JPH01100904A - Foil-wound transformer - Google Patents

Abstract

PURPOSE:To prevent deformation and breakage of both a nozzle for introducing cooling medium and a nozzle for ejecting cooling medium without excessive pressures of cooling medium being applied to both the introducing nozzle and the ejecting nozzle, by employing a specific structure in which the nozzle for introducing cooling medium and the nozzle for ejecting cooling medium, which are disposed in the upper and lower sections of a cooling panel, respectively, are provided for the respective one end parts with expansion rooms through diaphragms, and each the diaphragm employs a rupture disk which is broken at the pressures below the allowable pressures of each the nozzle main body. CONSTITUTION:The nozzle 16 for introducing cooling medium and the nozzle 19 for ejecting cooling medium, which are disposed in the upper and lower end sections of a cooling panel 6, respectively, are provided for the respective one end parts with expansion rooms 32 through rupture disks 31. Now, each the rupture disk 31 is so formed as to be broken at the pressures below the allowable pressures of each of the main bodies of the introducing nozzle and the ejecting nozzle. Therefore, in an external closed-circuit failure, even if the cooling medium 15 flows out from the main body of the cooling panel 6 resulting from a radial electromagnetic force being generated excessively and suddenly, since the rupture disk 31 is broken and the flowed out cooling medium flows into the expansion room 32, the expansion room 32 sufficiently prevents the pressures of the cooling medium from rising rapidly. As a result, the deformation and breakage of both the nozzles can be effectively avoided.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a foil-wound wire with a built-in cooling panel inside the winding formed by overlapping and winding a metal sheet and an insulating sheet 1 to 1. It concerns transformers.

(Prior art) A foil-wound transformer, in which a metal sheet and insulation sheets 1 to 1 are layered and wound around a core leg to form a foil winding, has a good space factor for the conductor per turn, so it is It has the advantage of being smaller and lighter than transformers that use rectangular wire conductors.

However, in order to realize a transformer with higher voltage and larger capacity, it is essential to further improve the cooling efficiency of the winding and to provide the winding with high insulation ability. For this reason, it has been considered to incorporate a cooling panel in which a refrigerant flows within the windings to directly cool the heat generated from the windings.

As this conventionally proposed foil-wound transformer, for example, the one described in US Pat. No. 4,039,990 is known.

As shown in FIG. 3, this foil-wound transformer has a winding formed by overlapping and winding a metal sheet 2 and an insulating sheet 3 around an iron core leg 1. This winding consists of a low voltage winding 4 and a high voltage winding 5, and an annular cooling panel 6 is built into each of these windings 4,5.

Here, as shown in FIG. 4, the cooling panel 6 has an introduction nozzle 16 that feeds the refrigerant 15 into the cooling panel 6 through the refrigerant introduction port 14 of the cooling panel, and the introduced coolant! l! 1t15
The refrigerant 15 is composed of a flow path section 17 through which the refrigerant 15 flows, and a refrigerant outlet nozzle 19 that does not send the refrigerant 15 out of the cooling panel 6 from the refrigerant outlet section 18 of the cooling panel. In addition, refrigerant 15
The configuration of the flow path portion 17 through which the water flows is as shown in FIG. That is, a gap 22 is formed by disposing a large number of band-shaped spacing plates 21 between the two metal cooling panel constituent plates 20 that make up the cooling panel 6. Refrigerant 15 is allowed to flow.

To cool the windings, a refrigerant 15 such as Freon R-113 or Fluorinert FC-75 is constantly poured into the gap 22 of the cooling panel 6 using the pump 7.
This is done by making the coil 5 take away the heat generated within the winding. The coolant 15 that has absorbed the heat is sent out to the outside of the winding through the outlet nozzle 19J, and is sent to the outside of the tank 8 for cooling. 9
It is cooled in the cooling panel 19 and fed into the cooling panel 6 again.

Note that the refrigerant 15 is once collected in the fruit pipe 10 before being sent to the cooling panel 6, but since the liquid collection pipe 10 maintains the same ground potential as the tank 8, etc., it is not connected to the metal sheet 2. Connection with the cooling panel 6 having the same potential is made via an insulating pipe 11.

