Metrology requirements of state-of-the-art protection schemes for DC microgrids

Environmental incentives to combat climate change are providing the motivation to improve the energy efficiency of power distribution systems and integrate state-of-the-art renewable technologies. Examples include wind/PV resources, energy storage systems and electric vehicles integrated via efficient power electronic converters (PEC). Subsequently, DC microgrids (MGs) and distribution systems are receiving considerable attention in the literature because they offer a simple, yet flexible, interface between these modern resources and consumers. However, many technical challenges relating to the design and standardization of DC protection devices still exist that must be overcome prior to widespread adoption. For example, many protection schemes tailored for DC MGs have been proposed but few of them have considered the metrology requirements for practical implementation. This paper will first review the key features of DC-side fault transients simulated on a DC MG model in MATLAB/Simulink, and analyse the disruptive impact on PEC components. Secondly, a review of newly published DC protection schemes is performed. These protection schemes are classified by their fundamental operating principles and mathematically-derived metrology requirements are given.