Damping Control of Offshore Wind Power Grid-Forming Flexible HVDC Grid-Connected System Considering the Influence of Measurement Delay

The grid-forming flexible HVDC system based on inertia synchronous control can enable the offshore wind farm to perceive the frequency change of the power grid, so as to provide effective inertia support for the onshore power grid. However, this paper shows that the measurement delay of the frequency change rate will introduce a negative damping effect, which will trigger the low-frequency oscillation of the offshore wind power grid-forming flexible HVDC grid-connected system. To this end, this paper firstly constructs a simplified analysis model of offshore wind power grid-forming flexible HVDC grid-connected system that calculates the impact of measurement delay, and then establishes a small signal model of the system, and quantitatively analyzes the influence of delay on system stability through the eigenvalue analysis method. In order to suppress the oscillation phenomenon, a feedforward differential damping control strategy and its parameter tuning method for measurement delay are further proposed. Finally, based on the PSCAD/EMTDC simulation platform, the proposed stability analysis conclusions and the effectiveness of the damping control strategy are verified.