Comparative Study on Renovation Schemes of Low Voltage Ride Through for Squirrel Cage Induction Generator Wind Turbine

With rapid increase of installed capacity of wind power in China,it becomes the necessary condition for grid-connected wind farms to possess the ability of low voltage ride through(LVRT),however traditional squirrel cage induction generator(SCIG) wind turbines do not possess LVRT ability.To solve this problem,criteria to evaluate different renovation schemes are put forward and several renovation schemes of LVRT for SCIG are analyzed and evaluated by the given criteria,and simulation study on some renovation schemes possessing higher feasibility is performed.Simulation results show that both renovation schemes utilizing dynamic voltage restorer(DVR) or improved power inverter can be used to implement the renovation of LVRT for SCIG wind turbines.Finally,movable LVRT test device is used to perform field testing for the scheme utilizing improved power inverter and the results of field testing conform to simulation results,thus the effectiveness of the renovation scheme is verified.