A high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure

Abstract

The present invention discloses a high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure. The conductor structure includes: a full-cable central skeleton composed of a spiral structure of a metal cable or a perforated stainless steel tube or a perforated copper tube or a stainless steel narrow strip wound by multi-stage twisting, a number of high-temperature superconducting sub-cables, a full-cable protective wrapping and a metal armor. The structures of the high-temperature superconducting sub-cable from the inside to the outside are: a sub-cable central skeleton, a sub-cable central skeleton wrapping, a high-temperature superconducting tape and a sub-cable wrapping. The sub-cable central skeleton is formed by multi-stage twisting of metal strands; the high-temperature superconducting tape is wound on the sub-cable central skeleton. The present invention has a compact structure, the conductor has a self-supporting function, and has the ability to carry high current under high fields. At the same time, it can reduce the AC loss of the conductor, improve the flexibility of the conductor and enhance the cooling capacity of the conductor, thereby improving the stability margin and operation reliability of the high-temperature superconducting conductor.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature superconductivity, and in particular relates to a structural design of a high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure. Background Art

[0002] Superconducting materials refer to conductors with zero resistance at a certain temperature. The use of superconducting materials to prepare superconducting coils has the advantages of high efficiency, low loss, high transmission current density and large irreversible field, so it has great application prospects in the field of electricity. With the improvement of human productivity and living standards, the demand for energy is also increasing. Among them, the use of nuclear fusion to generate nuclear energy has been widely concerned and studied as a cleaner and more reliable way. The ultimate goal of using nuclear fusion to generate nuclear energy is to achieve controlled nuclear fusion. The most likely way to achieve this goal is to rely on magnetic fields to constrain high-temperature fusion fuels, that is, magnetic confinement fusion. In magnetic confinement fusion devices, in order to enable high-parameter plasma to operate safely and stably, it is necessary to rely on superconducting magnets made of superconducting materials to generate a strong magnetic field of a specific shape to constrain it. In 1911, Dr. Onnes discovered that mercury has almost zero resistance below 4.2K. He then tried to use the superconducting material lead (which is superconducting at 7.2K) to make coils to obtain strong magnetic fields. However, he found that even at 4.2K, the coils would lose their superconductivity after generating a magnetic field of 0.055T. This is because the critical magnetic fields of pure metal superconductors discovered earlier were all low. This shows that when you want to obtain a strong magnetic field through a superconducting magnet, the superconducting material used in the magnet needs to have a high critical magnetic field. Therefore, high-temperature superconducting materials have great application potential in the magnets of the next generation of fusion demonstration reactors.

[0003] In recent years, the most notable high-temperature superconducting materials are the bismuth-based (BSCCO) superconductors prepared by the bismuth strontium calcium copper oxide powder tube method and the superconductors using rare earth barium copper oxide (REBCO), which are first-generation and second-generation high-temperature superconducting materials, respectively. However, since the superconducting performance of the first-generation high-temperature superconducting materials will be limited by the irreversible field with a lower value, the second-generation high-temperature superconducting materials have the advantages of high current carrying capacity at higher temperatures and higher irreversible field values ​​compared to the first-generation high-temperature superconducting materials. In fusion devices, since superconducting magnets are in a complex transient electromagnetic environment, the performance requirements for the magnets are higher. Therefore, by designing a suitable structure of high-temperature superconducting conductors, the high-temperature superconducting conductors can meet the performance requirements, thereby ensuring the safety and stability of the long-term operation of superconducting magnets. Summary of the invention

[0004] The purpose of the present invention is to provide a high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure, which can ensure a compact structure while still having high current carrying capacity and low AC loss under high fields, and at the same time can improve the flexibility of the conductor and enhance the cooling capacity of the conductor, thereby improving the stability margin and operational reliability of the high-temperature superconducting conductor.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A high-current high-temperature superconducting conductor based on a twisted cable structure central skeleton, comprising a full-cable central skeleton, a plurality of high-temperature superconducting sub-cables wound on the full-cable central skeleton, a full-cable protective wrapping wrapped around the outermost sides of the plurality of high-temperature superconducting sub-cables, and a metal armor; wherein the full-cable central skeleton is a metal cable formed by multi-stage twisting or a spiral tube or a perforated stainless steel tube or a perforated copper tube wound by a stainless steel tape, and the surface of the strands in the metal cable is plated with a high-resistance layer material; the plurality of high-temperature superconducting sub-cables are composed of a sub-cable central skeleton, a sub-cable central skeleton wrapping, a high-temperature superconducting tape, and a sub-cable wrapping; the sub-cable central skeleton is formed by multi-stage twisting of metal strands, and the surface of the metal strands is plated with a high-resistance layer material; the sub-cable central skeleton wrapping adopts a metal tape wrapped around the sub-cable central skeleton; the multiple layers of high-temperature superconducting tape are wound on the outside of the sub-cable central skeleton wrapping; the sub-cable wrapping is a metal tape arranged on the outside of the high-temperature superconducting tape.

