JPS62180910A - Superconductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a superconducting conductor, and more particularly, to a large current superconducting conductor suitable for use in loads, pulses, or alternating current.

[Conventional technology]

As an example of superconducting conductors, we take as an example a composite multicore superconducting conductor for AC (hereinafter referred to as AC conductor), which has been developed so far.
The conventional I″f technique will be explained.

, FIG. 5 shows a cross-sectional configuration of a typical conventional AC conductor. Normally, the AC conductor 1 ensures stability both thermally, diatically, and mechanically. to knee, thermal, dt
Regular electric current 4 metals such as copper, full miniu, and mu, which are good-natured conductors.
It is generally made up of 44 bodies, and a high-resistance metal inserted between these superconducting conductors to reduce AC interference. The AC conductor 1 shown in FIG. 5(a) has a large number of ultra-fine conductive filaments (~0.5 μm in diameter) 4 (~14,500 μm in diameter) as shown in FIG. 5(-)K.
Book) Embedded in copper 5, which serves as a stabilizing material, and surrounded by a highly abrasive metal 46 such as cupronickel, all in one! ! , the overturned superconducting strand (hereinafter referred to as strand) 2 is placed on the outside [and a dummy wire 3 made of copper 5 coated with cupronickel 6, which has the same diameter as the superconducting wire shown in Fig. 5(c) and cupronickel 6 is placed inside. The superconducting conductor having such a structure is disclosed in Japanese Patent Application Laid-open No. 74307/1983. ). In this AC conductor 1, in order to reduce AC loss, 4
Two improvements have been made. That is, (i) the superconducting filament 4 is made extremely thin to have a 1α diameter t 1−·t rn or less to reduce magnetization (lamination) loss, and (it) the AC conductor 1 is divided into minute regions using cupronickel 6.

It suppresses the generation of eddy currents induced by changes in the AC d current (@ field), and also between the strands 2 and between the dummy wires 3.
Furthermore, it prevents electromagnetic coupling between the wire 2 and the dummy wire 3,
01D Furthermore, the entire AC conductor 1 is twisted to further suppress the electromagnetic coupling (C), and the qφ element/gravel 2 is placed on the outside and the dummy wire 3 is placed on the inside, so that +!L flows through the element wire 2.
It is devised so that the alternating current magnetic field due to the i current is not applied to the dummy wire 3.

On the other hand, in order to improve stability, a large number of copper wires are included as dummy wires 3.

The diameter of this AC conductor 1 is ~0.1), the AC' current capacity is ~50 A under the magnetic field IT, and.

The AC loss is calculated to be ~105 W per conductor unit (m3) under an IT AC magnetic field at 50 Hz, and when converted to a conductor unit length (m), the loss is ~ several mW.

This AC conductor 1 is considered to have the best performance in the current state of the art.

is at the limit of technology. Since it is necessary to convert the st conductor filament 4 into a brush wire, the 1M diameter and current flow capacity of the AC conductor 1 have to be reduced.

In order to develop a Taisei-style AC conductor with low AC loss, a super 6-conductor stranded wire 8' (hereinafter referred to as a stranded wire) as shown in Fig. 6, which is a bundle of multiple AC conductors l described above, can be considered. . The biggest drawback of the stranded wire structure is that electromagnetic coupling occurs between the alternating current conductors 1 constituting the stranded wire structure, resulting in additional coupling loss. Various AC losses occur in the stranded wire 8', such as magnetization loss of the superconducting filament 4 itself, eddy current loss in the copper 5, coupling loss between the superconducting filaments 4, and coupling loss between the AC conductors 1 in question. However, among them, the coupling loss between the AC conductors 1 is the largest.

In addition, in Fig. 6, (a) is a double stranded wire, (b) is a braided wire, (
C) is what is called a shaped stranded wire. Each of these strands 8
Efforts have been made to reduce the coupling loss in ', but nothing has been found that satisfies both stability and low AC loss.

[Problem that the invention seeks to solve]

In the prior art described above, it is difficult to increase the current capacity of the AC conductor due to the necessity of thinning the superconducting filament 4. In addition, in developing large r[flow conductors], analytical ideas are required to reduce coupling loss.

The present invention has been developed based on the above-mentioned points, and its purpose is to provide a superconducting conductor having a practical current capacity as well as reducing cross current and loss.

[Failure to solve the problem]

The present invention achieves the intended purpose by spirally applying a composite multicore superconducting conductor along the outer periphery of a normal conductor so that right-handed and left-handed layers are alternated. be.

