Superconducting connector assembly and methods of assembly and disassembly

Abstract

According to one aspect, a superconducting connector assembly for electrically connecting a first superconducting cable and a second superconducting cable is provided, the superconducting connector assembly including at least one first superconducting cable terminal, the first superconducting cable terminal having at least one first opening for receiving an end of the first superconducting cable, and at least one second superconducting cable terminal, the second superconducting cable terminal having at least one second opening for receiving an end of the second superconducting cable. and an enclosing portion configured to receive and surround the first and second superconducting cable terminals, wherein the first and second openings overlap when the first and second superconducting cable terminals are received within the enclosing portion, and the enclosing portion is made from a material having a thermal expansion coefficient different from that of the first and second superconducting cable terminals such that the first and second superconducting cable terminals are compressed together to form an electrical interface at an operating temperature of the superconducting connector assembly.

Description

[Technical Field]

[0001] SUPERCONDUCTING CONNECTOR ASSEMBLY AND METHODS OF ASSEMBLY AND DISASSEMBLY FIELD OF THE DISCLOSURE The present disclosure relates to superconducting connector assemblies and methods of assembly and disassembly, and in particular, but not exclusively, to the application of superconducting connector assemblies and methods of assembly and disassembly to nuclear fusion reactors. [Background technology]

[0002] A tokamak is a nuclear fusion reactor that can confine a mixture of deuterium and tritium in a plasma by a magnetic field with a toroidal shape. A spherical tokamak is a compact version of the toroid in which the radius of the center of the toroid is minimized. Such a compact configuration is still topologically toroidal, but is called a spherical tokamak due to its spherical appearance.

[0003] Figure 1 shows a cross-section of a previously proposed tokamak configuration. Superconducting magnet assemblies 1, 2, 3 are arranged around a toroidal vacuum vessel 4. The superconducting magnet assemblies 1, 2, 3 may be formed from superconducting cables.

[0004] The superconducting magnet assembly 1 comprises a toroidal field coil that extends around a portion of the toroidal vacuum vessel 4. Multiple such toroidal field coils may be provided and distributed around the toroidal vacuum vessel 4. The toroidal field coils provide a magnetic field with magnetic field lines circulating around the center of the toroidal vacuum vessel 4, helping to contain the plasma.

[0005] The superconducting magnet assembly 2 comprises a poloidal field coil that extends around the toroidal vacuum vessel 4. Multiple such poloidal field coils may be provided, and may be distributed along the central axis of the toroidal vacuum vessel 4. The poloidal field coils help to shape and stabilize the plasma.

[0006] The superconducting magnet assembly 3 comprises a central solenoid that extends through the center of the toroidal vacuum vessel 4. The central solenoid is capable of inducing a current in the plasma to heat it.

[0007] The advantage of spherical tokamaks is their compact nature, which is expected to reduce capital costs. Other advantages include attractive plasma physics features. A key efficiency parameter, called beta, is the ratio of the thermal energy density stored in the plasma to the thermal energy density stored in the confining magnetic field. Spherical tokamaks can accommodate much higher beta values ​​than conventional tokamaks due to the higher ratio of plasma current to the magnetic field they can accommodate.

[0008] However, the more compact configuration of spherical tokamaks presents challenges. For example, there may not be enough space for shielding to ensure that magnet assemblies 1, 2, and 3 can withstand the entire reactor life. Consequently, magnet assemblies and their superconducting cables may require replacement during the reactor's life. Therefore, it is desirable to allow easy access to the magnet assemblies. To this end, it has previously been proposed to provide superconducting cables with disconnectable, easily detachable, or reattachable joints that allow for disassembly of magnet assemblies. However, previously proposed superconducting cable joints are not easily disconnected, e.g., by remote means, and add electrical resistance that affects their superconducting performance. Summary of the Invention

[0009] [Means for solving the problem] According to a first particular aspect, there is provided a superconducting connector assembly for electrically connecting a first superconducting cable and a second superconducting cable, the superconducting connector assembly comprising: at least one first superconducting cable terminal, the first superconducting cable terminal having at least one first opening for receiving an end of the first superconducting cable; at least one second superconducting cable terminal, the second superconducting cable terminal having at least one second opening for receiving an end of a second superconducting cable; an enclosing portion configured to receive and enclose the first superconducting cable terminal and the second superconducting cable terminal; Equipped with the first and second openings overlap when the first and second superconducting cable terminals are received within the enclosing portion; The surrounding portion is made from a material having a coefficient of thermal expansion different from that of the first and second superconducting cable terminals such that the first and second superconducting cable terminals are compressed together to form an electrical interface at the operating temperature of the superconducting connector assembly.

[0010] The first and second openings may overlap in a plane perpendicular to the longitudinal axes of the first and second openings. The first and second openings (and therefore the first and second superconducting cables) may extend alongside one another. The longitudinal axes of the first and second openings (and therefore the first and second superconducting cables) may be substantially parallel to one another.

[0011] The dimensions of the first and second superconducting cable terminations and the surrounding portion may allow for assembly of the superconducting connector assembly at room temperature (about 298 K). The surrounding portion may contract such that the first and second superconducting cable terminations are compressed together at cryogenic temperatures, for example, below about 100 K.

[0012] The first and second openings may be wider than the ends of the respective first and second superconducting cables. The first and second superconducting cables may be soldered to the first and second openings using, for example, an indium-based solder. The solder may be soft (compared to the terminals) to minimize stress in the terminals being transferred to the superconducting cables.

[0013] The superconducting connector assembly may be for use in a nuclear reactor, such as a nuclear fusion reactor, particularly a tokamak reactor. The reactor may include the superconducting connector assembly. The superconducting connector assembly may be used in other superconductor applications, such as MRI, NMR, particle accelerators, or any other application requiring superconducting connectors.

[0014] The superconducting connector assembly may provide an excellent electrical connection between the first and second superconducting cables, for example, due to the contact pressure that may be achieved between the first and second superconducting cable terminals without compromising superconducting performance. Compressive stresses may not be transmitted to the first and second superconducting cables, which may otherwise degrade their superconducting properties.

[0015] The superconducting connector assembly may also provide a compact configuration. Such a compact configuration may be beneficial in a nuclear fusion reactor, which may require a dense arrangement of superconducting cables to generate the necessary magnetic field. The superconducting connector assembly may also allow for easy disassembly and reassembly during reactor maintenance. The compact configuration may leave sufficient space between each superconducting connector assembly for robotic removal and reassembly of the connections.

[0016] The components of the superconducting connector assembly may be formed from materials that are not activated (e.g., not induced to be radioactive) in a radioactive environment. The first and second superconducting cable terminals may be formed from copper, such as oxygen-free high conductivity copper. The surrounding portion may be formed from aluminum.

[0017] The first superconducting cable terminal may be configured to surround the second superconducting cable terminal. The first superconducting cable terminal may be concentric with the second superconducting cable terminal. The first and / or second superconducting cable terminal may be concentric with the surrounding portion. The superconducting connector assembly may further include a sleeve. The second superconducting terminal may surround the sleeve. The sleeve may be concentric with the first and / or second superconducting terminal. The sleeve may define a coolant passage. The sleeve may be formed from stainless steel, Invar, or any other material that shrinks less than the first and / or second superconducting cable terminals.

[0018] The first and second superconducting cable terminals may be configured to be provided side by side, e.g., neither the first nor the second superconducting cable terminal surrounds the other. The first and second superconducting cable terminals may have substantially the same cross-sectional shape, e.g., rectangular. The first and second superconducting cable terminals may have substantially the same dimensions.

[0019] The superconducting connector assembly may include a first pair of first and second superconducting cable terminals and a second pair of first and second superconducting cable terminals. Electrical insulators may be provided between the first pair of first and second superconducting cable terminals and the second pair of first and second superconducting cable terminals. Additional pairs of first and second superconducting cable terminals may be provided, for example, with insulators provided between adjacent pairs. At least one additional insulator may be provided between the surrounding portion and the first and second superconducting cable terminals. The insulators and / or the additional insulators may be formed from stainless steel.

