Unified Control Framework for Multi-Mode Operation of Wind Farm

With an increasing penetration of wind power, more advanced active power control functionalities are included in grid codes for wind farms (WFs), such as maximum power point tracking (MPPT), power limit control (PLC) and power reserve control (PRC). This paper introduces a unified control framework for multi-mode operation of a WF, which features the deloaded control of wind turbine generators (WTGs) in the underlying level. In the WTG level, the multi-mode operation of a WTG is realized by modifying the deloaded ratio reference. In the WF level, the multi-mode operation of a WF is achieved by dispatching different types of active power command. The uniformity of the proposed control framework is embodied in that, whatever the requested operation mode of a WF is, the final implementation is to regulate the deloaded ratio of WTGs, which is convenient for the controller design of WTGs. Another advantage of the proposed framework is that it is independent of wind speed measurement. Finally, case studies based on the EMTP-RV are carried out to validate the proposed framework.