2006 Volume 126 Issue 8 Pages 742-752
In order to investigate the impacts of the integration of wind farms into utilities networks, transient stability should be analyzed before connecting wind turbine generator system (WTGS) to the power system. In this paper, a new logical pitch controller equipped with fuzzy logic controller (FLC) has been proposed, which can enhance the transient performance of WTGS during severe network disturbances. Moreover, it can maintain the output power at rated level when wind speed is over the rated speed. Before transient stability analysis, it is necessary to determine initial values of WTGS connected to the external network. In this paper, the initial value calculation method of WTGS is discussed at different wind conditions. Finally, in order to evaluate the effectiveness of the proposed controller in improving the transient stability, simulations have been carried out for severe network disturbances and windy conditions, considering mechanical dead zone of the pitch actuation system. Simulation results clearly indicate that the proposed controller can enhance the transient stability of wind generator at any network, fault or windy condition, and maintain output power of wind generator at rated level when wind speed is over the rated speed.