Fault current contributions of doubly fed induction generator wind turbines under different control strategies

With the increased penetration of wind energy into the power system, the fault ride-through ability of doubly fed generator (DFIG) has got more and more attention. Recent grid codes request DFIG stay connected to grid when system fault occurs and play an active role in grid voltage recovery. In this paper, a new voltage control strategy without crowbar is to improve fault ride-through characteristic. The transient characteristics of DFIG are analyzed. The fault current contributions DFIG with crowbar protection and proposed voltage control strategy are analyzed and compared based on mathematical expressions and equivalent circuits. The conclusion that fault current contributions of DFIG under two control strategies are different in amplitude and phase is obtained. At last, a 10KV distribution network with DFIG model under two control strategies set up in PowerFactory DIgSILENT. Simulation results show the different behavior of DFIG under different control strategies which will impact distribution network protection in different way.