Method and apparatus for cooling a superconducting cable

A superconducting cable assembly comprising:

• a superconducting cable comprising a plurality of cable segments;
• a plurality of cooling assemblies, each associated with a respective one of the plurality of cable segments, wherein each cooling assembly comprises:
• a first passage disposed concentrically around the respective cable segment and having first and second ends and an inlet for receiving a coolant;
• and
• a second passage disposed concentrically around the first passage and having first and second ends, wherein at least one of the first and second ends of the second passage is in communication with at least one of the first and second ends of the first passage, the second passage further having an outlet for returning the coolant.

A superconducting cable assembly comprising:

• a superconducting cable;
• a first annular passage disposed concentrically around the superconducting cable and having first and second ends and an inlet adapted to receive a coolant from a cryogenic refrigeration system, wherein the coolant flows in a first direction through the first annular passage;
• a second annular passage disposed concentrically around, and adjacent to the first annular passage and having first and second ends, wherein at least one of the first and second ends of the second annular passage is in communication with at least one of the first and second ends of the first annular passage, the second annular passage further having an outlet adapted to return the coolant to the cryogenic refrigeration system, wherein the coolant flows through the second annular passage in a second direction opposite to the first direction;
• and
• an outer area disposed concentrically around the second annular passage.