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Connected and Autonomous Electric Vehicle Charging Infrastructure Integration to Microgrids in Future Smart Cities
Published in Hussein T. Mouftah, Melike Erol-Kantarci, Sameh Sorour, Connected and Autonomous Vehicles in Smart Cities, 2020
Mohammad Sadeghi, Melike Erol-Kantarci, Hussein T. Mouftah
A wind turbine is used to generate electrical energy by converting wind energy into electricity. The wind turbine structure consists of two basic parts: electrical and mechanical parts. The motion energy of wind is captured in the form of rotational energy in the mechanical part, and then in the electrical part, this rotational energy is converted to electrical energy. The wind turbine includes three main components: the tower, the rotor, and the nacelle. The nacelle is equipped with an electrical generator and mechanical power transmission parts. The rotor normally includes more than two blades that extract motion energy from wind. Then, a gearbox is used to transfer the captured rotational energy to the shaft of an electrical generator to generate electric power. Wind turbines can be categorized into two categories: vertical and horizontal axis types. Vertical-type wind turbines are more common for small units and kW ranges up to 100 kW, while larger units are mostly horizontal wind turbines that support the order of MW.
Energy
Published in A.P.H. Peters, Concise Chemical Thermodynamics, 2010
Wind is simple air in motion. It is caused by the uneven heating of the earth’s surface by the sun. Since the earth’s surface is made of very different types of land and water, it absorbs the sun’s heat at different rates. During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating winds. At night, the winds are reversed because the air cools more rapidly over land than over water. Wind turbines convert the kinetic energy from the wind into mechanical energy, which is then used to drive a generator that converts this energy into electricity. In the same way, the large atmospheric winds that circle the earth are created because the land near the earth’s equator is heated more by the sun than the land near the North and South Poles. Today, wind energy is mainly used to generate electricity. Wind is called a renewable energy source because the wind will blow as long as the sun shines. This renewable source of energy has great potential in both onshore and offshore wind farms. Wind power is one of the cleanest and safest of all the renewable commercial methods of generating electricity.
Offshore Wind Turbines
Published in Srinivasan Chandrasekaran, Faisal Khan, Rouzbeh Abbassi, Wave Energy Devices, 2022
Srinivasan Chandrasekaran, Faisal Khan, Rouzbeh Abbassi
There are two types of wind turbines, namely the horizontal axis (HAWT) and the vertical axis wind turbine (VAWT). The major sub-systems of a wind turbine are blades, nacelle, controller, generator, rotor, and the tower (also called the mast). Rotor houses the blades, which in turn are attached to a hub of the turbine. The number of blades, their geometric profile, and their length govern the performance of a wind turbine. The upwind or downwind design approach is used in designing the rotor, while the design of the blades is governed by the method of controlling the pitch motion. Nacelle comprises the generator, controller, gearbox, and shafts and acts as a protective cover. The yaw-drive system controls the nacelle alignment, which connects the nacelle to the top of the tower. The gyroscopic moment is generated by the yaw of a wind turbine and is proportional to the rotational moment of inertia of the rotor. To avoid excess moments, the rate of yaw motion should be controlled. Rotor diameter and the nature of loading conditions determine the height of a tower at a given site. Dynamic coupling between the tower and rotor can lead to reduced life of the machine due to fatigue. The tower or the mast is about 60–80 m high and consists of three telescopic sections. The tower supports the wind turbine nacelle and the rotor. A generator is used to convert the mechanical output of the wind turbine to electrical output. Induction of synchronous generators is deployed, whose relative rotational speed between the rotor and the rotating magnetic field in the stator generates power. The difference between these respective speeds is called slip, which governs the wind turbine’s power output.
Servomotor Pitching Control Method for H-Type Darrieus Turbine
Published in Electric Power Components and Systems, 2023
Ramesh K. Kavade, P. M. Ghanegaonkar, Prateek D. Malwe, Chandrakant Kothare, Prashant Darade, Ghanashyam M. Chendke, Hitesh Panchal, Radhey Shyam Meena, Ibham Veza
The two main types of wind turbines are horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). Commercially speaking, HAWTs outpace VAWTs since most wind power producing facilities use huge HAWTs with plenty of power [3]. HAWTs are typically found in coastal regions, which are far from where power is first used. As a result, a decentralized power plant concept is needed, in which the sites of the power’s generation and use are the same. In metropolitan settings, there are additional sides VAWTs that can be used to generate electricity on their own. Due to their proximity to the ground or their installation on building roofs, this type of turbine requires less maintenance [4]. Commercially produced VAWTs have fixed pitch designs, which result in low power coefficients, especially at low tip speed ratios, and challenging first starts in light wind [5–7].
Influence factors of extraction behavior of modified suction caisson in sand by reverse pumping water
Published in Marine Georesources & Geotechnology, 2022
Dayong Li, Yun Bai, Fuquan Chen, Linping Chen, Yukun Zhang
For example, the lifespan of an offshore wind turbine is approximately 20–30 years. When the offshore wind turbine is decommissioned and needs to be dismantled, a wind turbine with higher power capacity is required, causing higher self-weight and greater wind load. Therefore, the existing suction caisson foundation should be extracted and will be replaced by a new suction caisson with higher bearing capacity to meet new needs. It has been proved that suction caissons can be partly extracted by applying overpressure between the caisson lid and the soil (Lehane, Elkhatib, and Terzaghi 2014; Zhang, Li, and Chen 2018). Lorenti, Shum, and Lehane (2009) carried out in-situ extraction tests on a suction caisson of 3.4 m in diameter and 12 m in height in soft clay and found that the overpressure first increases to the peak value of 415 kPa, then the overpressure reduces rapidly with further extraction displacement. Zhang, Ding, and Le (2013) conducted field tests on prototype suction caissons in soil consisting of organic silt, silty clay, and clay in Bohai Sea of China. The extraction test on a mooring platform with three suction caissons was discussed. Test results show that skin frictional force decreases due to the seepage effect caused by the overpressure. In addition, the suction caissons can be extracted by pumping water with the assistance of the pullout force. Le, Ding, and Zhang (2018) concluded that the suction caisson can be partly extracted without soil plug failure by reverse controlling the pumping rate to provide a reasonable overpressure.
Optimal post-warranty maintenance contracts for wind turbines considering availability
Published in International Journal of Green Energy, 2020
Rui Zheng, Yingzhi Zhang, Liudong Gu
The operating life of a wind turbine is usually 20 years. Based on a 3-year warranty, Figure 5 shows the effect of the contract’s duration s on the three options. Some findings are presented as follows: When the contract coverage increases, the servicing costs of the three options increases nearly linearly, which indicates that the contract coverage has influence on the three options. Moreover, the influence of contract coverage on option 1 is much greater than on option 2 and option 3.The cost difference between option 2 and option 3 is nearly the same for different contract coverages.