Title :
An improved control strategy for DFIG system and dynamic voltage restorer under grid voltage dip
Author :
Cheng, Peng ; Nian, Heng
Author_Institution :
Coll. of Electr. Eng., Zhejiang Univ., Hangzhou, China
Abstract :
With the increasing percentage of wind power in the utility grid, grid codes require that wind turbines must have low voltage ride through (LVRT) capability. Considering that doubly fed induction generation (DFIG) systems have the tolerance capability, to overcome the drawback of LVRT operation of DFIG system using crowbar, a dynamic voltage restorer (DVR) is connected to the stator side to prevent the stator voltage fast changing, and then the rotor side converter (RSC) can be in normal operation. A mathematical model of the rotor voltage of DFIG during a symmetrical voltage dip is presented to describe the allowable changing rate of the stator voltage. A new connection structure of DVR is proposed where DVR and GSC share a DC capacitor. Based on the coordinated control of the DFIG system and DVR, the active power regulation and reactive power compensation can be implemented under the grid fault. The simulation results for a 1.5MW DFIG system is given to show the effectiveness of the proposed protection compared to the rotor crowbar during grid fault.
Keywords :
asynchronous generators; machine control; power generation control; power generation protection; power system faults; rotors; stators; voltage control; wind power plants; DFIG protection; DFIG system; control strategy; doubly fed induction generation systems; dynamic voltage restorer; grid fault; grid voltage dip; low voltage ride through capability; power 1.5 MW; rotor side converter; stator side; stator voltage; symmetrical voltage dip; wind power; wind turbines; Mathematical model; Reactive power; Rotors; Stators; Torque; Voltage control; Voltage fluctuations; Doubly fed induction generation (DFIG); dynamic voltage restorer; low voltage ride through; symmetrical voltage dip;
Conference_Titel :
Industrial Electronics (ISIE), 2012 IEEE International Symposium on
Conference_Location :
Hangzhou
Print_ISBN :
978-1-4673-0159-6
Electronic_ISBN :
2163-5137
DOI :
10.1109/ISIE.2012.6237377