[0020] The superconducting connector assembly may further include a mechanical fastening means or assembly configured to mechanically clamp the first and second superconducting cable terminations together. The mechanical fastening means may be configured, for example, to apply a prestress or contact pressure that may compress the first and second superconducting cable terminations within the enclosing portions prior to thermal contraction of the enclosing portions. The mechanical fastening means may additionally or alternatively take up any slack due, for example, to manufacturing tolerances.

[0021] The mechanical fixing means may comprise at least one wedge having a taper angle capable of compressing the first and second superconducting cable terminations within the enclosing portion when the wedge is inserted between the enclosing portion and at least one of the first and second superconducting cable terminations.

[0022] The superconducting connector assembly may further include at least one locking feature configured to lock or secure the at least one wedge in an inserted position where the wedge is between the enclosing portion and at least one of the first and second superconducting cable terminals. The locking feature may include at least one screw that may engage the enclosing portion (or another component) to provide a counter force to hold the at least one wedge in place. A single locking feature may be configured to lock or secure multiple wedges in an inserted position.

[0023] The locking feature may comprise at least one screw that may extend in substantially the same direction as the first and second openings.

[0024] The locking feature may comprise a locking member which may have extending arms which may engage with the respective wedge. The locking member may comprise radially extending arms and may be cross-shaped, star-shaped or the like.

[0025] The locking feature may include a reaction portion that engages with one end of the enclosing portion. The locking member may engage with a wedge at the other end of the enclosing portion. A screw may couple the locking member to the reaction portion. The locking feature may include an insulator extending between the first pair of first and second superconducting cable terminals and the second pair of first and second superconducting cable terminals. The screw may engage with the insulator between the first and second pair of superconducting cable terminals. The reaction portion may be part of the insulator. The screw may extend in the same direction as the cable opening.

[0026] The mechanical fastening means may include at least one screw. The screw may engage with and extend through the enclosing portion so as to compress the first and second superconducting cable terminals within the enclosing portion when tightened. The screw may extend laterally, e.g., substantially perpendicular to the longitudinal direction of the first and second openings. For example, the screw may extend through a sidewall of the enclosing portion.

[0027] The mechanical securing means may comprise at least one pair of opposing wedges, one of which may be linearly movable relative to the other wedge such that corresponding wedge faces slide relative to one another to vary a lateral dimension of the opposing wedge pair. The mechanical securing means may comprise a plurality of opposing wedge pairs in a sawtooth configuration.

[0028] The mechanical locking means may comprise any other mechanical device such as an over-center cam, a plunger, or the like.

[0029] The mechanical securing means may be configured to be engaged or disengaged from the superconducting cable in the field by a remote tool, for example, remote from the connector assembly. The locking feature may be configured to be engaged or disengaged from the superconducting cable in the field by a remote tool, for example, remote from the connector assembly. Remotely connecting or disconnecting the connector assembly is advantageous due to the radioactive environment in which the connector assembly may operate.

[0030] The superconducting connector assembly may include at least one coolant passage configured to allow a flow of coolant through the superconducting connector assembly. The coolant may include a cryogenic fluid. At least one of the first and second superconducting cable terminals may include the coolant passage. The sleeve may define the coolant passage. The at least one coolant passage may be formed by a gap between the surrounding portion and at least one of the first and second superconducting cable terminals.

[0031] The first and second superconducting cable terminals may interlock with one another. For example, one (or both) of the first and second superconducting cable terminals may include a protrusion, and the other (or both) of the first and second superconducting cable terminals may include a receiving portion. The receiving portion may be configured to receive the protrusion. The electrical interface may be provided by opposing surfaces on the protrusion and the receiving portion.

[0032] The superconducting connector assembly may include a plurality of first superconducting cable terminals and a plurality of second superconducting cable terminals. The superconducting connector assembly may include a plurality of pairs of first and second superconducting cable terminals. The pairs of first and second superconducting cable terminals may be distributed in a circular arrangement. The pairs of first and second superconducting cable terminals may be distributed equiangularly in the circular arrangement. Each pair of first and second superconducting cable terminals may form a truncated sector in the circular arrangement. The surrounding portion may surround the pairs of first and second superconducting cable terminals distributed in the circular arrangement.

[0033] At least one of the first and second superconducting cable terminals may comprise a conductive portion and an insulating portion. The conductive portion may provide at least a portion of the electrical interface. The insulating portion of the first and second superconducting cable terminals may be provided at least at the interface between adjacent pairs of the first and second superconducting cable terminals.

[0034] The surrounding portion may include at least one rib. The rib may be a reinforcing rib that may reinforce the surrounding portion. The rib may increase the surface area of ​​the surrounding portion to increase the rate of heat transfer, for example, from the cryogenic fluid. The rib may be positioned to engage recesses or ribs of an adjacent superconducting connector assembly. The rib may assist in stiffening, cooling, and / or mosaicing.

[0035] The superconducting connector assemblies may be configured to be substantially tessellated with other superconducting connector assemblies. The surrounding portion may include one or more ribs. One of the ribs may be configured to cooperate with a recess or another rib of an adjacent superconducting connector assembly.

[0036] According to a second particular aspect, there is provided an assembly comprising a plurality of the aforementioned superconducting connector assemblies, which may be interdigitated with one another.

[0037] According to a third particular aspect, there is provided an assembly comprising the aforementioned superconducting connector assembly, a first superconducting cable, and a second superconducting cable.

[0038] The assembly may further include solder within the first and second openings. The solder may connect the first and second superconducting cables to the first and second superconducting cable terminals, respectively. The solder may have a Young's modulus or hardness less than the material of the first and second superconducting cable terminals. The solder may have a Young's modulus or hardness an order of magnitude less than the material of the first and second superconducting cable terminals. The solder may have an indium or soft solder eutectic-based component. For example, the solder may be primarily indium or eutectic-based.

[0039] According to a fourth specific aspect, there is provided a superconducting toroidal field coil assembly including the aforementioned superconducting connector assembly including a plurality of pairs of first and second superconducting cable terminals. Each pair of first and second superconducting cable terminals may be configured to connect ends of superconducting toroidal field cables to each other. The superconducting connector assembly may be centrally located with respect to a toroidal vessel for, for example, a nuclear fusion reactor.

[0040] According to a fifth particular aspect, there is provided a method of assembling a superconducting connector assembly for electrically connecting a first superconducting cable and a second superconducting cable, the superconducting connector comprising: at least one first superconducting cable terminal, the first superconducting cable terminal having at least one first opening for receiving an end of the first superconducting cable; at least one second superconducting cable terminal, the second superconducting cable terminal having at least one second opening for receiving an end of a second superconducting cable; an enclosing portion configured to receive and enclose the first and second superconducting cable terminals, the enclosing portion being made from a material having a thermal expansion coefficient different from the thermal expansion coefficients of the first and second superconducting cable terminals; Equipped with The method is: inserting the first superconducting cable terminal and the second superconducting cable terminal into the surrounding portion so that the first and second openings overlap; cryogenically cooling the superconducting connector assembly such that the first superconducting cable termination and the second superconducting cable termination are compressed together to form an electrical interface at an operating temperature of the superconducting connector assembly; Includes.

[0041] The method may further include the step of mechanically clamping the first and second superconducting cable terminals together to apply a prestress that compresses the first and second superconducting cable terminals within the enclosing portion before cryogenically cooling the superconducting connector assembly.

[0042] The method may further comprise the step of locking said locking feature to lock or secure the at least one wedge in the inserted position.

[0043] The method may further include, before inserting the first superconducting cable terminal and the second superconducting cable terminal into the surrounding portion, soldering an end of the first superconducting cable to a first opening of the first superconducting cable terminal and soldering an end of the second superconducting cable to a second opening of the second superconducting cable terminal.

