Voltage stability analysis on wind generation system from current control time-scale

With increasing penetration of renewable energy generators, such as wind doubly-fed induction generators (DFIGs), semiconductor based power converters are getting widespread applications into the traditional power system. Under this trend, future smart grid will become definitely a power electronic converters dominated power system. This change and evolution make it hard to describe the interactions between electronic converters and power system in traditional electromechanical or electromagnetic transient time-scale. Moreover, the renewable energy generation systems including the wind power system are often deployed geographically far away from the load centers and connected to relatively weak transmission networks, causing serious concerns on the voltage stability of point of common coupling (PCC). This paper mainly focuses on investigation of voltage stability of PCC in current control time-scale. The impacts of grid side converter and rotor side converter on voltage stability of PCC are examined so that a modified control strategy to improve the voltage stability of PCC is proposed. Simulation results of a wind generation system based on DFIG are presented to validate that voltage of PCC could maintain stability in current control time-scale when a wind generation system based on DFIG connected in a weak grid.