As the wind power penetration from large scale wind turbines, which are based on variable speed constant frequency (VSCF) doubly fed induction generators (DFIG), has been increasing rapidly in the transmission system, the grid codes for grid connected wind turbines evolve continuously and demand that the wind power generator has to ride through the grid faults, especially the grid voltage dips. In this paper, the influence of grid voltage dips on the DFIG is analyzed firstly. Meanwhile, the control objective of the low voltage ride through (LVRT) is proposed. Several types of LVRT technology for the DFIG wind turbine systems are then summarized and evaluated respectively. Finally, for the purpose of revealing the latest progress and the developing direction of this technology a valuable conclusion about the optimizing of the LVRT technology is drawn from the above discussion.%随着以变速恒频(VSCF)双馈异步发电机(DFIG)为主体的大型风力发电机组在电网中所占比例的快速提高,电力系统对并网风力发电机在外部电网故障、特别是电网电压骤降故障下的不问断运行能力提出了更高的要求.本文首先分析了电网电压骤降对DFIG运行的影响,提出了DFIG风力发电系统低电压穿越运行的控制目标,继而总结、评价了各种适合于DFIG风力发电系统的低电压穿越技术,最后指出了DFIG风电系统低电压穿越技术的优化方向,以期展示该技术的最新进展及发展趋势.
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