High-temperature superconducting solenoid coil system facing rapid current change and forming method

Abstract

The invention discloses a high-temperature superconducting solenoid coil system facing rapid current change and a forming method, and relates to the technical field of high-temperature superconducting. A CORC conductor formed by multiple layers of YBCO superconducting tapes, an outer armor and an insulating tape form a high-temperature superconducting cable which is tightly wound on the central framework. The shell sleeves the outer side after the high-temperature superconducting cable surrounds the central framework, and wraps the high-temperature superconducting cable together with the central framework; the upper and lower end covers are used for connecting the shell and the central framework, holes are formed in the end covers, and the pouring steel pipes are inserted into the holes of the end covers; the gap sealing glue is used for filling gaps between the end cover and the shell and gaps between the end cover and the central framework, providing a sealing environment and being used for sealing gaps between the pouring steel pipe and the end cover. The high-temperature superconducting solenoid coil is formed by sleeving solenoid coils with different diameters, and the upper flange and the lower flange are used for connection, so that the replaceability of the coil is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature superconductivity, and in particular relates to a high-temperature superconducting solenoid coil system and a forming method for rapid current changes. Background Art

[0002] Superconducting materials can be divided into low-temperature superconducting materials and high-temperature superconducting materials according to their critical temperatures. Low-temperature superconducting materials have been developed for a long time and the technology is relatively mature, but high-temperature superconducting materials have greater development potential. High-temperature superconducting materials usually have higher critical temperatures and critical magnetic fields. YBCO is a common copper oxide superconductor. Magnets wound with YBCO superconducting materials have high operating temperatures, low operating costs and good stability.

[0003] The CORC conductor is a compact and flexible superconducting conductor proposed by the National Institute of Standards and Technology and the University of Colorado. It is supported by a central copper skeleton, the outer layer of which is covered with insulating material, and the superconducting tape is spirally wound on the surface of the central skeleton. Its critical temperature increases with the number of winding layers. The CORC conductor has a circular cross-section, a simple manufacturing process, a high critical current density, and low inductance and AC loss. It is often used in high current transmission or magnetic coils.

[0004] High-temperature superconducting solenoid coils can be wound in double or single-pancake form, which can reduce the lateral bending damage of the strip, but there are gaps between the pancakes, and the number of coil joints is large, which will reduce the tightness and stability of the coil. Layer winding can also be used, using a long cable to wind and form at one time, which can reduce errors and the number of joints. The most critical thing in preparing layer-wound solenoid coils is the starting layer winding. The parallel winding method can be used, that is, the starting turn of the strip is first fixed on the central skeleton of the solenoid coil, and then the tension is loaded and wound along the axial direction of the central skeleton; the lamination method can also be used, that is, the strip is first wound around the skeleton, and the first turn is pressed when the second turn is wound, and it is pressed to prevent falling off, and then the winding is continued according to the normal process. However, the thickness of the starting turn of the lamination method coil is large, resulting in uneven coil thickness, which is easy to destroy the superconductivity of the coil, so the parallel winding method is generally used.

