JP2943032B2 - High temperature superconductor current lead - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature superconductor current lead, and in particular, a thermal anchor provided by a refrigerator is provided to facilitate reinforcement of the current lead body, prevention of breakage, reduction of heat intrusion and countermeasures against quench. The present invention relates to a manufactured high-temperature superconductor current lead.

[0002]

2. Description of the Related Art A conventional superconducting coil device 1 is shown in FIG.
An example will be described based on this. The superconducting coil device 1 includes a superconducting coil 2, a coil container 3, a refrigerant 4 (for example, liquid helium) in the coil container 3, a heat shield plate 5, a cryostat container 6, a positive electrode current lead 7, and a negative electrode. A current lead 8 for external use, an external power supply 9, a coil side connection line 10 and a power supply side connection line 11, and a guide tube 12 covering the positive electrode current lead 7 and the negative electrode current lead 8 are provided.

The superconducting coil 2 is electrically connected to an external power supply 9 through the positive electrode current lead 7, the negative electrode current lead 8, the coil side connection line 10, and the power supply side connection line 11.

In the case of a gas-cooled type current lead, as shown in the figure, a positive electrode current lead 7, a negative electrode current lead 8, and a coil side connection line are formed by the evaporative gas of the refrigerant 4 rising in the guide tube 12. The power supply 10 and the power supply side connection line 11 are cooled so as to suppress heat intrusion from the outside.

The whole or a part of the current lead 7 for the positive electrode and the current lead 8 for the negative electrode is made of a high-temperature superconductor having low thermal conductivity, for example, an oxide high-temperature superconductor. The amount of heat intrusion from the outside and the amount of Joule heat generated in the same part can be reduced.

The oxide high-temperature superconductor includes bismuth-based, yttrium-based, and thallium-based superconductors.

However, oxide high-temperature superconductors are difficult to weld with different materials (difficulty of electrical and mechanical connection), have low strength such as impact value, and apply force to attach electrode terminals. However, there is a problem such as difficulty in mechanical connection (mechanical connection difficulty), and mounting electrode terminals at both ends thereof has been an obstacle in forming a current lead.

Further, when an oxide high-temperature superconductor current lead is incorporated in a superconducting coil device, there is also a problem that the strength of the current lead body is insufficient, and the current lead body may be damaged by thermal shock and external vibration.

Further, when a high-temperature superconductor is used, it is, of course, necessary to cool it below its critical temperature.
There is a current lead according to 4-76707.

In this current lead, copper and an oxide high-temperature superconductor are joined to form a current lead, and cooling is performed by winding a cooling pipe through which liquid nitrogen flows around the current lead. Alternatively, the joint between the superconductor and copper may be cooled by directly contacting liquid nitrogen.

However, in this current lead, cooling of the current lead cannot be automated due to the use of liquid nitrogen which is troublesome in handling, and a mechanism for reinforcing the high-temperature superconductor against thermal stress due to cooling is provided. Are difficult, and when the high-temperature superconductor is quenched, current does not flow.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in particular, a current lead using a high-temperature superconductor such as an oxide high-temperature superconductor which becomes a superconductive state at a temperature of liquid nitrogen or higher. The current lead body can be cooled without using a cooling fluid such as liquid nitrogen, and the mechanical strength can be reinforced while ensuring the electrical connection between the superconducting coil side and the power supply side electrode terminals Accordingly, it is an object of the present invention to provide a high-temperature superconductor current lead having stable performance that prevents breakage, reduces intrusion heat, and facilitates quench measures.

[0013]

That is, the present invention provides a method of cooling a high-temperature superconductor such as an oxide high-temperature superconductor to a predetermined temperature by a refrigerator such as a small-sized Gifford McMahon refrigerator, and a method of cooling a current lead body. A superconducting coil and a high-temperature superconducting current lead capable of electrically connecting an external power supply, which are composed of a high-temperature superconductor and a good conductor, and are provided between the superconducting coil and the external power supply. A refrigerator disposed therein, a power supply side electrode terminal attached to a room temperature portion side of the refrigerator via a first insulating flange, and a superconducting coil attached to a refrigerator portion of the refrigerator via a second insulating flange. A current lead body that can be connected to the high-temperature superconductor and a good conductor integrally combined with the high-temperature superconductor. This conductor is a high temperature superconductor current lead the said current lead body, characterized in that the connectable to the power supply-side electrode terminal and the superconducting coil.

It is desirable that the good conductor be made of a wire member and be connected with slack at both ends.

[0015]

In the high-temperature superconductor current lead according to the present invention, since the high-temperature superconductor is connected to the cooling portion of the refrigerator disposed between the superconducting coil and the external power supply, the current lead body is cooled to a predetermined temperature. By maintaining the superconducting state, Joule heat generation can be suppressed, and heat intrusion can be suppressed by the high-temperature superconductor having low thermal conductivity.

Further, since the current lead body is composed of the high-temperature superconductor and the good conductor, even if the superconducting state is broken, a current flows through the good conductor portion and the state of conduction to the superconducting coil can be maintained.

