Inside-wind-farm/Wind-farm-grid sub-synchronous oscillation characteristics analysis in grid-connected system of multiple DFIGs

Abstract Aiming at the sub-synchronous oscillation (SSO) problem of grid-connected system multiple DFIGs, most existing theoretical studies take entire wind farm as a single-machine model, stand-alone model cannot reflect inside-wind-farm mode produced by interactions among DFIGs in farm. Therefore, this paper takes equivalent value DFIG-based to three establishes mathematical and modes through eigenvalue analysis participation factor analysis. The results show: When length transmission line increases, frequency inside-wind-farm/wind-farm-grid damping decreases stability weakens; when number decreases, increases enhances. Finally, time-domain simulation was built PSCAD/EMTDC verify correctness results.