JPH0430169B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a foil-wound transformer in which a cooling panel is built into a coil in which a foil conductor and an insulating sheet are wound in layers.

[Prior art and its problems]

Foil-wound transformers have a good space factor for the wrapped conductors, so
It has the advantage of being smaller and lighter than transformers that use wire conductors, but in order to be applied to higher voltage and larger capacity transformers, it is necessary to improve the cooling capacity of the coil and increase the insulation capacity. For this reason, a cooling panel through which a refrigerant flows is built into the coil, and the heat generated from the conductor of the coil is directly cooled.

As shown in FIG. 1, this kind of conventional foil-wound transformer has a coil body formed by overlapping and winding a foil conductor 2 and an insulating sheet 3 on the outside of an iron core 1, and this coil body consists of a low voltage coil 4. and a high-voltage coil 5, and an arc-shaped cooling panel 6 is built inside each of these coils. As shown in FIG. 2, this cooling panel is composed of a liquid introduction nozzle 7, a liquid outlet nozzle 8, and a parallel flow passage section 9. Inside it there is a third
As shown in the figure, thin ribs 10 are used as spacers.
A narrow gap 11 ensured by providing
By flowing a cooling medium 12 such as fluorocarbon into the coil using a pump 13, the heat generated in the foil-wound coil is removed and the coil is cooled. The cooling medium 12, whose temperature has increased by absorbing heat, is cooled by cooling water 15 in an external cooler 14, and is sent into the panel again. The liquid collection pipe 16 is made of metal such as stainless steel, and since an insulated pipe 17 is used to connect it to the cooling panel, the liquid collection pipe 16 has the ground potential of the tank 18 and the like.

On the other hand, the cooling panel and the foil conductor have almost the same potential because the cooling panel is wrapped in a coil, and insulation between them and the outside is provided by insulating SF ₆ gas19 sealed in the tank. I am treated well.

In FIG. 1, coil lead wires and bushings for drawing them out of the tank, which are not directly related to the present invention, are omitted for the sake of clarity.

The foil-wound transformer described above is called a separate foil-wound transformer because the circulation circuit through which the cooling medium flows and the insulating medium 19 are completely separated, and it is significantly smaller and smaller. Can be made lighter,
It has advantages such as high insulation reliability.

However, in this type of foil-wound transformer, current is concentrated at the upper and lower ends of the foil-wound conductor due to the eddy current effect, and heat is generated locally. In addition to this characteristic of foil-wound transformers, in conventional transformers, the ribs 20 in the cooling panel were arranged as shown in Figure 4, so the flow velocity distribution in the panel was significantly different from the heat generation distribution. It was not possible to prevent the local temperature rise.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to change the arrangement shape of the ribs so that the flow of the cooling medium in the cooling panel matches the heat generation distribution of the coil. The object of the present invention is to easily provide a foil-wound transformer that prevents local temperature increases in the coil and has high cooling efficiency.

[Summary of the invention]

In the present invention, a line connecting the ends of a large number of parallel ribs provided in a cooling panel forms a wedge-shaped liquid distribution part and a liquid collection part at the entrance and exit parts of the cooling panel, respectively, and the inclination of the line is the same as that of the cooling panel. By setting different values in the center and near the upper and lower ends, the flow velocity distribution of the cooling medium in the cooling panel is made to match the heat generation distribution of the coil, thereby achieving the above object.

〔Effect of the invention〕

According to the present invention, local temperature increases in the coil can be prevented and cooling efficiency can be increased.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 5 is a diagram showing the rib arrangement of a cooling panel constituting a foil-wound transformer according to an embodiment of the present invention. As shown in the figure, lines 23 connecting the ends of a large number of parallel ribs 22 provided in the cooling panel 21 form wedge-shaped liquid distribution portions 2 at the inlet and outlet portions of the cooling panel, respectively.
4. A liquid collection part 25 is formed, and the slope of the line is different between the central part 26 and the vicinity of both upper and lower ends 27 of the cooling panel, and the position change of the edge of the rib near both ends of the cooling panel is different from that in the central part. It's getting bigger. By arranging the ribs in the cooling panel in this way, the cooling medium supplied into the cooling panel will flow in large quantities to the top and bottom ends of the panel.
Absorbs locally generated heat caused by eddy current effects. This makes it possible to prevent a local temperature rise in the coil and easily provide a foil-wound transformer with high cooling efficiency.

FIG. 6 is a diagram showing another embodiment of the present invention.
As can be seen from the figure, there are three straight lines 28, 29, 30 for each of the inlet and outlet, which connect the ends of the many parallel ribs 22 provided in the cooling panel 21.
(28', 29', 30'), and the effect is similar to that of the embodiment shown in FIG.

In the above embodiment, the position of the ends of the parallel ribs 22 is arranged so that the flow rate (flow velocity) of the cooling medium near both ends of the cooling panel 21 is made larger than near the center of the cooling panel 21. The present invention is not limited to this, and the flow path resistance of the cooling medium flow path formed by the parallel ribs 22 may be set to be larger near the center of the cooling panel than that near both ends. The flow rate or flow velocity of the cooling medium near both ends of the cooling medium 21 may be made larger than that near the center.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a conventional foil-wound transformer, FIG. 2 is a diagram showing a cooling panel constituting a conventional foil-wound transformer, and FIG. 3 is a partially enlarged view of FIG. 2.
FIG. 4 is a diagram showing the rib arrangement of a cooling panel constituting a conventional foil-wound transformer, FIG. 5 is a diagram showing the rib arrangement of a cooling panel constituting a foil-wound transformer according to the present invention, and FIG. The figure is a diagram showing the rib arrangement shape of a cooling panel constituting a foil-wound transformer that is another embodiment of the present invention. 21... Cooling panel, 22... Rib, 23...
A line connecting the ends of the ribs, 24...Liquid distribution part, 25...
...liquid collection part, 26...panel center, 27...near the upper and lower ends.

Claims (1)

[Scope of Claims] 1. A foil-wound transformer having a built-in cooling panel in which a cooling medium flows inside a coil formed by wrapping a foil conductor and an insulating sheet in layers on the outside of an iron core, wherein: An inlet of the cooling panel is provided near both ends in the extending direction of the plurality of ribs provided.
The flow rate or flow velocity of the cooling medium in the vicinity of both ends of the cooling panel that forms a liquid distribution part and a liquid collection part that are connected to the outlet part and corresponds to a direction substantially perpendicular to the direction in which the ribs extend is determined in the central part of the cooling panel. A foil-wound transformer characterized by having a larger setting than that of the above. 2. A line connecting the ends of the ribs forms the liquid distribution section and the liquid collection section into a roughly wedge shape, and the slope of the line is different near the center of the cooling panel and near both ends, and the slope of the line is different near the center and both ends of the cooling panel. 2. The foil-wound transformer according to claim 1, wherein the change in position of the ends of adjacent ribs in the vicinity of the central portion is set to be larger than that in the vicinity of the central portion. 3. The foil-wound transformer according to claim 2, wherein the line connecting the ends of the ribs is a continuous curve. 4. The foil-wound transformer according to claim 2, wherein the lines connecting the ends of the ribs are composed of at least three straight lines.