Study of Application of Dynamic Voltage Restorer on Low Voltage Ride-Through Capability of Doubly Fed Induction Generator

When connecting to power grid, doubly fed induction generator (DFIG), whose stator connected with grid directly, is very sensitive to voltage variation and has limited ability to resist drop of grid voltage. So it is necessary to take auxiliary steps to improve the low voltage ride-though (LVRT) capability of DFIG. As a real time device of compensating voltage, dynamic voltage restorer (DVR), which is connected between wind generator and point of common coupling (PCC), can compensate voltage quickly and accurately. When voltage drops, DVR produces AC voltage by triggering its inverter module to compensate difference between fault voltage and normal voltage, thus improving LVRT capability. The simulation results on PSCAD/EMTDC platform make clear that DVR compensation strategy meets the requirement of LVRT perfectly.