In embodiments of the invention, a superconductor lead is configured to have less ohmic heating by its own current and less heat conduction from room temperature to cryogenic temperature, where a cryogenic apparatus is located. The superconducting lead with no ohmic resistance and low thermal conductivity disclosed herein maximizes current capacity by placing superconductors in parallel, each having equal current. Thus, the resistances are controlled to provide uniform current distribution through each superconductor of the high temperature superconducting (HTS) lead.

A superconductive cable installation includes at least one jointing pit (F) in which arrive superconductive cables (C1, C2), each superconductive cable (C1, C2) having a cable core surrounded by a cryogenic envelope (Cr1, Cr2) and at least one connection assembly (100) situated in the jointing pit (F) in such a manner as to connect two of the superconductive cables to produce a transmission link. The assembly has a jointing device (50) with two connection ports (P1, P2), each connection port being configured to receive the cable core of a respective one of the two superconductive cables (C1, C2). Two compensation devices (22a, 22b) are configured to absorb a variation in length of the cable core of a respective one of the superconductive cables caused by a variation in temperature for passage to the superconductive state. Each compensation device has an inlet end (Ee) configured to receive the cable core and an outlet end (Es) connected to a respective one of the connection ports in such a manner as to deliver the cable core to the jointing device.

A superconductive cable installation includes at least one jointing pit (F) in which arrive superconductive cables (C1, C2), each superconductive cable (C1, C2) having a cable core surrounded by a cryogenic envelope (Cr1, Cr2) and at least one connection assembly (100) situated in the jointing pit (F) in such a manner as to connect two of the superconductive cables to produce a transmission link. The assembly has a jointing device (50) with two connection ports (P1, P2), each connection port being configured to receive the cable core of a respective one of the two superconductive cables (C1, C2). Two compensation devices (22a, 22b) are configured to absorb a variation in length of the cable core of a respective one of the superconductive cables caused by a variation in temperature for passage to the superconductive state. Each compensation device has an inlet end (Ee) configured to receive the cable core and an outlet end (Es) connected to a respective one of the connection ports in such a manner as to deliver the cable core to the jointing device.

A high temperature superconducting (HTS) cable terminator including a first chamber having disposed therein a terminator block electrically connected to an HTS cable conductor received within the first chamber, a cryogenically sealed chamber, a cryogenically sealed chamber conductor electrically connected to the HTS cable conductor via the terminator block, where the cryogenically sealed chamber conductor has a first portion cryogenically sealed within the cryogenically sealed chamber and an end electrically connected to one or more electrical output conductors, and one or more refrigerant lines configured to feed gas refrigerant into the cryogenically sealed chamber, where the gas refrigerant configured to absorb heat from the cryogenically sealed chamber. Also included is a second chamber connected to the first chamber, the second chamber having disposed therein a heat exchanger thermally coupled to the one or more refrigerant lines and configured to extract heat from the gas refrigerant.

A high temperature superconducting (HTS) cable terminator including a first chamber having disposed therein a terminator block electrically connected to an HTS cable conductor received within the first chamber, a cryogenically sealed chamber, a cryogenically sealed chamber conductor electrically connected to the HTS cable conductor via the terminator block, where the cryogenically sealed chamber conductor has a first portion cryogenically sealed within the cryogenically sealed chamber and an end electrically connected to one or more electrical output conductors, and one or more refrigerant lines configured to feed gas refrigerant into the cryogenically sealed chamber, where the gas refrigerant configured to absorb heat from the cryogenically sealed chamber. Also included is a second chamber connected to the first chamber, the second chamber having disposed therein a heat exchanger thermally coupled to the one or more refrigerant lines and configured to extract heat from the gas refrigerant.

The invention relates to a method for cooling a superconducting cable (1) using a coolant containing or consisting of liquid nitrogen, wherein at least a part of the coolant is subjected to a subcooling step and thereafter brought into thermal contact with the superconducting cable (1) in a cooling cycle, wherein said subcooling step is at least in part performed using a refrigerant provided in a Brayton process in which at least a part of the refrigerant is cooled and heated in a main heat exchanger (11). According to the present invention, a part of the coolant is withdrawn from the cooling cycle and heated in the same main heat exchanger (11) in which at least a part of the refrigerant is cooled and heated in the Brayton process. A corresponding device and a corresponding system are also part of the present invention.

The invention relates to a method for cooling a superconducting cable (1) using a coolant containing or consisting of liquid nitrogen, wherein at least a part of the coolant is subjected to a subcooling step and thereafter brought into thermal contact with the superconducting cable (1) in a cooling cycle, wherein said subcooling step is at least in part performed using a refrigerant provided in a Brayton process in which at least a part of the refrigerant is cooled and heated in a main heat exchanger (11). According to the present invention, a part of the coolant is withdrawn from the cooling cycle and heated in the same main heat exchanger (11) in which at least a part of the refrigerant is cooled and heated in the Brayton process. A corresponding device and a corresponding system are also part of the present invention.

A superconducting power cable system, including: a superconducting power cable including a cryostat, a first cooling station, a second cooling station, wherein the superconducting power cable extends between the first cooling station and the second cooling station, wherein the first cooling station is configured to pump cooling fluid into the cryostat in a first direction towards the second cooling station and the second cooling station is configured to pump cooling fluid into the cryostat in a second direction, opposite to the first direction, towards the first cooling station, an access pipe assembly arranged between the first cooling station and the second cooling station, the access pipe assembly extending into the cryostat for tapping cooling fluid flowing from the first cooling station and the second cooling station from the cryostat, and a return pipe structure arranged externally to the superconducting power cable, the return pipe structure connecting the access pipe assembly to the first cooling station and to the second cooling station, and providing a respective return cooling fluid line from the cryostat through the access pipe assembly to the first cooling station and to the second cooling station.

A superconducting power cable system, including: a superconducting power cable including a cryostat, a first cooling station, a second cooling station, wherein the superconducting power cable extends between the first cooling station and the second cooling station, wherein the first cooling station is configured to pump cooling fluid into the cryostat in a first direction towards the second cooling station and the second cooling station is configured to pump cooling fluid into the cryostat in a second direction, opposite to the first direction, towards the first cooling station, an access pipe assembly arranged between the first cooling station and the second cooling station, the access pipe assembly extending into the cryostat for tapping cooling fluid flowing from the first cooling station and the second cooling station from the cryostat, and a return pipe structure arranged externally to the superconducting power cable, the return pipe structure connecting the access pipe assembly to the first cooling station and to the second cooling station, and providing a respective return cooling fluid line from the cryostat through the access pipe assembly to the first cooling station and to the second cooling station.

A pipe for a superconducting electrical connection, forming a unit intended to be connected at its ends for a formation of the superconducting electrical connection, includes a cryostat forming a pipe-in-pipe comprising an inner tube and an outer tube which are coaxial and a thermal insulator occupying the annular area between the outer tube and the inner tube; and a superconducting cable core housed inside the inner tube, the superconducting cable core having, at ambient temperature, an excess length with respect to the length of the cryostat such that, in its superconducting state, the length of the cable core is greater than or equal to the length of the cryostat.