Stability Improvement of DFIG based WECS Connected Power System Using Custom Power Devices

There is a continuously growing demand for wind power generation capacity. As the wind power generation, which depends on the weather, is integrated into the grid continuously and quickly, the influence of wind turbines on the grid power quality is becoming an important issue, especially the influence on voltage fluctuation and flicker. The system operators, who are responsible for maintaining power system stability and reliable power supply, have formulated specifications regarding grid integration of wind power generation. The reason is, when the wind power penetration level is high, the protective disconnection of a large amount of wind power will be an unacceptable consequence that may threaten the power system stability. In this paper we have have taken a test case of power system with and without custom devices which are main component of unified power quality conditioner (UPQC) or unified power flow controller(UPFC) and have shown effect of rating of these devices on stability of grid-connected doubly fed induction generator wind energy system(DFIG-WES).