[0007] Furthermore, after the high-temperature superconducting sub-cable is fixed on the central frame of the whole cable through twisting, a full-cable protective wrapping is applied to its outermost layer and then inserted into the metal armor.

[0008] Furthermore, the high resistance layer material may be nickel, chromium or tin.

[0009] Furthermore, the metal belt wrapped around the sub-cable is a stainless steel belt or a copper belt, the copper belt is plated with a high-resistance layer material, and the high-resistance layer material is nickel, chromium or tin.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The purpose of the present invention is to provide a high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure. Since the central skeleton is made of multi-stage twisted cables of metal strands and the high-resistance layer material and thickness on the surface of the metal strands are selected, the size of the AC loss can be controlled and a stable matrix is ​​provided for the conductor, so the high-temperature superconducting conductor can operate in an alternating current or a changing magnetic field; at the same time, the central skeleton made of multi-stage twisted cables of metal strands can also improve the flexibility of the high-temperature superconducting conductor; the porosity of the skeleton can be adjusted by selecting metal strands of different diameters and twisted cable pitches; the wrapping structure of the full cable central skeleton and the sub-cable central skeleton can not only improve the degradation of superconducting performance caused by stress and strain, but also control the resistance between the sub-cables by selecting the thickness of different metal strip materials or different coating materials and the thickness of different coating materials, thereby further controlling the AC loss, thereby improving the stability margin and working reliability of the high-temperature superconducting conductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the overall structure of a high-current high-temperature superconducting conductor according to an embodiment of the present invention;

[0013] Figure 2 A schematic diagram of the structure of a high-temperature superconducting sub-cable according to an embodiment of the present invention;

[0014] In the figure: 1. Central skeleton of the whole cable; 2. High-temperature superconducting sub-cable; 3. Protective wrapping of the whole cable; 4. Metal armor; 5. Central skeleton of sub-cable; 6. Wrapping of the central skeleton of sub-cable; 7. High-temperature superconducting tape; 8. Wrapping of sub-cable. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0016] like Figure 1 , Figure 2As shown, a high-current high-temperature superconducting conductor based on a twisted cable structure central skeleton of the present invention comprises a full cable central skeleton 1, a high-temperature superconducting sub-cable 2 wound on the full cable central skeleton 1, a full cable protective wrap 3 and a metal armor 4 wrapped around the outermost sides of several high-temperature superconducting sub-cables 2. The high-temperature superconducting sub-cable 2 is mainly composed of a sub-cable central skeleton 5, a sub-cable central skeleton wrap 6, a multi-layer high-temperature superconducting tape 7 and a sub-cable wrap 8. The sub-cable central skeleton wrap 6 is made of a metal tape, which is wound on the sub-cable central skeleton 5; the multi-layer high-temperature superconducting tape 7 is wound on the outside of the sub-cable central skeleton wrap 6; the sub-cable wrap 8 is a metal tape, which is arranged on the outside of the high-temperature superconducting tape 7.

