Adaptive IEC 61850-based protection for solar-powered DC microgrids

This paper focuses on the practical implementation and integration of adaptive protection in solar-powered DC microgrids, addressing unique challenges inherent in DC systems. Overcurrent (OC) protection, a crucial aspect in such microgrids, necessitates high-speed operation due to the rapid rise time of fault currents. To overcome these challenges, an adaptive OC scheme with high selectivity and speed is proposed. This scheme utilizes the IEC 61850 protocol for a communication-assisted approach to adapt the relay settings based on the adjacent relay operations and the grid status changes. By defining different setting groups for each OC relay and selecting them based on real-time grid and fault conditions, the scheme ensures efficient fault detection and clearance. Furthermore, the suggested approach involves operating with partial communication network coverage in DC microgrids, thereby simplifying the infrastructure and lowering costs compared to a fully comprehensive system. This method has been validated through RT-Lab and MATLAB/Simulink simulations, as well as experimental testing using an OPAL-RT real-time simulator and Zenon software. The positive results confirm that this integrated scheme effectively improves fault management in solar-powered DC microgrids, showcasing its real-world potential and dependability. This practical application of adaptive protection, along with IEC 61850 integration, presents a promising solution for boosting the performance and reliability of DC microgrid systems.