Free Three-Phase Power Calculator

Calculate real, apparent, and reactive power for a balanced three-phase electrical system.

V
A

Real Power (P)

29.44 kW

Apparent Power (S)34.64 kVA
Reactive Power (Q)18.25 kVAR

Real Power (P) vs Line-to-Line Voltage (V_LL)

Three-Phase Power Calculations

Three-phase systems are the standard for industrial power distribution.

Formulas

P = sqrt(3) x V_LL x I x cos(phi) (real power in watts)

S = sqrt(3) x V_LL x I (apparent power in VA)

Q = sqrt(3) x V_LL x I x sin(phi) (reactive power in VAR)

where V_LL is the line-to-line voltage, I is the line current, and cos(phi) is the power factor. These apply to balanced loads.

Example Calculation

A 400 V three-phase supply with 50 A line current at 0.85 power factor.

  1. 01S = sqrt(3) x 400 x 50 = 34,641 VA = 34.64 kVA
  2. 02P = 34,641 x 0.85 = 29,445 W = 29.44 kW
  3. 03Q = 34,641 x sin(acos(0.85)) = 34,641 x 0.5268 = 18.25 kVAR

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