 and supported, at its top and bottom, by a terminal flange 2 and an insulative spacer 3 respectively, and a cooler 5 installed over the bushing pipe 1. A fluid is filled in the bushing pipe 1 to thereby effect natural cooling. Of an internal space of the hollow conductor 4 and a space between the hollow conductor 4 and the bushing pipe 1, at least one space has partitioning ducts 8, 9 which partition this space in the vertical direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing which uses a fluid such as gas for natural cooling.

[0002]

2. Description of the Related Art In a power transmission system, a bushing in which a hollow conductor is arranged inside a porcelain insulator is used as a device for drawing an overhead wire in a transmission and transformation substation. Conventionally, such a bushing is configured as shown in FIG. That is, first, the terminal flange 2 and the insulating spacer 3 are connected to the upper and lower ends of the vertically long porcelain insulator 1, respectively. A hollow conductor 4 is housed inside the insulator 1 and is supported and fixed to the insulator 1 by a terminal flange 2 and an insulating spacer 3. Further, the cooler 5 is attached to the upper end of the porcelain bushing 1 via the terminal flange 2.
Are connected. And with the above configuration,
Normally, one sealed space surrounded by the porcelain insulator 1, the insulating spacer 3 and the cooler 5 is formed, and the space is filled with a fluid such as gas. The lower end of the insulating spacer 3 is connected to a bushing pocket 6 such as a transformer or a gas circuit breaker.
It is omitted here. In addition, holes 7 for fluid circulation are formed in the lower portions of the terminal flange 2 and the hollow conductor 4.

In the bushing of FIG. 3 having the above-mentioned structure, the hollow conductor 4 housed inside the porcelain bushing 1 generates heat due to electric resistance during its operation. This heat is
Due to the natural cooling phenomenon, the fluid such as the gas filled in the inner surface and the outer surface of the hollow conductor 4 is heated, and the fluid such as the heated gas is heated to the outside through the cooler 5 in the upper part or the insulator tube 1. Will be thrown away. In this case, the fluid such as gas is the upflow 11, 12 and the downflow 13,
As shown by 14, the temperature rises near the inner surface and the outer surface of the hollow conductor 4 and rises near the inner surface of the porcelain insulator 1 and the cooler 5.
It descends at a low temperature near the inner surface, and circulates in the bushing through the hole 7 formed in the lower portion of the terminal flange 2 and the hollow conductor 4.

[0004]

However, in the conventional bushing as described above, the cooler 5 and the porcelain insulator 1 are used.
The downward flow 13 generated near the inner surface of the hollow conductor 4 is opposite to the upward flow 12 generated near the outer surface of the hollow conductor 4,
The structure is particularly difficult to flow in a relatively narrow space above the porcelain bushing 1. Therefore, replenishment of fluid such as gas to the upflows 11 and 12 inside and outside the hollow conductor 4 (downflow 1
3) is reduced, and upflows 11 and 12 themselves are less likely to occur. Therefore, in the bushing as shown in FIG. 3, the gas circulation is not so effective and the cooling effect is not sufficient.

By the way, as a known example of such cooling of the bushing, for example, Japanese Patent Laid-Open No. 54-4268.
No. 9, JP-A-56-121207, and JP-A-5-58.
7-75424 and the like, but these technologies are
All of them are treated only as a downward flow is generated outside the conductor, and no consideration is given to the upward flow generated near the outer surface of the conductor having a high temperature. Therefore, also in these conventional techniques, as in the technique of FIG. 3, the upward flow and the downward flow interfere with each other in a relatively narrow space above the porcelain insulator, and effective circulation may not be performed. Guessed.

Generally, as means for lowering the conductor temperature, (1) increasing the diameter of the conductor or installing fins or the like to increase the surface area for heat dissipation, and (2) increasing the cross-sectional area of the conductor. It can be considered to increase the electric resistance to reduce the electric resistance and suppress the heat generation amount, and (3) increase the heat transfer coefficient on the conductor surface or the porcelain tube surface. However, the means (1) has drawbacks such as an increase in the size of the bushing and the inability to install fins from the viewpoint of insulation performance. Further, the means of (2) has a drawback that even if the thickness of the conductor is increased, the electric resistance does not decrease so much due to the skin effect of the current, and the effect is small in the end.
Further, in the means of (3), in order to increase the heat transfer coefficient, it is conceivable to increase the pressure of gas, but in this case, the pressure applied to the inner surface of the porcelain insulator becomes large,
There are drawbacks such as the risk of damage in the event of an earthquake or transportation. In particular, the bushing that has recently been adopted for UHV power transmission has a length of about 12 m and a weight of about 1 m.
It is estimated to be 0 tons, and cooling performance and strength are very important issues.

The present invention has been proposed in order to solve the above-mentioned problems of the prior art, and its object is to improve the circulation efficiency of fluid such as internal gas without increasing the size of the bushing. By doing so, it is possible to effectively reduce the temperature rise of the hollow conductor and provide an excellent bushing that can contribute to the improvement of the cooling efficiency.