[Effect]

That is, if the twisting pitch is made small, most of the alternating current magnetic field (gi east) applied to the twisted wires passes through without interlinking with the twisted wires, and the coupling loss is significantly reduced. However, when the twisting pitch is reduced, the twisted wires themselves form a regular long single-layer solenoid coil, *! When a current is passed through iI, most of the magnetic flux is confined within the stranded wire, and the magnetic field detected by the stranded wire becomes high.

Impedance of twisted gland (self-inductance), -i
becomes significantly larger. Therefore, by creating a composite multi-core superconducting conductor with a stranded wire structure in which right-handed winding, resonant, and percussion alternate, the magnetic field inside the stranded wire can be weakened, and at the same time, the impedance of the stranded wire can be reduced. It is possible to increase the current capacitance.

〔Example〕

The present invention will be described in detail below based on a practical example shown in one drawing. Incidentally, the same reference numerals are used for the same parts as in the past.

FIGS. 1(a) and 1(b) show an embodiment of the superconducting conductor of the present invention.

This figure shows the structure of an AC superconducting conductor 8 (hereinafter referred to as a stranded conductor) of a four-way stranded wire type having a circular cross section, as the basic concept of the present invention. As shown in the figure, it is a good idea to make the core normal conductor 9 located in the center a collection of dummy glands 3, similar to the central structure of the AC conductor l shown in Figure 5. , I will not discuss the details here. In this embodiment, around the normal conductor 9.

Take one AC conductor 1 as shown in Figure 5, wrap it one layer tightly to the left so that the winding pitch is equal to the diameter of the AC conductor 1, and then wrap another AC conductor on the outside. The conductor 1 is similarly wrapped tightly in a right-handed manner, and the outermost periphery is coated with an insulator 7 to form an rFfi conductive conductive crosspiece. Although the current capacity is simply doubled in this figure, it is possible to minimize alternating current losses, such as losses due to coupled direct current.

Needless to say, the number of layers must be at least two or more.

FIGS. 2(a) and 2(b) show 42 embodiments of the present invention.

As shown in Figure 1, it is possible to minimize AC loss by winding each wound with a single wire, but increasing the number of layers is the only way to increase the current. Generally speaking, if you have one wire and wind it in m layers, the current capacity can be increased by nxm times. In this example, n
=5. The case where m=4 and fW and It capacity are increased by 20 times is shown. For example, if the AC conductor 1 shown in FIG. 5 is used, a stranded conductor 8 of ~1000 A can be obtained in IT. For the purpose of eliminating the internal magnetic field of the stranded wire conductor 8, the number of layers (m) is desirably convergent; The change number and the diameter of the AC conductor 1 wound around each layer should be determined based on the conditions that the impedance of each layer is made as similar as possible.Such a design method should naturally be adopted, and will reduce AC loss. , align the impedance of each layer,
This technology is indispensable in order to obtain an AC layered conductor with a practical current capacity.

A third embodiment of the present invention is shown in FIGS. 3(a) and 3(b).

In [1] shown in FIGS. 1 and 2, it was stated that the stranded wire conductor 8 needs to be constructed with a multilayer structure, but when it is multilayered, there are 11! Magnetic coupling may occur, and countermeasures should be taken from the point of view of reducing AC loss. Therefore, in this embodiment, a high resistance layer or 18 electric gravel layers IO are inserted between each layer.

This high-resistance layer may be made of a high-resistance metal, a tetragonal metal oxide, a hypnotic organic substance, or the like. When using a high-resistance layer, some electromagnetic coupling is unavoidable, but it is advantageous in terms of mechanical strength and cooling of the stranded conductor 8; Although the bond can be completely broken, the mechanical strength and cooling performance are inferior.

Even if the impedance of each layer is the same, inserting the five-layer impedance layer 10 may cause unevenness in the direct current flowing in each layer, so it is better to have high-resistance layers in all phases. In any case, it is necessary to take measures to weaken the electromagnetic coupling between the eyebrows.

Embodiment #c4 of the present invention is shown in FIGS. 4(a) and 4(b).

