If 30MW of power at 45kV (rms) arrives at a town from a generator via 4.0ohlms transmission lines: details->

Question

calculate the emf at the generator end of the lines and the fraction of the power generated that is wasted in the lines.

Answer 1

Power = Volts times Amps, so 30,000,000 = 45,000 * I. Solve for I, I=667 amps. Then calculate the Voltage drop over the 4 ohm line as I*R, or 667 * 4 = 2,667 Volts, so the generator has to put out 45,000 + 2,667 = 47,667 Volts. Power lost is I squared R, or 667 squared times 4 =1.8. KW. These numbers are all rounded.