Question

If 65 kW is to be transmitted over two 0.100 ohm lines, estimate how much power is saved if the voltage is stepped up from 120 V to 1200 V

Answer 1

Answer: 5.91kw

Explanation:

given data:

power = 65kw

voltage stepped up = 120v t0 1200

R 0.100

Solution:

when the it is stepped to 120v

$P = VI \\65000/ 120I\\ I = 541.7A$

power loss

$(I^{2} )R*2\\= (541.7^{2})0.100*2\\= 58536.2w$

when it is stepped to 1200v

$\frac{65000}{1200} \\ I = 54.17A$

$(I^{2} )R*2\\= (54.17^{2})0.100*2\\= 586.9w$

total power saved

$= 65kw - 58.5kw - 0.59kw\\= 5.91kw$