The Large Disturbance Rotor Angle Stability with DFIG Wind Farms

The active and reactive power control capabilities of the DFIG during and after fault are of great importance to support the grid during large disturbances. This paper proposes a strategy to enhance the rotor angle stability by changing the shape of the deceleration area of a synchronous generator power-angle curve using the active power control capability of the DFIG. This proposed strategy is investigated first by using a simple test system, and subsequently tested by using more realistic large power system (e.g. RVS test system). The results show that the DFIG can maintain the terminal voltage angle almost constant by making active power zero and prioritizing reactive power during the fault. Subsequently, the DFIG active power is slowly increased after clearing the fault. This enables the synchronous generator to increase the electrical power output after the event and decrease the rotor angle deviation. Also, it helps to improve the shape of the deacceleration area of the synchronous generator power-angle curve and ultimately assist to improve rotor angle stability.