How much conducting material does a 3-phase line require compared to a single-phase line for the same power transmission?

In a three-phase power system, the amount of conducting material required is often less than double that of a single-phase line for transmitting the same amount of power. This is primarily because a three-phase system is more efficient in utilizing the available conducting material and can transmit power more effectively.

When considering the power equation, a three-phase system can transmit power at a lower current compared to a single-phase system for the same amount of power delivered. The three-phase system can have a reduced load per phase, which translates to a lower overall current. Consequently, this leads to a reduced cross-sectional area of conductors needed for the same power transfer, while also minimizing losses.

The 75% figure typically reflects the comparative efficiency and optimal use of materials in a three-phase configuration versus a single-phase setup. This efficiency results from the continuous power flow in a three-phase system, where the power is delivered more evenly and reduces the need for larger conductors that would be necessary for a single-phase line under the same power requirements.

Therefore, the requirement of 75% indicates that a three-phase line uses less conducting material while maintaining effective power transmission when compared to a single-phase line.