Enhancing low-voltage ride-through capability of PMSG based on cost-effective fault current limiter and modified WTG control

Abstract Series single-resistor based scheme (SSRBS) can achieve a favorable low-voltage ride-through (LVRT) enhancement, also has the advantages of low costs and complexity. Its basic idea is to increase the terminal voltage of wind turbine generator (WTG) during grid faults by inserting a series single-resistor into the grid-side circuit. However, traditional SSRBSs cannot tackle different grid voltage sag events due to the constant resistance of the inserted resistor. Besides, as a device-based scheme, the SSRBSs have weak cost-effectiveness especially, utilizing the superconducting fault current limiter (SFCL). To solve these problems, this paper proposes a cost-effective LVRT scheme by cooperating a resistive-type SFCL and two modified controls. In the cooperative scheme, a surplus power dissipating mechanism based on SFCL is designed, which provides a novel way for SFCL to improve LVRT capability. Moreover, modified reactive power control for WTG is proposed to ensure that SFCL can dissipate constant surplus power irrespective of grid voltage magnitude and to provide reactive power support. Additionally, another modified WTG control is proposed for assisting with the SFCL to dissipate surplus power, which reduces the tape usage and energy-loss of SFCL, thus improving cost-effectiveness. Several cases demonstrate the feasibility and superiority of this scheme.