Alternating Current (AC) transmission is the most common method used worldwide. AC systems are easily converted to different voltage levels using transformers, making them versatile for the power grid. They are used for both short and long distances.

Direct Current (DC) transmission, also known as HVDC (High-Voltage Direct Current), is becoming increasingly popular for very long-distance transmission. DC systems are more efficient over long distances and require fewer conductors than AC systems. However, converting voltage levels in DC systems is more complex, making them less practical for local distribution networks.