Determine the voltage drop in a power transmission line with a length of 500 m at a current in it of 15 A.

Determine the voltage drop in a power transmission line with a length of 500 m at a current in it of 15 A. The wiring is made with an aluminum wire with a cross section of 14 mm2.

The resistance of the wire R, Ohm, in the area under consideration can be determined by the formula

R = ρ * L / S,

where ρ = 0.028 Ohm * mm² / m – electrical resistivity of aluminum;

L and S are the length and cross-sectional area of the wire.

Then

R = 0.028 * 500/14 = 1 Ohm.

In accordance with Ohm’s law in the section of the circuit, the current strength I, A flowing through the wire can be found by the formula

I = U / R,

where U is the voltage drop across the considered section of the circuit.

Then

U = I * R;

U = 15 * 1 = 15 V.