Advantech ADAM-5511 Manual page 329

• What's the purpose of high voltage transmission?
We have all seen high voltage transmission towers. The power plant
raises the voltage while generating the power, then a local power
station steps down the voltage. What is the purpose of high voltage
transmission wires ? According to the energy formula, P = V * I, the
current is reduced when the voltage is raised. As you know, each cable
has impedance because of the metal it is made of. Referring to Ohm's
Law, (V = I * R) this decreased current means lower power losses in the
wire. So, high voltage lines are for reducing the cost of moving
electrical power from one place to another.