The electric power leaves the generator and enters a substation at the power plant. This substation uses large transformers to “step up” the generator’s voltage to extremely high voltages for long-distance transmission. Typical voltages for long distance transmission are in the range of 155,000 to 765,000 volts. The higher the voltage, the less energy is lost due to resistance [source: UCSUSA].
A typical maximum transmission distance is about 300 miles (483 kilometers). High-voltage transmission lines are quite obvious when you see them. They are huge steel towers strung out in a line that stretches toward the horizon.