Comparative Analysis of External Configuration based DFIG-LVRT Enhancement Schemes

Ever-growing penetration of wind energy conversion systems (WECS) into the grid, has made their continuous operation compulsory, even during sudden dips in the grid voltage. Also, they should deliver reactive power for better voltage recovery during the voltage dip. This capability of remaining connected and supporting reactive power to the grid during a sudden voltage dip, is defined as low voltage ride through (LVRT). Various international grid codes have been introduced on LVRT of grid-connected WECS, to maintain the power system stability. Doubly fed induction generators (DFIGs) are extensively used in high and medium power WECS applications, due to its several advantages. But the DFIG, is very much grid-sensitive, due to the presence of a direct link between DFIG-stator and the grid. So, along with the development of DFIG-WECS, a comprehensive understanding of proper LVRT topology selection, is also becoming much important. In this paper, various external configuration based LVRT solutions for DFIG, are compared in MATLAB / Simulink environment.