[0044] According to a sixth aspect, there is provided a method of disassembling a superconducting connector assembly to electrically disconnect a first superconducting cable and a second superconducting cable, the superconducting connectors comprising: at least one first superconducting cable terminal, the first superconducting cable terminal having at least one first opening for receiving an end of the first superconducting cable; at least one second superconducting cable terminal, the second superconducting cable terminal having at least one second opening for receiving an end of a second superconducting cable; an enclosing portion that receives and surrounds the first and second superconducting cable terminals such that the first and second openings overlap, the enclosing portion being made from a material having a thermal expansion coefficient different from that of the first and second superconducting cable terminals such that the first and second superconducting cable terminals are compressed together to form an electrical interface at an operating temperature of the superconducting connector assembly; Equipped with The method is: increasing the temperature of the superconducting connector assembly from an operating temperature such that the first superconducting cable terminal and the second superconducting cable terminal are depressurized; loosening or removing at least one of the first superconducting cable terminal and the second superconducting cable terminal from the surrounding portion; Includes.

[0045] The method may further include releasing the mechanical clamp clamping the first and second superconducting cable terminations together. The method may further include unlocking said locking feature to unlock or loosen the at least one wedge from the insertion position.

[0046] These and other aspects will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0047] Exemplary embodiments will now be described, by way of example only, with reference to the following drawings: [Brief explanation of the drawings]

[0048] [Figure 1] 1 is a schematic cutaway view of a previously proposed tokamak fusion reactor. [Figure 2] Figures 2a and 2b are collectively referred to as Figure 2, where Figure 2a is a perspective view of a superconducting connector assembly according to one example of the present disclosure, and Figure 2b is a side cross-sectional view of a superconducting connector assembly according to one example of the present disclosure. [Figure 3] FIG. 10 is a perspective view of a superconducting connector assembly according to another example of the present disclosure. [Figure 4] Figures 4a and 4b are collectively referred to as Figure 4, where Figure 4a is a cutaway perspective view of a superconducting connector assembly according to another example of the present disclosure, and Figure 4b is a side cross-sectional view of a superconducting connector assembly according to another example of the present disclosure. [Figure 5] Figures 5a and 5b are collectively referred to as Figure 5, where Figure 5a is a cutaway perspective view of a superconducting connector assembly according to another example of the present disclosure, and Figure 5b is a side cross-sectional view of a superconducting connector assembly according to another example of the present disclosure. [Figure 6] Figures 6a and 6b are collectively referred to as Figure 6, where Figure 6a is a perspective view of a superconducting connector assembly according to another example of the present disclosure, and Figure 6b is a side cross-sectional view of a superconducting connector assembly according to another example of the present disclosure. [Figure 7] Figures 7a and 7b are collectively referred to as Figure 7, where Figure 7a is an oblique view of a superconducting connector assembly according to another example of the present disclosure, and Figure 7b is a cross-sectional side view of a superconducting connector assembly according to another example of the present disclosure. [Figure 8] Figures 8a, 8b, and 8c are collectively referred to as Figure 8, where Figure 8a is a cutaway perspective view of a superconducting connector assembly according to another example of the present disclosure, Figure 8b is a perspective view of a superconducting connector assembly according to another example of the present disclosure, and Figure 8c is a side cross-sectional view of a superconducting connector assembly according to another example of the present disclosure. [Figure 9] FIG. 10 is a perspective view of a superconducting connector assembly according to another example of the present disclosure. [Figure 10] FIG. 10 is an end view of an array of superconducting connector assemblies according to another example of the present disclosure. [Figure 11] FIG. 10 is a perspective view of an array of superconducting connector assemblies according to another example of the present disclosure. [Figure 12] FIG. 10 is a perspective view of a superconducting connector assembly according to a further example of the present disclosure. [Figure 13] FIG. 10 is a cross-sectional plan view of a superconducting connector assembly according to a further example of the present disclosure. [Figure 14-1] Figures 14a and 14b are collectively referred to as Figure 14, where Figure 14a is a cross-sectional plan view of a portion of a superconducting connector assembly according to a further example of the present disclosure, showing disassembled first and second superconducting cable terminals, and Figure 14b is a cross-sectional plan view of a portion of a superconducting connector assembly according to a further example of the present disclosure, showing the first and second superconducting cable terminals assembled together. [Figure 14-2]Figures 14a and 14b are collectively referred to as Figure 14, where Figure 14a is a cross-sectional plan view of a portion of a superconducting connector assembly according to a further example of the present disclosure, showing disassembled first and second superconducting cable terminals, and Figure 14b is a cross-sectional plan view of a portion of a superconducting connector assembly according to a further example of the present disclosure, showing the first and second superconducting cable terminals assembled together. [Figure 15] FIG. 10 is a perspective view of a superconducting toroidal field coil assembly according to yet another example of the present disclosure. [Figure 16] FIG. 10 is a cross-sectional perspective view of a superconducting connector assembly according to a further example of the present disclosure. [Figure 17] 10 is a flowchart illustrating an assembly method according to another example of the present disclosure. [Figure 18] 10 is a flowchart illustrating a disassembly method according to another example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0049] Referring to FIG. 2 , the present disclosure relates to a superconducting connector assembly 100 for electrically connecting a first superconducting cable 102 and a second superconducting cable 104. The superconducting connector assembly 100 may connect superconducting cables in a nuclear reactor, such as a nuclear fusion reactor, particularly a tokamak reactor. The superconducting cables 102, 104 may form magnetic coils that contribute to one or more magnetic fields of the reactor. Therefore, components of the superconducting connector assembly 100 may be formed from materials that are not activated (e.g., not induced to be radioactive) in a radioactive environment. However, it is also contemplated that the superconducting connector assembly 100 may be used in other superconductor applications, such as MRI, NMR, particle accelerators, or any other application requiring superconducting connectors.

[0050] The superconducting connector assembly 100 includes a first superconducting cable terminal 110 and a second superconducting cable terminal 120. The first and second superconducting cable terminals 110, 120 are configured to cooperate with one another to form electrical contact therebetween. In the illustrated example, the first superconducting cable terminal 110 surrounds the second superconducting cable terminal 120, e.g., with the inner surface of the first superconducting cable terminal 110 engaging the outer surface of the second superconducting cable terminal 120. The first superconducting cable terminal 110 may be substantially tubular, particularly having a circular cross-section. The first superconducting cable terminal 110 may be concentric with the second superconducting cable terminal 120. However, as shown in FIG. 2b, the inner surface of the first superconducting cable terminal 110 and the outer surface of the second superconducting cable terminal 120 may be tapered (e.g., so that the diameter of each surface varies along the length of the terminal). The tapered surfaces may aid in assembly, particularly during remote operation, and may provide an interference fit.

[0051] The first superconducting cable terminal 110 includes at least one first opening 112 for receiving an end of the first superconducting cable 102. As shown, multiple first openings 112 may be provided, each receiving a corresponding first superconducting cable 102 or a strand / end of a single first superconducting cable having multiple strands / ends. The first openings 112 may be distributed around the first superconducting cable terminal 110, e.g., the first openings may be equiangularly distributed. The longitudinal axes of the first openings 112 may be generally parallel to one another. As shown in FIG. 2b, the first openings 112 may extend entirely through the first superconducting cable terminal 110 such that the first openings 112 are open at both ends, although in alternative configurations, the first openings 112 may be closed at one end of the first superconducting cable terminal 110. The first opening 112 may be circular, for example to accept a circular cable type (such as CORC™), or may be substantially square / rectangular to accept a CICC (cable in conduit) or laminated tape type configuration.

[0052] Similarly, the second superconducting cable terminal 120 includes at least one second opening 122 for receiving an end of the second superconducting cable 104. As shown, multiple second openings 122 may be provided, each receiving a corresponding second superconducting cable 104 or a strand / end of a single second superconducting cable including multiple strands / ends. The second openings 122 may be distributed around the second superconducting cable terminal 120; for example, the second openings may be equiangularly distributed. The longitudinal axes of the second openings 122 may be generally parallel to one another. The second openings 122 may be generally parallel to the first opening 112. As shown in FIG. 2b, the second openings 122 may extend entirely through the second superconducting cable terminal 120 such that the second openings 122 are open at both ends; however, in an alternative configuration, the second openings 122 may be closed at one end of the second superconducting cable terminal 120. With respect to the first opening, the second opening 122 may be circular, for example, to receive a circular cable type (such as CORC™), or may be substantially square / rectangular to receive a CICC (cable-in-conduit) or laminated tape type configuration. The first and second openings 112, 122 may have different shapes, for example, so that the superconducting connector assembly provides an interface between different types of superconducting cables.

