Improved Stepwise Inertial Control for Wind Turbines Considering Frequency Response of Synchronous Generators

With the continuous increase in wind power penetration, it is necessary for wind turbines (WTs) to have the ability to adjust the system frequency. When the WTs use inertial control for frequency regulation, the limited kinetic energy of the rotor is likely to lead to a secondary frequency drop (SFD). Taking full account of the advantages of the flexible control of WT and the continuous power regulation ability of synchronous generator (SG), the stepwise inertial control (SIC) for the WTs is improved by considering the frequency response characteristics of the SGs. When a load event occurs, the WTs’ output is increased at once, and the constant power is maintained for a certain period of time. When the frequency reaches the nadir, the output of the WTs decreases as that of the SGs increase to jointly make up for the load power shortage. While overcoming the SFD problem, the initial power support of SIC can be further improved, thereby reducing the maximum frequency deviation. This method is verified to be effect by the simulation results.