JPS59104108A - Self cooled gas insulated transformer - Google Patents

Abstract

PURPOSE:To enhance the measure of capacity of the possible limit of self cooling, to reduce the installing floor area, and to reduce the number of installation of the radiators of a self cooled gas insulated transformer by a method wherein cooling efficiency of insulating gas according to a natural convection is enhanced. CONSTITUTION:An upper header pipe 16 is arranged at the centrally upper side of the upper cover 10a of a transformer tank 1, and lower header pipes 32, 34 are arranged at both the sides of right and left of the upper cover 10a. Radiators 50 of the plural number are arranged in parallel and facing mutually on both the sides of right and left between the upper and the lower header pipes. The upper part sending in pipes 51 of the radiators 50 are connected to the upper header pipe 16, and the lower part sending out pipes 52 are connected to the lower header pipes 32, 34. Insulating gas 4 transmitted with heat generated from windings and a core ascends in an ascending gas pipe 14 from the upper branch pipe 11 of the upper cover 10a of the tank to reach the upper header pipe 16, and is conducted into the radiators 50 through the sending in pipes 51.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a self-cooling gas insulated transformer in which a heat radiator is disposed above a tank top cover.

Generally, in a self-cooling type gas insulated transformer, an insulating gas such as 5F6-/eggplant is sealed in a tank as a cooling medium, but the cooling temperature decreases each time due to natural convection of the refrigerant gas.

For this reason, the current density and magnetic flux density must be kept low so that the temperature difference between the windings and iron core, which are heating elements, and the refrigerant gas does not exceed the specified value, and the transformer capacity is 1000~
The maximum capacity is 3000KVA, and for those exceeding this capacity, a forced circulation system is adopted.

As a conventional transformer of this type, one having the structure shown in FIGS. 1 and 2 is known. In the figure, reference numeral 1 denotes a tank of a transformer, in which a winding 2 and an iron core 3 are housed, and an insulating gas 4 is sealed therein. Reference numeral 5 denotes a radiator, and a plurality of radiators are arranged along the left and right side plates 1111 of the transformer tank 1, and the feed pipe 6 of each radiator 5 is an upper branch pipe branched from the side plate of the transformer tank 1. 8, the delivery pipes 7 are connected to the lower branch pipes 9, respectively. The heat radiator 5 is of a self-cooling type that forms a continuous duct using a pipe or the like and radiates heat to the outside air from the surface of the duct.

The heat generated from the winding 2 and the iron core 3 is transferred to the insulating gas 4 in the tank 1, and the insulating gas 4, which rises due to natural convection due to the temperature difference, contacts the upper branch pipe 8 of the tank 1 as shown by the arrow. is led into the radiator 5 from the inlet pipe 6 to be read,
After being cooled by dissipating heat from the surface of the radiator 5, the circulation action of returning to the tank 1 from the lower branch pipe 9 connected to the delivery pipe 7 is repeated.

By the way, the external dimensions of the transformer tank 1 are determined by the sizes of the winding 2 and the iron core B, and the external dimensions of the necessary radiator 5 cannot be determined for the size of this tank. , the speed at which the insulating gas naturally convects is the radiator 5
It depends on the difference between the center height (cooling center height) of the winding 2 and the center height of the core A (heating center height).

In other words, the uniform heat transfer coefficient α of the winding and the iron core is proportional to the natural convection velocity of the insulating gas. This heat transfer coefficient α is expressed by the following equation.

K for ±α (1+h') where K: cooling coefficient, n: constant (n≧1°O) that varies depending on the cooling system.

As is clear from the above equation, K, which increases the natural convection velocity of the insulating gas to improve the heat transfer coefficient α of the next surface of the windings and iron core, thereby increasing the cooling efficiency, is determined by the difference between the cooling center height and the heat generation center height. It turns out that the difference 11 must be made thicker.

3- However, in conventional self-cooling gas insulated transformers, the radiator is placed along the side plate of the transformer tank, so there is a limit to the height, which is the basic external dimension of the radiator. It cannot be made higher than necessary, and therefore the difference between the cooling center height and the heating center height is relatively small. This reduces the natural convection speed of the insulating gas,
There was a drawback that the cooling effect of the windings and the iron core was not sufficiently exhibited, and the capacity of the transformer that could be self-cooled was also suppressed to within the conventional maximum limit.

In addition, in conventional self-cooling gas insulated transformers, in order to fully demonstrate the cooling effect, it is necessary to increase the external dimensions of the unit heat radiator or increase the number of radiators installed. Not only does the overall weight increase, but the width of the entire transformer also increases, and when installed inside a building or basement, it is often subject to floor space constraints2, requiring a large occupied floor space. This had the disadvantage of leading to a rise in construction costs.

This invention eliminates the above-mentioned drawbacks, improves the cooling efficiency by natural convection of the insulating gas, increases the capacity of the self-cooling limit, requires a small installation floor area, and furthermore allows heat dissipation. The purpose of the present invention is to provide a self-cooling type gas insulated transformer that is small and lightweight and can reduce the number of installed transformers.

Embodiments of the present invention will be described below with reference to the drawings.

