Enhanced Protection Selectivity in LVDC networks using a Superconducting Resistance

Low voltage direct current (LVDC) distribution systems have recently been considered as an alternative approach to facilitate the integration of distributed energy resources (DERs). However, DC protection is one of the key challenges facing the wider uptake of LVDC technologies. This is due the sensitivity of DC systems to rapid depression of DC voltages caused by short circuit faults, making DC fault location and protection selectivity very challenging. Superconducting materials are commonly used as part of a fault current limiter in AC and DC systems predominantly as a passive device, that can provide variable impedance during DC fault conditions whilst not impacting on the dynamic response of the grid during normal operation. Therefore, this paper presents a novel utilization of a superconducting resistance primarily as an indicator of fault location. The objective is to improve the selectivity of LVDC protection schemes where discerning between fault locations, particularly in electronic-based substations, is problematic.