Fully-Distributed Deloading Operation of DFIG-Based Wind Farm for Load Sharing

Abstract

A system-level consensus-based deloading operation is proposed for DFIG-based wind farm (WF) participating in system active power regulation. Rotor overspeeding control (ROC) and pitch angle control (PAC) are coordinated for load sharing among each wind turbine (WT). For ROC, a novel fully-distributed consensus protocol is developed for fair load sharing control without the need to know the total active power capacity. Considering the influences of wind turbines' individual differences and rotor speed limit, the amount of WTs involved in consensus protocol are dynamically adjusted according to their varying operating points. Further, a distributed optimization strategy is designed for active power setting-points allocation to curtail the utilization of WF's pitch angle during PAC. As the result, the proposed strategy can fully and quickly extract the available rotor overspeeding margin for a high kinetic energy storage and a better dynamic performance in ROC stage, and further minimize the dependency on pitch angle when facing deeper deloading operation. Case studies demonstrate the effectiveness of the proposed scheme.