DC-system grounding: Existing strategies, performance analysis, functional characteristics, technical challenges, and selection criteria - a review

• Published in: Electric power systems research 2022-05, Vol.206, p.107769, Article 107769
• Main Authors: Pourmirasghariyan, Mirsajed, Zarei, Seyed Fariborz, Hamzeh, Mohsen
• Format: Article
• Language: English
• Subjects: Circuits; Common-mode voltage (CMV); DC microgrid; Electric currents; Electricity distribution; Energy dissipation; Equipment safety; Fault detection; Fault ride-through capability; Grounding strategies; Overcurrent; Personnel safety; Power reliability; Short circuits; Short-circuit fault characteristics; Smart grid technology; Stray current
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2021.107769

•The existing grounding strategies of DC-systems are comprehensively reviewed.•The functional characteristics of DC grounding systems are introduced and elaborated.•The technical issues originating from DC grounding systems are precisely evaluated.•DC grounding systems are compared from various technical perspectives.•The most suitable grounding systems are specified for different applications. In this paper, the grounding system of DC-grids is elaborated; the subject which significantly impacts the design and operation of the DC-grids. The existing studies in the literature do not provide comprehensive information to analyze the different interactions between the grounding scheme and DC-grid. To cover the gap, this paper introduces a complete set of functional characteristics of DC-grids, and accordingly, the impact of grounding systems on the functional characteristics are analyzed from various technical perspectives. The introduced functional characteristics of DC-grids include (i)- common-mode voltage, (ii)- stray current, (iii)- short-circuit fault detection and protection, (iv)- fault ride-through capability, (v)- short-circuit fault response. To further analyze the interaction between DC-grids and grounding systems, some other technical issues are introduced in addition to the functional characteristics. The considered technical issues include personnel/equipment safety concerns, lifetime considerations, detection of DC faults, overcurrent/overvoltage during fault conditions, the power dissipation by the grounding system, insulation level, and service continuity for the sensitive loads. Considering the introduced functional characteristics and technical issues, and knowing their interaction with DC grounding systems, one can precisely choose the proper grounding system for a given application.