Fault Recovery of a Wind Farm with Fixed Speed Induction Generators Using a STATCOM

Abstract

This paper describes a feasibility study for a wind farm with Fixed Speed Induction Generators and having a STATCOM, combined with Mechanically Switched Capacitors, for reactive power control and fault recovery. The turbine blade and generator inertia, coupled with a shaft of finite stiffness, are modelled to represent torsional oscillation. This is important to represent the dynamic behaviour of the system adequately. Dynamic simulations show that fault ride-though capability of a wind farm can be met by using a STATCOM, and switching in shunt capacitors, when the overspeed protection is set at 1.1 pu. However, the wind turbine must be designed to cope with the mechanical stress resulting from a fault in the AC system with a large magnitude of voltage dip. Successful fault recovery is demonstrated for symmetrical and asymmetrical faults. The control strategy proposed here can be adopted for different grid code requirements and various wind farms.