In the context of electric utilities, a Transmission Line (TL) is the high-voltage (typically 100 to 800 kV) portion of the electrical grid that transports bulk electrical power over long distances from generation sources to distribution Substations or high-demand commercial facilities such as data centers. Typically, these conductors are supported by tall and durable steel transmission towers.
A TL operates at a higher voltage than a Distribution Line (DL).