Transient Behavior Analysis for a 2 MW Grid-Connected DFIG-based WECS under Partial Symmetrical Voltage Dips

Aiming to deeply understand the DFIG transient behavior if a grid fault occurs; then describe its equivalent model under this case, this paper deals with a theoretical analysis of a typical 2 MW DFIG-based WECS using the Superposition Principle Theory to analyze a partial symmetrical grid dips. Therefore the study has been achieved with emphasis on the impact of each voltage dip on the DFIG behavior. In fact as the DFIG is directly integrated to the grid via its stator and is controlled via its rotor by means of voltage-source current-regulated converter, the analysis aims to evaluate the low-voltage ride-through (LVRT) capability of the system, in which it can be known how the large induced rotor electromotive force can disturb the control scheme and what are the limits of such vulnerable rotor converter to keep working permanently, momentarily or even lost control definitely. The proposed analysis has been evaluated by simulation results using MATLAB/Simulink.