BACKGROUND:  The utility industry is poised for growth with an ever increasing global demand for electricity. With an estimated 80,000 miles of underground cable throughout the world, high-temperature superconducting (HTS) cables can potentially provide an enormous benefit to the utility industry and their customers. High-temperature superconducting cables provide striking economic and system benefits over conventional above-ground and below-ground transmission cables: higher power density (3-5x), near zero environmental impact and higher operating efficiency.

A major advantage of high-temperature superconducting cables versus conventional below-ground copper cables lies in the fact that high-temperature superconducting cables can increase the power handling capability and efficiency of conventional cable in areas that require additional power. This can be accomplished quickly without additional right-of-way or trenching. High-temperature superconducting cables offer the advantage of near zero environmental impact due to the fact these cables emit no heat or AC radiation.

Above ground cables emit heat, stray electromagnetic radiation and are increasingly being viewed as a significant eye sore. Under ground high-temperature superconducting cables possess none of these draw-backs.

Current generation high-temperature superconducting cables use liquid nitrogen as a coolant. The liquid nitrogen is pumped throughout the length of the cable to maintain the cable below the critical superconducting temperature. The pumping of liquid nitrogen throughout the length of the cable increases cost and decreases reliability.

INNOVATION:  This innovation consists of a method that eliminates the need for pumping of liquid nitrogen throughout the entire length of the superconducting cable. Eliminating the need to pump liquid nitrogen will eliminate the cost and eliminate the associated reliability issues. The innovation involves cooling the cable at periodic lengths and removing heat through a highly conductive copper cladding.

DEVELOPMENT TO DATE:  A high-temperature superconducting cable design has been analyzed through detailed simulations. The simulations prove the feasibility of cooling a HTS cable at periodic lengths without the expense and reliability concerns inherent with pumped liquid nitrogen throughout the cable. This innovations removes the heat surrounding the HTS via axially conduction through copper cladding. Simulations illustrate that a 100 m cable with a 10 cm radius and a 2 cm superconducting wire can be kept below 26 K.

Reference: UCLA Case No. 2003-469

US Patent Application: 20060260837