physics - trans. line
posted by lo .
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?
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