Modeling and control of a pitch-controlled variable-speed wind turbine driven by a DFIG with frequency control support in PSS/E

In recent years, due to the rising penetration of wind energy conversion systems (WECS) into the electricity networks, increasingly comprehensive studies and accurate dynamic models are required to analyze its behavior under grid faults. A complete model of a pitch-controlled variable-speed wind turbine driven by a doubly fed induction generator (DFIG) and its control scheme are implemented. All encompassed subsystems, such as wind turbine, pitch actuator, two-mass drive train model, DFIG model, converters and protections are modeled in FORTRAN using the power system simulation software PSS/E. A cascade control structure is used where the outer control loop concerns the speed control and the inner control loop is responsible for the electrical control. Additionally, a frequency control support is developed in order to accomplish with the Grid Codes requirements enhancing the grid power quality. The model performance under various system disturbances is tested by means of simulations.