Feasibility study on superconducting fault current limiting transformer (SFCLT)

This paper proposes a "superconducting fault current limiting transformer (SFCLT)" with functions of both superconducting fault current limiters and superconducting transformers. Concepts of the SFCLT are as follows: (1) When a fault occurs in a power system, the SFCLT acts as a fault current limiter with limiting impedance due to quench of the SFCLT windings, which improves the transient stability of the power system. (2) In the normal condition, the SFCLT behaves as a transformer with lower leakage impedance, which increases the static stability and the transmission capacity of the power system. (3) The limiting and leakage impedance of the SFCLT can simultaneously be optimized in the power system. Electro-magnetic transients program (EMTP) analyses revealed that the SFCLT could exhibit the multifunction of fault current limitation and power system stability improvement in a simplified model system. (C) 2000 Elsevier Science Ltd. All rights reserved.