Six questions about superconducting cable systems

Yes. The greatest potential for savings can be found in projects where medium-voltage HTS cables are used as a replacement for either conventional medium voltage or conventional high-voltage cable systems in urban settings. Savings are achieved through reductions in land take, civil works and permitting, and also through a reduced need for HV transformers and substations in city centres.

Current HTS projects are between 200m (about 600 feet) and 10km (6 miles). However, there is no technical limit to how long an HTS cable can be. Nexans manufactures superconducting cable in drum lengths of about 500m (1,640 feet) to ease handling on site.

An high temperature superconductor cable system (HTS) is managed in much the same way as a conventional cable system. The only difference is the need to manage the cryogenic system. Cooling is achieved using commercially-available equipment.

Aside from the routine inspection and maintenance of the cooling system, there are no special maintenance requirements associated with high temperature superconductor cables (HTS).

High temperature superconductor cable systems (HTS) have been used in grid applications for more than eight years, with complete success. A key point about superconducting cables is that they are less susceptible to ageing than conventional cables. This is because the extremely low temperature within the HTS cable minimises heating, extending the life of insulation within the cable. By contrast, heating is one of the main causes of insulation degradation and ageing in conventional cables. This suggests that the lifespan of high temperature superconductor cables (HTS) is likely to be equal to or potentially greater than that of non-HTS cables.

The coolant used in hight temperature superconductor cable systems (HTS) is nitrogen, which is chemically inert in both its liquid and gaseous states. It is not harmful to the environment.