JPS606084B2 - magnetic field generator - Google Patents

Description

[Detailed Description of the Invention] This invention provides an energy storage device using a superconducting coil,
The present invention relates to large-scale magnetic field generating devices such as nuclear fusion reactors, and particularly to devices that protect superconducting coils when quench occurs, reduce cooling medium consumption, and simplify re-excitation.

Superconducting coils are used in energy storage devices and large magnetic field generators in fusion reactors.

The magnetic energy accumulated by these large magnetic field generators is enormous, exceeding giga joule (=1 pijoule), and many ingenuity is required in manufacturing and operation. 1st
The figure is a circuit diagram of a large-scale magnetic field generator according to the prior art, in which 1 is a superconducting coil, 1-1 to 1-n are partial coils that are components of the superconducting coil 1, and 2-1 to 2-n are partial coils. 3-1 to 3-n are switches, 4-1 to 4-n are protective resistors, and the partial coil 1-
1 to 1-n are configured to be excited by independent excitation systems.

By the way, during the operation of the superconducting coil 1, one partial coil t, for example, 1-1, may be quenched (superconducting breakdown that cannot restore the original superconducting state).

In the prior art large magnetic field generator of FIG. 1, a switch 3-1 is connected to a quenched partial coil 1-1.
By opening the partial coil 1-1, most of the magnetic energy stored in the partial coil 1-1 can be rapidly absorbed by the protective resistor 4-1, and only a part of the magnetic energy is consumed in the cooling medium. It has the advantage that the temperature rise of 1-1 can be suppressed below the critical temperature (40 side or higher) at which the superconducting wire is damaged. Another advantage of this prior art large magnetic field generator is that even if one partial coil 1-1 quenches and the current in that partial coil becomes zero, the other partial coil 1-1
As long as the quench does not propagate to -2 to 1-n, the other partial coils 1-2 to 1-n remain excited, and it is possible to continue operation even if the magnetic field decreases slightly. .

FIG. 2 is a circuit diagram of yet another prior art large magnetic field generator in which the midpoints of the individual partial coils 1-1 to 1-m are grounded.

In this case, a voltage that is half the terminal voltage that occurs when partial coils 1 to 1 are quenched in FIG. It has the advantage that it becomes easier or that the number m of partial coils can be reduced to n/2. A superconducting coil 1, which is a component of a large-scale magnetic field generator according to the prior art, is, for example, a pancake-shaped superconducting coil shown in FIG. This superconducting coil 1 has a structure in which a plurality of pancake coils in which a superconducting wire 5 is wound with an inter-turn spacer 7 interposed therebetween are stacked and fixed in a winding frame 6 via an inter-layer spacer 8. 5 is electrically insulated both between turns and between layers by an interturn spacer 7 and an interlayer spacer 8, and the interlayer spacer 8 forms a gap 81 through which a cooling medium such as liquid helium flows. This gap 81 not only allows air bubbles of the cooling medium generated on the surface of the superconducting wire 5 to escape, but also has the role of replenishing the cooling medium. In the pancake-shaped superconducting coil shown in Fig. 3, pancake coil 1-1-
1-3 correspond to partial coils of the large magnetic field generator.

1 for each pancake coil 1-1 to 1-3
Pairs of current supply lead wires are attached, and the individual pancake coils 1-1 to 1-3 are electrically independent. The disadvantages of using this conventional pancake-shaped superconducting coil as the superconducting coil 1 of the prior art large-scale magnetic field generator will be described. When one pancake coil 1-2 of the pancake-type superconducting coil 1 shown in FIG. The cooling medium in contact evaporates and becomes a gas.

The evaporated gas spreads around the surrounding area over time, and pancake coils 1-1 and 1-3 adjacent to pancake coil-2 are covered with gas, and pancake coils 1-1 and 1-3 become insufficiently cooled. There is a good chance that it will quench. In this way, when a conventional pancake-shaped superconducting coil is used as a prior art large-scale magnetic field generator, the quenching is not limited to one pancake coil, but propagates to other pancake coils, It had the disadvantage that the cooling medium was consumed more and the excitation of all the pancake coils disappeared.

This invention was made in view of the above-mentioned drawbacks.
By protecting large superconducting coils from being damaged when they are quenched, and by limiting quenching to only the quenched partial coils, cooling medium consumption is reduced, allowing operation even if the magnetic field is slightly reduced. The purpose of the present invention is to provide a large-scale magnetic field generating device that can continue to operate.

FIG. 4 shows an embodiment of the present invention, in which a partition plate 9 is provided between adjacent pancake coils, and each pancake coil forms an independent space with respect to the cooling medium.

Although not shown in the figure, the cylindrical wall of the cryogenic container covers the outer periphery of the partition plate 9 and the winding frame 6, making each pancake coil independent. By providing this partition plate 9, even if the pancake coil 1-2 quenches and the cooling medium evaporates, it is possible to prevent the quench from propagating to the adjacent pancake coils 1-1 and 1-3. The consumption of cooling medium and the extinction of excitation can be limited to only the quenched pancake coil.

Although the partition plate 9 in the low-temperature container in this invention does not have to be completely airtight, it has airtightness against a pressure difference of about 0.5 to lk9/light and has the strength to withstand this level of pressure difference. This is desirable. Furthermore, the material of the partition plate 9 can be any type of material such as insulating material, stainless steel, copper, etc.
It may also be a composite whose metal surface is insulated. However, in superconducting coils placed in an alternating magnetic field, it is desirable to use insulating partition plates. Although the above invention relates to a pancake-shaped superconducting coil, this invention is not limited to pancake-shaped superconducting coils.

FIG. 5 is a diagram showing another embodiment of the present invention, in which a superconducting wire 5
This is a solenoid-type superconducting coil in which a plurality of solenoid coils 1-1 to 1-4, each of which is wound with a spacer 7 between turns, is housed in a low-temperature container 101. A partition plate 9 is provided between them.

Each solenoid coil is independently excited via a current supply lead wire 11. Note that the winding frame and interlayer smoother are not shown in FIG. In the invention shown in FIGS. 4 and 5, one pancake coil and one solenoid coil are respectively used as partial coils, but multiple pancake coils and multiple solenoid coils can also be used as partial coils. good.

As detailed above, the present invention relates to a large magnetic field generator that provides a partition plate between a plurality of partial coils constituting a superconducting coil and excites each partial coil independently. This prevents the generated quench from propagating to other partial coils, reduces energy consumption during quenching, and has the effect of allowing operation to continue even if the magnetic field is slightly reduced.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams of a large magnetic field generator according to the prior art, FIG. 3 is a partially cutaway perspective view of a conventional pancake-shaped superconducting coil, and FIG. 4 is a pancake-shaped superconducting coil of the present invention. FIG. 5 is a partially cutaway perspective view of a superconducting coil, and FIG. 5 is a sectional view of a solenoid-type superconducting coil according to another embodiment of the present invention. In the figure, 1 is a superconducting coil, 1-1 to 11n are partial coils, 2-1 to 21n are excitation power supplies, 3-1 to 31n are switches, and 4-1 to 41n are protective resistors. , 5 is a superconducting wire,
9 is a partition plate, and 10 is a low temperature container. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.・Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A plurality of partial coils wound with superconducting wire, a partition plate provided between the plurality of partial coils, a superconducting coil in which the plurality of partial coils are assembled in a low-temperature container, and the above. 1. A magnetic field generating device comprising a resistor connected in parallel to each partial coil, and an excitation wire that supplies power to each parallel body of the partial coil and the resistor via a switch. 2. The magnetic field generating device according to claim 1, wherein the middle point of each partial coil is grounded.