A comprehensive modeling framework for dynamic and steady-state analysis of voltage droop control strategies in HVDC grids

•Development of a comprehensive modeling framework for DC droop control analysis.•Similar dynamic performance is observed for different droop-based control characteristics.•Different droop characteristics lead to different steady-state operation points after converter outages.•Power flow models including droop control can accurately predict steady-state values after system contingencies.

This paper presents a comprehensive modeling framework to analyze and compare the performance of different voltage droop control characteristics in an HVDC grid. All models are fully derived mathematically, both for dynamic simulations and for steady-state power flow analysis. The main contribution lies in the development of a common modeling and control approach for the different droop-based control schemes that have been presented in the literature. The discussion includes power- and current-based droop control, either in their standard form or combined with a deadband, a constant voltage control or consisting of different slopes. Dynamic simulations show that, when applying a comparable underlying dynamic converter control framework, similar dynamic responses can be expected from the different droop control schemes, while the steady-state voltage deviations and power sharing after a contingency are different. A comparison with results from a full-detailed power flow implementation shows that these voltage deviations and power sharing can accurately be predicted by the derived steady-state power flow models, thereby avoiding the need for time-consuming dynamic simulations.