Comenius

PROGRAMME

Article Index
Renewable energy sources
Page 2
Page 3
Page 4
Page 5
All Pages

Tall towers are used to position the turbine at a sufficient height to have unobstructed access to the wind, so that the rotor faces the strongest and steadiest possible winds. A gear box and a switch called a ‘contactor’ is used in-order to ensure that regardless of fluctuations in the wind speed the turbine feeds its electricity into the grid at the correct frequency (50Hz) and voltage (230 volts). The contactor switch remains on until the wind drops to such a level that the turbine cannot capture sufficient wind energy, at which time it ‘drops out’ in-order to allow the rotor to rotate freely.

As the wind direction changes, the wind turbine needs to face into the wind. With large turbines, this ‘yaw’ rotation is carried out using electric motors whilst for small turbines this is done passively by using a vane at the back of the turbine.

Advantages

  • Turbines can be erected wherever the wind blows
  • They can function either as a stand alone or grid connected generating system
  • Wide range of sizes to fit every application
  • Their footprint (i.e land on which they are mounted) is very small
  • There is no operational pollution, no gaseous discharge and no waste
  • Very little maintenance required

Disadvantages

  • Output is not constant as moving air is always more or less varying in speed
  • When there is not sufficient movement in the air, no electricity is generated
  • Some audible noise is generated by the air passing the blade so for large grid connected turbines an exclusion distance of up to 400m is specified for housing (but not for agriculture)

Wind energy systems

grid turbines

Like photovoltaic systems, wind turbines can be operated either be linked to a grid or operated in a stand alone mode. Grid linked is the most common mode and this is especially important for the very large arrays now being erected off the UK coast.



 

Search

Language Selection

Find us on