Development of a DC hybrid fault-current limiting and interrupting device for microgrid applications with a new approach for current-limiting capability

Abstract

This research presents the development of a hybrid DC fault current limiter (HDCFCL) for microgrid applications. The proposed HDCFCL configuration comprises two parallel branches; the first is the main circuit, which includes a superconducting material as a current limiting element in series with the auxiliary solid-state switch. The second branch includes the commutation circuit, composed of two groups of ultra-fast turn-off semiconductor switches, IGCTs, connected back-to-back across the absorbing energy branch. A new approach to the current limitation is presented, where a superconducting fault current limiter is used to reduce the short circuit current together with a capacitor to absorb the energy of the commutation circuit during the interrupting process. The PLECS program was used to analyze the results theoretically, and they were verified via building and testing a laboratory prototype. The experimental results showed the capability of the proposed system isolating the fault within 3.6 ms, which is quite fast compared to other presented systems in the relevant literature.