DC Fault Current Limiting and Protective Relay Operation of Flux-Coupled Type SFCL-CB

초록

With the growing integration of renewable energy into power systems, research on DC systems has intensified, focusing on solutions to the rapid surge of fault currents and the lack of natural current zero crossings. Among these efforts, various fault current limiters and circuit breakers have been proposed; however, most of the existing studies focus only on the fast operation of the SFCL-CB itself and do not consider its impact on coordination with other protective relays in a practical DC system. To mitigate these issues, this paper proposed a novel flux-coupled DC SFCL-CB that determines whether a fault has occurred and its type from the fault current rate-of-change and adaptively adjusts its trip timing. PSCAD/EMTDC simulations show that it operates in inverse-time mode for distribution-line fault, definite-time mode for converter-side fault, and doesn't operate during load fluctuations, according to the current slope. The approach enhances both speed and protective coordination in DC system protection when an SFCL-CB is introduced.

키워드