An offshore wind turbine generates electricity for the National Grid.
The useful energy transfer in the wind turbine is:
The generator in the wind turbine transfers 36 MJ36\text{ MJ}36 MJ of energy in 4 minutes4\text{ minutes}4 minutes. The generator current is 250 A250\text{ A}250 A.
Calculate the output voltage of the generator.
The generator output voltage is then increased to 400 kV400\text{ kV}400 kV for transmission. Explain why electrical energy is transmitted using very high voltages.
The generator provides a direct current (d.c.). This d.c. is changed to an alternating current (a.c.). The frequency of the alternating current is 50 Hz50\text{ Hz}50 Hz.
Explain the meaning of 50 Hz50\text{ Hz}50 Hz alternating current.
Explain why the d.c. from the generator must be changed to a.c. before it is transmitted.
