Influence of Superconducting Fault Current Limiters on Traveling Wave Based Protection

Superconducting fault current limiters (SFCLs) have been used in electric power transmission systems to limit the current magnitudes when faults occur. Installation of SFCLs inevitably alters transmission line properties and thus may affect measurements in traveling wave based protection. In this paper, we investigate the impact of SFCLs on the performance of the traveling wave based protection schemes in high-voltage transmission systems. An SFCL and a 230 kV high-voltage transmission line are modeled into a simulation system in the electromagnetic transients program, version alternative transients program. The transmission line is represented by a frequency dependent model so that traveling wave characteristics can be effectively captured. We simulate faults on the transmission line, with the incoming and reflected traveling waves recorded and thoroughly analyzed. Also, the influence of SFCL stray capacitances on traveling wave shape is investigated. The results show that the traveling wave current magnitudes are attenuated by the SFCL and the shape of the traveling wave is slightly affected by SFCL stray capacitances. Possible consequences in protection performance are discussed and future research directions are suggested.