Steady-State Characteristic Study for Integration of DFIG Wind Turbines into Transmission Grid

Wind power has emerged as a promising renewable energy resource. A wind power plant, normally located in an area with reliably favorable wind speed, is connected to the grid through a transmission line. This paper presents a steady-state characteristic study of a DFIG-based wind energy conversion system (WECS) that is integrated into the power grid through a transmission system. Steady-state models in a d-q reference frame are developed for a single wind turbine, a simplified wind power plant, and an integrated WECS and grid system. In addition, a transient simulation system is built to validate the accurateness of the steady-state results by using MatLab SimPowerSystems. An integrative study is performed to investigate WECS parametric data simultaneously as the number of DFIG wind turbines connected to a wind farm changes under constant turbine driving torque and driving power conditions. Parallel and series compensations, usually used to improve WECS performance, are investigated. A comparative study is presented to illustrate the characteristic difference between WECSs using fixed-speed induction generators and variable-speed DFIGs.