JPS6231315B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric winding for a nuclear fusion device, and in particular, it is made up of a large number of windings of a conductor composed of a combination of a solid conductor and a hollow conductor, and the hollow conductor is connected to the outside. The present invention relates to an electrical winding for a nuclear fusion device formed by drawing out the wire.

Nuclear fusion devices that use magnetic fields to confine high-temperature, high-density plasma and extract heat from fusion reactions often require electric windings (hereinafter referred to as coils) that generate large magnetic fields in large spaces. Typically, a coil that generates a strong magnetic field has a structure with many turns and is excited by a large current. On the other hand, cooling the coil is essential for purposes such as reducing excitation power supply capacity and preventing insulation deterioration due to coil temperature rise. Generally, for this cooling, a method is adopted in which the conductor is made hollow and a cooling medium is circulated inside to directly cool the coil conductor. However, when a conductor with a large cross section is required for high current excitation, it is technically difficult to manufacture a hollow conductor with a large cross section, so a combination conductor of a hollow conductor and a solid conductor is used as the coil conductor. is normal.

This type of coil is shown in FIGS. 1 and 2.
As shown in the figure, a coil 1 has a solid conductor 3 and a hollow conductor 4.
However, in order to improve cooling characteristics, the thermal conductivity of the boundary layer between the two must be high, and a structure is adopted in which the solid conductor 3 and the hollow conductor 4 are integrated with a solder layer 5 or the like. The combined conductor of the solid conductor 3 and the hollow conductor 4 is insulated by an interlayer insulating layer 6, and a ground insulation layer 7 is applied thereon to electrically insulate the combined conductor from the ground. Then, a large current is passed through the conductor from an excitation power source to generate a high magnetic field, but in this case, heat is generated due to Joule loss occurring within the coil. In order to remove this heat, a cooling medium 8 is passed through the hollow conductor 4.

Incidentally, in the coil 1 having a structure in which the coil 1 is wound multiple times in multiple layers, after the cooling medium 8 has cooled the coil 1 by an appropriate length, the hollow conductor 4 extends the solid conductor 3 in the width direction, as shown in FIG. The cooling medium 8 is drawn out to the side of the coil across the coil 1, and is electrically insulated by a rubber hose 10 to guide the cooling medium 8 to the outside of the coil 1. Further, the outlet portion 11 of the hollow conductor 4
Considering securing the ground insulation thickness and creepage distance, it is necessary to have a structure in which an appropriate length is extended from the end face of the solid conductor 3, and the outlet portion 11 also needs to be provided with the earth insulation 7. Further, the hollow conductor 4 is usually thin in thickness in order to ensure the strength of the solid conductor 3 and to ensure a large flow rate of the cooling medium 8. Therefore, the heat capacity of the outlet portion 11 of the hollow conductor 4 is small, and the heat conduction from the solid conductor 3, which is a heat generating portion, is also small.

Pure water or the like having excellent electrical insulation properties is used as the cooling medium, and the outlet 11 of the hollow conductor 4 is electrically insulated from the cooling medium circulation system by a rubber hose 10 or the like. At the same time, the outlet portion 11 of the hollow conductor 4 is also electrically insulated. If the temperature of the cooling medium 8 is set high, there are problems such as thermal expansion displacement of the large coil, so the temperature of the cooling medium is normally set lower than the outside air temperature. The temperature of the conductor is higher than the outside temperature due to joule loss due to current flow. On the other hand, the outlet 11 of the hollow conductor 4 and the rubber hose 10 are usually connected at the connection part 13 in contact with the outside air. Furthermore, since no current flows directly through the outlet 11 of the hollow conductor 4 and the heat capacity of the hollow conductor 4 itself is small, the insulating surface of the outlet 11 of the hollow conductor 4 and the surface of the connecting fitting with the rubber hose 10 are The temperature is approximately the same as the coolant temperature and lower than the outside air temperature, so that moisture in the outside air condenses, reducing the electrical resistance of the insulating material surface at the outlet of the hollow conductor 4.

To prevent this, for example, as shown in FIG. 4, a heater 15 is installed outside the ground insulation 7 at the outlet of the hollow conductor 4, and the heat generated by the heater 15 lowers the temperature at the outlet of the hollow conductor 4 to the outside temperature. It is possible to prevent dew condensation by keeping the temperature higher than that. However, in this case, extra space is required due to the arrangement of the heater 15, and power loss of the heater 15 increases, which is not very preferable.

The present invention has been made in view of the above points, and its purpose is to prevent dew condensation with a simple structure and reduce the electrical resistance of the surface of the insulating material at the opening without using a heater or the like. It is an object of the present invention to provide an electric winding for a nuclear fusion device that is free of wires.

The present invention achieves the intended purpose by extending a hollow conductor to the outside through a metal fitting with good thermal conductivity fixed to a solid conductor.

Hereinafter, the present invention will be explained in detail based on the illustrated embodiments. Incidentally, the same reference numerals are used for the same parts as in the past.

