JPS63264815A - Superconductive cable - Google Patents

Abstract

PURPOSE:To improve cooling efficiency of a superconductor and an insulator by forming gaps inside the superconductor and the insulator so that coolants are passable therethrough and setting a pressure of the coolant, which flows in an inside coolant channel, higher than that of the coolant which flows in an outside coolant channel. CONSTITUTION:Superconductors 11 and 13 on the inside and the outside respectively are formed by bundling a large number of filament-shaped thin superconductive wires and provided with small gaps inside them so that coolants are passable therethrough. The insulator 12 is formed by laminating insulated paper in a layer shape, and the coolant is passable through the inside of minute gaps in the insulated paper. A pressure of the coolant, which flows in an inside coolant channel 10, is set higher than that of the coolant which flows in an outside coolant channel 14. Accordingly a part of the coolant, which flows in the inside coolant channel 10, passes serially through the inside superconductor 11, the inside of the insulator 12, the inside of the outside superconductor 13, and finally flows to the outside coolant channel 14, as shown in an arrow B. Hence, the respective superconductors 11, 13 and the insulator 12 are directly cooled by the coolant, and so the respective superconductors 11, 13 are improved in their cooling efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a superconducting cable using, for example, an oxide superconducting wire.

[Prior art] Recently, the critical temperature (
Various superconducting materials are being discovered that exhibit Tc) values higher than the liquid nitrogen temperature, and attempts are being made to create superconducting wires using these superconducting materials and to apply them to superconducting cables. be.

Figure 4 shows a conventional example of a superconducting cable, which consists of a plurality of superconducting conductors 2 made of an alloy or intermetallic compound having a refrigerant passage l inside, and an insulator 3 provided on the outside of the superconducting conductor 2. (three in this case) core materials 4 are placed in the outer refrigerant passage 5, and an insulating layer 6 is placed outside the outer refrigerant passage 5.
, a casing pipe 7, and an anticorrosive layer 8 are provided in this order.

A refrigerant such as liquid helium is circulated between the inner cooling passage 1 and the outer refrigerant passage 5 to cool the superconducting conductor 2 from the inside and outside, and the superconducting conductor 2 is used as a superconducting cable.

[Problems to be solved by the invention] However, in the case of the above type of superconducting cable,
Due to the temperature rise due to the eddy current loss in the conductor 2 and the dielectric loss in the insulator 3, the temperature of the refrigerant flowing through each refrigerant passage 1, 5 tends to rise, and therefore there is a problem that the length of the cooling section cannot be increased. In order to solve this problem, it is possible to increase the inner diameter of each refrigerant passage 1 and 5 to increase the amount of refrigerant flowing, but this would result in the entire superconducting cable having a large diameter. It has the disadvantage of being stored away.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and includes an inner refrigerant passage provided inside a superconducting conductor and an insulator provided outside. In the superconducting cable in which the superconducting conductor and the insulator are covered with an outer sheath and an outer refrigerant passage is provided between the insulator and the outer sheath, the superconducting conductor and the insulator each have a gap through which a refrigerant can pass. , the pressure of the refrigerant flowing through the inner refrigerant passage is set higher than that of the outer refrigerant passage, and in addition, between the inner refrigerant passage and the outer refrigerant passage, there is a A refrigerant flow resistance layer may be provided so that the flow resistance in the radial direction gradually decreases.

[Function] The superconductive conductor and the insulator have gaps through which the refrigerant can pass, and at the same time, the pressure of the refrigerant flowing in the inner refrigerant passage is set to be higher than that of the refrigerant flowing in the outer refrigerant passage. , a part of the refrigerant flowing through the inner refrigerant passage is
It flows through the gap between the superconducting conductor and the insulator toward the outer coolant passage. In other words, it flows in the radial direction of the superconducting wire. As a result, the superconducting conductor and the insulator are cooled from the inside, improving the cooling effect, suppressing the temperature rise due to dielectric loss of the insulator, and preventing the temperature rise of the insulator.

In addition, by providing a refrigerant flow resistance layer between the inner refrigerant passage and the outer refrigerant passage so that the flow resistance in the radial direction gradually decreases in the longitudinal direction of the refrigerant flow, the flow rate distribution of the refrigerant flowing in the radial direction is improved. This allows superconducting conductors and insulators to be efficiently cooled.

[Example] Hereinafter, an example of a superconducting cable based on the present invention will be described with reference to FIGS. 1 and 2.

This superconducting cable has an inner superconducting conductor 1 with an inner refrigerant passage ■0 inside! An insulator 12 and, if necessary, an outer superconducting conductor 13 are sequentially coated on the outside of the ! Open 4 and apply the anti-corrosion layer (outer covering)! 5 is provided. Note that an inner semiconducting layer and an outer semiconducting layer may be combined on the inside and outside of the insulator 12 if necessary.

The inner and outer superconducting conductors 11, 13 are, for example,
A-B-Cu-0 system (A is La, Y.

It is formed into a thin wire shape using an oxide-based superconducting material (Ma group elements such as Yb and Sc, and B represents an alkaline earth metal element such as Ba and Sr), and this thin filament-like superconducting wire is A large number of superconducting conductors 11 and 3 are bundled together, and a small gap exists inside the superconducting conductors 11 and 3, allowing the refrigerant to pass through the gap.

