Induced Torques on Synchronous Generators from Operation of Wind Power Plant based on Full-Load Converter Interfaced Wind Turbines

It is expected that large wind power plants (WPP) contribute to stable and reliable operation of the electric power system. This includes participation with delivery of system services such as voltage and frequency support. With variable-speed WPPs this can be achieved by adding auxiliary controllers that control the active and reactive power output accordingly.

While being designed for a given system service, any feedback control affects the closed-loop behavior of the overall system and thereby its small-signal stability properties. Eigenvalue analysis conveniently determines the stability properties from the closed-loop system. A method based on induced torque coefficients (ITC) is here presented for assessing the closed-loop behavior from the open-loop system.

Results are presented using both modal analysis and ITC prediction, which demonstrate that the dominant closed-loop behavior can be predicted with the presented method. The work is based on a nonlinear, dynamic model of the 3.6 MW Siemens Wind Power wind turbine.