Research on Active Support Control Strategy of Double-Fed Wind Generator Unit for System Inertia Requirement

The frequency response of the ‘double high’ power system with high proportion of new energy and high proportion of power electronic equipment decreases, and the system inertia decreases, which leads to the deterioration of frequency regulation performance. In this paper, aiming at the problem that the overall inertia level of the system is low and the frequency is high when small disturbances occur after the doubly-fed wind turbine is connected to the grid, firstly, a grid-structured active support control strategy for the rotor-side converter of the doubly-fed wind turbine is proposed to release the kinetic energy contained in the rotor shaft and improve the active and reactive power support ability of the wind turbine. Secondly, considering that the DC link capacitor of the back-to-back converter of the doubly-fed wind turbine has some available energy, a grid-side active support control strategy is proposed. The phase angle of the output voltage of the grid-side converter is added to the phase angle feedback to increase the output power of the grid-side converter and improve the frequency of the system during the disturbance. The lowest point; finally, taking the three-machine nine-node system as an example, the effectiveness of the proposed method is verified by simulation under small disturbance.