Review of Control Strategies for Dfig Wind Turbine to Enhance Lvrt Capability

Wind energy is the fastest growing renewable energy source. Double Fed Induction Generator, which is predominantly used nowadays in wind turbines, is very sensitive to grid disturbances and can damage the power electronic converters due to over voltage and over current. Therefore, protection elements which disconnect the machine during fault are very essential. But, in such cases, the reliability of the system gets affected which is not acceptable due to the high penetration of wind energy into the grid. Low voltage ride through (LVRT) is a mechanism by which the wind turbine can be connected to the system during the voltage dip. This is achieved by either hardware or software implementation on the converter of rotor side and grid side which will prevent the converter from tripping and thereby provide uninterruptible operation to the DFIG during severe grid voltage faults. An analysis of different LVRT control strategies has been carried out in this paper.