Wind turbine generator
A Wind turbine generator is a device consisting of basic mechanical parts: the rotor, blades, the generator, the tower and the control system. The rotor consists of a hub on which wind blades are fixed, usually in a number ranging from 1 to 3.
The wind crosses both sides of the blade, faster on the top, creating a low pressure area. The pressure difference between the two surfaces indicates the aerodynamic lift. The aerodynamic lift determines the rotation around the hub. Simultaneously a drag force (drag) is generated, perpendicular to the lift opposed to the motion. Most turbines are designed to generate a maximum power at a fixed wind speed.
Wind generators can be classified into two categories- orizontal axis or vertical axis- according to the rotor placement in respect to the wind direction.
Orizontal axis wind generators are more technologically advanced and more widely spread. Orizontal axis wind generators can be divided into 3 groups according to their typology, gerator power, rotor diameter.
- Small size p<100 kw d<20 m
- Medium size 100 kw
- Large size p>1.000 kw d>50 m
The so called micro wind refers to small size turbines, that are the plants from 50 up to 100kW, which can be used both in connection to the power grid and off grid. Their height is from 20 up to 30 m. Medium size turbines include power plants from 100 up to 900KW. Large size plants include power plants above 900 kW.
Micro wind plants advantages:
- energy production through low intensity wind;
- low noise level;
- low environmental impact;
- safety and reliability;
- guarantee of a smooth operating even in the event of turbulent wind.
A wind farm is costituted by a group of wind turbines.
