In a balanced three-phase system, how is total real power P related to the real power per phase P_phase?

In a balanced three-phase system, how is total real power P related to the real power per phase P_phase?

• A. P = P_phase
• B. P = 3 × P_phase
• C. P = 2 × P_phase
• D. P = P_phase / 3

Answer: (B)

In a balanced three-phase system, the total real power is the sum of the real power in each phase. Each phase delivers the same real power, so P_A = P_B = P_C = P_phase. Adding them gives P = P_A + P_B + P_C = 3 × P_phase. This means the three phases collectively supply three times the power of a single phase.

In a balanced three-phase system, the total real power is the sum of the real power in each phase. Each phase delivers the same real power, so P_A = P_B = P_C = P_phase. Adding them gives P = P_A + P_B + P_C = 3 × P_phase. This means the three phases collectively supply three times the power of a single phase.