FRT improvement strategy for offshore wind farm considering operation state

Considering the influence of crowbar action, terminal voltage and wind speed difference caused by wake effect in wind farm, dynamic reactive power limit of doubly-fed induction generator(DFIG) is analyzed in this paper. To improve integrated fault ride-through (FRT) ability of offshore wind farm, combining with characteristics and reactive power compensation configuration of offshore wind farms, an improved coordination control strategy is proposed, with containing maximum reactive power support during the low voltage ride-through(LVRT) by adjusting rotor current to make full use of reactive power of DFIG and the ability improvement of high voltage ride-through(HVRT) by controlling DFIG fast output inductive reactive to suppress voltage swell during the recovery period of fault. To verify the proposed strategy, simulation model based on DIgSILENT/PowerFactory is set up. The simulation results show that the improved strategy can help the grid voltage recover rapidly during the fault period and effectively improve the transient voltage level of the fault grid.