A high-voltage transmission line with a resistance of 0.30 /km carries a current of 1040 A. The line is at a potential of 680 kV at the power station and carries the current to a city located 159 km from the station.

(a) What is the power loss due to resistance in the line?
b) What fraction of the transmitted power does this loss represent?

1 answer

Lets assume it is a three phase transmission line, three wires running 159000 m

Total power loss: 3*.30*159*1040^2=about 15megawatts.

Total power transmitted: 680k*3*1040= about 2 G watts The 3 is because there are three phases.

fraction=about 15M/2000M=less than 1 percent.

check my thinking