Diagram of an electrical system Color Key Substation Black: Generation Step Down Subtransmission Blue: Transmission Transformer Customer Green: Distribution Transmission lines 26kV and 69kV 765,500,345,230,and138kV Generating station Primary Customer 13kV and 4k\ Transmission Customer Secondary Customer Generating 138k∨or230kV 120V and 240V Step Up Transformer Transmission and distribution losses in the usa were estimated at 7. 2% in 1995 The system of generating stations, substations and transmission lines is called the electric power grid. Most of the electric power companies in North America are integrated into a single power grid (3000 power plants 200,000 miles of high-voltage transmission lines) for reasons of economy, availability of backup power for emergencies, and ability to trade energy Wireless Transmission of Electricity?Transmission and distribution losses in the USA were estimated at 7.2% in 1995 . Diagram of an electrical system The system of generating stations, substations and transmission lines is called the electric power grid. Most of the electric power companies in North America are integrated into a single power grid (3000 power plants, 200,000 miles of high-voltage transmission lines) for reasons of economy, availability of backup power for emergencies, and ability to trade energy. Wireless Transmission of Electricity?!