JPS62193233A - Liquid cooling gas insulated induction electric apparatus - Google Patents

Abstract

PURPOSE:To reduce the consumption of a refrigerant liquid by providing an expansion which can shrink in the direction of an axis according to the shrinking of a winding on the side wall of a cylindrical insulation tank consisting of an inner insulation cylinder and an outer insulation cylinder. CONSTITUTION:The main body 1 of a transformer is carried in a vacuum heat drying furnace and, e.g., dried by using circulating passages 12A, 12B as humidity removing holes and the reduction of a clamping load due to the dry contraction of a fiber insulating material is compensated by increasing the screwing of a clamping bolt 22. Expansion insulating couplings 39A, 39B are shrinked according to the dry contraction of windings 3A, 3B including end insulations 4A, 4B, the depth of an insulating tank 35 can be made an optimum dimension required for the maintenance of cooling performance and insulating performance of the windings 3A, 3B, a pressure ring 21 which is made a ground electric potential by increasing a clamping load to the windings 3A, 3B in the direction of an axis from the outside of the insulating tank can be provided outside of a lid plate 38 and the volume of the insulating tank 35 can be reduced. This can reduce the consumption of a refrigerant liquid 14.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a liquid-cooled gas cooling system that uses a refrigerant liquid to cool windings housed in an insulating tank that partitions an insulating gas space in the tank and a cooling liquid circulation path. Related to insulated induction appliances, especially the structure of insulation tanks.

[Prior art and its problems]

In recent years, in place of conventional insulating oil, flame-retardant insulating gases such as SF and gas have been used in combination with flame-retardant and insulating refrigerant liquids such as fluorocarbon and 70N. Electrical appliances are attracting attention, and recently there has been a demand for higher voltage and larger capacity of this type of induction electric appliance. However, refrigerant liquid is much more expensive than insulating oil, and has the property of dissolving a large amount of insulating gas and reducing the withstand voltage strength. By cooling the refrigerant by sensible heat with the refrigerant liquid, and by airtightly separating the insulating gas space and the refrigerant liquid by an insulating tank, the usage tf of the refrigerant liquid is reduced, and mixing of the refrigerant liquid and the insulating gas is prevented. A so-called liquid-cooled gas-insulated induction electric appliance is known in which a nearby high electric field portion is insulated with a refrigerant liquid having high withstand voltage strength.

FIG. 4 is a schematic side sectional view showing the conventional structure of a liquid-cooled gas-insulated induction appliance. In the figure, 1 is the iron core 2 and the winding 3A
, 3B is the main component, and the main component is the guide, SF,
Windings 3A and 3B are housed in a tank 10 containing an insulating gas 11 such as gas, and include end insulation 4A and 4B.
The inner insulating cylinder 6A, the outer insulating cylinder (5B, i+
'C, board 7. A ring 1 and a pedestal 4C made of an insulating material are housed in an annular cylindrical insulating tank 5 which has a hollow part 5A in the center which has a hollow part 5A through which the legs of the iron core 2 pass through. A metal pressing ring 21. is placed on the lower frame 2B coupled to the iron core 2 through the metal pressing ring 21. The windings 3A, 3B are connected to the upper frame 2A by a tightening bolt 22 that passes through the cover plate 8 in an airtight manner and is connected to the upper frame 2A.
By applying a predetermined tightening load in each axial direction, it is configured to be compressed and supported between a pair of upper and lower frames 2A and 2B. The inside of the insulation tank 5, which is airtightly divided from the insulation gas space 11, is filled with a refrigerant liquid 14 such as fluorocarbon or fluorocarbon, and one end communicates with the insulation tank 5 via the bottom plate 7 and the lid plate 8. The winding 3 is connected to the winding 3 through circulation passages 12A and 12B whose other ends communicate with the external cooler 13.
The windings are cooled by the rapid heating of the refrigerant liquid 14 that is forcedly circulated within A and 3B. Therefore, the refrigerant liquid 14 and the insulating gas 11 are separated by the insulation Wi5, and the use of the expensive refrigerant liquid 14 can be limited to the winding portion that generates a large amount of heat.
By preventing the melting of the refrigerant and the foaming of the refrigerant liquid due to rapid cooling, the pressure resistance strength of the refrigerant liquid 14 can be maintained at a high level, so that high-voltage aH4 electric appliances can be manufactured economically. .

