Droop setting design for multi-terminal HVDC grids considering voltage deviation impacts

• DC voltage deviations under normal operation for both current droop control and power droop control are analysed.
• Investigated the effect of voltage derivation on the power flow in a multi-terminal DC grid.
• A novel droop setting design method is proposed to consider the impact of voltage deviation for achieving a precise power dispatch.
• Effects of voltage deviations on power sharing accuracy and transmission loss are analysed.

In multi-terminal high voltage direct current (HVDC) grids, the widely deployed droop control strategies will cause a non-uniform voltage deviation on the power flow, which is determined by the network topology and droop settings. This voltage deviation results in an inconsistent power flow pattern when the dispatch references are changed, which could be detrimental to the operation and seamless integration of HVDC grids. In this paper, a novel droop setting design method is proposed to address this problem for a more precise power dispatch. The effects of voltage deviations on the power sharing accuracy and transmission loss are analysed. This paper shows that there is a trade-off between minimizing the voltage deviation, ensuring a proper power delivery and reducing the total transmission loss in the droop setting design. The efficacy of the proposed method is confirmed by simulation studies.