Extra-Fast DC Distribution System Protection for Future Energy Systems

DC distribution systems are being widely adopted in many industrial, commercial, and military energy systems such as commercial buildings, data centers, railway electrification systems, off-shore wind farms, and shipboard power systems. A dc distribution system can improve energy efficiency and reduce the size or weight of power systems. A typical dc distribution system, like the ones mentioned, includes multiple power electronics converters, distributed capacitors, active loads, and short lines with low impedance. Thus, in case of a short circuit fault, the dc fault current increases extremely fast without zero-crossing. This is a great challenge for dc system protection. In addition, in-line dc series arc faults are also a potential threat that must be detected and localized to reduce fire hazards. This paper presents a comprehensive protection approach leveraging the converter fault current limiting function as well as an advanced fault localization approach to achieve reliable fault detection, localization, and isolation. Numerical simulation and experimental tests are used to validate the effectiveness of the proposed method.