Analysis of Protection Coordination for OCRs in DC Distribution System with Distributed Generation

DC distribution systems are becoming more widespread in various fields like data centers, electric vehicle charging infrastructure, and microgrids because DC distribution systems offer lower power conversion losses compared to AC systems. In DC distribution systems, protection coordination among overcurrent relays (OCRs) is important for selectively isolating faults and ensuring system stability. However, integration of distributed generation (DG) in system, such as photovoltaic (PV), impacts the magnitude and rate of change of fault currents, which in turn can change relay operating characteristics and coordination time interval (CTI). In this paper, variations in fault current magnitude and change rate based on fault location and the point of common coupling (PCC) for distributed generation in DC distribution systems were analyzed and coordination time interval were also examined.