Investigations of voltage stability improvement in grid connected wind energy conversion system by incorporating facts devices

Abstract

Now a day s wind power is increasingly installed to meet the additional loads in developed countries like India. The several types of wind turbine generators are available and installed. Out of which the DFIG is most employed generator for wind turbine rating above 1 MW because DFIG has the advantages of variable speed operation with constant frequency and decoupled control of active and reactive power. Also the converter rating newlinedepends only on rotor power which results in reduced size, light weight, low cost and small losses compared to other types of wind energy conversion system. DFIG based wind turbine system is connected to grid for supplying the load reliability especially from the point of low voltage ride through capability enhancement. When DFIG is connected to grid, it feeds power from stator and rotor through a full scale power converter. However the grid connected DFIG based Wind Energy Conversion System (WECS) is very sensitive for grid fault. During grid fault conditions larger voltages are indirect in the rotor circuit that will destroy the rotor side converter. Also the corresponding voltage sag collapses the electromagnetic torque. Hence Doubly Fed Induction Generator (DFIG) will be decoupled from the grid during faults due to high newline