Power line

Power lines are wires that conduct electricity through to another place. Many have transformers.  The original power is made at a power plant.  The voltage of the power at the end is usually 100V (Japan), 120V (North and Central America, parts of South America and Africa, and Saudi Arabia), or 220-240V (most of the rest of the world). "Step-up" transformers increase the voltage in electric power distribution grids, and increase it greatly in long electric power transmission lines. The power at the end is "stepped-down" by another transformer so it can be distributed and used. 

Very long power lines carry high voltage DC.  Alternating current (AC) from the power plant is stepped up to a high voltage and rectified to make it Direct Current.  At the other end it goes through an inverter to make the electricity AC again, and stepped down.  

Related pages
 Electricity
 Static electricity
 Power line communication

Category:Electricity