[0008]

The bushing of the present invention comprises:
Equipped with a porcelain insulator, a hollow conductor housed in the porcelain insulator, supported above and below by a flange for terminals and an insulating spacer, and a cooler installed on the upper portion of the porcelain insulator. In the bushing for carrying out, the partition duct for partitioning this space inside and outside is installed in at least one of the inner space of the hollow conductor and the space between the hollow conductor and the porcelain bushing. ..

Specifically, it is possible that the partition duct is installed in the internal space of the hollow conductor, and the upper part of the partition duct is shaped to expand in the cooler. In addition, the hollow conductor is extended to near the upper part in the cooler, and the partition duct is installed in the internal space of the hollow conductor, and further, the upper part of the partition duct and the lower part of the cooler. It is also possible to install a connecting pipe leading to the.

[0010]

According to the present invention having the above-mentioned structure, the partition duct can separate the flow paths of the fluid such as gas according to the flow direction, so that the fluid circulation efficiency can be improved. it can. Therefore, the temperature difference between the fluid above and below the bushing can be suppressed to a small level, and the heat transfer coefficient on the surface of the hollow conductor can be improved, so that the temperature rise of the conductor can be effectively reduced and the cooling efficiency can be greatly improved. It will be possible.

When the partition duct is installed in the inner space of the hollow conductor and the upper part of the partition duct is widened in the cooler, an upflow from the hollow conductor and a downflow in the cooler occur. Since it is possible to prevent the interference, the fluid circulation efficiency can be further improved.

Further, the hollow conductor is extended to near the upper part of the cooler, the partition duct is installed in the internal space of the hollow conductor, and the connecting pipe leading to the lower part of the cooler is installed on the upper part of the partition duct. In this case, since the interference between the ascending flow and the descending flow in the cooler can be more positively prevented, the fluid circulation efficiency can be further improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the bushing according to the present invention will be described below with reference to FIG. The same parts as those of the conventional example shown in FIG.

The basic structure of the bushing shown in FIG. 1 is the same as that of the conventional example shown in FIG. That is, first, the terminal flange 2 and the insulating spacer 3 are connected to the upper and lower ends of the vertically long porcelain insulator 1, respectively. In addition, the hollow conductor 4 is housed inside the porcelain bushing 1, and the terminal flange 2
The insulating spacer 3 supports and fixes the insulator 1. Further, a cooler 5 is connected to the upper end of the porcelain bushing 1 via a terminal flange 2. With the above-described structure, one sealed space normally surrounded by the porcelain insulator 1, the insulating spacer 3 and the cooler 5 is formed, and the space is filled with a fluid such as gas. The lower end of the insulating spacer 3 is connected to the bushing pocket 6 such as a transformer or a gas circuit breaker, but the configurations of these other connecting devices are omitted here. In addition, holes 7 for fluid circulation are formed in the lower portions of the terminal flange 2 and the hollow conductor 4.

In addition to such a basic structure, in this embodiment, in accordance with the features of the present invention, the partition duct 8 is installed inside the hollow conductor 4, and the hollow conductor 4 is provided.
A partitioning duct 9 is also installed between the insulator pipe 1 and the insulator pipe 1.
These partition ducts 8 and 9 are installed substantially concentrically with the insulator tube 1 and the hollow conductor 4. Furthermore, the upper portion of the partition duct 8 is shaped to expand like a funnel inside the cooler 5.

In the bushing having the above-described structure, the flow of fluid such as gas filled in the inside always causes an ascending flow due to buoyancy on the inner and outer surfaces of the hollow conductor 4 which is the heat generating surface, and the cooling surface. A downward flow is always generated on the inner surface of the porcelain bushing 1. That is, as shown in FIG. 1, in the regions between the inner surface of the hollow conductor 4 and the partitioning duct 8 and between the outer surface of the hollow conductor 4 and the partitioning duct 9, the upward flows 21 and 22 are always generated, and A downflow 23 is always generated between the partitioning duct 9 and the inner surface of the porcelain bushing 1. Therefore, in the conventional example, the upward flow 22 and the downward flow 23 are separated by the partitioning duct 9 even in the narrow space above the porcelain tube 1 where the upward flow and the downward flow are opposite to each other. The fluid can be circulated smoothly without being hindered.

Further, in the hollow conductor 4, an ascending flow 21 is generated outside the partition duct 8, whereas in the partition duct 8, a downflow 24 is newly generated. In this case as well, since the upflow 21 and the downflow 24 are separated by the partitioning duct 8, the upflow 21 and the downflow 24 are separated in the same manner as the upflow generated on the inner surface of the hollow conductor 4. Not be
The fluid can be circulated smoothly.

Further, since the upper portion of the partition duct 8 is expanded like a funnel, the upward flow 21 from the inner surface of the hollow conductor 4 is increased.
And the downward flow 25 generated by being cooled in the cooler 5 hardly interfere with each other. Therefore, the ascending flow 21 from the inner surface of the hollow conductor 4 can smoothly flow into the cooler 5, and the descending flow 25 from the cooler 5 can smoothly flow into the partition duct 8. Therefore, the fluid circulation efficiency can be further improved.

