Advanced Controls for Wind Power Plant Ancillary Services

This paper develops advanced controls to improve wind turbines ancillary services. Different controls are proposed to enhance the reactive power capabilities of a permanent magnet synchronous generator (PMSG). Recently, due to their substantial energy integration into power systems, wind power plants have to comply with Grid Code Requirements (GCR) set by power system operators. Voltage Ride Through (VRT) is one of the most important GCR of the Tunisian Power System Operator "STEG" (SocieteTunisienned'Electricite et de Gaz). The developed controls enable wind turbines reactive power production or absorption based on two hierarchical control signals emanating from the dispatching, or from voltage regulation controller at the Point of connection (Poc). The ramp up and down rates in reactive power absorption or supply must comply with the GCR. A recent control concept named synchronverter is used to control the reactive for compliance with the Tunisian GCR. With both Voltage Oriented (VOC) and synchronverter controls, the desired wind plant reactive capabilities are achieved with or without sufficient wind velocity. Thus, wind turbines are able to operate as static synchronous condensers (STATCOMs) under the so called "WindFree-Reactive Power" Control.