What do transmission lines primarily transmit?

Transmission lines primarily transmit electricity generated at power plants to distribution networks. This process is essential for delivering electricity to consumers, as transmission lines are designed to carry high-voltage electricity over long distances efficiently. When large amounts of electricity are generated, it needs to be transported to various locations where it can be utilized, and this is where transmission lines play a crucial role.

Transmission lines operate at high voltages to minimize power losses during the journey from substations to end-users, making them fundamental components of the electrical grid infrastructure. The focus on electricity being transmitted highlights their primary purpose, distinguishing them from other potential functions of other types of lines or systems. This is why the selected answer accurately reflects the main role of transmission lines within the electrical power system.