Fault ride through improvement of fixed speed wind turbine using CR-FCL with its modified control strategy

This paper proposes a controllable resistive type fault current limiter (CR-FCL) with its modified control strategy to improve fault ride-through capability (FRT) of fixed speed wind turbine (FSWT). Investigated system includes squirrel cage induction generator, the CR-FCL, and the FSWT connected to infinite bus through double-circuit transmission line. The CR-FCL is located in beginning of the parallel line. The proposed structure with its modified control method inserts an optimum value of resistance during fault to achieve maximum FRT capability. It will be shown that this optimum value depends on fault location and pre-fault active power. Two different wind speeds will be applied to the investigated system, which cause two various output powers. Then, it will be proved that each condition needs its own optimum resistance during the fault to achieve the maximum FRT capability of the FSWT. PSCAD/EMTDC is utilised to show accuracy of the proposed scheme and analytical analysis.