Wind energy is considered one of the most important sources of renewable energy in the world, because it contributes to reducing the negative effects on the environment. The most important types of wind turbines are horizontal and vertical axis wind turbines. This work presents the full details of design for vertical axis wind turbine (VAWT) and how to find the optimal values of necessary factors. Additionally, the results shed light on the efficiency and performance of the VAWT under different working conditions. It was taken into consideration the variety of surrounding environmental conditions (such as density and viscosity of fluid, number of elements of the blade, etc.) to simulate the working of vertical wind turbines under different working conditions. Furthermore, the effect of the design factors was investigated such as the number and size of the blades on the behavior and performance of VAWT. It was assumed that the vertical wind blade works in different sites of Iraq. QBlade software (Version 8) was used to achieve the calculations and optimization processes to obtain the optimal design of vertical axis wind turbines that is suitable for the promising sites. The results proved that accurate results can be obtained by using QBlade software.

Photovoltaic (PV) panel temperature plays a vital role in the performance of PV panels. When PV temperature increases, the electrical power and efficiency decrease. In the present study, a simple simulated model is derived and implemented for a 70-W finned PV panel and the results are compared with those for a reference (unfinned) PV panel. The effect of various parameters including fin diameter, fin height, ambient temperature, fin coverage-to-area ratio, and solar irradiance level on PV performance are examined. It is concluded that more electrical power is generated under moving air than under still air conditions as solar irradiance increases. The optimum values for fin diameter, fin height, and fin coverage-to-area ratio are 0.005 m, 0.25 m, and 50%, respectively. The maximum simulated power difference between the finned and unfinned PV panels is 5 W under realistic weather conditions. The amount of power generated during the summer season would be about 3.32 kW•h greater than that by the reference PV panel over the same period. The root square percent deviation values between the results of the proposed model and previously published experimental data for panel temperature, electrical power, and electrical efficiency are 3.36%, 5.26%, and 5.48%, respectively.

To damp the low-frequency oscillations which occurred due to the disturbances in the electrical power system, the generators are equipped with Power System Stabilizer (PSS) that provide supplementary feedback stabilizing signals. The low-frequency oscillations in power system are classified as local mode oscillations, intra-area mode oscillation, and interarea mode oscillations. Double input multiband Power system stabilizers (PSSs) were used to damp out low-frequency oscillations in power system. Among dual-input PSSs, PSS4B offers superior transient performance. Power system simulator for engineering (PSS/E) software was adopted to test and evaluate the dynamic performance of PSS4B model on Iraqi national grid. The results showed that after installing the PSS in a specific plant the oscillation of rotor angle, bus frequency, speed, power flow is better than without PSS during the disturbances that occurred during the simulations.  All the PSS/E simulation and tests were done in the National dispatch center (NDC) laboratory, Ministry of Electricity.  

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To damp the low-frequency oscillations which occurred due to the disturbances in the electrical power system, the generators are equipped with Power System Stabilizer (PSS) that provide supplementary feedback stabilizing signals. The low-frequency oscillations in power system are classified as local mode oscillations, intra-area mode oscillation, and interarea mode oscillations. A suitable PSS model was selected considering the low frequencies oscillation in the inter-area mode based on conventional PSS and Fuzzy Logic Controller. Two types of (FIS) Mamdani and suggeno were considered in this paper. The software of the methods was executed using MATLAB R2015a package.