Cooperative Control of SFCL and SMES for Protecting PMSG-Based WTGs Under Grid Faults

To meet the requirement of grid codes about low voltage ride through (LVRT) of wind turbine generators (WTGs), a cooperative control scheme of resistor-type superconducting fault current limiter (SFCL) and superconducting magnetic energy storage (SMES) for improving the LVRT capability and transient stability of permanent magnetic synchronous generator (PMSG) based WTGs is investigated in this paper. In the proposed scheme, the SFCL is utilized to increase the output active power from grid side converter (GSC) to half of the pre-fault value, and the other half is absorbed by SMES so as to reduce its maximum energy storage capacity. In addition, a SFCL's resistance estimation method is introduced by using the grid-side voltage phasor relation that is established based on the grid voltage vector oriented control of GSC. Finally, a PMSG-based WTG integrated with the SMES and SFCL is built in PSCAD/EMTDC. Performance evaluations and comparisons demonstrate the advantages of the proposed scheme in improving the transient stability of PMSG and reducing the capital cost for superconducting devices.