Modeling of DFIG Based Wind Turbine Mitigating Dynamic Behavior under Varying Load and Asymmetrical Fault Conditions

Abstract

The integration of renewable energy resources, such as wind energy system, with utility grid is an important issue in the present power scenario. The study on performance of grid connected doubly fed induction generator (DFIG) based wind turbine (WT) system is relevant in this regard. DFIG has many advantages over other generators for variable speed application for harnessing wind energy through WT. In this work, a grid connected DFIG based WT is proposed considering voltage regulation and power loss as performance indicators of the system during varying load conditions at different locations. Ability of WT to stay connected to gird during grid fault is known as low voltage ride-through (LVRT) capability. Moreover, the studies on LVRT capability for DFIG based WT is a popular challenge for the researchers to propose a robust system considering variable load and severe fault conditions. Moreover, a comparative study is carried out between a crowbar and DC chopper protection schemes during severe asymmetrical fault condition resulting in satisfactory LVRT capability of proposed system. It is observed that the recovery period for DC chopper is increased as system reactive power requirement increased to settle DC-link voltage to its steady state value. Also it is found that the DC-link voltage is smoothened more in case of DC chopper protection compared to crowbar protection while DC chopper and crowbar resistances are set with same magnitude. The simulation results based on MATLAB-SimPowerSystems are explained.