[0017] like Figure 1 As shown, the full cable central skeleton 1 is composed of a metal cable formed by multi-stage twisting or a spiral tube wound with a stainless steel belt or a perforated stainless steel tube or a copper tube, so as to stabilize the cable structure. The central skeleton using a metal cable can control the size of the AC loss by selecting a suitable torque and adjusting the high-resistance layer material and thickness on the surface of the metal strands by using an electroplating process. The metal cable can also be used as a stable matrix. By selecting metal strands of different diameters and twisting torque, the porosity between the metal cables can be adjusted to serve as a channel for the coolant. The high-temperature superconducting sub-cables 2 are twisted on the central skeleton 1 of the whole cable. The use of multiple high-temperature superconducting sub-cables can improve the current-carrying capacity of the high-temperature superconducting conductor; then the whole cable protective wrapping 3 is implemented on the outermost layer of several high-temperature superconducting sub-cables 2 to fix the sub-cables and protect them when threading the cable. At the same time, the resistance between the sub-cables can be controlled by selecting different metal strip materials and their thicknesses, or plating high-resistance layer materials on the surface of the metal strip materials, because different metal thin strip materials and thicknesses, different high-resistance layer materials and thicknesses have different resistances; then the whole cable is inserted into the metal armor 4, so that the high-temperature superconducting conductor has good self-support and provides a pressure vessel for coolant.

[0018] like Figure 2As shown, the sub-cable central skeleton 5 of the high-temperature superconducting sub-cable 2 is made of metal strands through multi-stage twisting. By selecting different twisting torques and adjusting the high-resistance layer material and thickness on the surface of the metal strands by electroplating process, the size of the AC loss can be controlled. The metal cable can also be used as a stable matrix. The gap between the metal cables also serves as a channel for the coolant. The porosity between the metal strands can be adjusted by selecting metal strands of different diameters and twisting torques. The sub-cable central skeleton wrapping 6 uses a metal belt, such as a stainless steel belt or a copper belt or a copper belt coated with a high-resistance layer material, which is wound on the sub-cable central skeleton 5 to smooth the surface of the sub-cable central skeleton 5 and avoid or reduce damage or strain to the high-temperature superconducting tape; then the high-temperature superconducting tape 7 is wound on the sub-cable central skeleton wrapping 6 in multiple layers. As the number of tapes increases, the current carrying capacity of the conductor is enhanced; then the sub-cable wrapping 8 is wound on the multiple layers of high-temperature superconducting tape 7. By selecting different metal thin strip materials and thicknesses and selecting different plating materials and thicknesses, the resistance between the sub-cables can be controlled. The metal strip refers to the stainless steel strip or copper strip used in various wrapping layers; the coating material and its thickness refer to the high-resistance layer material coated on the surface of the wrapping strip or metal strand through the electroplating process, such as nickel, chromium or tin, and its thickness can be controlled by the electroplating process.

[0019] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific examples described or replace them in a similar manner. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure, characterized in that: The invention comprises a full cable central skeleton (1), a plurality of high-temperature superconducting sub-cables (2) wound on the full cable central skeleton (1), a full cable protective wrap (3) wrapped around the outside of the plurality of high-temperature superconducting sub-cables (2), and a metal armor (4); wherein the full cable central skeleton (1) is a metal cable made of multi-stage twisted cable or a spiral tube wound with stainless steel strip or a perforated stainless steel tube or a perforated copper tube, and the surface of the strands in the metal cable is plated with a high-resistance layer material; the plurality of high-temperature superconducting sub-cables (2) are composed of the sub-cable central skeleton (5), the sub-cable central skeleton (6), and the metal armor (4). The invention relates to a cable substructure, comprising a frame wrap (6), multiple layers of high-temperature superconducting tapes (7) and a cable substructure (8); the cable substructure (5) is made of metal strands twisted in multiple stages, and the surface of the metal strands is plated with a high-resistance layer material; the cable substructure (6) is made of a metal tape wound around the cable substructure (5); the multiple layers of high-temperature superconducting tapes (7) are wound around the outer side of the cable substructure (6); and the cable substructure (8) is a metal tape wound around the outer side of the multiple layers of high-temperature superconducting tapes (7).

2. A high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure according to claim 1, characterized in that: After the plurality of high-temperature superconducting cables (2) are twisted and wound on the central frame (1) of the whole cable, a whole-cable protective wrapping (3) is applied to the outermost layer thereof, and then the cables are inserted into the metal armor (4).

3. A high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure according to claim 1, characterized in that: The high resistance layer material is nickel, chromium or tin.

4. A high-current high-temperature superconducting conductor based on a central skeleton of a twisted cable structure according to claim 1, characterized in that: The metal belt wrapped around the sub-cable is a stainless steel belt or a copper belt, and the copper belt is plated with a high-resistance layer material, and the high-resistance layer material is nickel, chromium or tin.

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