JPH04372B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a foil-wound transformer in which a cooling panel is built into a winding formed by overlappingly wound a foil conductor and an insulating sheet.

[Technical Background of the Invention] Foil-wound transformers, in which metal foil is wound around the core leg to form a foil winding, have a good space factor for the wrapped conductor, so it is not possible to use ordinary wire conductors. It has the characteristics of being smaller and lighter than conventional transformers.

However, in order to realize higher-voltage, larger-capacity transformers, it is essential to further improve the cooling ability of the windings and to provide the windings with high insulation ability. It has a built-in cooling panel through which refrigerant flows, and is configured to directly cool the heat generated from the windings.

This conventionally proposed foil-wound transformer has a winding formed by overlapping and winding a foil conductor 2 and an insulating sheet 3 on the outside of an iron core 1, as shown in FIG. 1, for example. This winding consists of a low voltage winding 4 and a high voltage winding 5, and an annular cooling panel 6 is built in each of these windings. This cooling panel 6
As shown in FIG. 2, it is comprised of an introduction nozzle 7 into which liquefied refrigerant enters, an outlet nozzle 8 through which this refrigerant 12 exits, and a flow path section 9 for the introduced refrigerant.

Inside the flow path portion 9, as shown in FIG. 3, a large number of thin ribs 10 are provided as spacers for maintaining the panel 6 and this panel at a predetermined distance. In the long and narrow gap 11 formed by providing this rib 10, the Freon R-
A refrigerant 12 such as 113 or Fluorinert FC-75 is constantly supplied by a pump 13, and the refrigerant 12 removes the heat generated within the foil-wound winding, thereby cooling the coil. The refrigerant 12, whose temperature rises and is partially vaporized by absorbing this heat, is sent out to the outside of the winding through the outlet nozzle 8, and is cooled by the cooling water 15 in the cooler 14 provided outside the tank 18. ,
It becomes liquid again and is sent into the cooling panel 6 again. In addition, the refrigerant that has been cooled by the cooling water and liquefied again is sent to the liquid collecting pipe 16 made of metal such as stainless steel before being sent to the cooling panel 6.
The liquid collection pipe 16 is connected to the tank 18.
An insulating pipe 17 is provided in the middle to connect to the cooling panel 6 which has the same potential as the foil conductor 2 and the same potential as the foil conductor 2. The cooling panel 6 is in contact with the foil conductor 2 in order to cool the foil conductor 2 by thermal conduction, and the cooling panel 6
is wound up in the winding, substantially the same voltage is applied to the cooling panel 6, and insulation between the foil conductor 2 and the cooling panel 6 and the outside is provided by an insulating conductor sealed in the tank 18, for example. This is done using an insulating gas 19 such as sulfur fluoride (SF ₆ ).

The foil-wrapped transformer described above uses refrigerant 1 for cooling.
It is called a separate foil-wound transformer because the circulation circuit through which the gas 2 flows and the insulating gas 19 are completely separated, and it is significantly smaller and smaller than a conventional transformer using a wire conductor. It has advantages such as being lightweight and having high insulation reliability.

[Problems in the Background Art] By the way, preventing local heating is the most important issue in improving the reliability of this type of separate foil-wound transformer, and therefore it is necessary to keep all parts of the windings at a constant temperature. It is necessary to maintain it. In order to maintain the entire winding at a predetermined temperature or lower, it is required to delicately adjust the cooling effect according to the amount of heat generated in each part of the winding. This adjustment can be achieved by changing the flow rate of the refrigerant, but it is therefore necessary to finely adjust the flow rate by appropriately arranging ribs within the panel. However, in the past, no consideration was given to the flow velocity distribution within the cooling panel 6, and the ribs disposed within the cooling panel 6 were simply arranged in parallel at equal intervals, ignoring the flow velocity. The placement was merely a suggestion.

However, with such a rib arrangement, the flow of the refrigerant 12 stagnates in the center of the cooling panel 6 and the flow speed is delayed, as shown in the flow velocity distribution graph in FIG. As a result, there was an inconvenience in that the cooling effect was uneven.

If the flow velocity locally becomes uneven during cooling by the refrigerant 12, the cooling effect in this area decreases, causing local heating of the foil-like conductor in the vicinity, and this heat generation damages the insulating sheet and causes the windings to deteriorate. The wires were exposed and adjacent windings were shot, resulting in shot between turns, which could lead to serious accidents such as fire.

[Object of the Invention] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to average the flow of refrigerant in the cooling panel so as to match the heat generation distribution of the foil conductor, and to improve the flow of the winding. An object of the present invention is to provide a foil-wound transformer with high cooling efficiency that prevents local temperature increases.

[Summary of the Invention] The foil-wound transformer of the present invention has a plurality of parallel ribs provided in the cooling panel, and the distance between the ends of the ribs and the end on the side of the cooling panel extends from the vicinity of the cooling panel inlet and outlet to the inner part. By forming triangular liquid separating parts and collecting parts between the refrigerant inlet/outlet part and the flow path between each rib, the flow velocity distribution of the refrigerant in the cooling panel is averaged. It has been transformed into

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to FIG. 6.

