3-Phase PQ Meter

Three-phase active / reactive power meter using instantaneous power theory — no fundamental-frequency parameter is needed. Takes the three phase voltages (Va, Vb, Vc) and currents (Ia, Ib, Ic) as control signals and computes total three-phase active power P = Va·Ia + Vb·Ib + Vc·Ic and instantaneous reactive power Q = [(Vb−Vc)·Ia + (Vc−Va)·Ib + (Va−Vb)·Ic] / √3. Both outputs are smoothed by a first-order low-pass filter 1/(τs+1); for a BALANCED sinusoidal set P and Q are already constant so τ mainly matters for unbalanced or distorted inputs. P and Q are three-phase totals (3× the per-phase value for a balanced system). Set τ = 0 for the raw instantaneous values.

Category: Continuous

Ports

Name	Direction	Value type	Notes
va	input	double
vb	input	double
vc	input	double
ia	input	double
ib	input	double
ic	input	double
p	output	double
q	output	double

Parameters

Name	Label	Type	Default	Units	Description
time_constant	τ (s)	double	0.0167	—	Time constant of the first-order low-pass filter applied to both P and Q (1/(τs+1)). For balanced inputs the instantaneous P and Q are already ripple-free, so this mainly smooths unbalanced / harmonic-laden inputs. Set τ = 0 to output the raw instantaneous values with no filtering.