Abstract:
The general grid-forming VSC-HVDC system can provide frequency and voltage support for the system by simulating the characteristics of synchronous generators. However, in the conventional power synchronous grid-forming control, due to the adoption of the frequency regulation into the damping unit, the power of the VSC-HVDC often fluctuates with the frequency variation. Based on the mechanism and analysis of the synchronous generator frequency regulation and the damping part, the optimized damping control strategy with the grid-forming control is proposed, meeting the requirements of the precision control and the damping demand with a sudden power mutation at the same time. Then the design principles of the damping coefficients and the filtering time constant are proposed by using the small signal stability analysis. Finally, the effectiveness of the proposed strategy is demonstrated by the electromagnetic transient simulation and the field test in the YU-E(Chongqing-Hubei) VSC-HVDC project.