In this embodiment, a large number of ribs 10 extending parallel to the lateral direction of the panel are provided at equal intervals in the cooling panel 6, and a flow path 2 is provided between each rib 10.
0 is formed. Introduction nozzle 7 of each rib 10
The side edges are located at a position farther away from the side edge 6a of the cooling panel 6 as the rib 10 at the bottom of the cooling panel is closer to the introduction nozzle 7, and the introduction nozzle is located between the introduction nozzle 7 and the end of each rib 10. A triangular liquid separating portion 21 is formed with the 7 side widened. Therefore, at the entrance portion of each channel 20, the end of the rib on the deep side of the panel protrudes beyond the rib on the introduction nozzle side, and this protrusion serves as the guide plate 20a to the channel 20.
It is becoming.

On the other hand, on the outlet nozzle 8 side of the cooling panel 6, the end of each rib 10 is located at a position farther from the side edge 6a of the cooling panel 6 as the rib is closer to the outlet nozzle 8. A triangular liquid collecting portion 22 with widened sides is formed.

Here, each rib 1 on the introduction nozzle 7 side
Each rib 10 is formed such that the line _l1 connecting the end of the rib 0 and the line _l2 connecting the end of the rib on the outlet nozzle 8 side are both straight and parallel. .

In the foil-wound transformer of the present invention having such a configuration, the refrigerant 12 that has flowed into the cooling panel 6 first flows from the introduction nozzle 7 toward the liquid separating section 21, and then flows through each channel subdivided by the ribs 10. The water is divided into 20 parts evenly.

At this time, the inflowing refrigerant 12 is guided by the guide plate 20a that protrudes toward the inner part of the flow path 20, and the refrigerant 12 flows into each flow path 20.
The flow is divided evenly between each part. Moreover, since the liquid separation part 21 has a triangular shape that becomes narrower toward the inner part, the refrigerant flowing from the introduction nozzle 7 sequentially flows into the flow path 2.
Since the inflow pressure is not concentrated only in the deep channel 20, the flow is effectively divided into all the channels without stagnation.

On the other hand, on the outlet nozzle side of the cooling panel, the flow path 2
Since the width of the liquid collection part 22 is wider on the outflow side where the amount of confluence of 0 is larger, the refrigerant 12 flowing out from the flow path between each rib 10 does not collide at the outlet of the flow path 20. , effectively merge and are promptly discharged from the outlet valve 8.

In this way, in this embodiment, the refrigerant 12 evenly flows through each channel 20 throughout the cooling panel 6, and as shown in FIG. The flow velocity at this point is significantly increased compared to the conventional example shown in FIG. 5, and a flow velocity distribution matching the heat generation distribution of the winding is formed. Therefore, since the cooling effect of the windings is uniformly exhibited, it is possible to eliminate temperature rise due to local insufficient cooling, and it is possible to realize a highly reliable foil-wound transformer with uniform cooling characteristics. can.

[Effects of the Invention] As described above, according to the present invention, the refrigerant flows over the entire surface of the cooling panel without stagnation, and the flow rate per unit time is constant in accordance with the heat generation distribution of the winding. This has the effect of preventing a local temperature rise in the wire and improving cooling efficiency. As a result, it is possible to provide a highly reliable foil-wound transformer with uniform cooling characteristics.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the schematic structure of a conventional foil-wound transformer, Fig. 2 is a schematic perspective view showing a cooling panel constituting a conventional foil-wound transformer, and Fig. 3 is the same as Fig. 2. Fig. 4 is a schematic cross-sectional view showing the rib arrangement shape of a cooling panel constituting a conventional foil-wound transformer; Fig. 5 is a perspective view of a partially enlarged cross-section; Fig. 6 is a schematic sectional view showing the rib arrangement shape of the cooling panel constituting the foil-wound transformer of the present invention;
The figure is a graph of the liquid amount and position per unit time in the cooling panel according to the present invention. 1... Iron core, 2... Foil conductor, 3... Insulating sheet, 4
...Low voltage winding, 5...High voltage winding, 6...Cooling panel, 7
...Introduction valve, 8...Output valve, 10...Rib, 1
2...Cooling conductor, 13...Pump, 14...Cooler, 1
5... Cooling water, 18... Tank, 19... Insulating gas,
20... Channel, 21... Liquid separating section, 22... Liquid collecting section, l ₁ ,
l ₂ ...Rib end line.

Claims (1)

[Claims] 1 A number of parallel ribs are provided in the panel inside the winding, which is made by overlapping a foil conductor and an insulating sheet on the outside of the iron core, and a flow path for the refrigerant is formed between each rib. In a foil-wrapped transformer with a built-in cooling panel that circulates refrigerant, the distance between both ends of each rib and the edge of the cooling panel is such that the distance between the ends of each rib and the edge of the cooling panel becomes narrower toward the inner part from the refrigerant inlet/outlet part. A liquid separation part and a liquid collection part are formed between the entrance and exit part and each channel, and the back side of the panel is narrower, and the lines connecting the ends of each rib in the liquid separation part and the liquid collection part are in a straight line. A foil-wound transformer characterized by being formed in a parallel shape.