On the other hand, the cooling panel 6 is made of the metal sheet 2 or the insulating sheet 3 in order to cool the windings by thermal conduction, as described above.
Furthermore, since the cooling panel 6 is wrapped in the winding, almost the same potential is applied to the cooling panel 6, and the insulation between the metal sheet 2 and the cooling panel 6 and the outside is as follows. This is done using an insulating gas sealed in the tank 8, such as sulfur hexafluoride (SF6 gas).

Furthermore, since the refrigerant inlet/outlet portion 14.18 of the cooling panel 6 wound up in the winding is provided to protrude from the end of the winding, an electric field is concentrated near this refrigerant inlet/outlet portion 14.18. This is likely to occur, and in order to prevent this, an electric field mitigation shield (not shown) is attached near the refrigerant inlet/outlet portion 14, 18.

In addition, stainless steel is used as the material for the cooling panel 6 built into the winding of the foil-wound transformer in order to prevent a large amount of current from flowing due to linkage leakage flux. That is, two stainless steel plates with a thickness of about 1 mm are used as the component plate 20 in FIG.
The surrounding area is solidified by welding and is shaped like a bag. A large number of band-shaped spacer plates 21 as shown in FIG.
A gap of about m is provided.

The foil-wound transformer described above is called a separate foil-wound transformer because the circulation circuit through which the refrigerant for cooling flows and the insulating gas are completely separated, and it is called a separate foil-wound transformer. Compared to transformers that use conductors, they have the advantage of being significantly smaller and lighter, and have higher insulation reliability.

By the way, in the foil-wound transformer with the above configuration,
When an excessive current flows due to an external short circuit, a radial electromagnetic mechanical force as shown by the arrow 23 in FIG. An electromagnetic mechanical force is generated. In this case, an excessive and rapid compressive force acts on the portion of the cooling panel 6 where the windings 4 and 5 are inserted, and the cooling panel 6 is forced into the gap 2 through which the refrigerant 15 flows.
2 is suddenly deformed by being crushed. In response to this sudden deformation of the cooling panel 6, the refrigerant 15 in the cooling panel 6 tries to flow out to the outside of the winding through the introduction nozzle 16 and the outlet nozzle 19, but
Since the cross-sectional area of the inlet/outlet nozzle 16° 19 is very small, the outflow to the outside cannot follow the sudden deformation of the cooling panel 6, resulting in a sudden pressure rise. If such a sudden pressure increase occurs, the introduction nozzle 16 and outlet nozzle 19 provided at the upper and lower ends of the cooling panel 6 may be deformed by the flowing refrigerant, or the refrigerant inlet section 14 and refrigerant outlet section 18 may be damaged. There was a risk of damage at the welded parts, etc., which was a problem. Furthermore, since the insulated pipes connected to the inlet and outlet nozzles 16 and 19 are generally made of metal materials, their strength is low.
There was a problem with the damage.

(Problems to be Solved by the Invention) As described above, in conventional foil-wound transformers, the cooling panel is deformed by the electromagnetic mechanical force generated in the event of an external short circuit accident, causing damage to the inlet and outlet nozzles. There were problems that could arise.

The present invention was proposed in order to solve the problems of the prior art, and its purpose is to prevent deformation and deformation even in response to excessive and sudden radial type f11 mechanical force that occurs during an external short circuit accident. It is an object of the present invention to provide a highly reliable foil-wound transformer having a cooling panel that can withstand sufficient resistance without being damaged.

[Configuration of the invention].

(Means for Solving the Problems) The foil-wound transformer of the present invention has an expansion chamber extending through a partition wall to the refrigerant nozzle and outlet nozzle provided at the upper and lower ends of the cooling panel, and The structure is characterized in that a rupture disc that ruptures at a pressure lower than the allowable pressure of the nozzle body is used as the partition wall.

(Function) In the foil-wound transformer of the present invention having the 414 configuration as described above, an excessive and sudden radial type i.f.
When the cooling panel is deformed due to the generation of mechanical force and the refrigerant pressure inside the cooling panel rises rapidly, the rupture disc, which has a lower allowable pressure than the nozzle body, breaks and the refrigerant that flows out expands. Flows into the clothing seedlings. Therefore, a sudden increase in refrigerant pressure can be absorbed in the expansion chamber, so that excessive refrigerant pressure is not applied to the inlet nozzle and the outlet nozzle, and deformation and breakage of both nozzles can be prevented.

