A study of Doubly Fed Induction Generator's low voltage ride through capabilities

Doubly Fed Induction Generator (DFIG) is widely used for wind turbine electricity generation. In this work power interchange between a wind farm and power grid is studied in the presence of symmetrical three-phase and asymmetrical phase to ground faults. The wind farm comprises six 1.5MW wind turbines connected to 25kV distribution systems that exports power to 120kV grid through a transmission line. A fault causes the line voltage to drop and line current to increase. We studied impact of transmission line faults on the operation of the wind farm in both voltage regulation and VAR regulation modes. The wind turbine design includes under-voltage protection circuitry that monitors the line voltage for faults and trips the wind farm if the line voltage drops below 0.75 pu for t>0.1s. For the present work, Matlab/Simulink original protection system was used.