Wind turbine control design to enhance the fault ride-through capability

This paper presents a control strategy for wind turbines to enhance their fault ride-through capability. The controller design is based on pitch controlled variable speed wind turbine equipped with doubly-fed induction generator (DFIG). The fault ride-through is realized by injecting a crowbar with variable resistance on the generator rotor circuit. To reduce the mechanical loads induced by grid faults, the wind turbine controller is improved by means of filtering techniques which alleviate the loads on the turbine blades and drive-train. The performance of the control strategy is tested by simulation. It is shown that the combined mechanical and electrical controller design significantly improves the wind turbine fault ride-through capability. The effects of the fault ride-through strategy on both the wind turbine and electric network are then analysed.