FIG. 5 shows an embodiment of the present invention. Also in this embodiment of the figure, the hollow conductor 4 is installed and wound approximately at the center of the solid conductor 3 in the width direction 9, and the hollow conductor 4 is wound in the winding direction 16. It traverses the solid conductor 3 in the rear width direction 9 and is taken out to the outside. In this embodiment, a metal fitting 14 with good thermal conductivity is attached to the end face of the solid conductor 3, and the hollow conductor 4 is drawn out through a groove 17 for the hollow conductor 4 provided in the metal fitting 14. The hollow conductor 4 is fixed to the metal fitting 14 with good thermal conductivity by welding or soldering in the groove 17 of the metal fitting 14 with good thermal conductivity.
The metal fitting 14 is made of copper having sufficient thermal conductivity, and is fixed to the solid conductor 3 with a dovetail structure provided on the end face of the solid conductor 3. and,
The metal fitting 14 is fixed in such a way as to maintain sufficient thermal contact between the solid conductor 3 and the metal fitting 14, and the hollow conductor 4 is connected to the rubber hose 10 at the connecting portion 13 at a portion slightly protruding from the metal fitting 14. It is connected to the. Note that the earth insulation 7 and the interlayer insulation 6 include the metal fittings 14.

Next, the effectiveness of the present invention will be explained using FIG. 6. First, in the conventional case without the metal fitting 14, the temperature near the cooling water inlet is almost equal to the cooling water inlet water temperature, and the cooling water temperature is generally selected to be lower than the atmospheric temperature. Moisture in the atmosphere condenses. Therefore, the condition for preventing dew condensation is to keep the conductor surface temperature higher than the atmospheric temperature.

In FIG. 6, in an example in which the electric winding is designed with the following dimensions, the temperature Tt at the leading edge of the metal fitting 14 is as follows.

Cooling water inlet temperature To=10℃ Hollow conductor cross-sectional area S=25mm×25mm Cooling water flow rate v=5m/sec Conductor height H=500mm Conductor thickness D=50mm Fittings height h=100mm Fittings width w=50mm Fittings, Hollow conductor soldering dimension P = 5mm Solid conductor current conductivity i = 7A/mm ² Outside air temperature Tf = 30℃ Calculating the tip end temperature Tt of the metal fitting 14 under these conditions, Tt≒55℃ and atmospheric temperature Tf = 30 ℃, and the surface temperature of the ground insulation 7 can also be higher than the atmospheric temperature, so there is no condensation.

By adopting the structure of this embodiment as described above,
In addition to the result that the heat capacity of the outlet of the hollow conductor 4 is significantly increased, the Joule heat generated in the solid conductor 3 is gradually transmitted to the metal fitting 14 through the dovetail portion by thermal conduction and escapes to the cooling medium 8. As a result, the temperature of the part of the hollow conductor 4 that comes into contact with the outside air at the entrance/exit part is not likely to drop due to the heat generated by conduction, and the surface temperature can be kept higher than the outside air temperature, preventing condensation of outside air moisture and deterioration of the ground insulation 7, etc. It can be prevented.

This effect is particularly noticeable for electrical windings that are pulse-excited. That is, compared to the temperature drop of the cooling medium 8, the rate of temperature drop of the solid conductor 3, which is a heating element, and the metal fitting 14 is slow in terms of heat capacity. This makes it difficult for the temperature to drop below the outside temperature and prevents condensation. Furthermore, according to this structure, since the metal fitting 14 has a reinforced shape at the outlet of the hollow conductor 4, the vicinity of the outlet is subject to reaction force by the rubber hose 10, restraint reaction force due to relative displacement, or electromagnetic force due to the surrounding magnetic field. It has the effect of becoming strong against stress such as force.

According to the electrical winding for a nuclear fusion device of the present invention described above, the hollow conductor is drawn out through the metal fitting with good thermal conductivity fixed to the solid conductor, so it is easy to use without using a heater or the like. Since dew condensation can be prevented with this configuration, the electrical resistance on the surface of the outlet insulator does not decrease, so it is very effective when employed in an electrical winding for this type of nuclear fusion device.

[Brief explanation of the drawing]

Figure 1 is an external perspective view of an electric winding for a fusion device.
Fig. 2 is a sectional view taken along the line A-A in Fig. 1, Fig. 3 is a partial perspective view showing the vicinity of the outlet of a conventional electric winding, and Fig. 4 is another view of the outlet of a conventional electric winding. A partial perspective view showing an example, FIG.
FIG. 6 is a sectional view of the vicinity of the outlet for explaining the effects of the present invention. DESCRIPTION OF SYMBOLS 1... Coil, 3... Solid conductor, 4... Hollow conductor, 5... Solder layer, 6... Interlayer insulation layer, 7... Earth insulation layer, 8... Cooling medium, 10... Rubber hose, 11 ...Hollow conductor outlet part, 13...Connection part,
14...Metal fittings, 15...Heater.

Claims (1)

[Scope of Claims] 1. Electricity for a nuclear fusion device that is made up of a large number of turns of a conductor that is a combination of a solid conductor and a hollow conductor, and that cools the inside by flowing a cooling medium through the outlet portion that is drawn out. An electric winding for a nuclear fusion device, characterized in that in the winding, the hollow conductor is drawn out through a metal fitting with good thermal conductivity fixed to the solid conductor. 2. In what is stated in claim 1,
An electric winding for a nuclear fusion device, characterized in that a fixing portion between the metal fitting and the solid conductor has a dovetail shape.