Question

Question: Determine the most economical cross-section of a three-core cable 300 m long supplying a load of
150 kW at 400 V and 0.85 p.f. lagging for 5000 hours in a year and no load for the rest of the year.
The cost of the cable including its installation is Rs. (200a + 40)/m where “a” is in square cm. Interest
and depreciation on total cost is 15% and unit cost of energy loss is 15 paisa. Assume resistance of
1 km length and 1 cm section of single core conductors as 1/5.8 Ω.

Answer 1