Novel Frequency Control Strategy by Wind Turbines Considering Wind Speed Fluctuations and Optimized Power Point Tracking

Abstract

Wind Turbine (WT) is one of the main renewable energy sources (RES) in the world. However, if a large number of WTs is connected to a power system, the system inertia will be decreased. Thus, system operators require WTs to support frequency control for assisting the frequency recovery when a disturbance occurs. This study established user-defined models (UDM) in PSS/E for WT's frequency control functions. The typical frequency controls and optimized power point tracking (OPPT) method were investigated and established in PSS/E. Most of the literatures did not consider a complete control structure with adaptive control techniques and wind speed variation. Thus, this study proposed a novel frequency control strategy for WTs based on wind speed variation and OPPT, which can adjust the supporting power from WTs efficiently according to wind speeds, and make WTs effectively utilize their stored kinetic energy. This study also used the real Taiwan power system for simulations, and considered a cascading tripping of synchronous generators and wind speed variations. According to the simulation results, the proposed control strategy improves the system performance on frequency response and surpasses other mature control method.