Coordinated Control and Operation Stability Analysis of Multi-port DC Substation Applied in Power Distribution System

DC distribution system has been accepted as a promising solution for future power system construction. The multiport DC substation severing as dc hub in intricate meshed grid takes role of energy routing and voltage dispatching. In this article, an overall control strategy is proposed for a multiport dc substation applied in city power distribution system and enables to achieve transmitted power coordinate control with four terminals connected with dc grids. Operation stability research on DC substation under different working conditions are conducted based on generation Nyquist criterion (GNC) and D-Q small-signal impedance model derived in a uniform rotating coordinate. Besides, accuracy of theoretical impedance model is validated by measurements in Matlab/Simulink. Finally, simulation results are carried out in PLECS to test the working performance of the multiport DC substation under coordinated control and verify correctness of analysis on operation stability.