Western Power Distribution has integrated two 12 kV superconducting fault current limiters (sFCL) from Nexans Deutschland GmbH (CSA CSM) into the Birmingham UK power grid. The installation is part of FlexDGrid, a £17M project that aims to both reduce power cuts and carbon emissions and to increase the capacity of existing networks to facilitate the distribution of renewable energy in Birmingham. Nexans’ technology opens up new ways of designing distribution grids, such as coupling busbars to maintain a reliable power supply during maintenance, and therein helps achieve FlexDGrid objectives by enabling higher power feed-in from distributed or renewable electricity sources.

“We’re excited to have completed delivery of superconducting fault current limiters to Western Power Distribution for permanent integration into the grid,” says Frank Schmidt, head of the Superconductivity Business Unit at Nexans. “This further demonstrates Nexans’ ability as market leader in superconducting systems for power grids. This contract represents Nexans’ commitment to continuing the deployment of state of the art equipment to address the world’s ever-changing energy needs.”

Since 2005, Nexans has successfully installed its sFCLs at five locations around Europe, including the Ampacity project in Essen, Germany, where the sFCL has been in successful operation since March 2014. The Birmingham project is Nexans’ third sFCL installation in the UK. Nexans delivered its first sFCL to the Chester Street substation in late 2015 and the second to Bourneville substation. The Birmingham contract includes design, fabrication and permanent installation of its devices, including associated switchgear in the distribution grid operated by Western Power Distribution.

sFCLs can help reduce the need for new substations and, more significantly, can provide effective protection from fault currents. Caused by short circuits in the grid, fault currents are a growing challenge for power grid operators worldwide. These destructive currents can be generated by a variety of factors, including lightning or downed power lines. As electricity demand and generation has grown and power grids have become more interconnected, the magnitude of these fault currents has increased significantly. To counter this, utilities have installed large equipment and a variety of fault current mitigation systems such as fault current limiting reactors. Each of these approaches, however, has distinct drawbacks, most notably in terms of cost.

Nexans developed superconducting fault current limiters as part of its commitment to provide the most innovative and reliable solutions to future proof grids. The technology is based on the physical properties of the ceramic superconducting material employed. Nexans uses AMSC’s Amperium® wire in the superconducting components of sFCL devices. In its operating state, the material acts as a near perfect electrical conductor without ohmic resistance and therefore doesn’t affect grid operations. A fault current, however, will transform the superconductor into a resistive material, increasing the resistance and reducing the fault current in a few milliseconds.