3 and 4 are examples of the present invention. An upper branch pipe 11 is branched at two locations on the longitudinal center line of the upper lid 10a of the transformer tank 1, and the upper branch pipe 11 is provided at two locations.
The 7 flange 15 at the lower end of the rising gas pipe 14 is brought into contact with the flange 12 at the upper end and tightened with bolts and nuts, and the -1- rising gas pipe 14 is vertically installed. An upper header pipe 16 is connected to the upper end of the rising gas pipe 14 in a horizontal direction.

At the lower ends of the opposing side plates 10b and 10c of the tank 1 of the transformer, lower branch pipes 18.20 are branched at symmetrical positions with respect to the upper branch pipe 11, and the tips of the lower branch pipes 18.20 are provided. On the fly Fuji 19, 21,
The flanges 25 and 27 at the bent portions of the lower ends of the descending gas pipes 24 and 26 are joined together and tightened with bolts and nuts, so that the descending gas pipes 24 and 26 are erected vertically. The descending gas pipe 24.26 is fitted with a flange 29.30 at its two ends, which is flush with the two ends of the upper branch pipe 11 of the transformer tank 1. This descending gas pipe 24゜2
6 upper end (respectively, force, lower header pipe 62° 64
Install it horizontally. The lower header pipe 32.34 is attached to the flange 29.30 at the upper end of the descending gas pipe 24.26.
The flanges 36, 37 of the connecting portions 33, 35 branched from the flange 33, 35 are joined, and the connection is made by tightening with bolts and nuts.

As described above, the upper ladder pipe 16 is installed above the center of the upper lid 10a of the transformer tank 1, and the lower ladder pipe 2.34 is installed on both left and right sides of the upper lid 10a, parallel to the length direction of the transformer. between the upper header pipe 16 and the lower header pipe 62. 51 is connected to the upper header pipe 16, and the lower delivery pipe 52 is connected to the lower header pipes 32 and 34 by joining flanges (not shown), respectively.

In this way, the radiator 50 is installed above the upper cover 10a of the transformer tank 1, and if necessary, the radiator 50 is installed above the upper cover 10a of the transformer tank 1. A support stand may be placed between the radiator 50 and the rising gas pipe 16 by interposing an appropriate fixing member between the radiator 50 and the rising gas pipe 16. It may also be supported by welding to the

When the heat radiator 50 is arranged as shown in 11, the insulating gas 4, to which the heat generated from the winding 2 and the iron core 6 is transferred, flows from the upper branch pipe 11 of the tank top lid 10a to the upper branch pipe 11 of the tank top lid 10a as shown by the arrow. The rising gas rises inside the tube 14 and reaches the upper header pipe 16, and is guided from the lower header pipe 16 to the heat radiation 'A' juice 50 via the feed pipe 51. The insulating gas cooled by the radiator 50 is transferred from the delivery pipe 52 to the lower header pipe 62.6.
4, descending gas pipe 24.2 via connecting pipe 33.3
6 and returns to the tank 1 through the lower branch pipes 18, 20 of the tank side plates 10b, 10c.

As in the above embodiment, in this invention, the heat sink 50 is disposed above the tank 1, and the difference between the height of the cooling center and the height of the heat generating center is made larger than in the conventional case. The natural convection velocity of the insulating gas is increased, which makes it possible to improve the heat transfer coefficient on the surfaces of the windings and core.

In addition, in this invention, since the radiator is installed above the transformer tank, the width of the entire transformer can be kept within the width of the transformer itself and the descending gas pipes on both sides. It becomes possible to significantly reduce the installation floor space of the entire device.

In addition, in the radiator of the present invention, the rising gas pipe of the upper header pipe is connected to the upper branch pipe of the transformer tank by a flange to the attachment/detachment port, and the connecting pipe of the lower header pipe is detachably connected to the descending gas pipe by the flange. Since the descending gas pipe is also removably connected to the lower branch pipe of the transformer tank by a flange, each part can be separated from these 7 lunges, and the radiator and transformer can be separated from each other. It is also possible to disassemble and transport the single unit and assemble it on site.

8- FIG. 5 is another embodiment of the present invention. In this embodiment, the upper cover 10a of the transformer tank 1 is formed into a semi-cylindrical shape which is curved upward with a suitable radius of curvature. The rising gas pipe 14 is formed into an upwardly tapered shape by gradually reducing its cross-sectional area from the lower end to the upper end (C).

The rest of the structure except for the shape of the transformer tank upper cover and the two-fold gas pipe shown in "2" is the same as the embodiment shown in FIGS. 3 and 4, so the same parts are designated by the same reference numerals. , detailed explanation will be omitted.

With the configuration of this embodiment, the fluid resistance of the insulating gas 4 raised by natural convection is reduced, so that the natural convection velocity is further increased beyond the increasing effect of the increase in the difference between the cooling center height and the heat generation center height. It will increase.

