BEHAVIOUR OF DFIG UNDER FAULT GENERATED TRANSIENTS

Sudden increase in load at load bus or initiation of the fault can cause momentarily voltage sag at load bus which in turn can cause problems for locally served load. The collector bus at which wind turbine generators are connected may trip the wind turbine generator in response to the sudden voltage sag due to fault or sudden load change as DFIG has limited reactive power support capability and hence limited LVRT (Low Voltage Ride Through) capacity .Therefore the voltage instability is the crucial problem in maintaining the uninterrupted operation of the wind turbine equipped with DFIG. And most of the utilities, demands that the wind generator has to remain connected to the network and provide necessary support to the network during temporary disturbances in the network. This paper investigates the use of DFIG in the wind farm for purpose of stabilizing the grid voltage after grid side disturbances such as some types of faults and sudden load changes.