By the way, in the liquid-cooled gas-insulated induction electric appliance configured as described above, the windings 3A and 3B are generally formed by inter-section cooling between a plurality of flat ring-shaped section coils formed by winding insulated conductors in the radial direction. Disc windings are used that are stacked and arranged with a spacer intervening to hold the duct.
Conductor insulation coating, spacer and winding end insulation 4 A
, 4"B etc. are made of fibrous insulating materials such as insulating paper and presspod, which have excellent permeability to the refrigerant liquid 14. Because it contains moisture, the induction electric appliance main body 1 that has been assembled is stored in a vacuum heating drying oven and subjected to a drying process.However, the fibrous insulating material loses several percent of its thickness in the drying process. Because it has the property of shrinking and undergoes dimensional shrinkage due to axial tightening load, the end insulation 4A,
The axial height of the windings 3A and 3B including wire 4B often shrinks by about 100 mm during the drying and tightening process.

Therefore, when the insulation tank 5 is formed using fiber-reinforced plastics (FRP) with excellent airtightness and mechanical strength, the insulation tank 5 made of FRP does not shrink when dried.
In this case, only the windings 5A and 3B will shrink by 100 m, and as the axial dimension of the wires shrinks, a wasted space will be created inside the insulation tank 5, and the metal that will be at ground potential will be Since the suppression ring 21 made of aluminum is disposed within the insulation tank 5, it is necessary to further increase the axial dimension of the insulation tank 5 by the thickness of the suppression ring 21. As a result, there is an idle space 15 above the insulation 415 that does not contribute to insulation or cooling of the windings, which increases the axial dimension of the insulation tank 5 and increases the amount of expensive refrigerant liquid 14. There are drawbacks that cause economic disadvantage. Furthermore, the contraction of the winding is caused by the tightening port 22.
This leads to an increase in the length of the winding, which makes the axial tightening force of the winding unstable, and also leads to disadvantages such as an increase in liquid leakage at the penetrating portion of the cover plate 8.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned situation.

It is an object of the present invention to provide an economical liquid-cooled gas-insulated induction electric appliance in which an insulation tank can be reduced in the axial direction in accordance with drying shrinkage of windings, etc., and the amount of refrigerant liquid used is small.

[Key points of the invention]

The present invention follows the shrinkage of the windings on the side wall portion consisting of the inner insulating cylinder and the outer insulating cylinder of an insulating tank formed in an annular cylindrical shape to accommodate the winding including end insulation. An extensible part that can be contracted in the axial direction is provided, and an axial tightening load fI' is applied to the winding from the outside of the insulation tank, and winding #i! By configuring the insulating tank to be compressed and supported between a pair of upper and lower frames fixed to the iron core, wasted volume of the insulating tank is eliminated.
Therefore, the amount of expensive refrigerant liquid used can be reduced to the amount necessary for cooling and insulating the windings.

[Embodiments of the invention]

The present invention will be explained below based on examples.

FIG. 1 is a schematic side sectional view of a main body portion of an induction electric device showing an embodiment of the present invention, and the same parts as in the prior art are given reference numerals 10'' and detailed explanation thereof is omitted.

