Expandable multiterminal DC systems based on voltage droop

This paper introduces a decentralized control scheme for the parallel connection of multiple rectifiers feeding a DC network with numerous inverters. The coordination of multiple HVDC power systems without explicit communication is accomplished by the use of DC-side voltages as a "droop" mechanism. The DC side voltage serves the role of frequency in an ordinary AC system. The approach is most suitable to superconducting DC systems and to DC systems that span small distances and where voltage is relatively uniform throughout the DC system. This paper presents the concept in the context of a high capacity superconducting 10 kV urban infeed.>