The fast growth of wind generation has led to concern about the effect of wind power on the transient stability of the electric grid. New studies must be performed in order to evaluate the behaviour of the wind farms after severe faults and improve the design of the wind farms in an efficient and economical way. Under such circumstances, the most demanding requisite for wind farm is the Fault Ride-Through (FRT) capability. Wind farms connected to high voltage transmission system must stay connected when a voltage dip occurs in the grid, otherwise, the sudden disconnection of great amount of wind power may contribute to the voltage dip, with terrible consequences. Therefore, the dynamic and transient analyses of wind generators are necessary. This book proposes some methods with suitable control strategies for wind power application that helps wind farms to be connected during grid disturbances, achieving the grid code provisions in both steady and transient conditions. The results in this book can be significant in understanding the transient stability phenomena of fixed and variable speed wind turbines and also in designing of wind farms based on transient stability requirements.

The grid codes require taking into account the reactive power of the wind farm/park in order to contribute to the network stability, thus operating the wind farm as active compensator device. This book gives a comparative study of stabilizing wind farms using flexible ac transmission systems (FACTS) units like the (Static Synchronous Compensator) STATCOM and the variable speed wind turbines like the Doubly Fed Induction Generators (DFIGs) during wind speed change and grid fault. Both systems can provide reactive power to the wind farms during dynamic and transient conditions. Simulation analyses were carried out in laboratory standard simulation software called power system computer aided design/electromagnetic transient including DC (PSCAD/EMTDC). The simulated results show that the wind farms could be effectively stabilized with both systems. However, the cost is reduced with the DFIGs system because, apart from generating electric power during steady state, it can also provide reactive power through its frequency converters to stabilize the wind farms without the need of an external reactive power compensation units like the STACOM.