Wind Power Generators
Voltage generation In large-scale wind power stations (over 100 - 150 kW), 3-phase alternating current is normally generated with 690 V voltage. With the aid of a transformer located close to the station (or within the column) this voltage is then transformed into 10 000 to 30 000 Volts (50/60Hz.), varying according to the local mains voltage. The majority of the world's wind power stations use a so-called 3-phase asynchronous generator with squirrel-cage motor (also referred to as induction generators) for the generation of alternating current. Although this type of generator is not much used outside the wind power industry, considerable experience has been built up with the use of this machine. The interesting point about this generator is that it was originally conceived as an electric motor. In fact, one third of the world's electricity consumption is accounted for by the induction motor as it drives machines in factories, pumps, fans, compressors, lifts and other applications which require electrical energy to be converted to mechanical energy. One reason for selecting this type of generator is its reliability and low cost. In addition, it also offers a number of mechanical properties which are of value for wind power stations, most notable of which are generator slip and a certain overload capacity.