  Resilience is emerging as an evolving notion, reflecting a system's ability
to endure and adapt to sudden and catastrophic changes and disruptions. This
paper spotlights the significance of the quantitative resilience indices of
medium-voltage DC (MVDC) distribution technology in marine vessels, notably
naval ships. Given the intricate electrical requirements of modern naval ships,
the need for a robust power supply underlines the imperative of resilient DC
microgrids. Addressing this, our study introduces a novel quantitative metric
for operational resilience of DC microgrids based on the measured voltage of
main DC bus. This metric not only fuses real-time tracking, compatibility, and
computational efficiency, but also adeptly monitors multiple event phases based
on time-domain analysis of dc bus voltage dynamics. The intricacies of the dc
bus voltage, including overshoots and undershoots, are meticulously accounted
for in the algorithm design. With respect to existing research that typically
focuses on offline resilience assessments, the proposed index provides valuable
real-time information for microgrid operators and identifies whether microgrid
resilience is deteriorating over time.
