Evaluation of the mainstream wind turbine concepts considering their reliabilities

Wind turbine technologies have reached such a stage that the power rating of a single unit installed for grid connection has well exceeded MW level, and this trend is still developing. Some previous work has been carried out by researchers to compare different wind turbine concepts, but most of these comparisons assume ideal operating conditions. In this paper, an economic evaluation of the mainstream wind turbine concepts rated at 5 MW for onshore sites by taking into account their reliabilities is made. Also not only the low-voltage designs but also medium voltage designs are presented. The comparison results suggest that the direct drive wind turbines produce the highest annual energy, but the doubly fed induction generator typed wind turbines still appear the most economic at this power rating.