Fault behavior of wind farms with fixed-speed and Doubly-Fed Induction Generators

This paper focuses on the fault current contribution of wind farms with Fixed-Speed (FSIG) and Doubly-Fed Induction Generators (DFIG). The fault current delivered by a single FSIG during both symmetrical and unsymmetrical faults is found analytically and validated through simulations. Simulations of a detailed model of a wind farm with several FSIG or DFIG are then performed to investigate the total fault current contribution at the Point of Common Coupling. The scope is to check the validity of a single-machine approach to predict the fault contribution of the wind farm. It has been found that both in the case of FSIG and DFIG wind farms, the single-machine approach is reasonable. For DFIG wind farms, the initial operating point of each DFIG has an important impact on its fault current and the single-machine should be given an initial slip close to the average slip of all DFIG in the wind farm.