The power production from wind energy in the world is growing very fast and the Nordic countries are performing an important role in it, not only taking advantage of theirs renewable resources but also developing the suitable technology for that. During the last 20 years the wind energy technology has been strongly developed, increasing from single 55kW wind turbines to single 2MW and 3MW wind turbines installed in large wind farms. Within a few years several wind farms of hundreds of MW and high number of wind turbines will be under construction on the Baltic Sea, the North Sea and on shore in the Nordic countries. Consequently, large amounts of energy and power coming from wind will be injected into the Nordic grid. Nevertheless, increasing the penetration level of wind power generation into the power system produces impacts on the power system performance, operation and control. Hence, more careful studies on wind power generation and its interaction with the power system stability need to be done for finding suitable solutions and making the power system reliable. This project is aimed at performing these studies. The main objective into the project is to develop reliable models suitable for studying the implications of operating the Nordic grid with a large amount of energy and power coming from wind farms.