Multiple machine representation of DFIG based grid-connected wind farms for SSR studies

Abstract

This work studies the Sub-Synchronous Resonance (SSR) interactions that can take place when a DFIG-based wind farm is connected to the electrical grid through a series-compensated transmission line. As opposed to recent literature on the subject, a multiple machine model is employed to represent the wind farm. This representation allows taking into account machine speed variability due to wind parks being spread over large extensions of land. Additionally, a three-mass model is used to describe the dynamics of the turbine-generator set (instead of the recurrently employed two-mass model). The obtained simulation results show that simplified modeling of DFIG-based wind farms can have a fairly significant impact on SSR related studies.