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In this paper, the problems of optimal mixed variable-pitch-angle control and variable-speed control of wind turbines for all operating regions are considered. A new optimal controller, based on minimum torque control and minimum lost wind-energy capture, for maximizing wind energy extraction is designed. Furthermore, a new optimal controller, based on minimum torque control, for output power leveling is designed. In special cases, such as saturated controller, fixed-pitch-angle control, and constant rotor speed, control mixed control problems are studied. [ABSTRACT FROM AUTHOR]

Wind energy is leading technology among renewable energy resources, and many countries have ambitious wind energy plans for future. Wind-rich sites which are a variable source of energy, are mostly located in remote areas that transmission network in these areas cannot absorb additional power from new wind sites. Therefore, a non-physically firm connection strategy is key to its cost-effective and timely integration to presently constrained transmission networks. This problem is computationally challenging and a proper method is needed to relieve this computationally burden of the problem. In this paper, it is shown that the large-scale linear programming is exploitable by benders decomposition method. Hourly wind speed data are used to accurately model the effects of wind speed pattern on unit commitment (UC) and DC optimal power flow (OPF) problem for an entire year. The results show effectiveness of a proper wind capacity allocation method on the total investment and operation costs and overall wind energy penetration into the power system. [ABSTRACT FROM AUTHOR]

In this paper, the size of a stand-alone wind/PV/battery system is optimized. The hybrid system is consisting of three major power sources: wind turbine generator, photovoltaic arrays, and storage batteries that the characteristics of components are commercially available. This study is performed for a region in North-West of Iran. The optimization problem is subject to economic and technical constraints. System costs involve investments, replacements, and operation and maintenance as well as loss of load costs. The technical constraint, related to system reliability, is expressed by the equivalent loss factor. The reliability index is calculated from component's failure that is including of wind turbine, PV array, battery and inverter failure. In this study, size of components related to three different systems is evaluated and they are compared with each other. The simulation results indicate that the hybrid system can be the best alternative for this region that has minimum costs and can satisfy the constraints. Also, the error of measurement propagation for hybrid system is calculated In this study particle swarm optimization algorithm is used for optimal sizing of system's components. [ABSTRACT FROM AUTHOR]

The goal of this paper is to present an algorithm for increasing output power in wind farms with high wake losses. In some wind directions, wake effects cannot be neglected because the distance between turbines may be less than 5–8 times of rotor diameter. The purpose of presented algorithm is to determine coefficient of performance ( C P ), thrust coefficient ( C T ), pitch angle ( β ) and rotational speed ( ω ) of each turbine by using wake effects equations so that wake losses in the wind farm becomes minimum which result in increasing output power of wind farm. PSO algorithm is used for optimization. Finally, a sample wind farm consisting of 16 turbines is used as a case study and the results show that there is a noticeable increase in the amount of wind farm output power rather than the time which no control and optimization is used. The conclusion is that the presented algorithm is suitable for wind farms with high wake losses and little distance between their turbines and is very effective for increasing their output power. [ABSTRACT FROM AUTHOR]