Enhanced Low Voltage Ride- Through Control Capability of a DFIG-Based Wind Power Plant

Abstract

As per the grid code requirements for low voltage ride-through (LVRT), the wind turbine generator (WTG) should survive and produce reactive power to prop up the grid voltage during a disturbance. The manuscript proposes an enhanced LVRT control capability of a doubly fed induction generator (DFIG) based wind power plant (WPP). To accomplish it, the rotor side converter (RSC) controller of the DFIG is provided with adaptive reactive current to voltage (IQ-V) characteristics and the WPP controller provides different reference voltage to each DFIG, relying on their rotor voltage margins (RVM). Thus, the DFIGs in a WPP injects different amount of reactive power into the grid to prop up voltage at point of interconnection (POI). To survive the DFIG during a fault, the reference electromagnetic torque in the RSC of the DFIGs is decreased proportionate to the weighting factor and voltage sags at the terminals of the DFIGs intending to monitor the voltage rise across the capacitor of the DC-link. The proposed method is tested for 120 MVA WPP consisting of twenty 6-MVA DFIGs. The results validate the ability of the proposed method to produce additional reactive power in comparison to the conventional method to contribute to the POI voltage and regulate voltage rise in DC-link of the DFIGs during a grid disturbance.