الفهرس 
Wind Energy over the world
Theoretical BackgroundOnly 14 pages are availabe for public view
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Abstract
Due to their widespread and cost-effective use, renewable energy resources are now being prioritized all over the world, especially with the diminishing fossil fuel reserves and continuous electricity demand. Particularly for wind energy, there is ongoing research for further developments to enhance the electrical performance of the wind energy conversion systems (WECS).
One of the major problems facing the integration of WECS to the grid is the voltage stability, especially when they are connected to weak grids. A possible solution for this problem is the use of flexible AC transmission system (FACTS) devices that are widely used with a variety of power systems.
In this thesis, a techno-economic assessment for three FACTS devices; STATCOM, SSSC and UPFC is presented. The chosen FACTS are based on voltage source converter (VSC) technology, and they represent shunt, series and series-shunt connections. In the technical assessment, an improved voltage IV index is presented to show the contribution of the FACTS devices during single, double and triple line faults to improve the voltage stability of the system. To improve the system response, a PI self-adaptive controller is used with the FACTS devices after being validated against PI and Proportional-Integral-Acceleration (PIA) controllers. The parameters of the proposed controller are optimized using the Equilibrium Optimizer (EO) technique.
To test the proposed approach, several case studies are simulated in the MATLAB/SIMULINK environment, where, the required models and controllers are implemented. In addition, the EO technique is implemented in the MATLAB environment to identify the optimal parameters for the different controllers. The results show the effectiveness of the proposed approach in achieving the required technical improvements.
For the economic assessment, the overall cost of the FACTS devices and their annual instalments are obtained. In addition, guidelines are presented to calculate the threshold annual loss in energy from the proposed wind farm where, the cost of this annual loss in energy should compensate the FACTS device’s annual instalment, according to this threshold annual loss in energy, it could be possible to decide if it’s mandatory to install the FACTS devices or not. To consider the environmental impact, CO₂ emissions are estimated to show the effect of FACTS devices on reducing these emissions. Moreover, the associated carbon credit certificates that can be obtained are taken into consideration. At the end of the economic assessment, a cost related index is presented to express the cost variation between the FACTS devices as it includes the overall cost paid for the FACTS devices and the economic benefits that could be obtained due to the installation of the FACTS devices. This index will help the system operators to compare between the FACTS devices from the economic point of view.
Finally, to combine both assessments, a new weighed techno-economic index (TEI) is presented considering different technical and economic weights. In this combined index, the technical term includes the voltage improvement due to using the FACTS devices while the economic term includes the overall cost paid for the FACTS devices and the economic benefits gained. Accordingly, a breakeven point is defined to select the best device to be used with the proposed system considering both the technical and economic aspects.
Keywords— WECS, FACTS devices, STATCOM, SSSC, UPFC, EO, PI Self-Adaptive Controller, IV index, CR index, TEI.