ANALYSIS AND IMPROVEMENT OF THE DOUBLY FED INDUCTION GENERATOR DURING GRID VOLTAGE FAULTS

The increasing size of wind farms requires power system stability analysis including dynamic models of wind Power generation. Nowadays, the most widely used generator type for units above 1MW is the doubly-fed induction machine. The behavior of these machines during grid failure is an important issue. In this paper, a theoretical analysis of the dynamic behavior of the doubly fed induction generator (DFIG) during a single phase fault is proposed. MATLAB/Simulink is implemented to build the dynamic model of DFIG. Simulation results verify that, rotor voltage and stator flux in phase which fault occurs, decrease exponentially according to the stator time constant. A detailed comparison between single-phase and three-phase voltage dip is also investigated. It is widely proved that, when fault occurs, the rotor voltage is faced with hazardous condition, so a crowbar is utilized in order to limit these adverse voltages.