A Differential Decaying DC Component Based Unit Protection For Transmission Networks With SFCL

Several elements supervise transmission line protective relays to assure their security and selectivity. These elements are crucial for fault detection and interruption by various protection schemes. Superconducting fault current limiters (SFCLs) can inherently affect the currents and voltages, thereby impacting the performance of these protection elements. The influence of various SFCLs on transmission line unit protection strategies is investigated, and a differential decaying DC component (DDCCdiff) based logic is proposed in this paper. The DC component at each end is extracted using the adaptive modified FIR notch filter and the modified discrete Fourier transform technique. The energy of the DDCCdiffis estimated using the Hilbert transform, which is used as a fault detection index. Different test systems fitted with various SFCLs, modeled using EMTDC/PSCAD, are used for validation. The obtained findings, as assessed by simulating many disturbances, show that the proposed strategy is effective.