A cascading trip-off of doubly-fed induction generators from grid in a wind turbine clusters has been analyzed in this paper. The cascading trip-off mechanism is investigated. Relevant factors to the cascading trip-off are analyzed， such as operational state of doubly-fed induction generator， value of voltage dip， Crowbar protective setting value of doubly-fed induction generator and so on. Technical measurements for reducing the risk of cascading trip-off are presented. Simulation results show the effectiveness of the above analysis and measurements.