In addition, the insulator 12 is made of layers of insulating paper (kraft paper, plastic laminated paper, synthetic paper, etc.)
This is also made of a material that allows the refrigerant to pass through the interior through minute gaps in the insulating paper.

Further, on the outer periphery of the outer superconducting conductor 13, a tape (refrigerant shielding material) 16, in which stainless steel tape and Tetron tape are alternately wound, is installed as shown in FIG. It is wound multiple times so that the flow changes from large to small.

Inside each of the inner and outer refrigerant passages IO1!4, refrigerants such as liquid N1 and liquid helium are flowing from left to right as shown by arrows (A) in FIG. . Here, the pressure of the refrigerant flowing through the inner refrigerant passage IO is pressurized to be higher than the pressure of the refrigerant flowing through the outer refrigerant passage 14.

In such a superconducting cable, each inner and outer superconducting conductor l! , 13. As described above, the insulator 12 allows the refrigerant to pass therethrough, and furthermore, since the refrigerant flowing through the inner refrigerant passage 10 has a higher pressure than the refrigerant passing through the outer refrigerant passage 14, the inner refrigerant passage A part of the refrigerant flowing through the inner superconducting conductor 11, the insulator 12, and the outer superconducting conductor t, as shown by the arrow (b) in FIG.
3 and flows into the outer refrigerant passage 14.

In this way, the inner and outer superconducting conductors 11 and 13 and the insulator 12 are directly cooled by the coolant flowing in the radial direction of the superconducting wire from the inner coolant passage 10 to the outer coolant passage 14. Its cooling effect is greatly improved. Therefore, the temperature rise due to dielectric loss of the insulator 12 is suppressed, thereby preventing the temperature rise of the refrigerant, and each superconducting conductor! ! , 13 cooling efficiency is improved.

In addition, a tape 16 wrapped around the outer periphery of the outer superconducting conductor 13
As a result, the refrigerant flows out from the outer periphery of the outer superconducting conductor 13 where the tape 16 is not wound. However, in this outflow portion, that is, between each tape 16, the refrigerant flow resistance changes in the flow direction of the refrigerant. Therefore, the distribution of the flow rate of the refrigerant can be controlled on the upstream side and the downstream side of the flowing refrigerant, and therefore, the length of the cooling section can be increased by efficiently cooling.

In the above embodiment, the pressure in the inner refrigerant passage 10 is higher than that in the outer refrigerant passage 14, and the refrigerant is caused to flow from the inside to the outside, but is it the other way around? Alternatively, the outer refrigerant passage 14 may be made to have a high pressure so that the refrigerant flows inward.

In the above embodiment, the superconducting cable is a single-core superconducting cable, but as shown in FIG. The same can be done for lines.

Furthermore, the superconducting conductor of the superconducting cable in the present invention may be a conventionally known alloy type, intermetallic compound type such as Nb type, or B aP bB i represented by ABO*.
Oss S rT io 3, (S r, B a)T
It may also be an oxide-based material such as iO2, (Ca, Sr)Tios.

[Effects of the Invention] As explained above, according to the superconducting cable of the present invention, an inner refrigerant passage is provided inside the superconducting conductor, and an insulator is provided outside, and the insulator is covered with an outer jacket to form the insulator. In a superconducting wire in which an outer refrigerant passage is provided between the
The superconducting conductor and the insulator each have a gap through which a refrigerant can pass, and the pressure of the refrigerant flowing through the inner refrigerant passage is set higher than that of the refrigerant flowing through the outer refrigerant passage. It flows both axially and radially, cooling the superconducting conductor and insulator from the inside. Therefore, the cooling effect of superconducting conductors and insulators is greatly improved,
Temperature rise due to dielectric loss of the insulator can be suppressed.

Furthermore, since the cooling efficiency is improved and the superconducting conductor can be cooled in a short time, the setup time required to cool it from room temperature to a superconducting state can be shortened.

Furthermore, by providing a refrigerant flow resistance layer between the inner refrigerant passage and the outer refrigerant passage so that the flow resistance in the radial direction gradually decreases in the longitudinal direction of the refrigerant flow, the refrigerant flow 11 flowing in the radial direction is Since the distribution can be controlled, the superconducting conductor and the insulator can be efficiently cooled, thereby making it possible to increase the length of the cooling section of the superconducting wire.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a superconducting cable showing an embodiment of the present invention, Fig. 12 is a sectional view of the same side, Fig. 3 is a longitudinal sectional view of another embodiment, and Fig. 4 is a longitudinal sectional view of a conventional superconducting wire. It is a front view. 10120...Inner refrigerant passage, 11.13.2
1...Superconducting conductor, 12.22...Insulator, 15...Outer cover (corrosion protection layer), I6...
...Tape (refrigerant flow resistance layer).

Claims (2)

[Claims] (1) In a superconducting wire in which an inner refrigerant passage is provided inside a superconducting conductor, an insulator is provided outside, the insulator is covered with an outer sheath, and an outer refrigerant passage is provided between the insulator and the outer sheath. , wherein the superconducting conductor and the insulator each have a gap through which a refrigerant can pass, and the pressure of the refrigerant flowing through the inner refrigerant passage is set higher than that of the outer refrigerant passage. cable. (2) A patent claim characterized in that a refrigerant flow resistance layer is provided between the inner refrigerant passage and the outer refrigerant passage so that the flow resistance in the radial direction gradually decreases in the longitudinal direction of the refrigerant flow. A superconducting cable according to item 1.