Identification of Key Mechanism Behind Arc Re-Ignition in LC Commutator-Based DC Circuit Breakers

High Voltage Direct Current (HVDC) systems, crucial for renewable energy and long-distance transmission, encounter DC fault management challenges due to absent natural zero crossings and rapid fault propagation, causing energy dissipation and re-ignition issues during DC interruption. Prior research has identified various factors influencing re-ignition, including current magnitude, zero-crossing slope, and cooling efficacy. However, experimental variation in these factors often leads to contradictory outcomes, highlighting a gap in our understanding of re-ignition phenomena. This paper examines DC circuit breakers, particularly LC commutator-based compact breakers, efficient in rapidly commutating fault currents to a capacitor, reducing contact erosion. These breakers offer effective DC fault interruption solutions, but arc re-ignition management is a persistent challenge. The focus is on identifying critical mechanisms behind arc re-ignition. Our study presents an integrated model combining arc physics with LC circuitry to simulate arcing stages in DC interruption. Investigating three electrode cooling scenarios, we emphasize the importance of the thin boundary layer to prevent re-ignition. Two strategies are proposed to improve breaker performance: increasing sheath voltage via contact material changes or extending cooling time with a larger capacitor. These approaches highlight the vital role of boundary layer temperature management in preventing re-ignition, offering significant insights for advancing HVDC fault management.