How wind turbines work
A wind turbine generator consists of a concrete foundation, a fixed support tower, a nacelle (generator and gearbox assembly) and a three-blade rotor assembly. Wind turbines are electronically controlled with on-board computers that automatically start, stop and monitor each turbine. The turbines start generating electricity in a light breeze (14 km per hour), and reach full production in steady winds (around 50 km per hour). To avoid damage in gale force winds (90 km per hour), the wind turbines automatically feather their blades into the wind for minimum resistance and effectively shut down. Allowing for the times when there is too little or too much wind , the wind turbines each generate around 7,500 MWh of electricity each year.
The diagram below shows the components inside the turbine nacelle.
When the rotor assembly turns in the wind, it rotates a shaft that is connected to a large gearbox, which in turn drives an electrical generator. The generator converts rotational energy into electrical energy at 690 volts AC. The blade angle of the rotor is automatically and continuously adjusted, via on-board computer control, to optimise rotation speed and therefore electricity generation for any given wind condition. The generated power is fed via flexible cables to a kiosk transformer at the base of each tower, which steps up the voltage to 33,000 Volts. A combination of ridge-top buried cables, then overhead power lines, transfers the generated power to a switchroom and substation in the valley below. From there the voltage is stepped up again via a 105 MVA transformer to a higher voltage suitable for long distance transmission, typically 275,000 volts and fed into thegrid via a high Voltage transmission infrastructure.
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View a 3d visualisation of a Wind Farm generating power into homes.
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