[0053] The superconducting connector assembly 100 further includes an enclosing portion 130 configured to receive and surround the first superconducting cable terminal 110. The enclosing portion 130 is configured to cooperate with the first superconducting cable terminal 110. In the illustrated example, the enclosing portion 130 encloses the first superconducting cable terminal 110, for example, with an inner surface of the enclosing portion 130 engaging an outer surface of the first superconducting cable terminal 110. The enclosing portion 130 may be substantially tubular, particularly having a circular cross-section. The enclosing portion 130 may be concentric with the first superconducting cable terminal 110. The enclosing portion 130 may include flanges 131 at its ends, although such flanges may be omitted, for example, to facilitate mosaicing.

[0054] The superconducting connector assembly 100 may further include a central portion, such as a sleeve 140. The second superconducting terminal 120 may surround the sleeve 140, for example, with the inner surface of the second superconducting cable terminal 120 engaging the outer surface of the sleeve 140. The second superconducting cable terminal 120 may be substantially tubular, particularly having a circular cross-section. The second superconducting cable terminal 120 may be concentric with the sleeve 140. The sleeve 140 may define a passage 142 capable of receiving a coolant flow. In an alternative configuration, the sleeve 140 may be replaced with a solid central portion.

[0055] As best shown in FIG. 2b, when the first and second superconducting cable terminals 110, 120 are assembled within the enclosing portion 130, the first and second openings 112, 122 overlap. In particular, the first and second openings 112, 122 (and thus the cables 102, 104) may overlap in a plane perpendicular to the longitudinal axes of the first and second openings. The first and second superconducting cables 102, 104 may extend through most, if not all, of the respective first and second openings 112, 122. Thus, the first and second superconducting cables 102, 104 may extend alongside one another for a significant portion of the length of the superconducting assembly 100. In this manner, a good electrical connection can be achieved between the first and second superconducting cables 102, 104 and the respective first and second superconducting terminals 110, 120, minimizing electrical resistance between the cables.

[0056] 2b illustrates first and second superconducting cables 102, 104 extending from opposite ends of the superconducting connector assembly 100, e.g., the first superconducting cable 102 extending from the first end and the second superconducting cable 104 extending from the second end. Thus, the superconducting connector assembly 100 may be disposed between the first and second superconducting cables 102, 104. However, it is also contemplated that the first and second superconducting cables 102, 104 may extend from the same end of the superconducting connector assembly 100.

[0057] The dimensions of the first and second superconducting cable terminals 110, 120 and the surrounding portion 130 may allow for assembly of the superconducting connector assembly 100 at, for example, standard room temperature (approximately 298 K). However, the surrounding portion 130 has a different coefficient of thermal expansion than the coefficient of thermal expansion of the first and second superconducting cable terminals 110, 120. The difference is that as the superconducting connector assembly 100 cools to an operating temperature (e.g., a cryogenic temperature below approximately 100 K), the surrounding portion 130 contracts more than the first and second superconducting cable terminals 110, 120. As a result of the relative contraction rates, the first superconducting cable terminal 110 and the second superconducting cable terminal 120 are compressed together. This improves the performance of the electrical interface at the operating temperature of the superconducting connector assembly 100.

[0058] Central portion or sleeve 140 may also have a coefficient of thermal expansion that is different from the coefficient of thermal expansion of first and second superconducting cable terminals 110, 120. Central portion or sleeve 140 may contract less than second superconducting cable terminal 120 as the temperature decreases. For example, the relative contraction as the temperature decreases may cause second superconducting cable terminal 120 to be compressed relative to sleeve 140. In this manner, first and second superconducting cable terminals 110, 120 may be compressed between surrounding portion 130 and sleeve 140.

[0059] The first and second superconducting cable terminals 110, 120 may be formed from copper, such as oxygen-free high conductivity copper. The surrounding portion 130 may be formed from aluminum. The sleeve 140 may be formed from steel, such as stainless steel, Invar, or any other material that shrinks less than the first and / or second superconducting cable terminals 110, 120.

[0060] While the first and second superconducting cable terminals 110, 120 may be made from the same material and therefore have the same thermal expansion characteristics, it is also contemplated that the first and second superconducting cable terminals 110, 120 may be formed from different materials and have different thermal expansion characteristics. For example, the first superconducting cable terminal 110 may contract at a greater rate as its temperature decreases than the second superconducting cable terminal 120. Thus, cooling of the superconducting connector assembly 100 may cause compression due to the relative contraction rates between the first and second superconducting cable terminals 110, 120.

[0061] The first and second openings 112, 122 may be the same size as or wider than the ends of the respective first and second superconducting cables 102, 104 (e.g., at both standard room temperature and the operating temperature of the superconducting connector assembly 100). The first and second superconducting cables 102, 104 may be soldered to the first and second openings using solder 114, 124, such as an indium-based or eutectic solder. The solder 114, 124 may be soft (compared to the first and second superconducting terminals 110, 120) to minimize compressive stresses in the terminals 110, 120 that are transmitted to the superconducting cables 102, 104. For example, the solder may have a lower Young's modulus or hardness value (at the operating temperature of the superconducting connector assembly 100) than the material of the first and second superconducting cable terminals 110, 120. In particular, the solder may have a Young's modulus or hardness that is an order of magnitude less than the material of the first and second superconducting cable terminals 110 , 120 .

[0062] Referring to FIG. 3 , another example of a superconducting connector assembly 200 is shown. The superconducting connector assembly 200 differs from the superconducting connector assembly 100 in that a first superconducting cable terminal 210 and a second superconducting cable terminal 220 are disposed side-by-side. In particular, neither the first nor the second superconducting cable terminal 210, 220 surrounds the other. An enclosing portion 230 surrounds both the first superconducting cable terminal 210 and the second superconducting cable terminal 220. Otherwise, the features described with respect to the superconducting connector assembly 100 can also be applied to the superconducting connector assembly 200. Furthermore, the features described with respect to the superconducting connector assembly 200 can also be applied to the superconducting connector assembly 100.

[0063] First and second superconducting cable terminals 210, 220 may have substantially the same cross-sectional shape (e.g., rectangular) and may have substantially the same dimensions. Surrounding portion 230 may define an opening that receives first and second superconducting cable terminals 210, 220. The surrounding portion opening may have a rectangular cross-section.

[0064] The superconducting connector assembly 200 may include a first pair of first and second superconducting cable terminals 210, 220 and a second pair of first and second superconducting cable terminals 210′, 220′. An electrical insulator 250 may be provided between the first pair of first and second superconducting cable terminals 210, 220 and the second pair of first and second superconducting cable terminals 210′, 220′. The insulator 250 may be formed from stainless steel, such as austenitic stainless steel, or any other insulating material. At cryogenic temperatures, stainless steel acts as an insulator. Thus, the superconducting connector assembly 200 can connect multiple separate electrical connections.

[0065] Further pairs of first and second superconducting cable terminals may be provided, for example with insulators between adjacent pairs. The first and second superconducting cable terminals may be arranged in a row within the enclosing sub-opening.

[0066] At least one additional insulator 260 may be provided between the inner wall of the surrounding portion 230 and the first and second superconducting cable terminals 210, 220. The additional insulator 260 may be formed from stainless steel, such as austenitic stainless steel, or any other insulating material.

[0067] The first superconducting cable terminal 210 includes at least one opening 212 for receiving a first superconducting cable (not shown in FIG. 2 ). The second superconducting cable terminal 220 includes at least one opening 222 for receiving a second superconducting cable (not shown in FIG. 2 ). In the illustrated example, the first and second superconducting cable terminals 210, 220 each include two openings, although other numbers of openings are contemplated. Each opening of a particular superconducting cable terminal can receive a separate superconducting cable or an end / strand of a particular superconducting cable. With respect to the superconducting connector assembly 100, the first and / or second openings 212, 222 may be circular, for example, to receive a circular cable type (such as CORC™), or may be substantially square / rectangular to receive a CICC (cable-in-conduit) or laminated tape type configuration. The first and second openings 212, 222 may have different shapes, for example, so that the superconducting connector assembly 200 provides an interface between different types of superconducting cables.

