BESS Support to DFIG-based Wind Turbines connected to medium-voltage distribution networks

Although the DFIG-based wind turbine is the most widely used wind generator topology, it is highly sensitive to grid disturbances. In fault conditions, the DFIG rotor side converter may suffer damage caused by rotor overcurrents. Also, the DC link voltage may surpass the allowable limits due to overvoltages, causing the wind power plant getting tripped by the protection system. Another issue related to wind power generation is wind uncertainty, which can cause power fluctuation at the generator output. Thus, this paper evaluates the ability of a Battery Energy Storage System (BESS) to regulate the DFIG output power, and its influence to improve the DFIG Fault Ride-Through (FRT) capacity. To perform these analyses, the BESS is connected to the point of common coupling of a distributed wind turbine, and the system transient and steady-state responses are verified. The results showed that a BESS could regulate the DFIG output power, but it represented an ineffective approach to enhance the FRT capacity of the tested wind turbine.