JPH0645156A - Gas insulation transformer - Google Patents

Abstract

PURPOSE:To enhance a gas insulation transformer in natural convection cooling performance by a method wherein insulating gas flowing into a transformer tank as cooled down by a panel radiator is directed into a heat releasing part. CONSTITUTION:A heat releasing part 2 composed of an iron core 3 and a winding wire 4 is housed in a transformer tank 1 together with insulating gas 9, where the transformer tank 1 is equipped with panel radiators 5 linked to an up-flow gas pipe 16 and a down-flow gas pipe 18 through the intermediary of an upper header 7 and a lower header 17. Insulating gas 9 which is heated by the heat releasing part 2 and cooled down by the panel radiator 5 is made to flow into the lower part of the tank 1 as a gas flow 19A through the downflow pipe 18. A gas guide 21 is provided blocking a space between the lower edge of the winding wire 4 and the inner wall of the transformer tank 1 to make the cooled gas flow 19A flow into inner gas ducts 10A and 10B preventing it from branching off toward an outer gas duct 10C. By this setup, a gas insulation transformer is enhanced in cooling capacity by a gas flow of a natural convection rate proportional to an increase in difference between the heights of a cooling center and a heat releasing center.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-cooling gas-insulated transformer in which a radiator is arranged at a high position with respect to a heat generating portion to improve convective heat transfer performance, and more particularly, a convection circulation passage in a transformer tank. Regarding the improvement of the structure of.

[0002]

2. Description of the Related Art A gas-insulated transformer that uses an inert gas such as sulfur hexafluoride gas (SF ₆ gas) as an insulating medium that also serves as a cooling medium has excellent withstand voltage performance and cooling performance of SF ₆ gas. It can be used to form a high-voltage, large-capacity transformer in a small size, and can lower the noise of the transformer by utilizing the sound insulation of SF ₆ gas, which is higher than that of insulating oil. Since the noise can be further reduced by eliminating the noise of the blower and the ventilation fan as a formula, a self-cooling type gas insulated transformer is generally used as a transformer for indoor installation.

FIG. 4 is a cross-sectional view schematically showing a conventional self-cooling type gas insulated transformer, in which an iron core 3 and a main winding thereof are provided with a winding 4 such as a primary winding 4A and a secondary winding 4B coaxial with each other. The heat generating portion 2 of the transformer wound in a circular shape is housed in the transformer tank 1 and the withstand voltage performance of the winding 4 is maintained by the insulating gas 9 sealed at a predetermined pressure. Further, a plurality of panel radiators 5 are arranged around the transformer tank 1, and an upper portion thereof is a header-7.
And the upper part of the transformer tank 1 via the upper connecting pipe 6, and the lower part thereof communicates via the lower connecting pipe 8 with the transformer tank 1.
The plurality of panel radiators 5 are connected in parallel to the transformer tank 1 by communicating with the lower part of the. On the other hand, between the iron core 3 inside the heat generating part 2 and the winding 4A, and between the windings 4A and 4A.
Internal gas ducts 10A and 10B that also serve as a gas insulating space and a cooling gas passage are formed between the two Bs, and the winding 4
An outer peripheral gas duct 10C as a gas insulating space is formed between B and the transformer tank 1.
The panel radiator 5 forms a circulating cooling passage for the insulating gas 9.

That is, the heat loss generated in the heat generating portion 2 is transferred to the insulating gas 9 in the cooling duct, and the temperature of the insulating gas 9 rises, whereby natural convection occurs in the duct.
The insulating gas that has risen due to convection is guided to the panel radiator 5 through the upper connecting pipe 6 to perform heat exchange with the outside air,
Insulating gas whose temperature has decreased and specific gravity has increased is lower connecting pipe 8
Is guided to the lower part of the transformer tank 1 via the flow path and is returned to the cooling duct again to form a convection gas circulation path,
The heat generating part 2 is cooled.

