Understanding Wind Turbines: Components, Control Strategies, and Speed Regulation
PREGUNTA 1.:
????P is the coefficient of performance, also called power coefficient, the ratio of power extracted by the turbine to the total contained in the wind resource. The maximum theoretical value of ????P possible is 16/27=0.593 known as the Betz limit. The practical value of ????P is in the range of 0.35–0.40.
PREGUNTA 2
The capacity factor (CF) of a wind turbine is the actual energy output for the year divided by the energy output if the turbine operated at its rated power output for the entire year. Capacity Factor = Average Output / Peak Output ≈ 30%
PREGUNTA 3
.COMPONENTS OF A HAWTs: Nacelle: The nacelle contains the key components of a wind turbine, including the gearbox, and the electrical generator. Rotor Blades: The rotor blades capture the wind and transfer its power to the rotor hub. The generator then turns this movement into electricity. Hub: The hub of the rotor is attached to the low speed shaft of a wind turbine. Low Speed Shaft: The low speed shaft of a wind turbine connects the rotor hub to the gearbox. The rotor rotates at about 19–30 rotation per minute (rpm) in a 1,000kWe wind turbine. Gearbox:. Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 19 to 30 rpm to about 1,000–1,800 rpm, which is required by most generators to produce electricity. High Speed Shaft with Its Mechanical Brake: This drives the generator and employs a disc brake, which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies. Electrical Generator: The generator converts the mechanical energy of the rotating shaft into electrical energy. Yaw Mechanism //Electronic Controller// Tower// Anemometer // Wind Vane PREGUNTA 4. Darrieus Wind Turbine:. It is the most common type of VAWT Generally, an external power source is required to start the rotation. The starting torque is very low. Savonius Wind Turbine: It consists of two half-cylinders mounted on a vertical shaft that has an S-shape appearance when viewed from the top. This drag-type VAWT turns relatively slowly, but yields a high torque. Most of the swept area of a Savonius turbine is near the ground. Son baratos y confiables. They are cheap and reliable. Giromill Wind Turbine: H-bar design, in which the ‘egg beater’ blades of the Darrieus design are replaced with straight vertical blade sections attached to the central tower with horizontal supports.
PREGUNTA 5.
Control strategies: There are three main strategies for regulating the amount of power captured by the rotor1) Passive stall control or fixed pitch: ▪ The generator reaction torque regulates rotor speed below rated operation to maximize energy capture. ▪ The power delivered by the rotor is limited at high winds, ▪ The pitch angle is fixed and tip brakes are the only part of the blade which can rotate to spill off the spare energy and shut down the wind turbine.2) Variable pitch control:. ▪ The blades regulate the power delivered by the rotor ▪ To maintain power and rotor speed to their rated value, the torque is held constant and the pitch is continually. 3) Active stall control ▪ This technique is a combination of stall and pitch control. ▪ The blades are designed in a similar way as stall control blades but the entire blade can be turned ninety degrees to adjust its pitch
PREGUNTA 6.Types of wind turbine speed regulation
.There are essentially two types of wind turbine speed regulation: Constant Speed Wind Turbines: Based on a gearbox and an asynchronous generator The gearbox speeds up the rotational shaft speed from the rotor to a fixed generator. Many different options to achieve speed variation: • Dual speed generators with pole switching . • High slip asynchronous generators for a low range of variable speed. • Doubly fed induction generators for a moderate range of variable speed. • Direct drive systems for a wide range of variable speed.