Investigation and enhancement of SFCL impacts on DFIG-based wind turbine during fault and post-fault

Abstract

DFIG is generally used in wind turbines because of its many advantages. However, DFIGs are sensitive to the network faults. When a fault occurs, the DFIG rotor current is increased and its converters may be damaged. A general solution to protect the DFIG converters is crowbar protection. However, when the crowbar is activated, the rotor-side-converter is disconnected and DFIG control may be lost. Therefore, reducing the crowbar operation time is essential. The SFCL can present an efficient protection against severe faults. However, recovery time of SFCL has undesirable effects. In this study the impacts of SFCL on fault-ride-through capability of DFIG are investigated in detail by considering the thermal model of resistive-type SFCL. The simulation results illustrate that by applying the SFCL, the rotor current is decreased and fault-ride-through capability of DFIG is enhanced. Finally, a novel approach to suppress unpleasant influences of nonzero recovery time of the SFCL is proposed.