Further, by making the length of the good conductor longer than that of the high-temperature superconductor and projecting it at both ends, the connection can be made at the good conductor portion. The good conductor expands and contracts in response to the contraction stress, so that mechanical and electrical connectivity can be maintained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-temperature superconductor current lead 20 according to an embodiment of the present invention will be described with reference to FIGS. However, the same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a perspective view of a high-temperature superconductor current lead 20. The high-temperature superconductor current lead 20 includes a refrigerator 21 such as a small Gifford McMahon refrigerator, a power supply side electrode terminal 22, , A first insulating flange 23, a second insulating flange 24, and an insulating fixing material 25.
, A first connection cooling plate 26, and a second connection cooling plate 27
And a first current lead body 28 and a second current lead body 29.

The refrigerator 21 is of a two-stage refrigerating type, comprising an upper flange 21A and a first-stage cooling section 21B having a cooling temperature of 80K.
And a second-stage cooling unit 21C having a cooling temperature of 20K.

The refrigerator 21 is fixed between the upper flange 21A and the cryostat container 6 via a first insulating flange 23.

The power source side electrodes terminals 22, the first connecting the cooling plate 2
6 and the second connection cooling plate 27 are made of a good conductor such as silver, copper, or aluminum.

The power supply side electrode terminal 22 is inserted and fixed in the fixing hole 23A of the first insulating flange 23.

The second insulating flange 24 is fixed between the first cooling part 21 B of the refrigerator 21 and the first connection cooling plate 26.

The first current lead body 28 comprises a high-temperature superconductor 28A made of an oxide high-temperature superconductor or the like and a wire-shaped good conductor 28B made of a low-resistance material such as silver or silver-plated copper or aluminum. I do.

The upper and lower ends of the good conductor 28B are fixed to the fixing holes 26A of the first connection cooling plate 26 and the second connection cooling plate 2
7 and fixed by soldering.

The second current lead body 29 includes a high-temperature superconductor 29A made of an oxide high-temperature superconductor or the like, and silver,
Alternatively, it is composed of a wire-like good conductor 29B made of a low-resistance material such as silver-plated copper or aluminum.

In the second cooling section 21C of the refrigerator 21, the second connection cooling plate 27 is fixed to the upper flange portion 25A of the insulating fixing material 25, and the upper and lower portions of the good conductor 29B of the second current lead body 29 are fixed. Both ends are inserted into the fixing holes 27A of the second connection cooling plate 27 and the fixing holes 25C of the lower flange portion 25B, respectively, and fixed by soldering.

Good conductor 29B of second current lead body 29
Is connected to the superconducting coil 2.

The configuration of the first current lead body 28 or the second current lead body 29 is arbitrary. As a molding method, a CIP (hydrostatic isostatic press) or rolling process is performed, and a sintering method, a partial melting The high-temperature superconductors 28A and 29A and the good conductors 28B and 29B are integrally molded by a method, a melting method, or the like.

The current lead body may have a cylindrical current lead body 30 shown in FIG. 3, a plate-shaped current lead body 31 shown in FIG. 4, or any other configuration.

The good conductor 28A of the first current lead body 28 and the good conductor 29A of the second current lead body 29
The connection portions to the first connection cooling plate 26, the second connection cooling plate 27, and the insulating fixing material 25 are each provided with a slack.

Similarly, the portion of the power supply side electrode terminal 22 between the first insulating flange 23 and the second insulating flange 24 has a slack.

The high-temperature superconductor current lead 2 having such a configuration
0, when the refrigerator 21 is started, the temperature of the first stage cooling unit 21B becomes 80K or less in a few minutes,
When the temperature of 1C becomes equal to or lower than 20K, the first current lead body 28 and the second current lead body 29 are cooled below their critical temperatures, and function as a first-stage thermal anchor and a second-stage thermal anchor, respectively. .

The current from the external power supply 9 is supplied to the power supply side electrode terminal 22, the first connection cooling plate 26, the first current lead body 28, the second connection cooling plate 27, and the second current lead body 29. The superconducting coil 2 is supplied to the superconducting coil 2.

At this time, since the first current lead body 28 and the second current lead body 29 do not have a current-carrying resistance, there is no Joule heat, and the first current lead body 28 and the second current lead body 29 Has a low thermal conductivity, so that heat entering the superconducting coil 2 can be reduced.

High-temperature superconductor 28A and high-temperature superconductor 2
Since the good conductor 28B and the good conductor 29B integrally formed with the high temperature superconductor 9A absorb thermal stress and the like, the high temperature superconductor 28A and the high temperature superconductor 29A during cooling and generation of electromagnetic force.
Will not be damaged.

Moreover, since the upper and lower ends of the good conductor 28B and the good conductor 29B and the power supply side electrode terminal 22 are slack, the function of absorbing thermal stress can be improved.

