A utility has to deliver of electrical power to a town situated away
PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A utility has to deliver 2MW of electrical power to a town situated 120km away. The pair of conductors that make up the transmission line have a total resistance of 8Ω.
(i) If the power is sent out at an rms voltage of 10kV, calculate the rms current in the line.
(ii) Determine the power that will be wasted as heat in the conductors and express this loss as a percentage of the power being transmitted.
(iii) The utility decides instead to use a transformer to raise the sending-end voltage to 100kV (rms) while keeping the power to be delivered unchanged. Repeat the calculations of parts (i) and (ii) for this new voltage.
(iv) Comment briefly on the numerical results obtained above.