What is the voltage range of "transmission" lines?

The voltage range defined for "transmission" lines is typically 100kV to 765kV. Transmission lines are designed to transport electricity over long distances from power plants to substations, and this high voltage range is essential for reducing energy loss during transportation. High voltage levels are employed to minimize the current flowing through the lines, which decreases the resistive losses (I²R losses) that occur in conductors as electricity travels.

Operating within this voltage range enables transmission systems to effectively manage large amounts of electrical power, ensuring it can be distributed efficiently to various locations. Lines operating above 765kV are often categorized as ultra-high voltage transmission lines, used in specific applications but are not included in the standard definition of transmission line voltage.