Problem-2

A junior engineer for Evergy has been given the assignment to design a new 4.16 kV.

three-phase feeder that will have the following characteristics:

The total length of feeder = 5000 ft

Load: Ten 500 kVA (three-phase), 0.9 lagging power spaced every 500 ft with the first

load 500 ft from the substation

Voltage drop: Not to exceed 5% from the sub to the last load

Figure. 2 illustrates the new feeder.

The engineer has decided to use 336,400 26/7 ACSR (Linnet) conductors constructed

on 45 ft poles with 8 ft crossarms. The spacings of the conductors on the crossarms

are 2.5, 4.5, and 7.0 ft.

a. Determine the percent voltage drop to the last load point and the total three-

phase power loss for the feeder as shown in Figure. 2

b. Lump the total feeder load at the midpoint of the feeder and compute the

percent voltage drop to the end of the feeder.

c. Use the "exact lumped load model and compute the percent voltage drop to

the end of the line and the total three-phase power loss down the line.