A Flexible Operation Strategy of Wind Turbine Using Droop-Based Pitch Angle Control for Frequency Regulation

This paper proposes a flexible operation strategy for wind turbines (WTs), based on pitch angle control to improve frequency regulation (FR) performance. This strategy is achieved by pitch-droop control which adjusts WTs’ output power by controlling blade pitch angle according to the grid frequency deviation. In addition, it expands the operation region of WTs to motoring in which the turbine blade turns into a mechanical load to absorb and reserve excessive power from other generators and prevent WTs from curtailment. Consequently, WTs produce maximum power when the grid frequency decreases below the nominal frequency and consume surplus power when the grid frequency increases above it. Compared with conventional methods, the proposed strategy enables WTs to provide a widened range of FR and avoid a shutdown. In order to verify the proposed strategy, a microgrid simulation that is highly penetrated by renewable energies has been implemented. As a result, despite sudden load shedding and connections, the grid frequency remains in a stable range due to the flexible operation of the WT.