The National Grid

Question 1

Power equations (for the national grid)

Answer 1

Power (W) = current (A) x p.d (V)
Power (W) = current^2 (A) x resistance (ohms)

Question 2

Order of national grid

Answer 2

1) power station
2) step-up transformer (increase p.d, decrease current)
3) plylon and wires
4) step-down transformer (decrease p.d, increase current)
5) buildings

Question 3

Why do we use transformers in the national grid?

Answer 3

Step-up transformers to decrease the current as it travels to the step-down transformer (decreases electrical energy dissipating into the surroundings as heat/ improve efficiency) and step-down transformers to decrease voltage to safe levels (230V) to supply to buildings