[0068] The same aperture arrangement may be applied to a second pair of first and second superconducting cable terminals 210', 220', such that first superconducting cable terminal 210' includes at least one aperture 212' and second superconducting cable terminal 220' includes at least one aperture 222'. The apertures 212', 222' of the second pair of first and second superconducting cable terminals 210', 220' may receive different superconducting cables from the first pair of first and second superconducting cable terminals 210', 220'.

[0069] The surrounding portion 230 may include at least one rib 232. As shown, multiple ribs 232 may be provided. The ribs 232 may extend longitudinally along the outer surface of the surrounding portion 230, e.g., in the same direction as the openings 212, 222. Although not shown, ribs in other directions may be provided, e.g., extending around the perimeter of the surrounding portion. The ribs 232 may increase the structural rigidity of the surrounding portion 230. The ribs 232 may also increase the surface area of ​​the surrounding portion 230, e.g., increasing the rate of heat transfer from the cryogenic fluid. This may aid in cooling the connector assembly 200 and effective contraction of the surrounding portion 230.

[0070] Additionally, as described in more detail below with reference to FIG. 11, the ribs 232 may be positioned to engage recesses or ribs on adjacent superconducting connector assemblies 200 to aid in tessellation of adjacent superconducting connector assemblies 200.

[0071] The surrounding portion 230 may include a flange 234 around at least one end of the surrounding portion 230. The rib 232 may abut the flange 234. The flange 234 may increase the structural rigidity of the surrounding portion 230.

[0072] The superconducting connector assembly 200 can include at least one coolant passage configured to allow the flow of coolant through the superconducting connector assembly 200. The coolant may include a cryogenic fluid. For example, the first and / or second superconducting cable terminals 210, 220, 210', 220' can include additional openings or passages 224, 224' (shown in FIG. 11 ) for receiving the flow of coolant. Such additional passages 224, 224' can extend through the length of the superconducting cable terminal.

[0073] Additionally or alternatively, at least one coolant passage may be formed by a gap 236 between surrounding portion 230 and at least one of first and second superconducting cable terminals 210, 220. Such a gap 236 may be formed between adjacent further insulators 260, for example, at a corner of an interior wall of surrounding portion 230. Gaps 236 may help prevent further insulators 260 from adversely affecting the compression provided by surrounding portion 230, for example, by preventing further insulators 260 from interfering with one another.

[0074] Otherwise, superconducting connector assembly 200 functions in the same manner as superconducting connector assembly 100. In particular, surrounding portion 230 contracts more than first and second superconducting cable terminals 210, 220, 210′, 220′, such that first and second superconducting cable terminals are pressed together at the operating temperature of superconducting connector assembly 200.

[0075] 4 to 9 , the superconducting connector assembly 200 can further include mechanical fastening means configured to mechanically clamp the first and second superconducting cable terminals 210, 220 together. The mechanical fastening means can be configured, for example, to apply a prestress that can compress the first and second superconducting cable terminals 210, 220 within the enclosing portion 230 prior to thermal contraction of the enclosing portion. Such prestress can assist in the assembly of the superconducting connector assembly 200 and can help prevent the first and second superconducting cable terminals 210, 220 from slipping out of the enclosing portion 230 prior to thermal contraction. The mechanical fastening means can also compensate for thermal stress caused by the contraction of the enclosing portion 230. This can therefore increase the pressure acting on the first and second superconducting cable terminals 210, 220, further improving the performance of the electrical connection therebetween.

[0076] 4 and 5, the mechanical fastening means may comprise at least one bolt, stud, or screw (not shown) extending through at least one hole 238 in the enclosing portion 230. As shown, there may be a plurality of holes 238 that can receive corresponding screws. The screw and hole 238 may extend laterally, for example, substantially perpendicular to the longitudinal direction of the first and second openings, through the sidewall of the enclosing portion 230. The hole 238 may be provided between the ribs 232. The screw and hole 238 may be threaded so that the screw engages with threads in the hole and pressure at the end of the screw is transmitted to the enclosing portion 230. The screw may act on a further insulator 260 that can distribute a compressive force acting on the first and / or second superconducting cable terminals 210, 220. Thus, tightening the screw may compress the first and second superconducting cable terminals 210, 220 within the enclosing portion 230.

[0077] Figure 4 shows a configuration in which the screws and holes 238 are provided on two (adjacent) sides of the enclosing portion 230. Figure 5 shows an alternative configuration in which the screws and holes 238 are provided on all sides of the enclosing portion 230. However, the screws and holes may be provided on any number of sides or any other combination of sides (e.g., opposing sides).

[0078] As shown in FIGS. 6 and 7, the mechanical fastening means can include at least one wedge 280 for insertion between the surrounding portion 230 and at least one of the first and second superconducting cable terminals 210, 220, 210′, 220′. The wedge 280 can replace (or be provided in addition to) one of the additional insulators 260. The wedge 280 can be an insulator. The wedge 280 can be formed from stainless steel, such as austenitic stainless steel, or any other insulating material. The wedge 280 can be inserted in a direction parallel to the longitudinal axis of the openings 212, 222. As best shown in FIGS. 6b and 7b, the taper angle of the wedge 280 can compress the first and second superconducting cable terminals 210, 220, 210′, 220′ within the surrounding portion 230 when the wedge 280 is inserted.

[0079] FIG. 6 shows an example having two wedges 280 arranged perpendicular to one another. In such a configuration, the wedges 280 can compress the first and second superconducting cable terminals 210, 220, 210', 220' in the vertical direction. FIG. 7 shows another example having four wedges 280, e.g., one wedge on each surface of the inner wall of the enclosing portion. In the example of FIG. 7, a pair of wedges 280 can compress the first and second superconducting cable terminals 210, 220, 210', 220' in each direction. It will be appreciated that other numbers of wedges 280, e.g., one, three, or any other number, can be used.

[0080] 6-9, the superconducting connector assembly 200 may further include at least one locking feature configured to lock or secure the mechanical fastening means in place. For example, the locking feature may lock the wedges 280 in their inserted position. The locking feature may include a screw 282 that engages with the enclosing portion 230 to provide a counterforce that holds one of the wedges 280 in place. As shown in FIGS. 6 and 7, one screw 282 may be provided for each wedge 280. The screw 282 may extend through a tab on the end of each wedge 280 and into the flange 234 of the enclosing portion 230. The screw 282 may extend in substantially the same direction as the first and second openings 212, 222 (and thus the superconducting cable).

[0081] As previously mentioned, one screw may be provided for each wedge 280. However, with reference to FIGS. 8 and 9, a single locking feature may be configured to lock or secure multiple wedges 280 in their inserted position. In the example shown in FIG. 8, the locking feature includes a locking member 284 having arms 286 extending radially from a hub 287. Each arm 286 may engage with a respective wedge 280 at its distal end. In the illustrated example with four wedges 280, the locking member 284 may have a cross-shaped configuration. FIG. 9 shows an alternative configuration in which the cross-shaped locking member 284 is replaced with a locking member in the form of a plate 285. The edges of the plate 285 may engage with the wedges 280 to hold them in place. The plate 285 includes a series of holes or slots that align with the openings 212, 222 to allow passage of the superconducting cable. The shape of such holes or slots may correspond to the shape of the respective openings 212, 222.

[0082] In both of the examples shown in FIGS. 8 and 9 , the screw 288 can engage with the locking member 284. The screw 288 may then engage with a reaction portion 289 that transmits a retaining force to the surrounding portion 230. Again, the screw 288 can extend in the same direction as the cable openings 212, 222. The reaction portion 289 can also function as an insulator 250 disposed between the first pair of first and second superconducting cable terminals 210, 220 and the second pair of first and second superconducting cable terminals 210′, 220′. At one end, the insulator 250 can include a threaded hole for receiving the screw 288. The other end of the insulator 250 can engage with the surrounding portion 230 to transmit a reaction force from the screw 288 to the surrounding portion 230. For example, the insulator 250 can include a surface 290 that engages with an edge of the surrounding portion 230. The examples shown in Figures 8 and 9 preferably reduce the number of screws that need to be tightened or loosened, thereby simplifying the assembly or disassembly process.

