JPS62154708A - Gas-insulated transformer - Google Patents

Abstract

PURPOSE:To obtain the small-sized gas insulated transformer having high cooling efficiency and simple structure by a method wherein a clamp with which an iron core will be clampled is formed into hollow structure, a liquid cooling medium is fed into the clamp from outside a tank, and the clamp is cooled from inside. CONSTITUTION:The liquid cooling medium 12 fed into a tank 1 passing through an upper pipe 8a by a pump 11 passes pipes 9a, 9b and 10, and fed into the upper and the lower clamps 5a, 5b, 6a and 6b. At this point, the clamps 5a, 5b, 6a and 6b are cooled by the liquid cooling medium 12, the liquid cooling medium 12 collected in the clamps 5a, 5b, 6a, and 6b overflows from exhaust pipes 13a, 13b, 14a and 14b, and it is collected at the bottom part of the tank 1. The liquid cooling medium 12 collected at the bottom part of the tank 1 passes the lower pipe 8b and sent to a cooler 7 passing through a lower pipe 8b by a pump 11, and the liquid cooling medium 12 is circulated repeatedly. As a result, the lower clamps 5a, 5b, 6a and 6b are uniformly and effectively cooled by the liquid cooling medium 12 from the inside of the hollow part.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a gas insulated transformer, and in particular, the invention relates to a gas insulated transformer. This article relates to a gas insulated transformer.

[Technical background of the invention and its problems] Generally, large-capacity, large-sized transformers used in power generation and substations are oil-immersed transformers in which a tank is filled with insulating oil as an insulating and cooling medium. ing.

However, in the unlikely event that an accident occurs, this oil-immersed transformer may cause a fire or the like due to the oil, which may also cause secondary disasters such as environmental pollution.

In addition, as the storage capacity increases, the size of the equipment increases, resulting in problems such as expansion of installation space and increased transportation costs. For this reason, in recent years, there has been a tendency to use smaller gas-insulated transformers, which are highly safe and free from the risk of fire, as transformers installed in underground substations and the like, especially in urban areas. This gas insulated transformer has a tank filled with a nonflammable insulating gas such as SFsF2 gas instead of insulating oil together with the main body of the equipment to insulate and cool the equipment. However, the cooling capacity of insulating gas is much lower than that of insulating oil, and therefore, in gas-insulated transformers that use insulating gas for both insulation and cooling, the cooling effect is poor, so at most the resulting kVA is relatively small. This could only be done for large capacity transformers. For this reason, in order to make the gas-insulated transformer more human-friendly, the equipment inside the tank is insulated using an insulating gas with good insulation properties, and the equipment is cooled using fluorocarbons (C2Cj!a F).
A transformer is being considered in which a liquid with good insulating properties such as 3) or 70 linat (Os Ft s O) is atomized and sprayed onto the main body of the device, such as the valley wire, iron core, and clamp. However, the clamps that tighten the core of the transformer are made of iron for strength reasons, and local heating occurs when the leakage magnetic flux from the windings enters.Therefore, simply spraying a mist of cooling medium onto the clamps does not provide a sufficient cooling effect. Moreover, in order to spray the cooling medium evenly over the entire clamp, it is necessary to prepare equipment such as a large number of nozzles, which has the drawback of making the structure complicated and expensive.

[Object of the Invention] In view of the above points, an object of the present invention is to provide a gas insulated transformer that has a high cooling effect, particularly a cooling effect of the clamp portion, is small, and has a simple structure.

[Summary of the Invention] In order to achieve the above objects, the present invention makes the clamp for tightening the iron core hollow, and cools the clamp uniformly and effectively from the inside by feeding a liquid cooling medium into the clamp from outside the tank. In addition, the liquid cooling medium stored in the clamp is caused to overflow, thereby circulating the liquid cooling medium stored at the bottom of the tank to a cooler outside the tank.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a transformer tank, which houses the contents of the transformer consisting of an iron core 2 and a winding 3 wound around it. It is enclosed in.

5a, 5b and 6a, 6b are upper and lower iron clamps, respectively, which clamp the iron core 2 from both sides in the stacking direction. Upper and lower clamps 5a, 5b and 5a.

