Regarding the installatoin of the HDPM6000 head unit(single phase)

[Tomohiro-Okada]

Hi,

I use the HDPM6000 head unit in split (2-phase) mode. In this setup, I originally wired the main CTs as follows:

Main CT for phase R → 1A (black), 1A (white)
Main CT for phase N → 1N (black), 1N (white)
Main CT for phase T → 1B (black), 1B (white)

However, the Phase N current did not appear in PME. I then rewired the main CT for phase N to 1C (black), 1C (white), and the Phase N current appeared.

Therefore, my understanding is that when using the HDPM6000 head unit in split (2-phase) mode, the main CTs must be wired as follows:

Main CT for phase R → 1A (black), 1A (white)
Main CT for phase N → 1C (black), 1C (white)
Main CT for phase T → 1B (black), 1B (white)

Is this correct?

Regards,

Okada

[Mehran_Mehrnia]

Hi @Tomohiro-Okada 

In split mode, only two phases and a neutral are defined, so a third phase (Phase C) does not apply.

Depending on whether the current inputs for Phase 1, Phase 2, and Neutral are wired, the neutral current is either measured or calculated.

What does the webpage display for head unit(PQM) when the CTs are connected as below?
Main CT for phase R → 1A (black), 1A (white)
Main CT for phase N → 1N (black), 1N (white)
Main CT for phase T → 1B (black), 1B (white)

Best Regards,

-Mehran

L3 Expert Advanced metering

[Mehran_Mehrnia]

Hi @Tomohiro-Okada 

Just to add some notes and provide clarification following my previous comments, after reaching out to the HDPM6000 team.

As explained above, in Split Mode, only two phases should be defined, and using phase C is incorrect.

Regarding the neutral current, the meter only measures it when a third CT is installed on the neutral conductor and connected to the neutral channel, which requires additional channels. Otherwise, the meter does not calculate neutral current as the vector summation of I1 and I2.

As previously mentioned, first, please check the current values on the meter’s webpage under the PQM tab. If the values are present there but not in PME, it is likely related to the meter’s driver and the associated Modbus registers that PME uses to poll values.

In this case, the PME team would be the best point of contact to provide further assistance through the EcoStruxure Power Monitoring Expert forum.

Best Regards,

-Mehran

L3 Expert Advanced metering

[Tomohiro-Okada]

Hi @Mehran_Mehrnia 

Sorry for late reply.

I tested what you mentioned before.

And the result is different from you mentioned.

(Please refer to attached PDF file.)

Do you have any idea?

Regards,

Okada

[Tomohiro-Okada]

Hi @Mehran_Mehrnia

I did additional test of the HDPM6000's split mode using PME.

The result was same as the web page of the HDPM6000 and the value of the main CT of the 1C appears in both of the Ic and In icons.(using default template)

Do you have any idea about this result?

I have one more question.

Does the value of the I average is the average value of the Ia and Ib in the split mode?

Regards,

Okada

[Mehran_Mehrnia]

Hi @Tomohiro-Okada 

No worries, and thank you for bringing this to our attention.

You are correct, and as confirmed by the HDPM6000 team, in Split Mode the Neutral is currently derived from the C phase, which is not the expected behavior and will be corrected in a future release.

As a temporary solution and as you have already tested and observed, the Neutral CT should be connected to 1C+ and 1C- in order for the Neutral current to appear on the webpage. If this is a test bench, that should not be an issue; however, for a large number of installations and wiring, unfortunately, when the fix is released in a future firmware update, the Neutral CT will need to be rewired back to 1N+ and 1N-.

Regarding the average calculation, you are correct, it is the average of Ia and Ib, as the Neutral current is not included in Iavg even in 3 phase system.

Best Regards,

-Mehran

L3 Expert Advanced metering

[Tomohiro-Okada]

Hi @Mehran_Mehrnia 

Thank you for your reply.

I hope the firmware can be released soon.

I now understand how the HDPM calculates average current.

As for the BCPM, I believe its average current is the average of I1, I2, and I3.

Could you explain the reason for this difference?

(The PME's default template of the BCPM also calculate the average current using I1, I2, I3.)

Regards,
Okada

[Mehran_Mehrnia]

Hi @Tomohiro-Okada 

You're welcome.

I don’t know much about the BCPM (the predecessor), but in the HDPM6000 (the successor and next-generation solution), the definition of Average Current (I_avg) is the average of the phase currents only, excluding the neutral.

If the system is in split mode, it means only Phase 1 (I1) and Phase 2 (I2) are available, so Phase 3 (I3) will be ignored. However, due to a firmware issue in this specific situation, the meter can represent the neutral current only when connected to Phase 3 (I3). As a result, the value shown for I3 actually refers to the neutral current.

The PME driver for HDPM6000 follows the same rule: in split mode, it considers only I1 and I2 for Iavg. However, I am not certain how the PME driver handles split mode for BCPM, or if it is supported.

Best Regards,

-Mehran

L3 Expert Advanced metering