Advanced Short-Circuit Current Calculation for Doubly-Fed Induction Generator Based Wind Turbines According to IEC 60909

In this paper, an advanced approach to calculate the short-circuit current contribution of wind turbines based on doubly fed induction generators (DFIGs) according to IEC 60909 for a three-phase short-circuit is presented and analysed. The initial short-circuit current contribution of the DFIG for various rotor voltage settings is calculated with the top and bottom envelope derived by several interpolations. Due to unreliable results, an advanced analytical approach is proposed. Within this approach, a simplified impedance calculation for DFIG is suggested with an additional correction factor to counteract inaccuracies of the considered assumptions. Therefore, a possibility for deducing an advanced consideration of the stator current and the LSC grid current of DFIG in IEC 60909–0 is displayed.