Generalized Impedance Sensitivity Based Sub- /Super-synchronous Mitigation Scheme in D-PMSG Wind Farm

Abstract

Several sub-/super-oscillation (SSO) accidents occurred led by grid integration of D-PMSG wind farm seriously affected the safe and stable operation of the power system. Therefore, it is urgent to find a solution to effectively mitigate SSO. At present, the research on the direct-drive permanent magnet synchronous generators (D-PMSG) wind farm integrated power system is mainly focused on the interaction between a single unit or the overall wind farm and the system. There is a lack of research on the participation degree of units with different control parameters once SSO occurs. To fill this gap, this paper proposes the concept of generalized impedance sensitivity. It finds units that are more capacitive than other units under the condition of unit’s impedance changing: prone-to-oscillate unit and relatively prone-to-oscillate unit. Based on this, a suppression scheme is proposed to add damping only at the prone-to-oscillate units and the relative ones. The time-domain simulation verifies the conclusion that the prone-to-oscillate units and relative ones have a high degree of SSO participation and the effectiveness of the mitigation scheme.