[0083] 4-9 illustrate various possibilities for the mechanical locking means. However, it is contemplated that the mechanical locking means may take different forms, such as an over-center cam or any other type of mechanical means. The mechanical locking means may be applied to any of the superconducting connector assemblies 100, 200 described above. Regardless of the form the mechanical locking means takes, the mechanical locking means may be configured to be engaged or disengaged with the superconducting cables 102, 104 in the field by a remote tool, e.g., remote from the connector assemblies 100, 200. Similarly, the locking feature may be configured to be engaged or disengaged with the superconducting cables in the field by a remote tool, e.g., remote from the connector assemblies 100, 200.

[0084] 10 and 11, there may be a plurality of the aforementioned superconducting connector assemblies 100, 200. The superconducting connector assemblies 100, 200 may be connected to one another, for example, in a mosaic, and may be linked together to form a larger assembly of connector assemblies 100, 200.

[0085] 10 shows a first assembly 300 comprising a plurality of superconducting connector assemblies corresponding to the previously described superconducting connector assemblies 100. However, to aid in tessellation, the surrounding portion 130 may be substantially hexagonal in shape. The first assembly 300 may comprise an outer sheath 310 containing a plurality of superconducting connector assemblies 100.

[0086] FIG. 11 illustrates a second assembly 400 including multiple superconducting connector assemblies corresponding to the superconducting connector assemblies 200 described above. While four superconducting connector assemblies 200 are shown, it can be understood that more or fewer superconducting connector assemblies 200 can be provided. The superconducting assemblies 200 can also be arranged differently than shown in FIG. 11 , e.g., as wires or in any other shape / configuration. An outer sheath (not shown) can be provided. Such an outer sheath can provide a layer of insulation. (Although FIG. 11 illustrates only one of the superconducting connector assemblies 200 with the first and second superconducting cable terminals 210, 220 inserted, it can be understood that the other superconducting connector assembly 200 can include the respective first and second superconducting cable terminals 210, 220.) As mentioned above, the surrounding portion 230 may include one or more ribs 232. The ribs 232 may cooperate to connect the superconducting connector assemblies 200 to one another. For example, a rib 232 of one superconducting connector assembly 200 may cooperate with a rib or recess of an adjacent superconducting connector assembly 200. A recess may be formed between two adjacent ribs 232. In this manner, adjacent connector assemblies 200 may interlock, providing a highly adaptable assembly.

[0087] 11 also shows an optional positioning mechanism 270 provided on the insulator 250 (which may be provided independently of the second assembly 400). The positioning mechanism 270 may interlock with an adjacent first or second superconducting cable terminal 210, 220. The positioning mechanism 270 may comprise an abutment shoulder that extends into a corresponding recess in the first or second superconducting cable terminal 210, 220. The positioning mechanism 270 may help hold the components together during assembly of the superconducting connector assembly 200.

[0088] 10 and 11 may provide gaps between adjacent superconducting connector assemblies 100, 200 and / or outer sheaths 310. Such gaps may form passages that can receive coolant flow, for example, in a manner similar to the additional openings or passages 224, 224′ shown in FIG.

[0089] 12 and 13, a further example of a superconducting connector assembly 500 is shown. The superconducting connector assembly 500 differs from the superconducting connector assemblies 100, 200 in that the superconducting connector assemblies 100, 200 include multiple pairs of first and second superconducting cable terminals 510, 520. An enclosing portion 530 collectively surrounds the pairs of first and second superconducting cable terminals 510, 520. Otherwise, the features described with respect to the superconducting connector assemblies 100, 200 are also applicable to the superconducting connector assembly 500. Furthermore, the features described with respect to the superconducting connector assembly 500 are also applicable to the superconducting connector assemblies 100, 200.

[0090] Each pair of first and second superconducting cable terminals 510, 520 includes a first superconducting cable terminal 510 and a second superconducting cable terminal 520 configured to be electrically coupled to each other to form an electrical connection. Each of the first and second superconducting cable terminals 510, 520 receives a corresponding superconducting cable 502, 504. Thus, each pair of first and second superconducting cable terminals 510, 520 can electrically connect the superconducting cables 502, 504 connected to that pair of first and second superconducting cable terminals 510, 520 to each other. However, as described in more detail below, adjacent pairs of first and second superconducting cable terminals 510, 520 may be electrically isolated from each other.

[0091] As best shown in Figures 12 and 13, the pairs of first and second superconducting cable terminals 510, 520 may be distributed in a circular arrangement, for example, with each pair of first and second superconducting cable terminals 510, 520 forming a truncated sector of the circular arrangement. (Each pair of first and second superconducting cable terminals 510, 520 may be, for example, substantially trapezoidal in shape with a curved surface facing the surrounding portion 530.) The pairs of first and second superconducting cable terminals 510, 520 may be distributed equiangularly in the circular arrangement. The surrounding portion 530 surrounds the pairs of first and second superconducting cable terminals 510, 520. The surrounding portion 530 may have a generally circular cross-section. The pairs of first and second superconducting cable terminals 510, 520 may also have a substantially circular cross-section.

[0092] Superconducting connector assembly 500 functions in substantially the same manner as superconducting connector assemblies 100, 200. In particular, surrounding portion 530 is configured to thermally contract more than first and second superconducting cable terminals 510, 520, such that the first and second superconducting cable terminals are pressed together at the operating temperature of superconducting connector assembly 500. As surrounding portion 530 contracts, the pair of first and second superconducting cable terminals 510, 520 is compressed together (e.g., circumferentially), and the first and second superconducting cable terminals 510, 520 within each pair are also forced toward each other.

[0093] 14 illustrates a pair of first and second superconducting cable terminals 510, 520. As illustrated, the first and second superconducting cable terminals 510, 520 may interlock with one another. For example, the first superconducting cable terminal 510 may include a protrusion 516, and the second superconducting cable terminal 520 may include a receiver 528 configured to matingly receive the protrusion 516. Additionally, the second superconducting cable terminal 520 may include a pair of additional protrusions 526a, 526b, and the first superconducting cable terminal 510 may include a pair of additional protrusions 526a, 526b configured to matingly receive the pair of additional receivers 518a, 518b. The pair of additional protrusions 526a, 526b may be provided on either side of (or at least partially define) the receiver 528 of the second superconducting cable terminal 520. Similarly, a pair of additional receivers 518a, 518b may be provided on either side of protrusion 516 of first superconducting cable terminal 510. As a result of this configuration, first and second superconducting cable terminals 510, 520 may matably interlock with one another.

[0094] The opposing contact surfaces of the protrusion 516 and the receiving portion 528 can form an electrical interface. Similarly, the opposing contact surfaces on the pair of further protrusions 526 a, 526 b and the pair of further receiving portions 518 a, 518 b can also form an electrical interface. In this way, a large contact area for the electrical interface can be provided. Therefore, the electrical resistance at the interface can be reduced.

[0095] The protrusion 516 and / or the further protrusions 526a, 526b may extend substantially radially of the superconducting connector assembly 500. Similarly, the opposing contact surfaces may also extend substantially radially of the superconducting connector assembly 500. As a result, the electrical interface may be perpendicular to the circumferential direction of the superconducting connector assembly 500. This orientation may maximize the contact pressure between the opposing electrical contact surfaces as the surrounding portion 530 contracts. This may also reduce the electrical resistance at the interface.

[0096] Continuing to refer to FIG. 14, first superconducting cable terminal 510 can include at least one conductive portion 519a and insulating portion 519b. Similarly, second superconducting cable terminal 520 can include at least one conductive portion 529a and insulating portion 529b. Conductive portions 519a, 529a can provide at least a portion of the electrical interface. For example, sidewalls of protrusions 516, 526a, 526b and recesses 518a, 518b, 528 can include conductive portions 519a, 529a. In contrast, insulating portions 519b, 529b can be provided at least at the interface between adjacent pairs of first and second superconducting cable terminals 510, 520, for example, so that adjacent pairs can be insulated from each other. As best shown in FIG. 14b, insulating portions 519b, 529b can form carriers for respective conductive portions 519a, 529a. The conductive portions 519a, 529a may be made of a conductive material such as copper, and the insulating portions 519b, 529b may be made of an electrically insulating material such as stainless steel.