[0005] When superconducting coils operate under conditions of rapid current changes, they face many risks. Rapid changes in current will cause the superconducting coils to generate changing magnetic fields, and the interaction between the magnetic field and the current will generate large stresses in the superconducting coils. Superconducting coils that experience rapid current changes for a long time may suffer from material fatigue damage due to repeated stress cycles, threatening the operational safety of the superconducting coils. For energy storage superconducting magnets, if the current changes too quickly, it may cause energy to be released too quickly, thereby damaging the insulation material or other components of the coil. Once such risks occur, the superconducting coils are likely to quench, causing serious economic losses. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a high-temperature superconducting solenoid coil system and molding method for rapid current changes, wherein multiple solenoid coils of different diameters are solidified separately and then assembled together to form a whole. The present invention selects a CORC conductor made of a shell and YBCO high-temperature superconducting material, which not only reflects the advantages of high critical current and high critical magnetic field of the high-temperature superconducting coil, but also improves the reliability of the solenoid coil in dealing with rapid current changes and reduces the cost of accidents.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A high-temperature superconducting solenoid coil system for rapid current changes comprises a central frame, a high-temperature superconducting cable, a shell, an upper end cover, a lower end cover, an upper flange and a lower flange; the central frame, the high-temperature superconducting cable, the shell, the upper end cover and the lower end cover constitute a single high-temperature superconducting solenoid coil, and a plurality of high-temperature superconducting solenoid coils constitute a high-temperature superconducting solenoid coil system; the high-temperature superconducting cable is a CORC conductor composed of multiple layers of YBCO superconducting tapes, which is wrapped with insulating tape and tightly wrapped around the central frame; the shell is sheathed on the outside of the high-temperature superconducting cable after the high-temperature superconducting cable wraps around the central frame; The upper end cover and the lower end cover are made of G10 material and are used to connect the outer shell and the central frame; the upper end cover and the lower end cover are both circumferentially evenly opened with holes for glue injection, and another hole is provided for extending the head end or the end of the high-temperature superconducting cable; each high-temperature superconducting solenoid coil is solidified and formed separately, and then a single high-temperature superconducting solenoid coil with a small diameter is inserted into a single high-temperature superconducting solenoid coil with a large diameter, and the two coils are coaxially arranged in series, and upper flanges and lower flanges are installed at both ends of the multiple high-temperature superconducting solenoid coils that have been inserted, thereby forming a high-temperature superconducting solenoid coil system including multiple layers of parallel high-temperature superconducting solenoid coils.

[0009] Furthermore, a plurality of holes are formed on the upper flange and the lower flange.

[0010] Furthermore, the holes with small diameters correspond to the holes of the upper end caps and the lower end caps of each internal coil, and there are also holes with large diameters.

[0011] Furthermore, the central skeleton, the outer shell, the upper end cover and the lower end cover form an inner cavity, and the high-temperature superconducting cable is wrapped in the inner cavity.

[0012] Furthermore, gap sealing glue is applied to the gaps formed by the upper end cover, the lower end cover, the central frame and the outer shell respectively.

[0013] The present invention also provides a molding method for a high-temperature superconducting solenoid coil system for rapid current changes, which adopts a curing molding method to perform curing molding on a single high-temperature superconducting solenoid coil, including: inserting a casting steel pipe into the holes of an upper end cover and a lower end cover, and applying a gap-sealing glue to seal; adopting a bottom-up and top-out casting method, allowing the curing glue to enter from the casting steel pipe of the lower end cover, flow through the inner cavity formed by the outer shell, the central skeleton, the upper end cover, and the lower end cover, and then flow out from the casting steel pipe of the upper end cover to the external environment after immersing the high-temperature superconducting cable; after the curing glue fills the inner cavity, the upper end cover and the lower end cover are clamped with an F-type clamp. , compress and fix the single high-temperature superconducting solenoid coil as a whole to ensure the stability of the single high-temperature superconducting solenoid coil during the curing process; then send the single high-temperature superconducting solenoid coil into the curing furnace for heating and baking to solidify the curing glue and complete the curing of the single high-temperature superconducting solenoid coil; finally, the single high-temperature superconducting solenoid coil with a small diameter is inserted into the single high-temperature superconducting solenoid coil with a large diameter, and the two coils are coaxially arranged in series, and upper flanges and lower flanges are installed at both ends of the multiple high-temperature superconducting solenoid coils, thereby forming a high-temperature superconducting solenoid coil system including multiple layers of parallel high-temperature superconducting solenoid coils.

[0014] Furthermore, the casting steel pipe is inserted into the hole of the end cover for subsequent casting of curing glue.

[0015] Furthermore, the gap between the cast steel pipe and the end cover is sealed by a gap sealing glue.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] Most existing solenoid coils only have a central frame and an outer shell, with multiple layers of superconducting conductors wound inside. They only need to be solidified once, which makes the design and processing relatively simple. However, once an accident occurs, the superconducting conductor inside the coil is damaged and the entire solenoid coil loses its ability to work.

[0018] The solenoid coil of the present invention is composed of a plurality of coils with different diameters, each of which has a central skeleton and an outer shell, which can prevent other coils from being affected after one coil is burned to a certain extent. Once a quench accident occurs, the corresponding quench detection system and quench protection system will start to work, and quickly cut off the power supply after detecting the quench signal to prevent further damage to the coil. Therefore, after an accident occurs, the coils in the present invention will not be completely damaged, and only the damaged internal coils can be replaced, and other intact coils can be retained, thereby reducing the cost of the accident. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A partial cross-sectional view of a high-temperature superconducting solenoid coil system for rapid current changes according to the present invention;

[0020] Figure 2 It is a schematic diagram of a top view structure of a high-temperature superconducting solenoid coil system for rapid current changes of the present invention without an upper flange;

[0021] Figure 3 It is a schematic structural diagram of a single solenoid coil of the present invention.

