The proposed hybrid system generates AC power by combining solar and wind energy converted by a doubly-fed induction generator (DFIG). The DFIG, driven by a wind turbine, needs rotor excitation so the stator can supply a load or the grid. In a variable-speed wind energy system, the stator voltage and its frequency vary with wind speed, and in order to keep them constant, variable-voltage and variable-frequency rotor excitation is to be provided. A power conversion unit supplies the rotor, drawing power either from AC mains or from a PV panel depending on their availability. It consists of a multilevel inverter which gives lower harmonic distortion in the stator voltage. Maximum power point tracking techniques have been implemented for both wind and solar power. The complete hybrid renewable energy system is implemented in a PSIM-Simulink interface and the wind energy conversion portion is realized in hardware using dSPACE controller board.

With the rising global warming issue and an ever-increasing dependency oil problem, wind power seems to be an alternative source of energy which is clean, non-polluting, and cost effective. The European 20-20-20 goals as well as national targets for the next ten years require a substantial increase in installed renewable capacity in France. Maïa Eolis is a leading French wind project developer and independent renewable energy producer which helps France to meet its new renewable energy targets. Even if the general opinion on wind energy is rather positive, developing a wind power project is a complex process in France because there are many regulations and new environmental constraints due to the Grenelle 2 law. Many administrative and legislative barriers consequently slow down every step of the development process. This includes handling and coordinating the permitting and application process, realizing pre-feasibility studies, and identifying the best suited sites for wind turbines, taking into account obstacles, aesthetics, and other environmental issues, in order to capture as much wind as possible. Ensuring local support is another key element of the success of a project in order to integrate it in the best possible way in its environment.

The research presented considers the effect of varying shear web spacing and mass for two blades; a61.5m 5MW blade (based on the NREL5MW reference turbine) and a 100m 13.2MW blade (based onthe SNL100 blade). The variations are analyzed using HAWC2 aeroelastic simulations and Abaqus/CAE finite element simulations;and the effect of the variations is measured by comparing natural frequencies, loads, tip deflection,equivalent fatigue loads, material strength and buckling. Additionally, a tool was developed to facilitatethe modeling of blade variations. Varying the web spacing showed that the web placement is able to reduce loads, tip deflection, and equivalentfatigue loads. Mass variations demonstrated that reducing the mass will decrease edge-wise loadingand equivalent fatigue loads. The increase in blade size has shown that edge-wise fatigue loads becomelarger than the flap-wise fatigue loads for the larger blade.

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No / In this study, a new methodology to optimally allocate wind turbines (WTs) in distribution networks is proposed. A market-based optimal power flow is used to determine the optimal numbers and capacities of WTs in a way that maximises the social welfare. The method is conceived for distribution network operators to strategically allocate WTs in distribution networks. The proposed method by yielding location-specific WTs capacity settlement both in terms of cost reduction and consumers' benefits is consistent with distribution network topology and constraints. The method is solved by using step-controlled primal dual interior point method considering network constraints. The effectiveness of the proposed method is demonstrated with two radial distribution systems including an 84-bus 11.4 kV and a 69-bus 11 kV network.

No description available.

Wind power is a fast-growing source of non-polluting, renewable energy with vast potential. However, current wind technology must be improved before the potential of wind power can be fully realized. One of the key components in improving wind turbines is their blades. Blade failure is very costly because blade failure can damage other blades, the wind turbine itself, and possibly other wind turbines. A successful structural health monitoring (SHM) system incorporated into wind turbines could extend blade life and allow for less conservative designs. Impedance-based SHM is a method which has shown promise on a wide variety of structures. The technique utilizes small piezoceramic (PZT) patches attached to a structure as self-sensing actuators to both excite the structure with high-frequency excitations, and monitor any changes in structural mechanical impedance. By monitoring the electrical impedance of the PZT, assessments can be made about the integrity of the mechanical structure. Recent advances in hardware systems with onboard computing, including actuation and sensing, computational algorithms, and wireless telemetry, have improved the accessibility of the impedance method for in-field measurements. The feasibility of implementing impedance-based SHM on wind turbine blades is investigated in this work. Experimentation was performed to determine the capability of the method to detect damage on blades. First, tests were run to detect both indirect and actual forms of damage on a section of an actual wind turbine blade provided by Sandia National Laboratories. Additional tests were run on the same blade section using a high-frequency response function method of SHM for comparison. Finally, based on the results of the initial testing, the impedance method was utilized in an attempt to detect damage during a fatigue test of an experimental wind turbine blade at the National Renewable Energy Laboratory's National Wind Technology Center. / Master of Science

