Block diagram of basic wind energy conversion system:
Components of wind power plant and their functions:
1) Rotor /Blade/Aero-turbine: Blade extracts significant power from the wind. They convert the force (K.E.) of the wind into the rotary motion to generate useful mechanical power.
2) Hub: Hub of the wind turbine is that component which connects the blades to the main shaft and ultimately to the rest of drive train. Hubs are generally made up of steel.
3) Main Shaft (Low speed shaft): It is provided for transfer of torque from the rotor blade to the rest of the drive train. It also supports weight of rotor. Speed of the shaft is low, is about 30 to 60 rotations per minute.
4) High speed shaft: It is connected to generator via-gearbox. Speed of the wind turbine is low; gearing arrangement increases the speed of rotation to the level as per design. e.g. 1500 rpm for 50 Hz frequency and 1800rpm for 60 Hz frequency necessary to generate electricity with the help of generator. Gear box is one of the heaviest and most expensive component in wind turbine.
5) Coupling: Coupling are used to connect shaft together
Between main shaft and gear box
Between gear box output and the generator.
6) Brakes: The brakes are fitted to stop the wind turbine. By applying the brakes when dangerously strong wind are approaching i.e. when wind speed exceeds55-65 miles per hour, the wind turbine is stopped to avoid damage. In case of emergency also it is used to stop the rotation of turbine. To take down the turbine for maintenance, brakes are applied to stop it.
7) Yaw Controller: It brings the blades towards the face into the wind direction i.e. it detects the direction of wind. It performs the task of orienting the rotor in the direction of wind.
8) Pitch Controller: The pitch controller adjust automatically the pitch of each blade i.e. blade can be rotate to increases efficiency in low wind and to decrease in very strong winds (to protect the wind turbine)
9) Electrical Generator: Function of generator is to convert mechanical energy produced by wind turbine into electrical energy.
10) Anemometer: It is a wind direction sensor with digital display. Used in areas where AC power is not available. It monitors wind speed and stores max and average value.
11) Controller: Controller takes data from anemometer (which measures the wind velocity): The controller sense wind direction & wind speed The controller protect wind turbine from abnormal wind conditions, excessive temperature rise of generator, electrical fault etc.
12) Nacelle: Nacelle cover provides weather protection for the principle components of the wind turbine. It is structure that houses all of the generating components like-gearbox, rotor shaft and brake assembly etc.
13) Tower: A tower is needed to elevate the blades to where the wind is stronger and smoother. Towers are supports to raise the main part of the turbine up in the air.