Question

A high voltage (4.0×105 V) power transmission line delivers electrical energy from a generating station to a substation at a rate of 1.5×109 W. What is the current in the lines?

Answer 1

In order to find the current, we can use the formula below for the electric power:

$P=I\cdot V$

Where I is the current (in A) and V is the voltage (in V).

So, using P = 1.5 * 10^9 W and V = 4 * 10^5 V, we have:

$\begin{gathered} 1.5\cdot10^9=I\cdot4\cdot10^5\\ \\ I=\frac{1.5\cdot10^9}{4\cdot10^5}\\ \\ I=0.375\cdot10^4\\ \\ I=3.75\cdot10^3\text{ A} \end{gathered}$

Therefore the current is 3.75 * 10^3 A or 3.75 kA.