In a three-phase system, how is power calculated?

In a three-phase system, power calculation includes a factor that accounts for the phase relationship between voltage and current, as well as the number of phases involved. The formula for calculating power in a three-phase system incorporates the square root of three (√3), which arises from the geometry of three-phase circuits and is fundamental in balancing loads across three distinct phases.

The formula Power (P) = √3 x Voltage (V) x Current (I) x Power Factor (PF) accurately reflects this scenario, as it multiplies the line-to-line voltage by the current and adjusts for the power factor, which accounts for the phase difference between the voltage and current waveforms. This is essential in understanding real power consumption, as the power factor indicates the efficiency with which the electrical power is being converted into useful work output.

In contrast, the other options simplify the power calculation to two-phase or single-phase systems, neglecting the phase relationships crucial to three-phase circuits. For instance, using just Voltage (V) x Current (I) does not factor in the impact of multiple phases or the power factor, making it insufficient for a comprehensive understanding of power in a three-phase system. The option involving Voltage (V)² / Resistance (R) pertains to