Grid codes require wind farms to stay connected and continue generation in the main system low voltage emergency conditions. Due to the limited capacity of converters， DFIG wind turbines may suffer from over rotor currents or over voltages in the DC-links. As a result， appropriate control and protection schemes must be applied. This paper discusses a control and protection scheme for the low voltage ride through（LVRT） operation of DFIG wind turbines. Simulations on a 1.5 MW commercial DFIG wind turbine demonstrate that the timing of deactivating crowbar and the value of the series resistor have critical effects on the converter safety and the system recovery. By use of a rotor crowbar connected with a series resistor and a modified control strategy on the grid-side converter， the DFIG wind turbine is capable of riding through voltage dips up to 15% without absorbing a lot of reactive power， which greatly contributes to the main system voltage recovery.