[0097] The first superconducting cable terminal 510 may include a first opening 512 for receiving the first superconducting cable 502, and the second superconducting cable terminal 520 may include a second opening 522 for receiving the second superconducting cable 504. In particular, the conductive portion 519a of the first superconducting cable terminal 510 may include the first opening 512. Similarly, the conductive portion 529a of the second superconducting cable terminal 520 may include the second opening 522. The openings 512, 522 may be arranged in a row, for example, with a row of openings 512, 522 for each opposing contact surface. FIG. 14a shows the first and second superconducting cables 502, 504 in place, but these are omitted from FIG. 14b. In addition to the openings 512, 522, the first and second superconducting cable terminals 510, 520 may also include coolant passages 514, 524.

[0098] Although described as separate first and second superconducting cable terminals 510, 520, it is also envisioned that first and second superconducting cable terminals 510, 520 may be part of a single component that forms an electrical interface. It is also envisioned that conductive portions 519 a, 529 a may be considered first and second superconducting cable terminals 510, 520, respectively. In either case, contraction of surrounding portion 530 may press electrical contact surfaces together to reduce electrical resistance.

[0099] 14 , superconducting connector assembly 500 can further include mechanical fastening means in the form of opposing wedges 580. Wedges 580 can be disposed between rows of conductor openings 522 in second superconducting cable terminal 520. However, it is also contemplated that opposing wedges can additionally or alternatively be disposed between rows of conductor openings 512 in first superconducting cable terminal 510. One of opposing wedges 580 can be linearly movable relative to the other wedge 580 such that corresponding wedge surfaces slide relative to one another, changing the lateral dimensions of the pair of opposing wedges. In the particular example shown, moving one of wedges 580 increases the lateral spacing (e.g., circumferentially) between the rows of conductor openings 522, thereby increasing the contact pressure between the opposing electrical contact surfaces. The position of wedge 580 can be mechanically adjusted, for example, by a screw mechanism (not shown) extending through an opening in surrounding portion 530. As shown, there may be a plurality of opposing wedges arranged in a sawtooth pattern 580. Such a configuration provides additional compressive force to the electrical interface along the length of the electrical interface.

[0100] 15 and 16 , the superconducting connector assembly 500 may be provided in a superconducting toroidal field coil assembly 600. The superconducting toroidal field coil assembly 600 may correspond to the superconducting magnet assembly 1 shown in FIG. 1 . For example, each pair of first and second superconducting cable terminals 510, 520 of the superconducting connector assembly 500 may be configured to connect the ends of a particular superconducting toroidal field cable 602 to each other. In this manner, the superconducting connector assembly 500 can connect all of the superconducting toroidal field cables 602 together with a single connector assembly. The superconducting connector assembly 500 may be provided centrally with respect to a toroidal vessel 4, for example, for a nuclear fusion reactor. In particular, the superconducting connector assembly 500 may be provided at the top of the toroidal vessel 4.

[0101] FIG. 16 illustrates different paths for the first and second superconducting cables 502, 504 exiting the superconducting connector assembly 500. The first and second superconducting cables 502, 504 correspond to the first and second ends of particular superconducting toroidal field cables 602, 604. The first and second ends of the superconducting toroidal field cables 602, 604 may extend from the same side of the superconducting connector assembly 500. The first end of the superconducting toroidal field cable 602 (i.e., the first superconducting cable 502) may initially extend vertically downward, then rotate substantially 90 degrees and extend horizontally across the top of the toroidal vessel 4. The second end of the superconducting toroidal field cable 604 (i.e., the second superconducting cable 504) may continue vertically downward through the center of the toroidal vessel 4, for example.

[0102] While Figures 15 and 16 show the superconducting connector assembly 500 mounted on the top of the toroidal vessel 4, it is also contemplated that the superconducting connector assembly 500 may additionally or alternatively be mounted on the bottom of the toroidal vessel 4.

[0103] 17 , the present disclosure relates to a method 700 of assembling a superconducting connector assembly 100, 200, 500 to electrically connect a first superconducting cable 102, 502 and a second superconducting cable 104, 504. The method 700 includes a step 710 of inserting a first superconducting cable termination 110, 210, 510 and a second superconducting cable termination 120, 220, 520 into an enclosing portion 130, 230, 530 such that the first and second openings overlap. The method 700 further includes a step 720 of cryogenically cooling the superconducting connector assembly 100, 200, 500 such that the first superconducting cable termination 110, 210, 510 and the second superconducting cable termination 120, 220, 520 are compressed together to form an electrical interface at an operating temperature of the superconducting connector assembly.

[0104] Method 700 may further include, prior to cryogenically cooling 720 the superconducting connector assembly, mechanically clamping 715 the first and second superconducting cable terminations (e.g., if mechanical clamps are provided) to prestress the first and second superconducting cable terminations in compression within enclosing portion 130, 230, 530. Method 700 may further include locking said locking feature to lock or secure at least one wedge in the inserted position.

[0105] The method 700 may further include a step 705 of soldering the ends of the first and second superconducting cables 102, 502, 104, 504 to the respective first and second openings before a step 710 of inserting the first superconducting cable terminal 110, 210, 510 and the second superconducting cable terminal 120, 220, 520 into the surrounding portion 130, 230, 530.

[0106] 18 , the present disclosure relates to a method 800 of disassembling a superconducting connector assembly 100, 200, 500 to electrically disconnect a first superconducting cable 102, 502 and a second superconducting cable 104, 504. The method includes a step 810 of increasing the temperature of the superconducting connector assembly 100, 200, 500 from an operating temperature such that the first superconducting cable termination 110, 210, 510 and the second superconducting cable termination 120, 220, 520 are decompressed (e.g., no longer under thermal compression). The method 800 further includes a step 820 of loosening and removing at least one of the first superconducting cable termination 110, 210, 510 and the second superconducting cable termination 120, 220, 520 from the surrounding portion 130, 230, 530. Method 800 may further include step 815 of releasing a mechanical clamp (e.g., if such a mechanical clamp is provided) prior to step 820 of removing the first and / or second superconducting cable termination. Step 815 of releasing a mechanical clamp may include unlocking the locking feature described above.

[0107] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the principles and techniques described herein, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. 1. A superconducting connector assembly for electrically connecting a first superconducting cable and a second superconducting cable, comprising: at least one first superconducting cable terminal, the first superconducting cable terminal having at least one first opening for receiving an end of the first superconducting cable; at least one second superconducting cable terminal, the second superconducting cable terminal having at least one second opening for receiving an end of the second superconducting cable; an enclosing portion configured to receive and enclose the first superconducting cable terminal and the second superconducting cable terminal; Equipped with the first and second openings overlap when the first and second superconducting cable terminals are received within the enclosing portion; the surrounding portion is made from a material having a coefficient of thermal expansion different from that of the first and second superconducting cable terminals such that the first and second superconducting cable terminals are compressed together to form an electrical interface at an operating temperature of the superconducting connector assembly. Superconducting connector assembly.

2. 2. The superconducting connector assembly of claim 1, wherein said first and second superconducting cable terminations are formed from oxygen-free high conductivity copper.

3. 3. The superconducting connector assembly of claim 1, wherein said surrounding portion is formed from aluminum.

4. 4. The superconducting connector assembly of claim 1, wherein the first superconducting cable terminal is configured to surround the second superconducting cable terminal.

5. 5. The superconducting connector assembly of claim 4, wherein said first superconducting cable terminal is concentric with said second superconducting cable terminal.

6. 6. The superconducting connector assembly of claim 4 or 5, wherein the superconducting connector assembly further comprises a sleeve, and the second superconducting cable terminal surrounds the sleeve.

