Correlation among the transient characteristics of doubly fed induction generators under grid fault

Doubly fed induction generator (DFIG) under grid fault has increasingly gained attention among researchers for the better protection and control of power system. However, existing studies which focus on the single DFIG are incomplete, because other DFIGs can significantly affect the transient process of DFIG in the wind farm. Thus, this paper investigates the correlation among the transient characteristics of DFIGs when a three-phase fault occurs in power grids. A vector model of a DFIG is built with consideration for the excitation regulation. Transient processes of the DFIG when wind farm contains different numbers of DFIGs are mathematically deduced by dividing the fault process into two periods according to converter regulation. The analytic expressions indicate the relationship between the transient electrical variables of a DFIG and the number of DFIGs is proposed to acquire the varying pattern of the correlation. The correlation phenomenon is verified both through analysis and simulation, which pro...