A small town with a demand of 800 kW of power at 220 V is situated 15 km away from an electric plant generating power at 440 V. The resistance of the two wire line carrying power is `0.5Omega`.`km^-1`. The line gets power from the line through a 4000-220 V step-down transformer at a substation in the town.
Estimate the line power loss in the form of heat?

Explanation

Total resistance of the line`=0.5times15times2=15Omega` rms current through the line,
`I_(rms)=(power)/(vol t ag e)=(800times1000)/4000=200A`
`therefore` Power loss due to generation of heat
`=I_(rms)^2.R=(200)^2times15=600kW`