Application Fields

circuit scheme: potential application cases

Fault current limiter (detail in operation)

Vattenfall, Power station Boxberg

Nexans superconducting fault current limiters can be deployed in a wide range of configurations to ensure fault current management and power grid stabilisation. Typical applications are installations in transformer feeders, busbar couplings, and protection of superconductor cables.  A number of examples are outlined below. We are looking forward to discussing your specific requirements. Please contact us.
Cost-Efficient Power Upgrade in Medium Voltage Grids
If transformers at a substation are replaced due to rising grid loads, fault current levels may increase beyond the switchgear’s capability. In this case, a Nexans SFCL can be deployed to avert substantial additional cost for equipment upgrades: If installed in the substation bus-section, the device ensures that potential fault currents are kept below the short circuit rating of switching equipment in place.
Nexans 12-100Modernization of Urban Grids
Rapidly rising loads demand large-scale expansions of power grid capacity in metropolitan areas more and more frequently. In these cases, lack of space and the difficulty of obtaining rights-of-way are critical issues for grid operators. Nexans supplies an efficient packaged solution: In inner cities, space-consuming high voltage installations in need of refurbishment can be replaced by superconducting medium voltage cable systems. Superconductor cables can transport large amounts of medium voltage power practically loss-free over distances that would conventionally require high voltage transmission. Additionally, Nexans SFCL technology for overload protection enables highly compact superconductor cable designs which can effectively multiply transmission capacities in existing cable routings. Moreover, superconducting cables have no electromagnetic or thermal impact on their environment which facilitates both projects in existing routings and planning of new underground power lines.
Protecting Industrial Power Supplies 
Electricity supply systems for high-powered industrial drives frequently require customized switchgear with very high short circuit current ratings. Safeguarding such power supplies with a Nexans SFCL offers both technical and economic advantages: SFCLProspective fault currents are limited to a maximum that permits applying off-the-shelf switching equipment. At the same time, the device’s response characteristics can be adapted to specific requirements. Layouts that will tolerate inrush currents several times exceeding the drive’s nominal current without triggering the limiting function have been comprehensively proved in power plant applications.
Integrating Distributed Generation in Medium Voltage Grids
Connecting distributed power to the electricity supply infrastructure frequently involved constructing high voltage installations with additional lines and transformers. This is necessary because substation equipment of an adjoining medium voltage grid was insufficiently rated for increased fault current levels. By deploying Nexans SFCLs in outgoing transformer feeders, operators can integrate substantial generation capacities safely into medium voltage grids.

Protecting Grids Subjected to Frequent Fault Events

Overload protection by Nexans SFCLs significantly improves the efficiency of power grid operation in geographic zones marked by frequent environmental faults. A superconducting fault current limiter has practically no ohmic resistance that will cause sustained electrical losses and affect stable grid operation. Power grids may be struck and damaged by lightning and resulting short circuit currents may lead to secondary failures of operating equipment and power outages. Installed in busbar couplings of grids concerned, Nexans SFCLs will effectively control short circuit induced power surges. In order to avoid sustained electric losses during regular grid operation while safeguarding effective prolonged-interval fault current control, a Nexans SFCL can be installed with a parallel connected conventional reactor.

Meshing of Grids
Power supply security can be strengthened significantly, in the course of grid expansion, if grid sections fed from different substations are mesh-connected. Nexans SFCLs integrated in grid couplings provide a cost-effective and easy-to-deploy solution in such environments where grid-meshing would otherwise increase fault current levels beyond the short circuit capability of operating equipment in place.