Protection system behavior of DFIG based wind farms for grid-faults with practical considerations

Doubly-Fed Induction Generators (DFIGs) are commonly utilized in wind farms nowadays due to their advantages as compared with single fed ones. Control complexities and their unique dynamic characteristics may, however, raise different problems during abnormal or faulty operating conditions. Accordingly, the behavior of the associated protective elements at the Point of Common Coupling Point (PCC) may be affected during grid faults remarkably. These situations are investigated thoroughly in this paper. Detailed dynamic modeling of a 60 MW off-shore wind farm is utilized including the rotor protection circuitry with either crowbar or DC chopper. Also, the own protective functions of the rotor converters are considered. Different simulation examples are illustrated to clarify the related impacts of the DFIGs on utilized protective elements with large integrated wind farms.