By the way, it is known that the heat transfer coefficient of the iron core and the surface of the winding is proportional to the natural convection velocity in the cooling ducts 10A and 10B, and this natural convection velocity is the center height of the radiator ( It is known that it is proportional to the difference between the cooling center height) and the heating center height (heating center height). However, the panel radiator 5 is installed around the transformer tank 1.
In the above self-cooling gas-insulated transformer, which is arranged side by side, the difference between the cooling center height and the heat generation center height is small, and the heat transfer coefficient in the heat generation part cannot be made large. Alternatively, it is necessary to take measures such as increasing the number of panel radiators 5 installed in order to suppress the rise in the winding temperature, and as a result, the installation space of the gas insulated transformer including the panel radiators.
There was a problem that the space increased.

FIG. 5 is a schematic cross-sectional view showing an improved conventional self-cooling type gas-insulated transformer, in which a panel radiator 5 is arranged above a transformer tank 1 and an upper portion thereof is an upper header-7. And the rising gas pipe 16 to communicate with the upper part of the transformer tank 1, and the lower part of the panel radiator is connected to the lower header-17.
By communicating with the lower part of the transformer tank 1 through the descending gas pipe 18 and the descending gas pipe 18, the difference between the height of the cooling center and the height of the heat generating center is significantly increased.
A self-cooling gas-insulated transformer that is configured to increase the natural convection velocity and heat transfer coefficient in A and 10B, and at the same time, adds a shielding hood to the panel radiator 5 to improve the heat exchange efficiency with the outside air. The vessels are already known (Japanese Patent Publication No. 64-652)
7 publication).

[0007]

In the improved conventional self-cooling type gas-insulated transformer, the installation area of the gas-insulated transformer is greatly reduced by disposing the panel radiator 5 above the transformer tank 1. At the same time, the effect of improving the natural convection velocity and the heat transfer coefficient in the heat generating part is expected. However, when the amount of insulating gas circulating between the panel radiator 5 and the transformer tank 1 increases as the difference between the cooling center height and the heat generation center height increases, the panel radiator 5 cools and the descending gas pipe 18 Insulating gas 9 flowing into the transformer tank 1 from
Gas flow 9A flowing into the internal gas ducts 10A and 10B
And a gas flow 9B that flows into the rising gas pipe through the outer peripheral gas duct 10C and has a small contact area with the winding and a low gas flow 9B that contributes to cooling. It was found that the natural convection velocity did not increase as much as expected, and therefore the heat transfer coefficient in the heat generating part 2 could not be improved as much as expected.

That is, the cross-sectional area in the horizontal direction of the outer peripheral gas duct 10C, which is held between the outside of the heat generating portion 2 and the side wall of the transformer tank 1 as a gas insulating space or a space for disposing a high voltage lead or the like, is Since the cross-sectional area of the internal gas ducts 10A and 10B is usually considerably large and the fluid resistance is low, for example, when the insulating gas is forcedly circulated, a large amount of the insulating gas flows in the outer peripheral gas duct having a low resistance, and the gas flow rate in the heat generating portion is increased. Is known to decrease. However, in the conventional gas insulation transformer in which the difference between the height of the cooling center and the height of the heat generation center is small, the rising gas flow due to the temperature rise of the insulating gas in the internal gas ducts 10A and 10B and the temperature decrease of the insulating gas in the panel radiator 5 are performed. And the descending gas flow due to act on each other in series,
Circulation of insulating gas occurs due to natural convection, and although the fluid resistance is low in the outer peripheral gas duct, the amount of heat transfer to the insulating gas is small, so the rising gas flow that is generated is small and the amount of gas diverted to the outer peripheral gas duct is also small. Are known. On the other hand, in the latter case where the difference between the height of the cooling center and the height of the heat generating center is increased, the influence of the fluid resistance of the duct becomes more noticeable as the circulation amount of the insulating gas increases, and the panel is passed through the peripheral gas duct with low resistance. It was found that the amount of insulating gas flowing back to the radiator is large and does not sufficiently contribute to the cooling of the heat generating portion 2, so that the expected improvement effect of the cooling performance cannot be obtained.

An object of the present invention is to improve the natural convection cooling performance by guiding the insulating gas cooled by the panel radiator and flowing into the transformer tank into the heat generating portion.

[0010]

In order to solve the above problems, according to the present invention, there is provided a transformer tank in which a heat generating portion including an iron core and a winding wound around the iron core is housed together with an insulating gas. A plurality of panel radiators connected to an ascending gas pipe branched from the upper part and a descending gas pipe branched from the lower part through an upper header and a lower header, respectively,
Insulation gas that naturally cools the heat-generating part by natural convection is cooled by the panel radiator and flows back to the heat-generating part through the descending gas pipe for cooling, and flows into the lower part of the transformer tank through the descending gas pipe. A gas guide that guides the insulating gas into the heat generating portion is arranged so as to close between the lower edge of the winding and the inner wall surface of the transformer tank.