7. 4. The superconducting connector assembly according to claim 1, wherein the first superconducting cable terminal and the second superconducting cable terminal are configured to be provided alongside each other.

8. 8. The superconducting connector assembly of claim 1, wherein the superconducting connector assembly comprises a first pair of the first and second superconducting cable terminals and a second pair of the first and second superconducting cable terminals, and an electrical insulator is provided between the first pair of the first and second superconducting cable terminals and the second pair of the first and second superconducting cable terminals.

9. 9. A superconducting connector assembly according to claim 1, further comprising mechanical fastening means configured to mechanically clamp together the first and second superconducting cable terminations.

10. 10. The superconducting connector assembly of claim 9, wherein the mechanical fastening means is configured to provide a prestress that compresses the first and second superconducting cable terminations within the enclosing portions prior to thermal contraction of the enclosing portions.

11. 11. The superconducting connector assembly of claim 9 or 10, wherein the mechanical fixing means comprises at least one wedge, the taper angle of the wedge compressing the first and second superconducting cable terminals within the surrounding portion when the wedge is inserted between the surrounding portion and at least one of the first and second superconducting cable terminals.

12. 12. The superconducting connector assembly of claim 11, further comprising at least one locking feature configured to lock or secure the at least one wedge in an inserted position where the wedge is between the surrounding portion and at least one of the first and second superconducting cable terminals.

13. The superconducting connector assembly of claim 12 , wherein a single locking feature is configured to lock or secure multiple wedges in the inserted position.

14. 14. The superconducting connector assembly of claim 12 or 13, wherein the locking feature comprises at least one screw extending in substantially the same direction as the first and second openings.

15. 15. A superconducting connector assembly as described in any one of claims 9 to 14, wherein the mechanical fixing means comprises at least one screw that engages with and extends through the surrounding portion so as to compress the first and second superconducting cable terminals within the surrounding portion when tightened.

16. 16. A superconducting connector assembly as claimed in any one of claims 9 to 15, wherein the mechanical fixing means comprises at least a pair of opposing wedges, one of the wedges being linearly movable relative to the other of the wedges such that corresponding wedge faces slide relative to each other and a lateral dimension of the pair of opposing wedges is changed.

17. 17. The superconducting connector assembly of claim 16, wherein said mechanical locking means comprises a plurality of opposing wedge pairs in a sawtooth configuration.

18. 18. The superconducting connector assembly of claim 1, wherein the superconducting connector assembly comprises at least one coolant passage configured to allow a flow of coolant through the superconducting connector assembly.

19. 20. The superconducting connector assembly of claim 18, wherein at least one of said first and second superconducting cable terminations comprises said coolant passageway.

20. 20. The superconducting connector assembly of claim 18 or 19, wherein at least one of the coolant passages is formed by a gap between the surrounding portion and at least one of the first and second superconducting cable terminations.

21. 21. The superconducting connector assembly of claim 1, wherein the first and second superconducting cable terminations interlock with respect to one another.

22. 22. The superconducting connector assembly of claim 21, wherein one of the first and second superconducting cable terminals comprises a protrusion and the other of the first and second superconducting cable terminals comprises a receiving portion, the receiving portion configured to receive the protrusion.

23. 23. The superconducting connector assembly of claim 22, wherein said electrical interface is provided by opposing surfaces on said protrusion and said receiver.

24. 24. A superconducting connector assembly as claimed in any one of claims 1 to 23, wherein at least one of the first and second superconducting cable terminals comprises a conductive portion and an insulating portion, the conductive portion providing at least a portion of the electrical interface.

25. 25. The superconducting connector assembly of claim 1, wherein the superconducting connector assembly comprises a plurality of the first superconducting cable terminals and a plurality of second superconducting cable terminals.

26. 26. A superconducting connector assembly as described in any one of claims 1 to 25, wherein the superconducting connector assembly comprises a plurality of pairs of the first and second superconducting cable terminals, the pairs of the first and second superconducting cable terminals being distributed in a circular arrangement.

27. 27. The superconducting connector assembly of claim 26, wherein each pair of said first and second superconducting cable terminations forms a truncated sector of said circular arrangement.

28. 28. A superconducting connector assembly according to claim 26 or 27, wherein the surrounding portion surrounds the pair of the first and second superconducting cable terminals distributed in the circular arrangement.

29. 29. A superconducting connector assembly according to any one of claims 1 to 28, wherein the surrounding portion comprises at least one rib.

30. 30. A superconducting connector assembly according to any one of claims 1 to 29, wherein the superconducting connector assemblies are configured to be substantially tessellated with others of the superconducting connector assemblies.

31. 31. The superconducting connector assembly of claim 30, wherein the surrounding portion comprises one or more ribs, one of the ribs configured to cooperate with a recess or another of the ribs of an adjacent superconducting connector assembly.

32. 32. An assembly comprising a plurality of superconducting connector assemblies according to claim 30 or 31, wherein the superconducting connector assemblies are tessellated with one another.

33. 32. An assembly comprising the superconducting connector assembly of any one of claims 1 to 31, the first superconducting cable, and the second superconducting cable.

34. 34. The assembly of claim 33, wherein the assembly further comprises solder in the first and second openings, the solder connecting the first and second superconducting cables to the first and second superconducting cable terminals, respectively, the solder having a lower Young's modulus or hardness than a material of the first and second superconducting cable terminals.

35. 35. The assembly of claim 34, wherein the solder comprises indium or a eutectic base component.

36. 29. A superconducting toroidal field coil assembly comprising the superconducting connector assembly of any one of claims 26 to 28, wherein each pair of the first and second superconducting cable terminals is configured to connect ends of a superconducting toroidal field cable to one another.

37. 1. A method of assembling a superconducting connector assembly for electrically connecting a first superconducting cable and a second superconducting cable, the superconducting connector assembly comprising: at least one first superconducting cable terminal, the first superconducting cable terminal having at least one first opening for receiving an end of the first superconducting cable; at least one second superconducting cable terminal, the second superconducting cable terminal having at least one second opening for receiving an end of the second superconducting cable; an enclosing portion configured to receive and surround the first superconducting cable terminal and the second superconducting cable terminal, the enclosing portion being made from a material having a thermal expansion coefficient different from a thermal expansion coefficient of the first and second superconducting cable terminals; Equipped with The method comprises: inserting the first superconducting cable terminal and the second superconducting cable terminal into the surrounding portion so that the first and second openings overlap; cryogenically cooling the superconducting connector assembly such that the first superconducting cable termination and the second superconducting cable termination are compressed together to form an electrical interface at an operating temperature of the superconducting connector assembly; A method comprising:

38. mechanically clamping the first and second superconducting cable terminals together to apply a prestress that compresses the first and second superconducting cable terminals within the enclosing portion prior to cryogenically cooling the superconducting connector assembly; 38. The method of claim 37, further comprising:

39. before inserting the first superconducting cable terminal and the second superconducting cable terminal into the surrounding portion; soldering an end of the first superconducting cable to the first opening of the first superconducting cable terminal; soldering an end of the second superconducting cable to the second opening of the second superconducting cable terminal; 39. The method of claim 37 or 38, further comprising:

40. 1. A method of disassembling a superconducting connector assembly to electrically disconnect a first superconducting cable and a second superconducting cable, the superconducting connector assembly comprising: at least one first superconducting cable terminal, the first superconducting cable terminal having at least one first opening for receiving an end of the first superconducting cable; at least one second superconducting cable terminal, the second superconducting cable terminal having at least one second opening for receiving an end of the second superconducting cable; an enclosing portion that receives and surrounds the first superconducting cable terminal and the second superconducting cable terminal so that the first and second openings overlap, the enclosing portion being made of a material having a thermal expansion coefficient different from that of the first and second superconducting cable terminals such that the first superconducting cable terminal and the second superconducting cable terminal are compressed together to form an electrical interface at an operating temperature of the superconducting connector assembly; Equipped with The method comprises: increasing the temperature of the superconducting connector assembly from the operating temperature so that the first superconducting cable terminal and the second superconducting cable terminal are depressurized; loosening at least one of the first superconducting cable terminal and the second superconducting cable terminal from the surrounding portion; A method comprising:

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