Fixed-Speed and Variable Speed (PMSG) Induction Generators Based Wind Farms with Statcom Control under Asymmetrical Grid Faults

Recently, renewable wind energy is enjoying a rapid growth globally to become an important green electricity source to replace polluting and exhausting fossil fuel. The stability of fixed-speed induction generator (FSIG)-based wind turbines can be improved by a StatCom, which is well known and documented in the literature for balanced grid voltage dips and comparing with the variable speed permanent magnet synchronous machine. Under unbalanced grid voltage dips, the negative sequence voltage causes heavy generator torque oscillations that reduce the lifetime of the drive train. In my project, investigations on an FSIG-based wind farm in combination with a StatCom and variable speed permanent magnet synchronous machine under unbalanced grid voltage fault are carried out by means of theory, simulations. A StatCom control structure with the capability to coordinate the control between the positive and the negative sequence of the grid voltage is proposed. The results clarify the effect of the positiveand the negative-sequence voltage compensation by a StatCom on the operation of the FSIG-based wind farm and variable speed pmsg. With first priority, the StatCom ensures the maximum fault-ride-through enhancement of the wind farm by compensating the positivesequence voltage. The remaining StatCom current capability of the StatCom is controlled to compensate the negative-sequence voltage, in order to reduce the torque oscillations. This total project is carried out in MATLAB SIMULINK software.