The transition process of wind turbine based on squirrel-cage induction generator when voltage sag and its low voltage ride-through method

摘要

This paper reveals two typical phenomena of Squirrel-Cage Induction Generator (SCIG) based wind turbine during the voltage sag, such as asynchronous induction generator out of step and the shocks of the electromagnetic torque with polarity reversal, the result shows low voltage ride-through(LVRT) capability of SCIG based wind turbine is very poor. A method of using a stator series resistance device is proposed for SCIG based wind turbine LVRT. Both detailed analysis and simulation results demonstrate it is a safety and effective method to ensure the SCIG based wind turbine against the impact of the PCC voltage sag, and provide maximum active and reactive power to support the grid stability and security.