[0022] In the figure: 1. upper flange; 2. outer shell; 3. lower flange; 4. lower end cover; 5. high-temperature superconducting cable; 6. central frame; 7. upper end cover. DETAILED DESCRIPTION

[0023] 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1-Figure 3 As shown, a high-temperature superconducting solenoid coil system for rapid current changes of the present invention comprises an upper flange 1, a housing 2, a lower flange 3, a lower end cover 4, a high-temperature superconducting cable 5, a central frame 6, and an upper end cover 7. The housing 2, the lower end cover 4, the high-temperature superconducting cable 5, the central frame 6, and the upper end cover 7 constitute a single high-temperature superconducting solenoid coil.

[0025] Specifically, the high-temperature superconducting cable 5 is composed of a CORC conductor, an external armor and an insulating tape, wherein the CORC conductor is made of multiple layers of YBCO high-temperature superconducting tapes wrapped on a hollow copper tube, the external armor separates the tape from the curing adhesive to prevent the performance degradation of the tape during curing, and the insulating tape is wrapped around the external armor to further improve the insulation capacity. The central skeleton 6 can reduce the eddy current loss during the operation of the coil, and because a CORC conductor with its own external armor is used, there is no need to process spiral grooves on the central skeleton 6, which reduces the difficulty of coil skeleton processing. The high-temperature superconducting cable 5 is tightly wrapped around the central skeleton 6 to ensure that there is no gap between each layer of cable. Before wrapping, a clamp is used to fix one end of the high-temperature superconducting cable 5 to prevent the cable from falling off during the wrapping process.

[0026] After the high-temperature superconducting cable 5 is wrapped around the central frame 6, the coil formed by the high-temperature superconducting cable 5 is sealed. In this embodiment, the outer shell 2 is mounted on the outside of the high-temperature superconducting cable 5, and then the upper end cover 7 and the lower end cover 4 are installed at the upper and lower ends respectively. Finally, the gap sealant is applied to the gaps between the outer shell 2, the lower end cover 4, the central frame 6, and the upper end cover 7. The upper end cover 7 and the lower end cover 4 are provided with holes.

[0027] After the sealing work, the individual high-temperature superconducting solenoid coils are cured respectively. The curing molding method is: insert the casting steel pipe into the holes of the upper end cover 7 and the lower end cover 4, and also apply the gap sealing glue to seal. The casting method from bottom to top and from top to outside is adopted, that is, the curing glue is allowed to enter from the casting steel pipe of the lower end cover 4, flow through the inner cavity formed by the outer shell 2, the central skeleton 6 and the upper end cover 7 and the lower end cover 4, and then flow out from the casting steel pipe of the upper end cover 7 after immersing the high-temperature superconducting cable 5, and flow into the external environment. After the curing glue fills the inner cavity, use an F-type clamp to clamp the upper end cover 7 and the lower end cover 4, compress and fix the coil as a whole, and ensure the stability of the coil during the curing process. Finally, the coil is sent to the curing furnace for heating and baking, so that the curing glue solidifies, and the curing of the single high-temperature superconducting solenoid coil is completed.

[0028] The upper flange 1 and the lower flange 3 are of the same annular shape, and the small diameter holes on the surface correspond one by one to the holes of the upper end cover 7 and the lower end cover 4, which are used to reflect the casting position of each coil inside. The large diameter holes are used to lead out the head and end of the high temperature superconducting cable 5 inside the high temperature superconducting solenoid coil system, which is convenient for subsequent connection with the superconducting joint. After all the high temperature superconducting solenoid coils are solidified, the high temperature superconducting solenoid coil with a small diameter is sleeved in the high temperature superconducting solenoid coil with a large diameter, and the coaxial series arrangement is arranged. The upper flange 1 and the lower flange 3 are installed at both ends to form a whole, and a multi-layer parallel solenoid coil is formed to generate an excitation magnetic field with a higher magnetic field strength. This increases the replaceability of the coil. If a quench accident occurs, the impact between the coils is small, and only the damaged coil needs to be replaced, which also reduces the cost of the accident.