Further, the gas guide is made of a plate-shaped insulating material having a vent hole communicating with the inside of the heat generating portion. Further, the gas guide is composed of a portion in which the lower frame of the iron core is expanded toward the inner wall surface of the transformer tank, has a vent hole communicating with the heat generating portion, and has an insulating material between the lower edge of the winding. It is assumed that an occluding material consisting of is provided.

[0012]

In the structure of the present invention, the gas guide for guiding the insulating gas, which is cooled by the panel radiator and flows into the lower portion of the transformer tank through the descending gas pipe, into the heat generating portion, is provided near the lower edge of the winding and the transformer. By arranging the inner wall surface of the tank so as to be closed, the insulating gas diverted to the outer gas duct is blocked by the gas guide, and the gas flow can be guided into the heat generating part, so that the cooling center in the inner gas duct It is possible to generate an insulating gas flow with a natural convection velocity that is proportional to the increase in the difference between the height and the height of the heat generation center, and the heat transfer coefficient in the heat generation part is increased in proportion to the difference between the height of the cooling center and the height of the heat generation center. However, the function of improving the cooling performance can be obtained.

[0013]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a schematic cross-sectional view showing a self-cooling type gas insulated transformer according to an embodiment of the present invention. The same components as those of the conventional art are designated by the same reference numerals, and a duplicate description will be omitted. In the figure, a transformer tank 1 containing a heat generating portion 2 including an iron core 3 and a winding 4 wound around the iron core 3 together with an insulating gas 9 has a rising gas pipe 16 branched from an upper portion thereof.
And a plurality of panel radiators 5 connected to the descending gas pipes 18 branched from the lower portion via upper headers-7 and lower headers-17, respectively, which are heated by the heat generating portion 2 and cooled by the panel radiators 5. Insulating gas 9 is descending gas pipe 1
It is configured to flow into the lower portion of the transformer tank 1 via 8 as a gas flow 19A. Further, the gas guide 21 is provided so as to close the vicinity of the lower edge of the winding wire 4 and the inner wall surface of the transformer tank 1 to prevent the cooled gas flow 19A from being diverted to the outer peripheral gas duct 10C side. Internal gas duct 1
It is configured to flow into 0A and 10B.

In the self-cooling type gas insulated transformer constructed as described above, all of the insulating gas flow 19A flowing into the lower portion of the transformer tank 1 flows into the internal gas ducts 10A and 10B, and the cooling center height and the heat generation center are increased. A gas flow having a natural convection velocity proportional to the difference with the height is formed in the internal gas ducts 10A and 10B, and convection heat transfer corresponding to the increase in the natural convection velocity is performed between the iron core and the winding and the insulating gas. The gas flow 19B heated by the heat transfer is cooled by the panel radiator 5 via the rising gas pipe 16 and is circulated again to the heat generating portion via the descending gas pipe 18. As a result, the heat transfer coefficient from the iron core and windings to the insulating gas was improved in proportion to the increase in the natural convection velocity, which was not possible with the conventional technology that merely increased the difference between the cooling center height and the heat generation center height. A self-cooling type gas insulated transformer having excellent cooling performance can be obtained. In addition, winding 4
If the is a disk winding, the internal gas ducts 10A, 10B
The gas flow 19A flowing in from below into the horizontal gas duct (not shown) orthogonal to the internal gas duct described above.
Although it is diverted as C and a part of it flows out to the outer peripheral gas duct 10C, this increases the heat transfer area with the windings, so that better cooling performance can be obtained.

FIG. 2 is a perspective view showing a gas guide in the embodiment of the present invention, and the structure thereof will be described with reference to FIG. The gas guide 21 is made of a plate-shaped insulating material having an outer diameter corresponding to the inner diameter of the transformer tank.
Vent holes 22 for guiding the gas flow 19A to the internal gas ducts 10A, 10B are formed at positions corresponding to the main legs of the and the lower surface of the winding 4, and are supported on the heat generating portion 2 side. Since the gas guide 21 configured as described above also functions as a part of the ground insulating material of the winding 4, it does not require a special installation space and shuts off the shunting of the insulating gas to the outer peripheral gas duct 10C. be able to.