In the figure, an insulating tank 65 housing windings 3A and 3B having end insulation 4A and 4B at both axial ends is airtightly connected at each end to a bottom part 57 made of a flat ring-shaped insulating material. A container part formed in an annular cylinder shape so as to surround the leg part of the iron core 2, and an inner and outer insulating cylinder 36A, 36B.
Expansion insulation joints 3 hermetically connected with 7 langes to each B
9A, 69B, and a cover plate 68 airtightly connected to the expansion and contraction insulating joints 39A, 39B with seven flange. together with the tightening ring 21 arranged on the cover plate 38,
By applying a tightening load with the tightening bolts 22, the frame is compressed and supported between the pair of frames 2A and 2B fixed to the iron core, and the bottom plate 37 and the cover plate 3
The windings 3A and 3B are cooled by the refrigerant liquid 14 that is forcedly circulated between the insulation tank 65 and the external cooler 15 through the circulation passages 12A and 12B whose ends are hermetically connected to the windings 3A and 3B. The structure is such that the withstand voltage of the high electric field area near the line is maintained.

FIG. 2 is a partially fragmented side sectional view of the main part of the insulation tank in the above-mentioned embodiment, and shows an expansion insulation joint 3 made of a molded product of rubber having refrigerant resistance, flexible synthetic resin, etc.
The insulating 7 langes 42A, 42B on the 9A, 59B side, for example, and the insulating 7 langes 41A, 41E on the insulating cylinder side are airtightly connected using insulating bolts 45 with the backing 44 interposed, and the 7 langes 43A, 43B are connected to a flat plate ring. By airtightly connecting the shaped cover plate 38 and the gap 44 using insulating bolts 45, an insulating tank 65 that airtightly surrounds the winding can be formed.

It goes without saying that the amount of expansion and contraction in the axial direction of the expansion and contraction insulating joints 39A and 39B is determined by taking into consideration the amount of drying and tightening shrinkage of the windings 3A and 3B.

In the liquid-cooled gas-insulated induction electric appliance configured as described above, the end insulation 4A, 4 is in an undried state or a temporarily dried state.
The insulation tank 65 that accommodates the windings 3A and 3B including B is attached to the cover plate 38 with the expansion insulation joints 39A and 39B slightly stretched.
The winding 3A can be closed by connecting the winding 3A by applying an axial tightening load to the insulation tank 35 via the tightening bolt 22 and the rigid tightening ring 21.

3B and the end portions R4A, 4B contract in the axial direction, the expansion insulating joints 39A, 39B contract, and the cover plate 68. Assemble the induction electric appliance main body 1 in which the windings 3A and 5B can be pressed and supported between the pair of frames 2A and 2B via the bottom plate 67 and the pedestal 4C, and the insulating tank 35 is fixed at a position determined by the thickness of the pedestal 4C. be able to. Therefore, the transformer main body 1 is carried into a vacuum heating drying oven, and, for example, the circulation passage 12 is
A.

12B is used as a dehumidification hole to perform a drying process, and the reduction in the tightening load due to drying shrinkage of the fibrous insulating material is compensated for by further tightening the tightening bolt 22. At this time, the end insulation 4
The expansion insulation joint 591.59B shrinks following the drying shrinkage of the windings 3A and 3B including A and 4B, and the depth of the insulation tank 65 is adjusted to maintain the cooling performance and insulation performance of the windings 6A and 3B. The pressing ring 21 can be made to the required optimum size and can be brought to earth potential by applying a tightening load in the axial direction of the windings 3A and 6BK from the outside of the insulation tank.
It is possible to arrange the insulation tank 6 on the outside of the cover plate 38.
5 can be further reduced compared to the prior art.

