Investigations on fault behaviour of grid connected DFIG based wind energy conversion systems

Strict environmental regulations and shrinkage of fossil fuel supplies necessitate the generation of electricity by using renewable energy sources. Most promising and popular source of green electricity is wind energy. WECS using DFIG is a meritorious option as it uses back to back power converters at a reduced rating, offers high controllability, allows maximum power extraction and individual control of active and reactive power components. Various performance indices like operation, control of power, cost and necessity of fault ride through are discussed in the available literature, which speaks very less on dynamic behavior of WECS using DFIG. In this work, an analysis based on the behavior of DFIG based WECS during symmetrical as well as unsymmetrical faults is presented. The analysis is performed to perceive the behavior of WECS under varying wind velocities or for below-synchronous and above-synchronous speeds of generator. A brief review on fault ride through capability enhancement of these systems is also presented.