What is wind?
Flowing of air or other gases through a planet’s surface is called wind.
What is wind energy?
Wind energy or wind power is the technology used to produce either electrical or mechanical energy from wind.
What is Wind Turbine?
Wind turbines are designed to convert the kinetic energy from the wind into mechanical power. This mechanical power can be used for some tasks like grinding grain or pumping water or can convert it into electrical energy.
What is a wind farm?
Wind farms are collections of wind turbines. Nowadays, electricity is much essential for our daily life and legacy energy-producing methods like thermal power plants are harmful to our nature due to global warming. So, the production of electricity from various renewable resources such as wind, tidal, etc are more important methods to produce electricity to meet our needs.
How to convert wind into electrical power?
The wind turbine rotates in the direction of a fan. The fan is designed to produce wind by using electrical energy but the wind turbines are designed to produce electricity from the wind. The flowing wind turns the blades that make shafts spin, which connects a generator to produce electricity.
Energy in the wind turns two or three blades (propeller) around a rotor. This rotor is attached to the main shaft of the wind turbine, which spins a generator to produce electricity.
Wind turbines are mounted on a tower to capture as much energy as possible. They can take advantage of the faster and less turbulent wind at 30 meters (100 feet) or higher above ground.
How does a wind turbine work?
The wind turbines consist of three blades that are mounted to a tower made from tubular steel. Some turbines have two blades or concrete or steel lattice towers. The tower, which is 100 feet or more above ground, allows the turbine to take advantage of faster wind speeds found at higher altitudes.
The propeller in the turbines catches the energy of the wind. The propeller or blade acts like the wing of the airplane. When the propeller catches the wind, a pocket of low-pressure air forms on one side of the propeller, and this low pressure of air makes the blade rotate, causing the rotor to rotate or move. The lift’s force is much higher than the force of the wind against the front side of the blade, which is called drag. The combination of lift and drag makes the rotor spin like a propeller.
A series of gears raise the rotor rotation from 18 RPM (revolutions per minute) to 1800 RPM. The speed allows the turbine to generate electricity in AC (Alternative Current).
A nacelle is a streamlined enclosure that houses key turbine components, which typically include the gears, rotor, and generator. Some of the nacelles at top of the turbine tower are large enough for a helicopter to land on.
The turbine’s controller is one of the major components of a wind turbine that helps to keep the speed of the rotor from exceeding 55 mph to keep away from damages due to the high-speed winds.
A device called an anemometer is designed to continuously monitor the speed of the wind and send the data to the controller. A brake is attached to the nacelle to stop the rotor in emergencies either mechanically, electrically, or hydraulically.
Types of Wind Turbines
There are two types of wind turbines available
- With the horizontal axis
- With vertical axis
The most widely used wind turbines have a horizontal axis: the propeller rotates around a horizontal axis. Horizontal axis wind turbines are two types
- Upwind:- The wind hits the blades before the tower. Upwind turbines consist of a yaw drive and a motor.
- Downwind:- The wind hits the tower before the blades.
Some manufacturers manufacture vertical axis wind turbines. But vertical axis wind turbines are not that much used in 100 KW capacity or larger (utility-scale market). The vertical axis wind turbines are again classified into two
• Drag-based turbines, also known as Savonius turbines, typically have rotors with solid vanes that rotate about a vertical axis.
• Lift-based turbines, also known as Darrieus turbines, have tall, vertical airfoils (some appear to have an eggbeater shape). The Windspire is a lift-based turbine that is currently being tested independently at the National Renewable Energy Laboratory’s National Wind Technology Center.
Wind Turbine Parts and Functions
A wind turbine is made up of the following parts. They are
- Anemometer
- Blades
- Brakes
- Controller
- Foundation
- Gear box
- Generator
- Hub
- Rotor
- Tower
- Nacelle
- Wind vane
- Yaw drive
- Yaw motor
Anemometer:
Anemometer is used to calculate the speed of the wind and sends the collected data to the controller.
Blades:
Some winds turbines have two blades and some contain three blades. This blade rotates when the wind blows on it.
Brake:
A disc brake, can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller:
The controller starts the machine at wind speeds ranging from 8 to 16 miles per hour (mph) and shuts it down at 55 mph. Turbines do not operate at wind speeds greater than about 55 mph because they could be damaged.
Gearbox:
Gears connect the low-speed shaft to the high-speed shaft, raising rotational speeds from 30 to 60 rotations per minute (rpm) to 1000 to 1800 rpm, the rotational speed required by most generators to generate electricity.
Foundation
The foundation is used to connect the tower to the ground and bears the turbine’s static and dynamic loads. Typically, a foundation made of steel and concrete is used to place the turbine on the ground for greater stability.
Tower
Wind turbine towers come in a variety of heights, with the average being around 50m and the tallest exceeding 200m.
To provide ultraviolet resistance, they are typically coated with a zinc-based finish as well as epoxy and urethane layers.
The average weight exceeds 40 tonnes, and the tower can frequently account for more than 10% of the total cost of a wind turbine.
Rotor
The rotor is the rotating part of a turbine; it is made up of three blades and the hub, which is the central part to which the blades are attached. A turbine does not have to have three blades; it can have two, four, or any number of blades. However, the three-blade rotor has the highest efficiency and other benefits.
The blades are hollow and made of composite material to be light and strong. The current trend is for them to be larger (for more power), lighter, and stronger. To be aerodynamic, the blades take the shape of an airfoil (similar to airplane wings). They are also not flat and have a twist between their root and tip.
Hub
The hub’s function is to hold the blades and allow them to rotate in relation to the rest of the turbine body.
Nacelle
The nacelle is housed on top of the tower that houses all of the components required for a turbine top. There are numerous components required for the proper and safe operation of a turbine, which is a complex electromechanical system. Among these components are the generator and the turbine shaft, which transfer the harvested power from the wind to the generator via a gearbox.
Generator
The generator is the component that converts the mechanical energy of the rotor, which is harnessed from the wind, into electrical energy. A generator is built in the same way as an electric motor.
At the commercial level, all electricity is generated using a three-phase alternate current. In general, the choice of generator is either synchronous or asynchronous (induction). Nonetheless, the induction generator has been associated with wind turbines thus far because a synchronous generator must turn at a tightly controlled constant speed (to maintain a constant frequency).
Wind vane:
Measures wind direction and communicate with the yaw drive to properly orient the turbine in relation to the wind.
Yaw drive:
Upwind turbines face the wind; the yaw drive keeps the rotor facing the wind as the wind direction changes. Downwind turbines do not require a yaw drive because the rotor is blown downwind by the wind.
Yaw motor:
Powers the yaw drive.