A tidal turbine generates electricity for the National Grid.
The useful energy transfer in the tidal turbine is:
The generator in the tidal turbine transfers 54 MJ54\text{ MJ}54 MJ of energy in 2 minutes2\text{ minutes}2 minutes. The generator current is 300 A.
Calculate the output voltage of the generator.
The generator output voltage is then increased to 275 kV275\text{ kV}275 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 60 Hz.
Explain the meaning of 60 Hz alternating current.
Explain why the d.c. from the generator must be changed to a.c. before it is transmitted.
