LVRT capability evaluation of DFIG based wind energy conversion system under type-A and type-C grid voltage sags

Renewable power generators (RPG) such as wind and solar energy penetrate to the modern power system. Doubly fed induction generator (DFIG) based wind energy conversion systems (WECS) are preferred due to its partial converter rating. This paper focuses on the performance analysis of low voltage ride-through (LVRT) capability of DFIG based WECS under balanced and unbalanced grid voltage sags. Grid code requirements are to be satisfied by the DFIG based WECS by providing support to the grid during the voltage dip caused by the various faults in the power system network. The fault ride-through (FRT) capability can be accomplished according to the grid code requirements by properly controlling the rotor side converter (RSC) and grid side converter (GSC). The controllers are adopted in MATLAB/Simulink for the better performance of the system during the voltage recovery with reactive power support. The performance is evaluated during the balanced (type-A) and unbalanced voltage sag (type-C). The suggested strategy enhances the retrieval of the system by providing reactive power support through the stator and through the GSC during balanced and unbalanced grid faults.