A wind turbine uses the aerodynamic power of the rotor blades to convert wind energy into electrical energy. The operating principle of rotor blades is similar to that of airplane wings and helicopter rotor blades. When the wind blows over the leaf, the air pressure drops on one side of the leaf. Lift and drag are created by the difference in air pressure on both sides of the blade. The lift is greater than the drag and the rotor turns. The rotor is connected directly to the generator (in the case of a direct drive turbine) or to the generator via a shaft and a series of gears (gears) to speed up the rotation and allow the use of smaller generators. Converting this aerodynamic force into the rotation of a generator creates electricity.
Types of Wind Turbines
The wind turbine has the following major types:
1) Vertical Wind Turbine
A vertical wind turbine is the most famous type of wind turbine. The components of this wind turbine are very near to the ground. These wind turbines have further two types:
- Drag-based turbines
- Lift-based turbines
2) Horizontal Wind Turbines
This turbine has at least three blades, a generator, and a shaft. One of the major advantages of this turbine is that it can be set in the forest in between the tall trees.
Wind Turbine Parts
The bottom of the turbine on land is underground and invisible because it is covered with mud. It is a large and heavy concrete structure that has to withstand the entire turbine and the forces acting on it.
In the case of marine turbines, the base is underwater and cannot be seen. With offshore turbines deep in the sea, the base floats, but its mass is sufficient to support the weight of the turbine and any forces it exerts and to maintain a vertical position.
Modern turbine towers are made of round steel tubes 3-4 m (10-13 ft) in diameter and 75-110 m (250-370 ft) high, depending on the size and location of the turbine. A rough estimate of the turbine tower is that the height of the tower is equal to the diameter of the circle formed by the rotation of the blades. In general, the higher the turbine, the higher the wind speed it receives. This is because the wind gets faster as it moves away from the ground (the wind speed will be different at different distances from the ground).
The rotor is the rotating part of the turbine and consists of (almost) three blades and a hub that connects the blades as a central part. The turbine does not necessarily have to have three blades. It can have two, four, or any other number of leaves. However, 3-blade rotors have advantages such as maximum efficiency.
The blade is not durable. Made of hollow composite material, light and durable. The trend is to make them bigger (for better performance), lighter and stronger. The blades are shaped like wings (similar to airplane wings) to allow for aerodynamics. Again, they are not flat and there is a twist between their roots and tips. The blade can rotate up to 90 ° around its axis. This movement is known as the step of the blade.
The nacelle is at the top of the tower and can accommodate all of the components that need to be placed on top of the turbine. A turbine is a complex electromechanical system with a significant number of components that can function normally and healthily. One of the main parts of the turbine of these components is the generator and the turbine shaft, which transmits the collected wind energy to the generator via gears.
The gearbox is an important part of the wind turbine and is located in the nacelle. Gearboxes increase spindle speeds from around 12-25 rpm * (most turbines today) to speeds that are suitable for your generators. Therefore, the wave on the generator side is called a “high-speed wave”.
The rotor has to turn relative to the tower because the turbine follows the wind and has to adjust its direction according to the wind direction. This rotation is known as the yaw movement, in which the nacelle and rotor rotate around the tower axis.
The generators used in modern wind turbines use the load difference to generate a voltage change as the driving force for the subsequent electricity.
This electricity is then distributed over the power lines to power the grid connected to the turbine.