Superconductors for network expansion – transporting high capacities in an energy-efficient mannerCase Study AmpaCity Project, Essen
The world’s longest superconductor cable is installed in Essen in 2013. A current limiter, which is also based on superconductor materials, protects the cable against excessive currents e.g. in case of a short circuit in the grid. The combination of both technologies by their manufacturer Nexans is exemplary for the modernisation of electricity networks in major cities throughout the world.
The system solution provides cables with a very high current-carrying capacity (or “ampacity”) which enables power distribution with minimal line losses even at a medium-voltage level of 10 kV. 110 kV high-voltage lines and substations in city centres, which until now have been necessary for an efficient electricity supply, could largely be dispensable in the future. According to a study assigned by network operator RWE, four city centre substations in Essen could be closed down as a result of a network modernisation with superconductor technology.
At the same time, authorization processes and routing problems as well as extensive construction work in city centre areas can be mitigated: superconductor cables which are protected by a current limiter do not call for an overload conductor and are therefore extremely compact. The system that is installed in Essen can transport the same amount of electricity as five conventional medium-voltage cables. In addition, it does not generate electromagnetic fields or heat emissions and the path for routing can be smaller than with conventional medium- or high-voltage cables. As a consequence, existing routes can be used for the network expansion, and high-ampacity superconductor cables can even be operated in close proximity to data lines and other utility systems without causing any problems.
To start with, AmpaCity provides a model for the urban network development. In the medium term, superconductor medium-voltage technology will also play an important role in the upgrading of wide-area distribution networks and in connecting renewable energy sources.
Nexans Deutschland GmbH
Dr. Joachim Bock
Director Sales and Market Development HTS Systems Nexans