Even if the high-temperature superconductor 28A or the high-temperature superconductor 29A is in a quench state and no current flows, the good conductors 28B and 29B formed integrally with the high-temperature superconductor 28A and the high-temperature superconductor 29A, respectively.
Current can be bypassed and the function as a current lead can be maintained.

Since the first current lead body 28 and the second current lead body 29 are similarly cooled even at a temperature of about 20 K of the second-stage cooling section 21C, the heat penetrating into the superconducting coil 2 is further reduced. It is small.

Further, the power supply side electrode terminal 2 is connected to the refrigerator 21.
2, first insulating flange 23, second insulating flange 24
And an insulating fixing material 25, a first connection cooling plate 26, a second connection cooling plate 27, a first current lead body 28, and a second connection cooling plate 27.
Since the current lead body 29 is mounted, the compact and easy-to-use high-temperature superconductor current lead 20 having the positive electrode and the negative electrode integrated with the refrigerator 21 as a core can be obtained.

Further, since the high-temperature superconductor 28A and the high-temperature superconductor 29A are used, the invasion heat from the outside can be reduced as described above.

The first current lead body 28 and the second current lead body 28 are connected via the first connection cooling plate 26 and the second connection cooling plate 27.
Since the current lead bodies 29 are mounted, it is possible to secure a mechanical reinforcement mechanism for the current lead bodies 28 and 29.

When the high-temperature superconductor 28A and the high-temperature superconductor 29A enter the quench state, the good conductor 2
Since a bypass circuit is formed on the side of 8B and the good conductor 29B, the energized state is maintained and safety is ensured.

In the high-temperature superconductor current lead 20 according to the above-described embodiment, the cooling temperature of the refrigerator 21 is set to 80K.
Although the first-stage thermal anchor provided by the first-stage cooling unit 21B and the second-stage thermal anchor provided by the second-stage cooling unit 21C having a cooling temperature of 20K are provided, the second-stage thermal anchor may be omitted.

The number of high-temperature superconductors used as the current lead body is arbitrarily selected according to the required current.

[0047]

As described above, according to the present invention, a refrigerator is used, and the current lead body is composed of a high-temperature superconductor and a good conductor. Therefore, it is compact and easy to handle, and the strength of the high-temperature superconductor is reinforced and damaged. A high-reliability high-temperature superconductor current lead capable of preventing heat from outside and reducing quenching easily can be obtained.

[0048]

[Brief description of the drawings]

FIG. 1 is a perspective view of a high-temperature superconductor current lead 20 according to one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the same high-temperature superconductor current lead 20;

FIG. 3 is a perspective view of the cylindrical current lead body 30;

FIG. 4 is a perspective view of the plate-shaped current lead body 31;

FIG. 5 is a schematic view of a conventional superconducting coil device 1.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Superconducting coil device 2 Superconducting coil 3 Coil container 4 Refrigerant (liquid helium) 5 Heat shield plate 6 Cryostat container 7 Current lead for positive electrode 8 Current lead for negative electrode 9 External power supply 10 Coil side connection line 11 Power supply side connection line 12 Guide tube 20 High-temperature superconductor current lead 21 Refrigerator (small Gifford McMahon refrigerator) 21A Upper flange of refrigerator 21B First stage cooling unit 21C Second stage cooling unit of refrigerator 21 22 Power supply side electrode terminal 23 1 insulating flange 23A fixing hole of first insulating flange 23 24 second insulating flange 25 insulating fixing material 25A upper flange portion of insulating fixing material 25B lower flange portion of insulating fixing material 25C fixing hole of insulating fixing material 25 26 first connection cooling plate 26A fixing hole of first connection cooling plate 26 27th 2 connection cooling plate 27A fixing hole of second connection cooling plate 27 28 first current lead body (high-temperature superconductor current lead) 28A high-temperature superconductor 28B of first current lead body 28 B first current lead body 28 Good conductor 29 second current lead body (high-temperature superconductor current lead) 29A high-temperature superconductor of second current lead body 29 29B good conductor of second current lead body 29 30 cylindrical current lead body 31 plate-shaped current Lead body

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01L 39/04 H01F 6/00 H01B 12/00-12/16 H01B 13/00 561-565

Claims (2)

(57) [Claims] 1. A high-temperature superconductor current lead capable of electrically connecting a superconducting coil to an external power supply, comprising: a refrigerator disposed between the superconducting coil and the external power supply; A power-supply-side electrode terminal mounted on the side of the refrigerator via a first insulating flange; and a second insulating flange and connection to a freezing portion of the refrigerator.
A current lead body attached via a cooling plate and connectable to the superconducting coil, the current lead body comprising a high-temperature superconductor and a good conductor of a wire member integrally combined with the high-temperature superconductor. With this good conductor, the current lead body is cooled by the connection cooling.
To the power supply-side electrode terminal via the plate, and an insulating fixing material
A high-temperature superconductor current lead characterized in that it can be connected to the superconducting coil through a coil. Wherein said good conductor, claim, characterized in that to be connected by slack at both ends of its 1
The high temperature superconductor current lead as described.