China's Institute of Electrical Engineering (IEE) has successfully demonstrated a superconductor-based fault current limiter for the first time in a power grid in China. The device was fabricated by IEE in collaboration with the Technical Institute of Physics and Chemistry and Hunan Electric Power Co. using “smart” high-temperature superconductor (HTS) wire manufactured by American Superconductor Corp. (AMSC; Westborough, Massachusetts, U.S.).

Since August 2005, IEE's fault current limiter device has successfully suppressed large spikes of current in the grid that were more than five times the normal levels. Superconductor wires possess unique physical properties that allow them to react instantaneously to current surges, passing electricity along at normal levels while also being able to recognize and then suppress large surges of electrical current. Suppressing spikes prevents damage to expensive electrical equipment in power grids. Fault current limiters cannot be made from conventional materials such as copper wire. The fault current limiter developed by IEE has a voltage rating of 10.5 kV and its normal operating current is 400 A.

According to Dr. Liye Xiao, deputy director of the IEE and director of the Applied Superconductivity Laboratory at the Chinese Academy of Science, this project is an important step in demonstrating the value of these devices in greatly improving the reliability and stability of power grids in China. “Demand for electric power in China continues to grow dramatically year over year,” says Dr. Xiao. “We need to utilize innovative devices, such as fault current limiters and superconductor transformers and power cables, to guarantee the reliability and stability of our power grids because electricity is the lifeblood of our rapidly growing economy.”