As described above, in the present embodiment, the circulation of the fluid such as gas inside the bushing can be smoothly performed inside or outside the hollow conductor 4, so that the circulation flow rate of the fluid such as gas is reduced. Can be increased. As a result, the temperature difference between the top and bottom of the bushing can be reduced, and the flow velocity on the surface of the hollow conductor 4 which is the heat generating portion also increases, so that the heat transfer coefficient of the same portion can be improved. Therefore, it becomes possible to effectively reduce the temperature rise of the hollow conductor 4 and significantly improve the cooling efficiency.

Next, FIG. 2 shows another embodiment of the present invention. In the bushing shown in FIG. 2, the hollow conductor 4 is extended to near the upper portion of the cooler 5, and the upper portion of the partition duct 8 installed therein is connected to the cooler 5 via a connecting pipe 10 such as a T-shaped branch pipe. It is an example connected to the lower part. Further, no holes 7 for fluid circulation are formed in the lower portions of the terminal flange 2 and the conductor 4. Further, the partitioning duct 9 installed between the hollow conductor 4a and the porcelain bushing 1 exists only near the upper portion of the porcelain bushing 1 and is not provided at the lower portion of the porcelain bushing 1.
The rest of the configuration is similar to that of the embodiment shown in FIG.

Even in the bushing thus constructed, the upward flows 31, 32 are generated in the region between the inner surface of the hollow conductor 4 and the partitioning duct 8 and between the outer surface of the hollow conductor 4 and the partitioning duct 9. Further, a downward flow 33 is generated between the partitioning duct 9 and the inner surface of the porcelain bushing 1. Also,
A downward flow 34 is generated inside the partition duct 8, and a downward flow 35 is generated inside the cooler 5.

Of these flows, the hollow conductor 4
The upward flow 31 generated between the partition duct 8 and the partition duct 8 is smoothly guided to the upper portion of the cooler 5 by the extending portion of the hollow conductor 4. Further, the descending flow 35 cooled in the cooler 5 passes between the cooler 5 and the extended portion of the hollow conductor 4,
It smoothly descends without being disturbed by the ascending flow 31, and is guided into the partition duct 8 through the connecting pipe 10. Therefore, even in the cooler 5, the interference between the ascending flow 31 and the descending flow 35 can be prevented more positively than in the above-described embodiment, so that the circulation efficiency can be further improved.
The cooling efficiency can be further improved.

By the way, in the present embodiment, the hollow conductor 4
The partitioning duct 9 between the porcelain tube 1 and the porcelain tube 1 is installed only near the upper part of the porcelain tube 1 where the upflow 32 and the downflow 33 are closest to each other, but in the vicinity of the lower part of the porcelain tube 1, the upflow 32 and the downflow 33 Since there is almost no problem of the reduction of the circulation efficiency due to the interference of, the effect of improving the circulation efficiency by the partitioning duct 9 can be expected sufficiently.

The present invention is not limited to the above-mentioned embodiments. For example, even if the partitioning duct is installed only inside or outside the hollow conductor, some effects are expected. it can. Further, the detailed configuration of the partition duct can be appropriately selected.

[0025]

As described above, according to the present invention, the partition duct is installed in at least one of the inside and the outside of the hollow conductor, so that the fluid such as gas in the inside can be prevented without increasing the size of the bushing. By improving the circulation efficiency, it is possible to provide an excellent bushing that can effectively reduce the temperature rise of the hollow conductor and contribute to the improvement of the cooling efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a bushing according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing an example of a conventional bushing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating pipe 2 ... Terminal flange 3 ... Insulating spacer 4 ... Hollow conductor 5 ... Cooler 6 ... Bushing pocket 7 ... Hole 8 ... Partition duct 9 ... Partition duct 10 ... Connection pipe 11, 12, 21, 22, 31 , 32 ... Upflow 13, 14, 23-25, 33-35 ... Downflow

Claims (3)

[Claims] 1. A porcelain insulator, a hollow conductor housed in the porcelain insulator, supported above and below by a flange for terminals and an insulating spacer, and a cooler installed on the upper portion of the porcelain insulator,
In a bushing for filling the inside of the porcelain tube with a fluid for natural cooling, at least one of the inner space of the hollow conductor and the space between the hollow conductor and the porcelain tube is a partition for partitioning this space inside and outside. Bushing characterized by the installation of ducts. 2. The partition duct is installed in the internal space of the hollow conductor, and the upper portion of the partition duct has a shape that expands in the cooler. Bushing. 3. The hollow conductor is extended to near an upper portion in the cooler, the partition duct is installed in an inner space of the hollow conductor, and further, the partition duct is provided on an upper portion. The bushing according to claim 1, further comprising a connecting pipe installed at a lower portion of the cooler.