Electromechanical Transient Behavior Of DFIG-Based Wind Turbine Under Grid Faults

As synchronous generators constitute traditional power system, rotor dynamic behaviors of all the synchronous generators together form the electromechanical transient process of the whole power system and determine its transient stability. However, with continuously increasing wind power penetration, electromechanical transient process of wind turbines(WTs) is more and more significant to electromechanical transient process and transient stability of future power system. Thus, comprehensive studies on electromechanical transient process of WT are fundamental to the transient stability analysis of future power system with highly-penetrated WTs.This thesis concentrates on the rotor dynamic behavior of doubly-fed induction generator(DFIG)-based WT during a symmetrical grid fault. Various factors, which has influence on input or/and output powers of DFIG rotor, including wind speed, strength of the grid, tracking dynamics of phase lock loop(PLL) and active power recovery rate after fault clearance, are considered. The objective of this thesis is to provide an insight into electromechanical transient process of DFIG-based WTs under grid faults.