I need to monitor a complex electric plants in a big house.
The main electric supply is 3 phase (with neutral), there is single 3 phase load (Heatpump) and a lot of single phase loads (heating, air change, pool pumps ecc ecc). There is also a PV 3 phase (11kW max power).
I think to dedicate a single Emontx3.4 for the PV with "emonTxV3_4_3Phase_Voltage.ino" and one AC adapter connected to PV L1.
For the other loads these is my choice:
1 Emontx3.4 with standard single phase .ino, with ac adaptor connected to L1, CT2 to CT4 for the single phase loads on L1 and CT1 for L1 of heatpump;
1 Emontx3.4 with standard single phase .ino, with ac adaptor connected to L2, CT2 to CT4 for the single phase loads on L2 and CT1 for L2 of heatpump;
1 Emontx3.4 with standard single phase .ino, with ac adaptor connected to L3, CT2 to CT4 for the single phase loads on L3 and CT1 for L3 of heatpump;
It's correct?
Or is better a single emonTx also for heatpump?
And to calculate the power of heatpump I must only sum the feed of the three CT1?
Another question: I calibrate each CT (Ical) for each emontx and Vcal with single phase .ino, I note the value of each Ical (CT1 2 3) and of Vcal; write the same value on 3 phase .ino, load .ino on emontx but the value of Vrms and power measured are not the same (Vrms is higher and power is lower).
Why??
Thanks
Re: 3 phase complex plant
If you read the notes in the comment at the beginning of the 3-phase sketch, you will see that it clearly states that the voltage for phases 2 & 3 are approximations, therefore the powers for these are approximations also.
So I recommend that you use one emonTx on each phase wherever possible.
For any 3-phase load, or indeed the overall house load, you add the real powers of the three phases supplying the load.
Calibration: The calibration constant applies only to one particular combination of sensor and input. Therefore if you use a different ac adapter on the same input, the constant will be different (because the adapter has changed); If you use the same adapter on a different emonTx, the constant will be different (because the voltage divider resistors and the voltage reference are different). The same applies to the C.T, burden resistor and voltage reference combination. See Building Blocks for an article about accuracy.