Hi all, this question regards measuring of high ac power (several hundreds of amps on 3x230 V grid, therefore hundreds of kVA) in much smaller Victron system. So far I have always installed Victron systems where grid measuring could be done either by Multis/Quattros themselves, or by one of the supported energy meters. Recently one of my clients came up with a project, where it would be desirable to use relatively small Victron system (3x5000VA multi-II) which would be used only as a backup for critical loads of one building, with relatively large ac coupled Fronius system (around 50 kWp on the INPUT of multis). However, the whole building has around 300A main circuit braker and therefore to successfully setup an ESS with a grid meter, I would need energy meter that can measure several hundreds of amps and comunicates with Cerbo. Could anyone give me a clue how to do this? The best option would be to use Victron energy meter VM-3P75CT (cince it should have the fastest measuring time and is made for victron), but it has only a range of 80A and I couldnt find if or how it is possible to use different current transformers which would allow larger current range. Thank you in advance for all your advises.
I use Carlo Gavazzi EM530 Energy meters with external 5A CTs for grid metering,
These are recognized by VenusOS and have a fast update rate like the Victron meter.
The EM540 is nearly identical but has internal CTs, but those are not large enough.
There are several different models, but only the EM530DINAV53XS1X is supported, RS-485 only. These are rather expensive.
I use CTs with a 40:1 ratio, meaning 200A is the maximum current.
Luckily, these were available on Amazon and were inexpensive (nodehawk brand).
You would need 5A CTs with a 60:1 ratio to measure up to 300A.
Finding suitable CTs may be challenging depending on your location.
We use ABB counters for our 250kVA transformer. The RS485 terminals A und B have diffrent definition for plus and minus or inverted and non inverted signals but worked out of the box with Venus-OS.
Be warned: ABB sells many many models silver/gold and others with more or less features direct or with CT of any size. As calibration expires within 7 years, there is no dealer what has everything on stock. Simply order the model of your choice with CT of your choice and it will be supplied 2-3 weeks later.
Thank you very much for your tips guys! I really appreciate it.
You are welcome.
I just noticed that is document has been updated:
SCT-T24 is a good pairing with this meter for the OP’s requirement.