As shown in the figure, 6b is formed in the shape of a hollow box with a rectangular cross section and a space inside. 7 is a cooler, which is installed outside the tank 1 and is connected to the tank 1 via piping 8a, 8b.
The upper piping 8a extends to the upper part of the iron core 2, and an even thinner piping 9a.

It communicates with the space between the upper clamps 5a and 5b via 9b. Further, the upper pipe 8a communicates with the space between the lower clamps 6a and 6b via a thin pipe 10. on the other hand,
One end of the lower pipe 8b communicates with the lower end of the tank 1, and the other end is connected to the cooler 7 via a pump 11.

From the cooler 7, upper and lower clamps 5a, 5b and 5 are connected via the pipes 8a, 9a, 9b and 10.
A liquid cooling medium 12 with good insulating properties, such as Freon (C2CJlsF3) or Fluorinert (C8FtsO), is sent to the spaces in the clamps 5a, 5b, and 5a.
.

The liquid cooling medium 12 sent into 6b is discharged through each discharge pipe 13a.
, 13b, and 14a, 14b and is stored at the bottom of the tank 1.

Next, the operation of the present invention will be explained. Insulation between the contents of the transformer and the tank 1 is ensured by an insulating gas 4 sealed in the tank 1 so that a predetermined insulation strength is maintained. On the other hand, the liquid cooling medium 12 sent into the tank 1 through the upper pipe 8a by the pump 11 is transferred to the pipes 9a and 9b.
and 10 into the upper and lower clamps 5a, 5b and 6a, 6b. Here, liquid cooling medium 12
The clamps 5a, 5b, 5a, 5b are cooled, and the liquid cooling medium 12 stored in the clamps 5a, 5b, 6a, 6b is discharged through the discharge pipes 13a, 13b and 14a,
It overflows from 14b and is stored at the bottom of tank 1. The liquid cooling medium 12 stored at the bottom of the tank 1 is sent to the cooler 7 through the lower pipe 8b by the pump 11, cooled there, and then transferred to the upper pipe 8a again in the same manner as above.
The cycle of being fed through the clamps 5a, 5b, 5a, and 5b is repeated. As a result, the upper and lower clamps 5a, 5b, 6a, (3b) are evenly and effectively cooled from the hollow interior by the liquid cooling medium 12.

Although not shown, local heating of the iron core 2, coil 3, or tank 1 is cooled by spraying liquid cooling medium 12 from above, as in the conventional case.

With such a configuration, the gas insulated transformer of the present invention is heated by the winding leakage magnetic flux.

The lower clamps 5a, 5b, 6a, 6b can be sufficiently cooled, and the upper and lower clamps 5a, 5 can be cooled by a large number of nozzles.
The structure is much simpler than the structure in which the liquid cooling medium 12 is sprayed onto b, 6a, and 6b.

[Effects of the Invention] As described above, according to the present invention, the clamp for tightening the iron core is made hollow, and by feeding a liquid cooling medium into the clamp from outside the tank, the clamp is cooled from the inside and the cooling medium is cooled inside the clamp. The liquid cooling medium stored at the bottom of the tank is circulated to the cooler outside the tank by overflowing the liquid cooling medium, so the cooling effect, especially the cooling effect of the clamp part, is high and the size is small. A gas insulated transformer with a simple structure can be obtained.

[Brief explanation of drawings]

The figure is a sectional view showing one embodiment of the present invention. 1...tank, 2...iron core, 3...winding, 4...
・Insulating gas, 5a, 5b, 6a, 6b,... Clamp, 7... Cooler, 8 a, 8 b, 9 a, 9 b,
10...Piping, 11...Pump, 12...
・Liquid cooling medium, 13a, 13b,'l 4a, 14b
...Exhaust pipe.

Claims (1)

[Claims] The contents of a transformer consisting of an iron core, a winding wound around the iron core, and a clamp for tightening the iron core are housed in a tank together with an insulating gas, and the transformer is heated by a liquid cooling medium fed into the tank from the outside. In a gas insulated transformer whose contents are cooled, the clamp is hollow,
A liquid cooling medium is sent into this clamp, and a discharge pipe is provided in the clamp to allow the liquid cooling medium stored in the clamp to overflow, and the liquid cooling medium stored at the bottom of the tank is circulated through a cooler installed outside the tank. A gas insulated transformer characterized by: