A high-fidelity resilient pentagrid protection strategy for multi-fault scenarios in DC microgrid

Abstract The rapid growth of renewable energy integration has positioned DC microgrids as a key enabling technology for modern low carbon power systems. However, solutions addressing challenges in DC grids, such as power quality, power flow control, stability, and protection, are still in the emerging stage. About 48% of the microgrid issues are concerned on ineffective protection and control methods that degrades the network power flow. A reliable protection scheme with grid resilience is important to protect the microgrid from all faults including rare faults such as cross-country fault and multi faults scenarios in a short span. Therefore, a composite graph-algorithmic method incorporating Tarjan, Johnson, Gap buffered, and Label Propagation algorithms is proposed to predict the fault location and isolation through smart relays programmed with python. Various faults such as line-to-line fault, line to ground fault, simultaneous fault and multifault scenarios are applied to a Penta microgrid system and the performance of the proposed algorithm is analysed with opal RT simulator. The results demonstrate that the proposed hybrid algorithm detects and clears faults within 170 µs, proving its robustness in system protection coordination.