Power Systems

Line voltage equals √3 times the phase voltage (V_L = √3 · V_phase), and the line current equals the phase current.

Line voltage equals phase voltage (V_L = V_phase), and line current equals √3 times the phase current (I_L = √3 · I_phase).

P = √3 · V_L · I_L · cos θ, where θ is the angle between phase voltage and phase current (the power factor angle).

Q = √3 · V_L · I_L · sin θ, measured in VARs (volt-amperes reactive).

S = √3 · V_L · I_L, expressed in volt-amperes (VA). It is the magnitude of the complex power.

S² = P² + Q², so S = √(P² + Q²). P is the horizontal leg, Q the vertical leg, and S the hypotenuse.