Three-phase AC

In alternating current voltage, which forms the basis of power transmission and distribution, it consists of three phases with waveforms shifted by 120° each. This method has become mainstream from the establishment of transmission and distribution systems to the present, as it is the most efficient for long-distance power transmission from power plants to consumers. When the transmission distance is long, high voltage such as extra-high voltage is used to reduce power loss in the wires. There are three wires (or four if there is a neutral line), and loads are connected to each phase, but it is necessary to balance the load across all phases.