Problem 69PE

Unreasonable Results (a) What current is needed to transmit 1.00×102 MW of power at 480 V? (b) What power is dissipated by the transmission lines if they have a 1.00 - Ω resistance? (c) What is unreasonable about this result? (d) Which assumptions are unreasonable, or which premises are inconsistent?

Solution 69PE

a.) The current needed is 2.08 x105 A

b.) The power dissipated is 43.3 GW

c.) The current value and the power dissipation value are very high and unreasonable. Such high value does not reflect the practical values for these quantities.

d.) The assumption which is causing the results in part (a) and (b) to be unreasonable is that the resistance of power transmission line is 1.00. The assumed value of resistance is very low. Such low value of resistance is not possible in a normal power transmission line.