AMSC, a global solutions provider serving wind and grid leaders, and Nexans, an expert in the cable industry (both CSA Corporate Sustaining Members), recently introduced to the North American market a medium voltage superconductor fault current limiter (SFCL) solution that is designed to meet many of the challenges caused by today’s highly interconnected networks and diversified generation sources.
Fault currents, which are caused by short circuits in the grid, are a growing challenge for power grid operators worldwide. These destructive currents can be caused by a variety of factors, including lightning or downed power lines. As electricity demand and generation have grown and power grids have become more interconnected, the magnitude of these fault currents has increased significantly. To counter this, utilities have long devised complicated operating schemes and have employed over-rated equipment and a variety of fault current mitigation systems such as fault current limiting reactors. However, each of these approaches has distinct drawbacks, most notably in the area of cost.
According to a report from the Electric Power Research Institute, “Utilities are seriously re-assessing fault current mitigation methods and consider emerging novel FCL technologies as vital alternatives to existing methods, provided these technologies prove to be the most cost effective means of fault current management.”
Fault current limiters are one of the key elements in the development of smart grids. The superconductor-enabled FCL being offered by Nexans and AMSC is a cost-effective, fast (response time of less than 2 milliseconds) and self-acting system that limits currents to safe, manageable values. The system is passive, typically sitting idle and “invisible” to the grid, but can sense and then suppress fault currents when they occur, sparing transformers, switchgear and other equipment from damage and protecting the broader power grid. Its ability to sit passively eliminates the losses associated with normal power flow along with many other constraints that are encountered with conventional solutions.
“Nexans has a lengthy history of meeting emerging utility market needs with innovative and highly reliable solutions,” said Jean-Maxime Saugrain, Nexans Corporate Vice President Technical. “For years, power grid operators worldwide have been forced to implement sub-optimized schemes to deal with rising fault current levels. That is no longer the case. With a decade of development and demonstrations behind us and initial deployments taking place in Europe, we are excited to be introducing SFCLs to the North American marketplace with AMSC.”
AMSC and Nexans are offering SFCL systems with ratings up to 36 kilovolts, allowing for their use on most utility electric distribution systems. These systems have been designed to offer numerous benefits. By lowering peak currents during faults, electric utilities can:
- Greatly reduce system equipment costs
- Defer or eliminate equipment replacement
- Increase equipment life
- Improve grid performance and operation
- Simplify renewables integration
- Improve operator safety
Electric utilities managing grids in urban centers are facing increasing load growth challenges. In these settings, substation expansion and construction can be exceedingly expensive and, while the interconnection of substations would be a compelling solution, it is often impossible due to the magnitude of fault currents that would result from these ties. By lowering fault current levels, SFCLs can overcome this impasse in a cost-effective manner and enable safe and reliable substation interconnections, providing utilities and their customers with unparalleled network reliability and resiliency. This is just one of the many compelling applications for the SFCL systems being offered by Nexans and AMSC.
Nexans has already installed SFCL systems in Germany and the United Kingdom and will install additional systems in Europe. “We are pleased to be expanding our product line and our relationship with Nexans with the launch of the SFCL,” said AMSC President and Chief Executive Officer Daniel P. McGahn. “Having successfully teamed to install superconductor power cables and develop and demonstrate SFCL systems, both AMSC and Nexans believe the time is now to begin capitalizing on the tremendous potential that exists for these offerings in the utility market.”
The Nexans/AMSC SFCL system will employ AMSC’s Amperium® superconductor wire, which is able to conduct approximately 200 times the electrical current of copper wire of similar dimensions. This wire is being used in numerous high-power applications, including SFCLs, power cables, motors and generators. AMSC will lead the North American marketing and sales efforts for the Nexans/AMSC SFCL solution.