What is the formula for three-phase real power (P)?

• A. P=IV²
• B. P=√3(IVpf)
• C. P=IVsinφ
• D. P=IV

Answer: (B)

The formula for three-phase real power (P) in an electrical system is indeed represented as P = √3(IVpf). In this formula, P stands for real power measured in watts (W), I is the line current, V is the line-to-line voltage, and pf signifies the power factor, which accounts for the phase difference between the voltage and current waveforms. The √3 factor arises in three-phase systems due to the relationship between phase and line quantities.

This formula effectively combines these components to provide an accurate measurement of real power in a three-phase system. It highlights the importance of the power factor, which is critical in understanding the actual power consumed in the system, as opposed to merely the apparent power (which would consider current and voltage without the power factor).

Understanding the derivation of this formula involves recognizing that in a balanced three-phase system, the total real power is the sum of the real power in each phase. The √3 factor comes from the geometry of how the voltage and current vectors relate in a three-phase circuit, specifically in a balanced load scenario.

The other options do not apply to three-phase systems or lack the necessary components to yield real power accurately. For instance, IV could represent the apparent power in a single