FIG. 6 is a schematic side sectional view of the main part showing a different embodiment of the present invention), in which the cover plate 48 is formed into a thick flat ring shape that can be inserted between the inner and outer peripheral insulating cylinders 46A and 46B, and the backing 4
7 is provided to provide an axially expandable part 4 which also serves as a seal part.
9 and a gold MM suppression ring 21. The tightening bolt 22 is eliminated, the cover plate 48 is also used as a suppression ring, and the spacer piece 54 inserted between the upper frame 2A and the cover plate 48 is configured to hold the tightening load in the axial direction. Unlike the previous embodiment, during the assembly and drying process of the induction electric device, a jack or the like is temporarily installed between the cover plate 48 and the two frames, and the windings 3A, 3 are inserted from the outside of the insulation tank 5°.
A tightening load in the axial direction is applied to B, and at the end of drying, a plurality of spacing pieces 54 whose thickness has been adjusted in advance are inserted in a circumferential direction of the cover plate 48 with the tightening load being increased somewhat. However, by removing the jacks, the insulation tank 5o can be pressed and supported between the upper and lower pairs of frames 2A and 2B with a predetermined tightening load applied to the windings 5A and 3B.
In addition, since the cover plate 48 freely moves in the axial direction following the shrinkage of the fibrous insulating material, it is possible to prevent idle spaces from being generated within the insulating tank. In addition, since the cover plate made of insulating material can also be used as part of the end insulation 4A, 4B of the entire winding 3A, 3B, the thickness of the end insulation 4A, 4B can be reduced.
In addition, since the voltage can also be applied to the spacer piece 54, the cover plate 4
Although the insulating tank 8 is formed thick, the axial dimension of the insulating tank 5o can be shortened.

〔Effect of the invention〕

As described above, the present invention provides an insulating tank that can expand and contract in the axial direction by providing an expandable part between the upper end of each of the inner and outer insulating tubes of the insulating tank that accommodates the liquid cooling winding and the cover plate. The structure is such that an axial load is applied to the windings from the outside of the insulation tank by means of a suppressing member placed above the lid plate. As a result, the insulation tank can be contracted by following the drying shrinkage of the fibrous insulation material of the winding including the end insulation and the contraction due to axial load, and the suppression ring, which is at ground potential, can be placed outside the insulation tank. This eliminates the shrinkage allowance for the winding, which was a problem with the conventional technology, and the idle space in the insulation tank that does not contribute to winding cooling and insulation, which is the storage space for the press ring. By making the tank smaller, the amount of expensive refrigerant liquid used is reduced, and therefore an inexpensive liquid-cooled gas-insulated induction electric appliance can be provided. In addition, by shortening or eliminating the tightening bolts and eliminating the through holes for the tightening bolts on the cover plate side, there is less risk of liquid leakage, and it is possible to prevent the insulating gas from dissolving in the refrigerant liquid. Since a stable axial load can be maintained and the winding can be firmly suppressed and supported together with the insulation tank between the pair of frames, it can contribute to higher voltage and larger capacity of induction electric appliances.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view of a main part showing an embodiment of the present invention, FIG. 2 is a partially fragmented side sectional view of an insulation tank portion in the embodiment,
FIG. 3 is a side sectional view of a main part showing a different embodiment, and FIG. 4 is a side sectional view showing a conventional technique. 1... 41r1. The main body of the vessel, 2 river iron cores, 2A, 2B.
... Frame, 3A, 3B... Winding, 4A, 4B.
...End insulation, 4C...Case, 5,35.50-...
Zetsu R Hinoki, 6A, 36A, 46A... Inner peripheral side insulation tube, 6
B, 56B, 46B... Outer peripheral side insulating tube, 7, 37.
...Bottom plate, 8゜38.48...Lid plate, 10...Tank, 11...Insulating gas, 12A, 12B...Circulation passage, 13...Cooler, 14...Refrigerant liquid , 15...
Idle space, 21... Pressing ring, 22... Tightening bolt, 39A, 39B... Expansion insulation joint, 47... Backing, 49... Expandable portion, 54... Spacing piece.
Figure 1 36B Figure 2

Claims (1)

[Claims] 1) The cylindrical winding part of the induction electric appliance, which is housed in a tank containing insulating gas, is housed in an annular cylindrical insulating tank that has a hollow part in the center through which the core leg passes. It is attached to the steel core and is pressed and supported by a predetermined tightening load between a pair of upper and lower frames fixed to the iron core, and is cooled by a refrigerant liquid that circulates through an external cooler that communicates with the insulation tank. A liquid-cooled gas-insulated induction electric appliance, characterized in that the insulating tank includes an expandable portion that can contract following contraction of the winding in the axial direction.