Analysis and validation of low voltage ride-through capability for DFIG based wind energy conversion system under symmetrical grid voltage sags

摘要

The power system network has been transformed to an intricate system with the addition of renewable power generators (RPGs) having environment protection aspects. The doubly fed induction generator (DFIG) based wind energy conversion systems (WECS) with power electronic converters are decoupled from AC grid. The method of support given to the grid by the renewable power generators is different from the traditional synchronous generators. This paper focuses on the low voltage ride-through (LVRT) capability of doubly fed induction generator based WECS with symmetrical voltage sag. A comprehensive analysis is performed on the stator flux variation during sudden voltage dip initiated by grid faults for different values of crowbar protection resistance. The rotor side convertor (RSC) and grid side converter (GSC) are controlled for the fault ride-through capability confirming to the grid code requirements. The suggested scheme enriches the recovery of the system by providing reactive power support through the stator and GSC during grid faults.