As shown in Figures 1 to 3: In the practical row, if the normal conductor 9 used as the core is □, if the copper IHi for stabilizing the superconductivity is sufficient in the entire stranded conductor 8, the core It is a wise measure to reduce the copper resistance of the parts and reduce the eddy current losses to AC losses there. For this purpose, in this example, ′
Using the normal conducting pipe 11 as a core, the AC conductor 1 is wound around the normal conducting pipe 1□1 to form the stranded conductor 8 in the same manner as described above.The material of the normal conducting pipe 11 is copper or Aluminum may also be used. Stainless steel may be used.1 Furthermore, the hollow part of the conduit pipe 11 may be vacuumed or filled with liquid (1), it may be filled with a ram, or it may be filled with supercritical helium. good. especially,
By replacing the core normal conductor 9 with the normal conductor pipe 11, the mechanical strength of the stranded conductor 8 in the longitudinal direction is significantly improved.

Next, the effectiveness of the present invention is confirmed by calculating the AC loss of the stranded wire conductor shown in FIGS. 2(a) and 2(b). The AC conductor l used is the one shown in Figure 5 (the superconducting filament is 0.5I).
im, 14,500 pieces) as is, and its AC loss is calculated as 1 under an AC magnetic field of 50Hz t'r.
05W,/m'. Five AC conductors 1 with insulation 7 removed are wound in 4 layers, and the core normal conductor has a diameter of 6
0 μm dummy wire 3 (gubronickel thickness 3.5 n
40 pieces (including diameter 0.4 rtm)
, the finished outer diameter of the stranded conductor 8 is 1.4 ran.

Calculations were performed under the condition that an alternating current magnetic field of 501-Iz-IT was applied to this stranded conductor, and the magnetization loss of the entire superconducting filament was 1.3 X l O' W/m3
．． The eddy current loss is 5.6X in the copper parts placed in each part.
10'W/m3. In addition, the cupronickel disposed in each part has a power of 2.3XI O'W/m", and the coupling loss occurring between each layer is 2.6X103W/m".
2-I x 10'W between 3.5 AC conductors
/m3. 3.2X with 3+m dummy wire of normal conductor part of core
The result was 5.0 x 103 w/mJ between the superconducting filaments in the 103 W/m" N AC conductor. Therefore, the total was 1.4 x 10" vV/m3.

Even though the '1tffl capacity was 20 times larger, the AC loss was only 14 times larger.

Needless to say, it is easy to construct a stranded wire conductor by appropriately combining each of the embodiments shown in FIGS. Variations of the above are possible, but none of the 8 nephews are particular about them.

〔Effect of the invention〕

According to the superconducting conductor of the present invention as described above, the composite multi-core conductor is wound around the outer periphery of the normal conductor in a four-circle shape so that right-handed and left-handed layers are alternately wound. , it is possible to construct a large-capacity AC superconductor without exceeding the conventional AC loss value per unit current capacity, and it can greatly contribute to the a conductivity ratio of various existing AC devices. , its industrial effects are enormous.

[Brief explanation of drawings]

FIG. 1(a) is a schematic configuration diagram showing one embodiment of the superconductor of the present invention, FIG. 1(b) is a sectional view thereof, and FIG. 3 and 4 respectively show other embodiments of the present invention, in which (a) is shown in FIG. 1 (a) and ('b) is shown in FIG.
A diagram corresponding to Figure (b), Figure 5 (a) is a cross-sectional view showing a conventional superconductor, Figures 5 (b) and (C) u superconducting strands constituting it, and four cross-sectional views of the dummy line, prisoner 6 (a), (b). and (c) are perspective views showing examples of stranded wire conductors according to the prior art, respectively. 1... AC conductor, 2... ka conductive wire, 3... dummy wire. 4...Superconducting filament, 5...Copper, f5...
・High resistance metal, 7...Excellent item, 8...Twisted wire conductor, 9
...Normal conductor, 1.0...Electrical insulator layer, 11.
...Shindo Kuibu in 1'.

Claims (1)

[Claims] 1. Consisting of a normal conductor and a composite multicore superconducting conductor in which right-handed and left-handed layers are wound spirally along the outer periphery of the normal conductor so that right-handed and left-handed layers are alternately wound. A superconducting conductor characterized by 2. When the composite multi-core superconducting conductor is wound with n pieces per layer (n=1, 2,...), the composite multi-core superconducting conductor has a dimension n times the diameter of the composite multi-core superconducting conductor. 2. The superconducting conductor according to claim 1, wherein the superconducting conductor is wound to have a pitch equal to that of the superconducting conductor. 3. A high-resistance layer or an electrical insulator layer is interposed between the layers of the composite multicore superconducting conductor wound alternately in right-handed and left-handed windings, according to claim 1. superconducting conductor. 4. The superconducting conductor according to claim 1, wherein the normal conductor is formed of a hollow pipe.