# Electricity question on the power generated by power stations.

1. Apr 14, 2013

### Delpo

1. The problem statement, all variables and given/known data

2)The power stations providing electricity for the National Grid generate electricity at 25kV. The typical demand on an average winter's day in the north-west of England is 6000MW. The current output form the generators is 240kV. Transformers raise the transmission voltage to 400kV. Assuming 100% efficiency in the transformers, the current is 15kA. Each pair of 400kV supergrid conductors has a resistance of 0.034Ωk/m.
How much power is lost per kilometre heating the conductors?
Books answer:7.65MW

2. Relevant equations

P=W/t=VQ/t=VI
V=IR
R=VI

3. The attempt at a solution
Can type my working out sorry.

2. Apr 14, 2013

### Staff: Mentor

We don't know how to help if you don't show your attempt...

3. Apr 14, 2013

### voko

We can't help you unless we can see you have tried to solve it.

4. Apr 14, 2013

### DrZoidberg

Are you sure you copied that text correctly? It seems to contain several errors. For example it should be 0.034Ω/km, not 0.034Ωk/m.
So each km of conductor has a resistance of 0.034Ω. The current is 15kA.
Now you just have to apply your equations.
V=IR
P=VI

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