How may we reliably detect the Power Factor PHASE in a Delta System?

ALL Voltages, Currents, Delta VA, Delta Watts, Delta VAR, and Delta PF all measure Perfectly.

The sign of the PF is continuing to be unreliable – we have tried many methods.

The system has a minimum of 500 Watts of real power.

The system is connected per figure 13.4 of AN-639.

CONSEL = 0b01

A_watts is read from 0xE513

C_Watts is read from 0xE515

**Delta_Watts** = A_Watts + C_Watts

A_VA is read from 0xE519

C_VA is read from 0xE51B

**Delta_VA** = A_VA + C_VA

**Delta_VAR** = sqrt(Delta_Watts^2 - Delta_VA^2)

**PF** = 100(Delta_Watts/Delta_VA)

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We have tried using the sign of FWATTS.

W**e **have tried using SUM1SIGN bit 3 from PHSIGN 0xE617.

W**e **have tried using SUM2SIGN bit 7 from PHSIGN 0xE617.

W**e **have tried using SUM3SIGN bit 8 from PHSIGN 0xE617.

We have tried using the sign of Delta_Watts.

We have had marginal success with the first 4 but do NOT obtain reliable results.

Please tell me the correct method for determining the phase of PF.

Thanks, Glenn Wilson Wilson@stny.rr.com

Hi,

Figure 13 in AN-639 is for a 3P4W wye system. Do you mean to use the configuration in figure 15?

We recommend looking at the sign of active and reactive power to determine the phase. To do so for your case, calculate the total fundamental reactive power as AFVAR+ CFVAR) . Donot use the vectorial method for VAR.

Then use the sign of active power and reactive power to determine the quadrant as shown in the following figure: