Simulation-Based Study on Dynamic and Transient Phenomena and Characteristics of Medium-low Voltage DC Grid

The DC transmission, distribution and networking have been applied to medium and low voltage power grids, and have exhibited apparent advantages and favorable application perspective. Different from traditional AC power grids, DC power grids have shown features of low inertia, weak damping and the inclination of oscillation. The intermix of fast switching transients and control dynamics makes the DC grid much more complicated. In addition, the power fluctuation of renewable energy generation and demand-response loads imposes difficulties on the stable and smooth running of the DC grid. However, no comprehensive study has been reported on dynamic and transient patterns and characteristics of the DC power grid. In this paper, through both simulation and theoretical analysis, the transient and dynamic characteristics of medium and low voltage DC power grids are systematically tested, classified and analyzed. Finally, the mechanisms and general conclusions are extracted and refined.