JPH0218912A - Foil wound transformer - Google Patents

Abstract

PURPOSE:To obtain a compact and inexpensive foil wound transformer having a small eddy current loss generated in a winding in addition to an eddy current loss generated in a tank, high quality and high performance by composing the tank of good conductive metal such as aluminum or the like. CONSTITUTION:A transformer body in which a metal sheet 2 and an insulation sheet 3 are superposed and wound on a core 1 is contained in a tank 8b sealed with insulating medium, and the tank 8b is composed of good conductive metal such as aluminum or the like. Accordingly, a leakage magnetic flux 12 is repelled by the tank 8b, a magnetic flux incident to the tank 8b is reduced, loss generated in the tank 8b is decreased, and a leakage magnetic flux is scarcely leaked outside the winding even at an outer winding 5. Thus, the eddy current loss generated in the tank is reduced, an overheat is prevented, and the eddy current loss generated in the winding can be simultaneously decreased.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a foil-wrapped transformer in which a metal sheet and an insulating sheet are layered and wound around an iron core and housed in a tank filled with an insulating medium. Concerning vessels.

(Prior art) Sheet-shaped windings conventionally used in foil-wound transformers are
Excellent winding space factor, good potential distribution,
Although it has been widely used because it is easy to manufacture, it has been limited to relatively small capacity transformers.

However, in order to realize higher-voltage, larger-capacity transformers, it is essential to further improve the cooling efficiency of the windings and provide the windings with high insulation ability. It has been considered to incorporate a cooling panel through which a refrigerant flows inside, so that the heat generated from the windings can be directly cooled.

Examples of this type of transformer include JP-A-54-16861.
No. 3 is known. This transformer consists of a metal sheet 2 and an insulating sheet 3 surrounding an iron core leg 1, as shown in FIG.
The winding wire is formed by overlapping and winding the wires, and the wire is stored in the tank 8a. Further, the tank 8a is generally made of a structural metal such as mild steel. This winding consists of an inner winding 4 and an outer winding 5, and an annular cooling panel 6 is built into each of these windings. The cooling panel 6 is composed of an introduction nozzle for feeding refrigerant, an outlet nozzle for sending out the refrigerant, and a cooling panel main body which is a flow path for the introduced refrigerant.

The cooling panel 6 is made up of two metal plates stacked one on top of the other with a narrow gap for the coolant to flow, and the periphery of the two metal plates is sealed by welding or the like. A refrigerant such as Freon R-113 or Fluorinert FC-75 is constantly poured into the vXrJJ of this cooling panel 6 using a pump 7, and the refrigerant is used to remove the heat generated within the foil-wound winding, thereby achieving cooling. The refrigerant that has absorbed the refrigerant is sent out from the outlet nozzle to the outside of the winding, cooled in a cooler 9 provided outside the tank 8a, and sent into the cooling panel 6 again.

In addition.

Before the refrigerant is sent to the cooling panel 6, it passes through the liquid collecting pipe 10.
However, since this liquid collecting pipe 10 holds the same earth potential as the tank 8a etc., the connection between the metal sheet 2 and the cooling panel 6 having the same potential is made through the insulating pipe 11. It is. The cooling panel 6 is made of metal sheet 2
In order to cool it by heat conduction, it is in contact with the metal sheet 2 or the insulating sheet 3, and since the cooling panel 6 is wrapped around the winding, almost the same voltage is applied to the cooling panel 6, and this The metal sheet 2 and the cooling panel 6 are insulated from the outside by an insulating gas such as sulfur hexafluoride (sFs) sealed in the tank 8a.

The foil-wound transformer described above has advantages over conventional transformers using rectangular wire-shaped conductors, such as being able to be significantly smaller and lighter, and having higher insulation reliability.

(Problems to be Solved by the Invention) In the foil-wound transformer having the above configuration, as the capacity of the transformer increases, the amount of leakage magnetic flux from the windings 4 and 5 increases, and the windings 4 and 5 themselves A large eddy current loss is generated in the mild steel tank 8a, causing local overheating. The occurrence of eddy current loss due to this leakage magnetic flux will be explained with reference to FIG. Winding 4
, 5 leaks from the winding to the insulating space 13.
, making a loop through tank 8a.

