Superconducting Power Cable

High-Temperature Superconducting (HTS) cables are a type of power cable that use superconducting materials to efficiently transmit electricity with virtually no resistance. These types of cables can transmit up to five times more power than conventional copper or aluminum cables of the same size, which can lead to more efficient and reliable power grids.

In 2006, American Electric launched a test of high temperature superconducting power cables operating at extremely low temperatures to reduce resistance to the flow of electric current. HTS cables could deliver up to five times more electricity than traditional conventional copper or aluminum cables. With their higher capacity, superconducting cables have the potential to increase the supply of electricity to an area using the existing underground cable footprint. Additionally, because HTS cables could carry more current at a lower voltage over longer distances, large power transformers could be located farther from urban centers and densely populated areas freeing up valuable real estate for development or green space. Although called high-temperature, this HTS system operated at temperatures just below the boiling point of liquid nitrogen (-321 degrees Fahrenheit).

How HTS Cables Work

1. Superconducting Materials: The key component of an HTS cable is a layer of superconducting material. This material becomes superconducting (i.e., has zero electrical resistance) when cooled below a certain critical temperature. High-temperature superconductors are materials that become superconducting at relatively high temperatures, the range of liquid nitrogen, as opposed to other superconductors that require cooling to near absolute zero.
2. Cable Construction: An HTS cable usually consists of several layers. The innermost layer is the superconducting material, typically a ceramic compound like Yttrium Barium Copper Oxide (YBCO) or Bismuth Strontium Calcium Copper Oxide (BSCCO). This is wrapped by a layer of insulation, then a copper shielding layer, another insulation layer, and finally an outer protective jacket. Some designs also include a cooling system to keep the superconductor at the required low temperature.
3. Cooling System: The superconducting material must be kept below its critical temperature to maintain zero electrical resistance. This is typically achieved using a cooling system that circulates liquid nitrogen around the cable.
4. Operation: When the HTS cable is cooled below its critical temperature, it can conduct electricity with virtually no energy loss, making it highly efficient for power transmission.

The main advantages of HTS cables are their high capacity and efficiency, compact size, and lower electrical losses compared to conventional power cables. They also produce less heat and are less susceptible to damage from high current loads.

However, there are also challenges to their wide-scale adoption. The main one is cost: HTS cables are currently much more expensive than conventional cables, both due to the cost of the superconducting material itself and the cooling systems required. There's also the complexity of integrating them into existing power grids.