FIG. 3 is a cross-sectional view of an essential part showing a different embodiment of the present invention, in which the gas guide 31 horizontally extends the lower frame 32 supporting the iron core 3 toward the side wall of the transformer tank 1. Internal gas duct consisting of a shelf-like expanded part 1
In addition to having a vent hole 33 communicating with 0A and 10B,
The present embodiment is different from the above-described embodiment in that a blocking member 34 made of an insulating material is provided to close the gap between the winding 4B and the gas guide 31, and the gas guide 31 may be formed of a thin metal plate. It may be made of a plate-shaped insulating material. In the gas guide 31 configured as described above, the mechanically strong frame also serves as a supporting member, and the closing member 34 also serves as a part of the ground insulation of the winding 4, so that the simplified gas guide is used. It is possible to block the split flow of the insulating gas to the peripheral gas duct.

[0017]

As described above, according to the present invention, the gas guide which is cooled by the panel radiator and guides the insulating gas flowing into the lower part of the transformer tank through the descending gas pipe into the heat generating portion is provided at the lower edge of the winding. It was arranged so as to block the vicinity and the inner wall surface of the transformer tank. As a result, the gas flow that bypasses the heat generating part and flows to the outer peripheral gas duct, which was a problem with the conventional self-cooling gas insulation transformer in which the difference between the height of the cooling center and the height of the heat generating center is increased, is blocked. It is possible to generate an insulating gas flow with a natural convection velocity in the internal gas duct in proportion to the increase in the difference between the center height and the heat generating center height, and to provide a self-cooling gas insulated transformer with excellent cooling performance. it can. In addition, the improved cooling performance enables the current density of the windings to be increased, so that the output capacity can be increased by keeping the size of the transformer as it is. There is an advantage that the transformer can be miniaturized. Furthermore, due to the synergistic effect of improving the cooling performance by arranging the panel radiator above the transformer tank and the effect of reducing the installation area, it is a small-sized, large-capacity, small-footprint, low-noise indoor gas. The insulating transformer can be provided economically and advantageously.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a self-cooling type gas insulated transformer according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a gas guide in the embodiment of the present invention.

FIG. 3 is a sectional view of a main part showing a different embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a conventional self-cooling type gas insulation transformer.

FIG. 5 is a sectional view schematically showing an improved conventional self-cooling type gas insulation transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transformer tank 2 Heat generating part 3 Iron core 4 Winding 5 Panel radiator 7 Upper header-9 Insulating gas 10A Internal gas duct 10B Internal gas duct 10C Peripheral gas duct 16 Rising gas pipe 17 Lower header-18 Down gas pipe 19A Cooled gas flow 19B Heated gas flow 21 Gas guide 22 Vent hole 31 Gas guide 32 Lower frame 33 Vent hole 34 Closing material

Claims (3)

[Claims] 1. A transformer tank containing a heat generating portion including an iron core and a winding wound around the iron core together with an insulating gas, and a rising gas pipe branched from an upper portion thereof and a descending gas pipe branched from a lower portion thereof, respectively. A plurality of panel radiators connected through a header and a lower header are provided, and the insulating gas that naturally cools the heat generating portion by convection is cooled by the panel radiator and is returned to the heat generating portion through a descending gas pipe. For cooling, a gas guide for guiding the insulating gas flowing into the lower part of the transformer tank into the heat generating part through the descending gas pipe is provided between the lower edge of the winding and the inner wall surface of the transformer tank. A gas-insulated transformer characterized in that it is arranged in a closed form. 2. The gas-insulated transformer according to claim 1, wherein the gas guide is made of a plate-shaped insulating material having a vent hole communicating with the inside of the heat generating portion. 3. The gas guide comprises a portion obtained by expanding the lower frame of the iron core toward the inner wall surface of the transformer tank, has a vent hole communicating with the inside of the heat generating portion, and is provided between the lower edge of the winding and the lower edge of the winding. The gas-insulated transformer according to claim 1, characterized in that a blocking member made of an insulating material is provided in the.