CT Clamp problems since adding PV Solar - CT placement?


#22

Thanks for the suggestion. Yeah, maybe I will give that a go.

I’ve just taken delivery of another CC sensor for my ‘generation’. I’ve tested this clamp and its accurate against what my SolarEdge is saying.

So i’m thinking
Sensor1/CT1: SolarEdge generation
Sensor2/CT2: This combined usage/generation total.

I’m then wondering whether I can use a Rule in the PVO integration service rather than relying on ‘net’ to do the job when the data hits the PVO site?


#23

@bankstownbloke any ideas or does PVOutput Integration Service have an option to enable net consumption?

i will probably need to set this up with my unit in the next month


#24

I’m not sure what is going on with these figures, what PVO is displaying or what the clamp is recording!?!?!?

Currently there is no one home, so the house baseline should be something between 200-250w.
I know the generation is correct as that is coming from the SolarEdge inverter (confirmed via the SolarEdge app), plus its a 3680 inverter, so its maxing out, which it does during sunny spells.

So if known baseline consumption is 250w and generation is 3681w… why is my clamp showing 6527w?

I’d expect power used to show (3681+250) = 3931? Not 6527?

I think I need to sit at home in front of the clamp / current cost monitor to see what the clamp is actually reading to eliminate me having some dodgy PVoutput setting skewing the displayed data. :frowning:

Once I know things look ok around clamp total - generation = power used then I can move forward.


#25

The integration service does not support n=1, a rule will not work as uploaded consumption power has no access to the corresponding generation and vice versa.


#26

Does n=1 work when one source is injected using addstatus (ie measureit) and the other coming from auto upload (like Solar Edge)?

Or would both data sources need to come from the same method; ie both via addstatus or both via automatic uploads for ‘net’ calculations to work properly?

Thanks.


#27

Net upload (n=1) always requires a corresponding generation upload. This can either be via API or Auto Uploader.

Gross consumption is calculated as -

Consumption = Generation + Net
  • Positive Net value = Import
  • Negative Net value = Export

The Net Data section in https://pvoutput.org/help.html#api-addstatus covers this in detail.


#28

Maybe as the inverter is 15 mins and measureit is 5 its not working or the fact its uploading generation after the net command. Maybe try the net delay of 15 or 20 minutes and see if it works…

But doesnt have to be sent in the same transfer? As long as you have generation sent to pvoutput then send the consumption with net it works it all out?


#29

They must be separate. It is not possible to send gross generation and net data in a single upload.


#30

You need to wire the CTs like in the attached (which is for 3 phase) This successfully cancels out the influence of solar in the consumption measurements. You then need to send each signal separately to pvoutput. If you look at “Beaglehome” you will see the result


#31

Thanks for that, its confused me greatly, LOL.

Are you saying that I need more clamps? Rather just one for generation and one for consumption?
Its all getting pretty complicated now… and I thinks it getting beyond my limited electrical know-how.


#32

No you only need 2 for a SINGLE phase system. The circuit is for mine which is 3 phase. The problem is that if you put the clamp upstream of the distribution board, the wiring carries both current that you are consuming AND solar generated current that you are putting back to the grid.

The single CT is not smart enough to differentiate between the two so you need some way to differentiate them.

The blue arrow in the diagram is the supply wiring that would be existing to your DB. This is the one carrying both Consumption ADN solar current WHICH IT YOUR PROBLEM - as illustrated by the dotted red arrow which represents the Solamar current fed back to the grid. Mathematically you could think of this as (TOTAL CURRENT = CONSUMPTION CURRENT - SOLAR CURRENT) SOLAR CURRENT is negative as it flows in the opposite direction

The solid red line is the wire from the solar inverter to your DB. Now, you KNOW this only carries the solar current.

Now for the truck. If you measure the combined cuttent in the 2 wires, the solar cancels out!..

CONSUMPTION CURRENT = TOTAL CURRENT + SOLAR CURRENT …

But TOTAL CURRENT = CONSUMPTION CURRENT - SOLAR CURRENT.

Wiring wise, if you pass the solar wire through the consumption clamp the solar component in the consumption wire is cancelled out and you see only consumption. HOWEVER, YOU NEED TO BE CAREFUL WITH THE DIRECTION OF THE SOLAR WIRE OR YOU WILL DOUBLE THE SOLAR READING.

Just to confuse you further separate issue, with CT’s you need to be careful with electrical noise from the inverter (especially Fronius) which can stuff up the readings. You will quickly see this if the inverter says its generating power at night.

In any case you do need to check the power displayed against the electricity company meter. The difference can easily be 10% which makes nonsense of installing ct’s


#33

Sorry. Just re-read your first post.

If you only want to measure consumption you only need one CT.

To solve your problem just loop the solar feed wire through the ct as in the diagram ( see CT-Ca).


#34

That would work but if your measuring net data it normally means your inverter isnt next to the switch board or is on a sub board.
Making it very difficult to do that anyway.

Are you able to clamp the consumption on the other side of generation or get the generation moved to the first wire off the main switch?


#35

Check here https://imgur.com/CbbGBpw how to connect consumption and production clap and or Dinrail, works like a charme.

Red consumption of the house, green production solar , blue measuring house consumption , purple measuring pv solar