When the leakage magnetic flux 12 enters the tank 8a, an eddy current flows in the tank 8a in a direction that cancels the leakage magnetic flux 12. However, since structural metals such as mild steel have high electrical resistance, the tank 8a
A large eddy current loss occurs within a.

On the other hand, eddy current loss also occurs in the metal sheet 2 that constitutes the winding. The leakage magnetic flux 12 tries to create a loop across the metal sheet 2 using the shortest magnetic path (minimum magnetic energy), but since the vertical width of the metal sheet 2 is large, the metal sheet 2
An eddy current flows in a direction that cancels the inward leakage of the magnetic flux 12 in the radial direction. This eddy current is particularly concentrated at the upper and lower ends of the metal sheet 2 and causes a large loss. This phenomenon is more noticeable in a foil-wound transformer using a sheet-shaped conductor because the width of the conductor is wider than in a transformer using a conventional rectangular conductor. This loss not only risks causing local overheating of the windings, but also increases the number of cooling panels needed to cool the windings, leading to increased costs and larger windings.

The present invention was made in consideration of the above drawbacks, and its purpose is not only to reduce the eddy current loss generated in the tank and prevent local overheating, but also to reduce the eddy current loss generated in the winding. Our objective is to provide a high quality, high performance, compact and inexpensive foil-wound transformer with reduced cost.

[Structure of the invention]

(Means for Solving the Problems) The foil-wound transformer of the present invention has a tank made of a highly conductive metal such as aluminum.

(Function) By configuring the tank with a highly conductive metal, the foil-wound transformer of the present invention electromagnetically repels winding leakage magnetic flux as if it were an electromagnetic shield, thereby reducing eddy current loss generated in the tank. This prevents overheating and at the same time reduces eddy current loss generated in the windings.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 and 2. Incidentally, the same members as those of the conventional type shown in FIGS. 3 to 4 are given the same reference numerals, and explanations thereof will be omitted.

In this embodiment, as shown in FIG. 1, a transformer main body in which a metal sheet 2 and an insulating sheet 3 are wound around an iron core 1 is housed in a tank 8b filled with an insulating medium. The tank 8b is made of a highly conductive metal such as aluminum.

In the foil-wound transformer of this embodiment having such a configuration, as shown in FIG.
is repelled, the magnetic flux incident on the tank 8b decreases,
The loss occurring in the tank 8b is also reduced.

This prevents local overheating of the tank. Also, the leakage magnetic flux 12 is repelled by the tank 8b.

Particularly in the outer winding 5, leakage magnetic flux is less likely to leak to the outside of the winding. This reduces the amount of current that flows in the direction that cancels out the leakage of magnetic flux in the radial direction.

Accordingly, the generated eddy current loss is also reduced. Additionally, the weight can be reduced compared to conventional mild steel tanks.

〔Effect of the invention〕

As described above, according to the present invention, by constructing the tank with a highly conductive metal such as aluminum, not only the eddy current loss generated in the tank but also the eddy current loss generated in the winding wire is reduced. , it is possible to provide a high-performance, compact, and inexpensive foil-wound transformer.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the foil-wound transformer according to the present invention, Fig. 2 is an enlarged view of the main parts to show its operation, and Fig. 3 is a cross-sectional view showing the configuration of a conventional foil-wound transformer. FIG. 4 is an enlarged view of the main part to show its effect. 1... Iron core 2... Metal sheet 3...
・Insulating sheet 4...Inner winding 5...Outer winding 8a...Mild steel tank 12...Leakage magnetic flux 8b...Aluminum tank Agent Patent attorney Noriyuki Chika Yudo Daishimaru Ken 1st figure 2nd figure 2nd figure

Claims (1)

[Claims] A foil-wound transformer comprising a metal sheet and an insulating sheet wound around an iron core, and housed in a tank filled with an insulating medium, characterized in that the tank is made of a highly conductive metal. vessel.