With growing concerns about environmental pollution and a possible energy shortage, great efforts have been taken by the governments around the world to implement renewable energy programs, based mainly on wind power, solar energy, small hydro-electric power, etc. With improving techniques, reducing costs and low environmental impact, wind energy seems certain to play a major part in the world's energy future. Due to its many advantages such as the improved power quality, high energy efficiency and controllability, etc., the variable speed wind turbine using a double-output induction generator (DOIG) is becoming a popular concept and thus the modeling of the DOIG based wind turbine becomes an interesting research topic. As the wind power penetration continually increases, power utilities concerns are shifting focus from the power quality issue to the stability problem caused by the wind power connection. In such cases, it becomes important to consider the wind power impact properly in the power system planning and operation. Unfortunately, few power system analysis tools have included wind turbine models such as have been developed for traditional Power generators. The paper develops analytical steady-state and Dynamic models to provide this insight and correlates the operating performance of DOIG for wind energy conversion systems using MATLAB-Simulink environment. This paper considers a grid-connected system; a further paper will describe a stand-alone system. © 2008 IEEE.