AMSC and Nexans have 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 has 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 fault current limiter 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.
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 is going to install additional systems in Europe.
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.