FIGS. 6 and 7 show still other embodiments of the invention. In this embodiment, the width dimension of the upper cover 10a of the transformer tank 1 is made smaller than the side plates 1 ob and 10 c.
The side surfaces of the descending gas pipes 24 and 26 having a rectangular cross section are closely welded to the outer surfaces of the side plates 101) and 10c of the transformer tank 1. The descending gas pipes 24 and 26 have a part of the lower end side surface cut out and are attached to the side plates 10b and 10 of the transformer tank 1.
It communicates with an opening 60 provided at c.

According to this embodiment, the descending gas pipes 24.26 and the side plates 10b, 10c of the transformer tank 1 are integrally connected, so that the descending gas pipes 24.26 are connected to the side plates 10b, 10b of the transformer tank 1.
, 10c, and there is no need to provide a separate reinforcing member, making it possible to reduce the weight of the entire transformer.

Good, descending gas pipe 24, 26 and side plate 1 of transformer tank 1
Since the space between 0h and 10c is eliminated, the width of the entire transformer is further reduced than in the embodiments shown in FIGS. 3 to 5.

The tank top lid 10a and the rising gas pipe 14 may be formed as shown in FIG.

FIG. 8 shows a modification of the embodiment shown in FIGS. 6 and 7, in which a descending gas pipe 24 with a circular cross section is connected to a side plate 10 of a transformer tank.
A splint 28 is inserted between the splint 28 and the end surfaces of the splint 28 in the length direction between the gas pipe 24 and the side plate 10 of the transformer tank.
1]. The splint 28 and the side plate 101) of the transformer tank may be fixed with bolts.

As described above, the present invention has a configuration in which the radiator is disposed above the upper lid of the transformer tank to minimize the difference between the height of the cooling center and the height of the heating center. Therefore, according to the present invention, the natural convection speed of the insulating gas is increased, and the cooling efficiency is greatly improved, so that the maximum capacity of the transformer that can be self-cooled can be made higher than before.

According to this invention, the cooling performance due to natural convection of the insulating gas is improved, so the radiator should be small.
Alternatively, the number of devices installed can be reduced.

Further, according to the present invention, since the installation floor area of the entire transformer is reduced, it can be installed in buildings, basements, etc. without requiring special occupied floor space, and the overall shape of the transformer is small. In addition to being lightweight, it is possible to reduce equipment costs and construction costs11-.

Furthermore, since the gas insulated transformer of the present invention can increase the capacity by self-cooling without using a blower,
Compared to a forced circulation gas insulated transformer of the same capacity, it consumes less electricity and contributes to energy conservation requirements.

The present invention can be applied not only to gas insulated transformers as described in detail, but also to gas insulated reactors, and can also be applied to oil-immersed transformers and oil-filled axles.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional self-cooling gas insulated transformer, Fig. 2 is a plan view thereof, Fig. 3 is a sectional view showing an embodiment of the present invention, Fig. 4 is a plan view thereof, and Fig. 5 6 is a sectional view showing another embodiment of the invention, FIG. 7 is a plan view thereof, and FIG. 8 is a modified example of the descending gas pipe. It is a partial horizontal sectional view. 10a: Tank top lid 10b, 10c: Tank side plate 12-11: Upper branch pipe 12: Flange 14 of upper 4-way branch pipe
:Rising gas pipe 15:L-f't gas pipe flange 16
: Upper header pipe 24, 26: Downward gas pipe 29.30
: Flanges 32, 34 of descending gas pipes: Ladder pipes to the bottom 33.35: Connecting pipes 36, 37 of lower header pipes: Flanges 5 of connecting pipes of lower header pipes
0: Heat radiator 51: Heat radiator inlet pipe 52: Heat radiator outlet pipe Patent applicant Fuji Electric Manufacturing Co., Ltd. Agent Patent attorney Tetsuya Mori Patent attorney Fuji Nai
Yoshiaki, Patent Attorney, Shimizu, Patent Attorney, Kajiyama Kyore Figure 3 6t, 5S JP-A-59-104108 (6)

Claims (1)

[Scope of Claims] (]) An upper header pipe is connected to the upper end of a rising gas pipe branched from the center of the tank top cover of the gas insulated transformer, and the upper header pipe is connected to the upper end of the rising gas pipe that branches from the lower end of the side panels on both the left and right sides of the tank. A ladder pipe is connected to the upper end KT section of the descending gas pipe installed upright, and a plurality of self-cooling radiators are arranged in parallel above the tank top cover between the upper header pipe and the lower header pipe. A self-cooled gas insulated transformer characterized in that the inlet pipe of the radiator is connected to the upper header pipe, and the outlet pipe of the radiator is connected to the lower header pipe. (2. In the self-cooling gas insulated transformer according to claim 1, the ascending gas pipe is removably connected to the upper branch pipe of the tank top cover, and the descending gas pipe is connected to the lower part of the W-continuation pipe of the ladder pipe. (3) In the self-cooled gas insulated transformer according to claim 1 or 2, the cross section of the tank top is curved upward. A self-cooling type gas insulated transformer in which the rising gas pipe is formed into a cross-sectional shape tapering in two directions. (4) A self-cooling gas insulated transformer according to any one of claims 1 to 3. A self-cooled gas insulated transformer in which the side surface of the down-north pipe is in close contact with the outer surface of the tank 1111+ plate.