3 phase power calc from Vabc and Iabc

Good day. During design and testionour power control devices we are using Power Analyer like Hioka. It produce direct measurment of phase ( phase to phase) voltages and current and calc Active and Reactive power.

In simulink i want to reproduce some kind of that calculation, I save currents and voltages from my Drive model to SDI data set and analyse int in Signal analyser.

Some body can help How to calc Active and Reactive power and COS fi ?

[Ananth kumar]

Usually power analyzer like Yokogawa defines the avergaing factor(if involved), number of samples and formula for calculating the power.

One example,

For calculating the active power,

active power in W = Va*Ia + Vb*Ib +Vc*Ic

reactive power in Var = (Vab*Ic+Vbc*Ia+Vca*Ib)/sqrt(3);

Apparent power in VA = sqrt(W^2+Var^2);

where Va, Vb, Vc are instantaneous phase voltage

Ia, Ib, Ic are instantaneous phase current

Vab, Vbc, Vca are instantaneous line-to-line voltage

Vab=Va-Vb;

Vbc=Vb-Vc;

Vca=Vc-Va;

[Andrey Er]

Sorry but Active power formula is W=Uphase*Iphase*K*cos Pfi, cos Psi may be lead or lag, so I cant Correctry calc power wtih out it.

[boris vuleta]

Hello, first of all you can calculate p = Va*Ia+Vb*Ib+Vc*Ic.... but if I saw it right you mentioned higher harmonics (It's Friday, I can't see anything anymore hah) so how excatly are you going to do any analysis when you have voltage and current valves with those components? First of all you need to extract those elements and then calculate every harmonic. So I'll quote your formula W=Uphase*Iphase*K*cos Pfi but with numbers 01,03,05 where they repsresent your harmonic index. If I were you, maybe the best or easiest way would be to do FFT of your signal, extract components of each harmonic and then caluculate Active or Reactive power using your formula.

Hope you got your answer or at least a new idea.

Greetings.

Answer 1

[Sabin]

You can use 'Power Measurement (Three-Phase)' from Simscape Electrical to compute the three-phase real and reactive power. You can find this block in Simscape/Electrical/Control/Measurements. Hope this helps.

[Andrey Er]

I seen that block but its works only with harmoinc free signals. And in my case i need information about how to calc power like Polwer Anayser.

Answer 2

[qaqcvc]

How about transform them into DQ frame, and calculate active power and reactive power with PQ theory? Not sure.

[Andrey Er]

Use trasformation on each harmonic? UdId+UqIq?