A uniform two-wire DC distributor that is 200 m long is loaded with 2 amperes/meter. Resistance of single wire is 0.3 Ω/km. Calculate the maximum voltage drop if the distributor is fed from one end.

Concept:

In a uniformly loaded distributor fed at one end, the maximum total voltage drop = IR/2

In a uniformly loaded distributor fed at both ends, the maximum total voltage drop = IR/8

The maximum voltage drop in the case of uniformly loaded distributor fed at both ends is one-fourth of the maximum voltage drop in the case of uniformly loaded distributor fed at one end.

Calculation:

Length of distributor = 200 m = 0.2 km

Current supplied by distributor = 2 amperes/meter

Total current supplied by distributor (I) = 200 × 2 = 400 A

The resistance of single wire = 0.3 Ω/km

Total resistance = 0.3 × 0.2 = 0.06 Ω

For Two wire, R = 0.06 × 2 Ω

Maximum voltage drop \( = \frac{{IR}}{2} = \frac{1}{2} × 400 × 0.06\times 2 = 24\;V\)