Improving fault ride-through capability of wind generation system using DVR

The depletion of fossil fuel and advancement in technology have made the wind generation as one of the important renewable energy source. With lot of wind generation systems added to the grid, issues related to the integration of wind generation with grid are also increasing. One such problem is grid instability due to multiple wind generation systems getting isolated from the grid during fault. In order to improve grid stability, wind energy systems are expected to ride-through the disturbances in the grid, called as fault ride-through capability. In this paper, the fault ride-through capability of an induction generator based wind generation system is estimated in terms of critical clearing time (CCT). A comparative study on determination of CCT using approximate steady state model and transient model of squirrel cage induction generator has been done. It was observed that when operating slip is high, CCT is same for both the cases while it differs significantly at lower operating slip values. A method has been proposed to improve the fault ride-through capability of induction generator based wind generation system using dynamic voltage Restorer (DVR). Simulation studies have been done on a grid connected squirrel cage induction generator based wind generation system and the results are presented.

► FRT capability of wind generation is estimated using critical clearing time.
► CCT obtained from steady state and transient models are compared.
► DVR is used to improve CCT of SCIG based wind generation system.