A Novel Post-Transient Voltage-Based Protection Scheme for DC Shipboard Systems

With increasing environmental concerns in transportation, existing shipboard power distribution systems are under pressure regarding system efficiency and fuel consumption constraints. DC shipboard systems are being considered as an effective solution to alleviate these pressures, offering convenient connections of variable speed engines, energy storages, and shaft generators. However, the development of fast, selective, and reliable protection solutions remains a key challenge, critical for the broader adoption of dc shipboard systems. Compared to existing HVdc grids and transmission systems, dc shipboards are more compact, leading to rapid propagation of fault disturbances. This necessitates more stringent protection coordination and selectivity requirements. This article develops a novel post-transient voltage (PTV)-based protection scheme. The method utilizes inherent PTV features to distinguish downstream and upstream internal and external faults. The proposed method provides anti-noise capabilities, overcoming selectivity limitations of existing voltage-based solutions when a lower sampling frequency is applied. The credibility and the effectiveness of the proposed scheme are tested against different fault scenarios applied on a dc shipboard test system built in power systems computer aided design (PSCAD)/electromagnetic transients including direct current (EMTdc) and validated in a real time (RT)-Box-based hardware testbed. Noise signals are considered in the tests to appraise the resilience of the developed protection scheme.