Superconducting Medium Voltage Cables (MV Cables)
Nexans provides superconducting medium voltage cables with a concentric three-phase architecture as well as single-phase MV transmission cables. At voltages up to 36 kV, these cables efficiently transmit power that would conventionally require high voltage installations.
In the course of metropolitan power supply modernization, superconducting MV cables can replace large parts of the inner-city high voltage power infrastructures: Removing expansive substations and switchyards in central locations can make valuable additional space available for urban development.
Superconducting MV cable systems by Nexans can also alleviate right-of-way problems of urban grid expansion projects as they are highly compact in comparison to a conventional 110 kV cable or a multitude of conventional 10 kV cables of similar current carrying capacity. The low space requirement of superconducting MV cables also facilitates installations in existing cable routings. This opens up a considerable potential because superconducting cables have no thermal or electromagnetic impact on their environment and routings are, for this reason, not subject to further limiting regulations.
A Nexans superconducting MV cable system was commissioned in the inner city power supply network of Essen, Germany, in March 2014. The 10 kV superconducting cable with a rated current of 2,300 A (40 MVA) will provide a transmission capacity that would require five conventional medium voltage cables which cannot be routed on site. Moreover, the power requirement of a superconducting cable with its cooling system amounts to a mere fraction of the transmission losses compared to a normal installation.
MV superconducting cables are incorporated in the conventional grid by a system solution comprising the cable with its three-phase terminations and a Nexans fault current limiter which offers efficient and low-loss short circuit current control. This set-up enables a simple and compact cable architecture without internal shunts for overload protection. At the same time, cable availability during fault incidents is substantially enhanced.
The liquid nitrogen cooling system of superconducting MV cables deployed for power transmission over longer distances must be supported, at suitable intervals, by cooling stations with a floor space of several square meters.