Main components of a wind turbine
To exploit the kinetic energy of the wind, by converting it into electrical energy available to be fed into the network or to supply loads in parallel, a wind turbine uses different components both mechanical as well as electrical. In particular, the rotor (blades and hub) extracts energy from the wind turning it into mechanical rotation energy and constitutes the "first motor" of the wind turbine, whereas conversion of mechanical energy into electrical energy is carried out by an electric generator according to suitable configurations to be illustrated in the following articles.
To summarize, the main components constituting horizontal axis wind turbines are (see Figure 2.1):
- blade support
- Pitch angle actuator
- main support
- main shaft
- aircraft warning lights
- mechanical brakes
- hydraulic cooling devices
- power converter and electrical control, protection and disconnection devices
- frame of the nacelle
- supporting tower
- yaw driving device
The converter and the transformer can be installed directly in the nacelle as Figure 2.1 shows, or positioned at the base of the tower. The installation of the transformer inside the nacelle allows balancing of the rotor weight, while positioning at the base allows a reduction in dimensions and weight of the nacelle.
In terms of costs, the percentage on the total cost of the different components is divided as shown in Figure 2.2.
Figure 2.2 - Wind turbine component cost (% of total)