Calculating Steady-State Operating Conditions for Doubly-Fed Induction Generator Wind Turbines

In this paper an analysis of steady-state operation in doubly-fed induction generator (DFIG) wind turbines (WT) is presented. A method based on the Newton-Raphson (NR) algorithm is proposed for obtaining the steady-state electrical variables of the machine under certain given conditions. It is of interest in the load flow analysis, when these machines are present in electrical system, but also for gaining initial conditions for dynamic analysis, as the variables in dynamic models must coincide with those in stationary models during steady-state operation. Results obtained from the stationary analysis allow us to initialize electrical variables for use in a third-order dynamic model of the DFIG. The method presented in this paper does not make use of a d-q reference frame. Some approximations made in other works have not been assumed here, which allowed us to obtain more accurate results.