Lecture 4A - Wind Energy Devices

Lecture 4A - Wind Energy Devices - 1/28/11 ECE 4364/5374G:...

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1/28/11 1 ECE 4364/5374G-4A (c) Saifur Rahman 1 Professor Saifur Rahman Electrical & Computer Engineering Dept. Virginia Tech ECE 4364/5374G: Alternate Energy Systems Lecture 4A: Wind Energy Devices ECE 4364/5374G-4A (c) Saifur Rahman 2 Of-shore Wind Energy Project - Europe
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1/28/11 2 ECE 4364/5374G-4A (c) Saifur Rahman 3 Chapter 5 WIND ENERGY CONVERSION SYSTEM In a wind energy conversion system, the wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Utility-scale turbines range in size from 100 to 5000 kilowatts. Smaller turbines, usually below 50 kilowatts, are used for homes, telecommunications dishes, or water pumping. See picture on the next page. More details at: Energy 101: Wind Turbines Video http://www1.eere.energy.gov/windandhydro/wind_how.html#energy101 ECE 4364/5374G-4A (c) Saifur Rahman 4 Picture: Courtesy of NREL Three-bladed Wind Turbine Generators
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1/28/11 3 ECE 4364/5374G-4A (c) Saifur Rahman 5 Internal workings of a Wind Turbine Generator Picture: Courtesy of NREL ECE 4364/5374G-4A (c) Saifur Rahman 6 Anemometer: Measures the wind speed and transmits wind speed data to the controller. Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate. Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies. DeFniJons of Parts of WTG Courtesy of NREL
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1/28/11 4 ECE 4364/5374G-4A (c) Saifur Rahman 7 Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat. Gear box: Gears connect the low-speed shaft to the high- speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. DefniJons oF Parts oF WTG, contd. Courtesy of NREL ECE 4364/5374G-4A (c) Saifur Rahman 8 Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity. High-speed shaft: Drives the generator. Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute. Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. DefniJons oF Parts oF WTG, contd. Courtesy of NREL
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5 ECE 4364/5374G-4A (c) Saifur Rahman 9 Source: ewea.org A Nacelle under ConstrucJon ECE 4364/5374G-4A (c) Saifur Rahman 10 Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
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This note was uploaded on 03/16/2012 for the course ECE 5374G taught by Professor Srahman during the Spring '12 term at Virginia Tech.

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Lecture 4A - Wind Energy Devices - 1/28/11 ECE 4364/5374G:...

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