The following report chronicles the University of North Texas Wind Turbine Project at Apogee Stadium. The timeline of events will include the feasibility study conducted by and for the university, grant awards from the Texas State Energy Conservation Office to fund the project, and a three-year sample of real time performance data since installation. The purpose of this case study is to compare the energy generation estimates by various stakeholders to the measured energy generation using a new but uniform performance relationship. In order to optimize energy generation in wind turbine generator systems, the most common wind speeds measured at the site should also be the most efficient wind speeds at which the wind turbine can convert the kinetic energy in the wind into mechanical energy and ultimately electrical energy. The tool used to convey this relationship will be a figure plotting the wind speed profile against the efficiency curve of the wind turbine. Applying this relationship tool to the UNT Apogee Stadium wind turbines provided valuable results. The most common wind speeds at Apogee Stadium are not the most efficient wind speed for the turbine. Also, the most common wind speeds were near the lower limit of the wind turbine’s performance parameters. This scenario was evident in both the energy generation predictions as well as the real-time recorded data. This case study will also present the economic analysis of the Apogee Stadium wind turbines using another tool that was not previously used in the feasibility study. The case study concludes with future steps to improve wind turbine performance, and to budget future cost using past, present and future energy savings.

Thesis (MScEng (Department of Mechanical and Mechatronic Engineering))--Stellenbosch University, 2006. / ENGLISH ABSTRACT: Wind conditions in South Africa determine the need for a small-scale wind turbine to produce useable power at windspeeds below 7m/s. In this project, a range of windspeeds, within which optimal performance o the wind turbine is expected, was selected. The optimal performance was assessed in terms of the Coefficient of Power(Cp), which rates the turbines blade's ability to extract energy form the avalible wind stream. The optimisation methods employed allowed a means of tackling the multi-variable problem such that the aerodynamic characteristics of the blade were ideal throughout the wind speed range. The design problem was broken down into a two-dimensional optimisaion of the airfoils used at the radial stations, and a three-dimensional optimisation of the geometric features of the wind rotor. by means of blending various standard airfoil profiles, a new profile was created at each radial station. XFOIL was used for the two-dimensional analysis of these airfoils. Three-dimensional optimisn involved representation of the rotor as a simplified model and use of the Blade Element Momentum(BEM) method for analysis. an existimg turbine blade, on which the design specifications were modelled, was further used for comparative purposes throughout the project. The resulting blade design offers substantial improvements on the reference design. The application of optimisation methods has successfully aided the creation of a wind turbine blade with consistent peak performance over a range of design prints. / Sponsored by the Centre for Renewable and Sustainable Energy Studies, Stellenbosch University

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / This paper describes a MEng thesis project for a MEng in Renewable Energy Systems program at the Centre for Renewable Energy Studies at the University of Stellenbosch, South Africa. The aim of this paper was to offer to SAB (South African Breweries), in Cape Town, a feasibility study for the possibilities of the usage of wind energy on site. The small scale wind power technology has a long history and has been in South Africa for more than a hundred years in the form of water pump wind mills. All wind mills have an absolute maximum power output defined by the Betz limit. The choice of a wind turbine depends not only on this, but also on the wind speed distribution, the power curve, the location and financing. The small scale turbines have many different design which are predominantly grouped in horizontal axis (HAWT) and vertical axis (VAWT) machines. The choice of turbine for SAB depends on the available wind energy, the available budget, the available space and the application. The aim of the measurements on site was threefold; find a correlation with existing weather stations in the area like at Cape Town International Airport, propose a turbine for SAB’s budget and research the possibility for installing the turbine on one of the buildings. This is also known as building integrated wind turbines. Wind speeds can increase over buildings due to venturi effects and it could therefore be viable to locate these acceleration zones and install a turbine there. The data analysis shows that the wind above the brewery is very well correlated with the wind at the airport. We can therefore use the average speed values of this station to predict average power production. This leads to the proposal of a 1kW or 3kW turbine from a South African manufacturer: Kestrel. Building integration is however not a good idea. The wind is too turbulent and can therefore not be used. This is mainly caused by the fact that the surroundings of the brewery are too high and irregularly shaped. This makes it difficult for the wind to “lower” in between the buildings and accelerate. The wind turbine for SAB is proposed to be installed on the highest point of the roof and based on the neighbouring average wind speed values. The wind turbine should be connected directly to the brewery’s grid with an inverter and would then solely function as an energy saver. Another important aspect is the promotional value in the energy efficiency strategy of SAB. / Centre for Renewable and Sustainable Energy Studies