[0029] 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 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 temperature superconducting solenoid coil system for rapid current changes, characterized in that: The invention comprises a central frame, a high-temperature superconducting cable, an outer shell, an upper end cover, a lower end cover, an upper flange and a lower flange; the central frame, the high-temperature superconducting cable, the outer shell, the upper end cover and the lower end cover constitute a single high-temperature superconducting solenoid coil, and a plurality of high-temperature superconducting solenoid coils constitute a high-temperature superconducting solenoid coil system; the high-temperature superconducting cable is a CORC conductor composed of multiple layers of YBCO superconducting tapes, which is wrapped with insulating tape and tightly wrapped around the central frame; the outer shell is sleeved on the outer side of the high-temperature superconducting cable after the high-temperature superconducting cable wraps around the central frame; the upper end cover and the lower end cover are used to connect the outer shell and the central frame; each high-temperature superconducting solenoid coil is cured and formed separately, and then a single high-temperature superconducting solenoid coil with a small diameter is sleeved in a single high-temperature superconducting solenoid coil with a large diameter, and the coils are coaxially arranged in series, and upper flanges and lower flanges are installed at both ends of the sleeved multiple high-temperature superconducting solenoid coils, thereby forming a high-temperature superconducting solenoid coil system including multiple layers of parallel high-temperature superconducting solenoid coils.

2. A high temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: A plurality of holes are formed on the upper flange and the lower flange.

3. A high temperature superconducting solenoid coil system for rapid current changes according to claim 2, characterized in that: The small diameter holes correspond to the holes of the upper end cap and the lower end cap of each internal coil, and there are also large diameter holes.

4. A high temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: The central frame, the outer shell, the upper end cover and the lower end cover form an inner cavity, and the high-temperature superconducting cable is wrapped in the inner cavity.

5. A high temperature superconducting solenoid coil system for rapid current changes according to claim 4, characterized in that: The gap sealing glue is applied to the gaps formed between the upper end cover, the lower end cover and the central frame and the outer shell respectively.

6. A high temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: The upper end cover and the lower end cover are made of G10 material.

7. A high temperature superconducting solenoid coil system for rapid current changes according to claim 1, characterized in that: The upper end cover and the lower end cover are both circumferentially evenly opened with holes for glue injection, and another hole is provided for extending the head end or the tail end of the high-temperature superconducting cable.

8. A forming method for a high temperature superconducting solenoid coil system for rapid current changes according to any one of claims 1 to 7, characterized in that: A single high-temperature superconducting solenoid coil is cured and formed by a curing molding method, including: inserting a casting steel pipe into the holes of the upper end cover and the lower end cover, and applying a gap sealing glue to seal; using a bottom-up and top-out casting method, allowing the curing glue to enter from the casting steel pipe of the lower end cover, flow through the inner cavity formed by the outer shell, the central frame, the upper end cover, and the lower end cover, and then immerse the high-temperature superconducting cable and flow out from the casting steel pipe of the upper end cover to the external environment; after the curing glue fills the inner cavity, the upper end cover and the lower end cover are clamped with an F-type clamp to form a single high-temperature superconducting solenoid coil as a The whole is compressed and fixed to ensure the stability of the single high-temperature superconducting solenoid coil during the curing process; then the single high-temperature superconducting solenoid coil is sent to the curing furnace for heating and baking to solidify the curing glue and complete the curing of the single high-temperature superconducting solenoid coil; finally, the single high-temperature superconducting solenoid coil with a small diameter is inserted into the single high-temperature superconducting solenoid coil with a large diameter, and the two coils are coaxially arranged in series, and upper flanges and lower flanges are installed at both ends of the multiple high-temperature superconducting solenoid coils, thereby forming a high-temperature superconducting solenoid coil system including multiple layers of parallel high-temperature superconducting solenoid coils.

9. The molding method according to claim 8, characterized in that: The pouring steel pipe is plugged into the hole of the end cover for pouring the subsequent curing glue.

10. The molding method according to claim 9, characterized in that: The gap between the cast steel pipe and the end cover is sealed by gap sealing glue.

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