JPS5875816A - Leaf winding transformer - Google Patents

Abstract

PURPOSE:To prevent a local temperature rise, by subdividing the inside of a cooling duct into a plurality of coolant passages, particularly making the coolants in the adjacent coolant passages different in flowing direction from each other thereby to provide a large temperature difference between the adjacent coolants. CONSTITUTION:A leaf conductor 2 and an insulating sheet 3 are laid one on top of the other and wound on the outside of an iron core 1 to constitute a low- voltage winding 4 and a high-voltage winding 5. Annular cooling ducts 6 are provided in these windings. The ducts 6 are filled with a coolant 9, which is circulated through coolant-introducing pipes 7, a cooler 11, a pump 10 and the ducts 6. Each duct 6 has the inside thereof subdivided into a multiplicity of axial coolant passages 14, which are adapted to make the coolant flow through the adjacent coolant passages in the directions opposite to each other. Thereby, there is provided a large temperature difference between the outlets and inlets of the coolant passages; therefore, a circumferential heat conduction is caused in the windings, thereby making it possible to prevent a local temperature rise.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foil-wound transformer in which a cooling duct is built into a foil-like winding formed by overlapping a metal sheet and an insulating sheet, and the winding is cooled by flowing a refrigerant therein.

Traditionally, foil-wound transformers have a cooling duct built into the coil, into which a refrigerant with excellent insulation properties is pumped.

The structure of the winding layer, which is configured to cool the winding layers, will be explained with reference to FIG. A ring-shaped cooling duct 6 is built into the coiled body of the fluorocarbons.
The refrigerant 9 that has been heated to 114 + FC75 is fed by the pump 10 to remove the heat generated from the first layer. The refrigerant flows from the cooling duct to the external cooler 11, where it radiates heat, and then is sent again to the cooling duct inside the roll by the pump lO. The liquid guide pipe 7 is made of metal such as stainless steel, but an insulated pipe 8 is used to connect it to the cooling duct 6, and the cooling duct is insulated from the ground potential such as a tank tank and a zero-roll tank. is insulated by an insulating medium 13 such as insulating oil, 8F, or gas sealed in the tank.

Note that in FIG. 1, the winding lead wire and the bushing for extending the wire to the outside of the tank 11, which are not directly related to the present invention, are omitted.

This type of foil-wound transformer is particularly useful since the refrigerant for cooling is completely separated from the insulating medium for insulation.
Here, we will call it a separate foil-wound transformer.

Conventionally, the flow direction of the refrigerant in the cooling duct of such a separate winding transformer has been either axially as shown in Figure 2 (14) or circumferentially as shown in Figure 2(b). Figure #Ij (→, ( #
In particular, when a foil-wound transformer has a large capacity, the amount of heat generated from the winding layer is large, so the temperature rise of the refrigerant 9 in the cooling duct 6 becomes large. As a result, a large-angle temperature distribution occurs within the coil, and the temperature locally becomes high particularly near the refrigerant outlet, that is, above the coil. This reduces the insulation performance of the insulation sheet and causes the transformer to overheat, which inevitably increases the refrigerant flow rate, which in turn requires an increase in the power of the refrigerant pump (as shown in Figure 2 (b)). A similar situation can be seen when the refrigerant is flowed in the circumferential direction.The purpose of the present invention is to take the above-mentioned drawbacks into account, and to alleviate the temperature difference within the coil in a senko rate type foil-wound transformer. It is said to provide a foil-wound transformer with less temperature rise.

That is, the present invention subdivides the inside of the cooling duct into a plurality of refrigerant flow paths in a separate foil-wound transformer, and in particular, by making the flow directions of the refrigerant different in adjacent refrigerant paths, the cooling duct 1. Uniform the temperature distribution of the refrigerant inside. It sleeps because it suppresses the temperature rise inside the foil roll.

Hereinafter, one embodiment of the present invention will be described in detail using FIGS. 4 to 7.

The foil-wound transformer of the present invention may have the same structure as shown in FIG. 1 except for the cooling duct, so the details thereof will be omitted.

In the embodiment shown in FIG. 4, the inside of the annular cooling duct 6 is subdivided into a large number of axial refrigerant passages 14, and the refrigerant is flowed in mutually opposite directions into adjacent refrigerant passages. Arrows indicate the direction of refrigerant flow. In other words, there is a large temperature difference between the outlet and inlet of the refrigerant flow path, so if this structure is used, the refrigerants in adjacent refrigerant flow paths will have a large 1 degree difference near both ends of the roll, and the refrigerants within one roll will have a large temperature difference between them. A circumferential temperature distribution as shown in FIG. 5 occurs. This can generate circumferential heat conduction within the roll and prevent local temperature increases.

As explained above, if the foil-wound transformer according to the present invention is used, the temperature difference within the windings can be alleviated and local temperature increases can be prevented.As a result, the insulation performance of the insulating sheet decreases and the transformer overheats. This makes it possible to reduce the refrigerant flow rate and pump power.

In addition, in the foil-wound transformer of the present invention, the inside of the cooling duct is subdivided and the flow direction of the refrigerant is changed so that the refrigerant in adjacent refrigerant flow paths provided in the cooling duct has as large a local temperature difference as possible. As shown in FIG. 6, the axial passage 14 in the cooling duct 6 may be reversed at one end, or as shown in FIG. It may be configured by subdividing into 14 parts. Arrows indicate the direction of refrigerant flow.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a conventional foil-wound transformer. Figure 2 (4) is a diagram showing the flow of refrigerant in a conventional cooling duct, Figure 3 is a schematic diagram showing the axial temperature distribution in the conventional refrigerant and the coil, and Figure 4 is a diagram showing the flow of refrigerant in a conventional cooling duct. 5 is a schematic diagram showing the circumferential temperature distribution inside the roll in the embodiment of the present invention shown in FIG. 4, and FIGS.
The figure shows main parts of another embodiment of the present invention. 0 2... Wound layer, 3... Insulating sheet, 6...
cooling duct. 9... Refrigerant, 14... Refrigerant channel. Fig. 1 7b (lλ=2, m2
Figure 3 (skin) (b) N acupuncture 1 level of the hair body. Figure 4 Figure 5 TjIA Pharmacopoeia Figure 6 Figure 7

Claims (2)

[Claims] (1) A foil-wound transformer is characterized by an inner roll made of overlapping metal sheets and insulating sheets. (2) The foil-wound transformer according to claim 1, wherein the refrigerant flow paths are arranged adjacent to each other in different directions of flow of refrigerant.