Power Differential Protection for Transmission Lines with Superconducting Fault Current Limiters

The increased generation capacity caused a subsequent increase in fault current levels. This necessitates the usage of superconducting fault current limiter (SFCL) in transmission lines. But, SFCL has a negative impact on line protection schemes. Accordingly, it is proposed in this study to develop power differential based protection scheme for effective detection and isolation of transmission line faults under the action of SFCL. Power characteristics of a high temperature superconducting (HTS) tape are obtained experimentally at different values of prospective currents. The developed power across the tape was large enough to be a key parameter in developing the protection scheme. Power differential protection scheme is developed and trip characteristics are specified based on normal loading conditions. The effectiveness of power differential scheme is validated through simulation studies on 220 kV transmission line. The fault types of 3-phase and single line-to-ground are considered. Also, the proposed scheme was examined for wide range of SFCL resistances between 10 Omega to 500 Omega. The proposed power differential protection scheme succeeded in fault detection for all considered conditions.