JPS61160917A - Foil wound transformer - Google Patents

Abstract

PURPOSE:To support windings reliably and to prevent the windings from slackening, vibrating and slipping down, by providing with neck portions at cooling duct ends extruded in the winding stacking direction, and by supporting direct the cooling ducts by the aid of the neck portions. CONSTITUTION:At the upper and bottom ends of cooling ducts 6 extruded in the winding stacking direction, cooling duct neck portions 15 are provided, which are supported with supporting insulators 16 from above or below them. The cooling duct neck portions 15 which are hollow are connected to coolant conduits 11 through insulating pipes to form coolant pathes between the conduits 11 and cooling ducts 6. The plural cooling ducts 6 are provided by one every several turns. Thus since the neck portions 15 by which the cooling ducts 6 are direct supported are provided at the cooling ducts 6 with a strong flexibility, sufficient mechanical strength can be attained, the winding end sections are not deformed and the cooling ducts are fixed forcibly, so that there is no fear that slackening, vibrating and slipping-down of the windings may result.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a foil-wound transformer in which a metal sheet and an insulating sheet are wound to form a foil winding, and a cooling duct is built in the foil winding. In particular, the present invention relates to a foil-wound transformer with an improved winding support structure.

[Technical pre-invention! ] Foil-wound transformers have a good space factor, so they can be made smaller and lighter. For this reason, small-capacity transformers with relatively low voltages of several KV and several hundred KVA have already been put into practical use and are now widely available on the market.

Recently, in view of its excellent advantages, research has been conducted to expand its application to higher voltage and larger capacity transformers, for example, 275 KV and 300 MVA. Achieving this expanded application depends on how the cooling capacity can be improved and the windings can be provided with high insulation capacity.

Although such high-voltage, large-capacity transformers have not yet been put to practical use, foil-wound transformers, which are already known and are currently being researched, have cooling ducts built into the windings and have excellent insulation properties. There is a so-called heat pipe type in which heat generated from winding loss is directly cooled by feeding refrigerant into the winding.

Figure 3 shows the basic configuration of such a foil-wound transformer. In the figure, 1 is a core leg, 2 is a metal sheet, and 3 is an insulating sheet, which are wound coaxially with the core leg 1 to form a low-voltage winding 4 and a high-voltage winding 5. A cooling duct 6 is wound inside each of the windings 4 and 5, and a refrigerant such as a fluorocarbon liquid is flowing inside the cooling duct 6.

This refrigerant is circulated by a pump 7, absorbing heat generated within the windings by the latent heat of evaporation of the refrigerant, and the vapor is cooled and condensed in a condenser 8 through a cooling water pipe 9. The liquefied refrigerant is stored in a refrigerant tank 10, and is further fed into the windings by a pump 7.

The refrigerant pipe line 11 constituting this refrigerant circulation cooling circuit is made of metal such as stainless steel, and this cold Is pipe line 11
and the cooling duct 6 are connected by an insulated pipe 12, and the refrigerant pipe line 11 is also connected to the ground potential of a tank 13 and the like. On the other hand, since the cooling duct 6 is built into the winding, it is electrically connected to the same potential as the adjacent winding. Each part of the winding is insulated by an insulating medium 14 such as insulating oil or SFs gas sealed in a tank 13.

[Problems with Background Art] However, the conventional foil-wound transformer as described above has the following problems.

In other words, in the conventional small-capacity, low-voltage foil-wound transformer,
Since the winding build is small and therefore the mountain and river are small, it can support its own weight by the winding force of the winding. For this reason, in conventional foil-wound transformers, a special support structure is not provided to support the windings in order to avoid complicating the structure and increasing the size of the image, and the windings are only supported by the winding force. was supporting.

However, in high-voltage, large-capacity transformers, the winding build stack becomes large, and therefore the dead weight increases significantly, so especially in the center of the winding where winding force is difficult to act, the same part becomes loose. In addition, the vibration of the winding increases due to the thermal expansion of the winding due to the operation of the transformer or the decrease in tension due to deterioration. There is a risk that the windings may slip off, which has been a problem.Therefore, high voltage, large capacity foil-wound transformers are required to have a special structure to support the windings.

In view of these problems, a method has been proposed in which the lower part of the winding is directly supported. For example, a method has been proposed in which a reinforcing insulating layer is attached to the ends of the windings, as seen in Jikoko 1963-1969, but in the stacking direction of the windings, the insulating sheets protrude more than the metal sheets. Therefore, if the winding is directly supported from below, the ends of the winding will be deformed, and this method is also difficult. Moreover, the windings include a cooling duct, which is several times to several tens of times thicker than the metal sheet or insulating sheet. Due to the need to maintain a hollow space for water to flow and to withstand the pressure of the enclosed gas, strong rigidity is often lost, so it cannot be deformed, and therefore cannot withstand the winding tightening force. Furthermore, gaps are likely to form between the cooling duct and the windings. Therefore, loosening and slipping of the windings are more likely to occur in the cooling duct portion.

Therefore, a special support structure is required for high voltage, large capacity foil-wound transformers such as those described above.

[Object of the Invention] The present invention has been proposed in order to eliminate the drawbacks of the prior art as described above, and its purpose is to support the winding wire more reliably, thereby reducing the loosening of the winding wire.

It is an object of the present invention to provide a foil-wound transformer which prevents vibration and slippage.

