الفهرس 
الغلافOnly 14 pages are availabe for public view
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Abstract
A majority of the wind turbines WTs installed were induction generators that absorb reactive power from the system even during normal operating conditions. Capacitors are usually connected to fixed speed wind turbines to enhance the system voltage. Mechanically switched fixed shunt capacitors can enhance the system’s voltage stability limit, but is not very sensitive to voltage changes. Also, voltage regulated by the wind generators equipped with only fixed capacitors can become higher than the voltage limit of 1.05 pu. Hence, additional compensating equipment is needed by the system in order to restore quickly after the fault has been cleared so as to maintain system stability and to avoid generator tripping.
This thesis presents the applicability of a ST A TCOM in wind farms has been investigated and it is able to supply reactive power requirements of the wind farm under various operating conditions, thereby improving the steady-state stability limit of the network. a voltage source inverter sinusoidal pulse width modulation SPWM technique based on STA TCOM is proposed to stabilize grid connected variable speed wind turbines under wind gust and three-phase fault disturbance.
Performance optimization of wind farms connected to the grid is the main point in this thesis, so genetic algorithms GAs tool is used to get optimum values for controller parameters of active power and reactive power controller.
The tuning method for PI controller using generalized Zeigler¬Nicholas used to get parameters of PI controller for proposed system.