- (Example) An example of the foil-wound transformer according to the present invention as described above will be specifically described with reference to the drawings. Note that the same members as those in the prior art shown in FIGS. 3 to 5 are designated by the same reference numerals, and explanations thereof will be omitted.

Structure of this embodiment In the embodiment shown in FIG. 1, the refrigerant introduction nozzle 16 and the introduction nozzle 19 provided at the upper and lower ends of the cooling panel 6 each have an expansion chamber 32 separated by a rupture disc 31. It has been extended. Here, the rupture disc 31 is made of a material, has a thickness dimension, or is processed such that it will rupture at a pressure lower than the permissible pressure of the main bodies of the introduction and extraction nozzles 16 and 19.

Note that the configuration other than the cooling panel is the same as that of the prior art shown in FIG. 3.

Effect of this embodiment* In the foil-wound transformer of this embodiment having the above-described configuration, the cooling panel 6 is deformed due to the generation of excessive and sudden radial electromagnetic mechanical force in the event of an external short circuit accident, and the cooling panel 6
Even if the refrigerant pressure within the nozzle suddenly rises and the refrigerant 15 flows out from the main body of the cooling panel 6 as shown in FIG. It flows into the expansion chamber 32. Therefore, a sudden increase in refrigerant pressure can be absorbed in the expansion chamber 32, which prevents excessive refrigerant pressure from being applied to the inlet nozzle 16 and the outlet nozzle 19 as in the prior art, thereby preventing deformation of both nozzles. Furthermore, there is no chance of breakage at the welded portions between the refrigerant inlet and the outlet 14.18. Furthermore, since excessive refrigerant pressure is not applied to the insulated pipe 11 connected to the inlet and outlet nozzles 16 and 19, the problem of damage to the insulated pipe 11 is also eliminated.

*Other Examples* In the present invention, the shape, dimensions, etc. of the introduction and outlet nozzles and the expansion chamber extending to each nozzle can be selected as appropriate. In addition, since the purpose of the present invention is to improve the cooling panel part in particular, there is no limitation such as, for example, the constant 1'8 of the transformer.
It can be widely applied to general foil-wound transformers of the separator type that have a built-in cooling panel.

[Effects of the Invention] As described above, according to the present invention, a simple configuration is achieved in which an expansion chamber is extended to the refrigerant introduction and outlet nozzles provided at the upper and lower ends of the cooling panel via a rupture disc. Through this improvement, the cooling panel can be made to have excellent durability that will not cause deformation or damage even under the excessive and sudden radial electromagnetic mechanical force that occurs in the event of an external short circuit accident, resulting in improved reliability. We can provide high quality foil-wound transformers.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a cooling panel used in an embodiment of the foil-wound transformer of the present invention, FIG. 2 is an enlarged plan view showing a refrigerant outlet nozzle of the cooling panel in FIG. 1, and FIG. FIG. 4 is a plan view showing a cooling panel of a conventional foil-wound transformer, and FIG. 5 is a partially enlarged perspective view of FIG. 4 without showing the cooling panel. DESCRIPTION OF SYMBOLS 1... Iron core leg, 2... Metal sheet, 3... Insulating sheet, 4... Low voltage winding, 5... High voltage winding, 6...
Cooling panel, 7...pump, 8...tank, 9...
・Cooler, 10..., liquid collection pipe 1.11...insulated pipe, 12...welded part, 13...refrigerant inlet part, 15
... Refrigerant, 16 ... Introduction nozzle, 17 ... Channel section, 18 ... Refrigerant outlet section, 19 ... Lead-out nozzle, 2
0... Cooling panel component board, 21... Spacing plate, 22.
... Gap, 23... Direction of radial electromagnetic mechanical force generated during an external short circuit accident, 31... Rupture disk, 32... Expansion chamber.

Claims (1)

[Claims] A metal sheet and an insulating sheet are layered and wound around an iron core to form a low-voltage winding and a high-voltage winding, and a cooling panel for refrigerant circulation is built into the winding along the axial direction of the winding. In a foil-wound transformer in which a high-voltage shield is formed at the end of the winding to constitute the contents of the transformer, and the contents of the transformer are housed in a tank filled with an insulating medium, the upper and lower ends of the cooling panel are An expansion chamber is provided in the provided refrigerant introduction nozzle and outlet nozzle through a partition wall, and a rupture disc that ruptures at a pressure lower than the permissible pressure of the nozzle body is used as the partition wall. foil-wound transformer.