Comparative power quality study of variable speed wind turbines

Abstract

Due to the variabilities inherent to natural wind resources and the associated electronic power present, wind power produces fluctuations in the generated power and harmonic injection entering the electric grid. This paper compares power quality issues and the impact on the power system of wind reliant power systems when using two different types of variable speed wind generators: the direct-drive permanent-magnet synchronous generator, and the doubly-fed induction generator. First, it gives an overview of the system structure of each generator, and then both systems are simulated to determine their behavior and the consequent impact on power quality. The power quality aspects addressed are voltage fluctuation (Flicker), current harmonics, response to voltage dip, and voltage stability. After this assessment, the contribution of both generators to severe three-phase faults was tested and then, finally, fault-ride through.