Counteracting the effects of symmetrical and asymmetrical voltage sags on DFIG-based wind power systems

摘要

This paper presents a novel coordinated performance augmentation scheme for Doubly-Fed Induction Generators (DFIG) to improve their response to symmetrical and asymmetrical voltage sags. The augmentation scheme consists of a protection system and a reactive power management strategy. The protection system limits the over current in the Rotor Side Converter (RSC) and keeps the dc-link capacitor voltage within an acceptable range; whereas, the reactive power management supports the grid voltage stability by either injecting or absorbing reactive power depending on the PCC (Point of Common Coupling) voltage. A grid-connected 9-MW DFIG wind farm has been used for simulation in MATLAB/Simscape Power Systems. Simulation results show that the performance of DFIGs improves significantly under the proposed scheme.