[IIA Summary of the Invention] The foil-wound transformer of the present invention has a cooling duct neck provided in a portion protruding in the direction of the winding stack, and the cooling duct 1- is directly supported through the cooling duct neck. According to
By fixing a highly rigid cooling duct, sufficient mechanical strength can be obtained and the windings can be supported reliably.

[Embodiment of the Invention] An embodiment of a foil-wound transformer according to the present invention will be described below with reference to FIGS. 1 and 2. Note that parts that are the same as those in the prior art are denoted by the same reference numerals, and description thereof will be omitted.

First, in FIG. 1, cooling duct necks 15 are provided at the upper and lower parts of the cooling duct 6 that protrude in the winding stack direction, and each cooling duct neck 15 is supported by a support insulator 16 from above or below, respectively. It is being

The cooling duct neck 15 is hollow and connected to the refrigerant pipe line 11 via the insulating vibrator 12 to form a refrigerant flow path between the cooling duct neck 15 and the cooling duct 6 . On the other hand, since the cooling duct 6 is built into the winding, it is electrically connected to the same potential as the adjacent winding. This cooling duct 6 is provided in multiple layers every few turns.

In addition, as shown in the cross-sectional view of the winding in FIG.
6d are inserted in order.

The operation of this embodiment having the above configuration is as follows. That is, the cooling duct neck 1 is attached to the highly rigid cooling duct 6.
5 and directly supports the cooling duct 6 via the cooling duct neck 15, an excellent winding support structure with sufficient mechanical strength can be obtained. According to this structure, there is no disadvantage of deforming the ends of the winding unlike when supporting at the bottom of the winding, and by firmly fixing the cooling duct,
The winding can be supported reliably, and there is no fear that the winding will loosen, vibrate, or fall off.

In addition, when inserting a divided cooling duct, in Fig. 2, for example, 6a and 6b have the same potential, so they can be supported by the same support insulator, which avoids complicating the support structure. 6X.

In particular, in this embodiment, main parts are provided above and below for one cooling duct and the cooling duct is supported from above and below, so that the windings can be held sufficiently even against mechanical forces such as short circuits.

It should be noted that the present invention is not limited to the above-mentioned embodiments. For example, a structure may be adopted in which only the upper part or only the lower part of the cooling duct is supported, and in that case, the structure can be simplified. Conversely, if two or more necks are provided at the top and bottom of the cooling duct, and the cooling duct is supported at multiple locations,
Mechanical strength can be further improved.

Further, in the above embodiment, the cooling duct neck is used as it is as a refrigerant flow path, but in the present invention, a cooling duct neck that is not a refrigerant flow path may be provided to support the cooling duct.

By the way, since the cooling duct 1- used in the present invention cools the heat of the windings by heat transfer, it is appropriate to use a material with excellent thermal conductivity, and a metal material is generally used. The cooling tact neck provided outside the windings does not contribute to the cooling effect of the windings, so if it is made of insulators,
This cold section duct neck may be made of an insulator. When the neck of the cooling duct is made of an insulating material, it is possible to easily realize a configuration in which the neck of the cooling duct is supported between the core legs or a point having a ground potential.

[Effects of the Invention] As explained above, according to the present invention, the cooling duct is provided with a neck of the cooling duct and the neck of the cold section is supported, thereby providing stable winding support with excellent mechanical strength. Since the structure can be obtained and the winding can be reliably supported by this support structure, it is possible to provide a foil-wound transformer that can prevent loosening, vibration, and slippage.

[Brief explanation of drawings]

1 and 2 are a cross-sectional view and a cross-sectional view, respectively, showing an embodiment of a foil-wound transformer according to the present invention, and FIG. 3 is a cross-sectional view showing an example of a conventional foil-wound transformer. DESCRIPTION OF SYMBOLS 1... Iron core leg, 2... Metal sheet, 3... Insulating sheet, 4... Low voltage winding, 5... High voltage winding, 6...
・Cold part duct, 7...Pump, 8...Condenser, 9.
... Cooling water pipe, 10 ... Refrigerant tank, 11 ... Refrigerant pipe line, 12 ... Insulated pipe, 13 ... Tank, 14
...Cooling medium, 15...Cooling duct neck, 16...
・Support insulator. 7317 Agent Patent Attorney Kensuke Chichi (1 other person) Figure 1 Figure 2

Claims (6)

[Claims] (1) In a foil-wound transformer in which a metal sheet and an insulating sheet are wound in a tank to form a foil winding, and a cooling duct is built inside the foil winding, the direction of the winding stack of the cooling duct is A foil-wound transformer characterized in that a cooling duct neck is provided in a protruding portion, and the cooling duct neck is supported by a supporting insulator. (2) The foil-wound transformer according to claim 1, wherein the cooling duct neck is a flow path for the refrigerant of the cooling duct. (3) The foil-wound transformer according to claim 1, wherein the cooling duct is provided with a plurality of cooling duct necks at the upper part, the lower part, or both sides thereof. (4) The foil-wound transformer according to claim 1, wherein the cooling duct is provided with one or more cooling duct necks that are not refrigerant flow paths at the upper or lower part or on both sides thereof. (5) The foil-wound transformer according to claim 1, wherein the neck portions of the cooling ducts are supported by the same support insulator so that the neck portions have the same potential. (6) The foil-wound transformer according to claim 1, wherein the cooling duct neck is formed of an insulating material.