Power consumption at the meter

Questions
#1

Hello,

I have a raspberry PI that pulls data from my Delta inverters over RS484, power and energy data is then uploaded to the two systems in PVoutput via the API using a python script. This system works well and I’ve been using this method for alost a year.

I recently had a ABB B23 meter installed and I’m pulling data from the meter over modbus such as import/export/net.

My question is - can I upload raw import/export/net data and PVoutput will do the math for me OR do I have to do the math to work out consumption first then upload it via the API.

I think If I need to do the math myself the formula would be:

consumption = (generation - export) + import

My setup looks like this but note I have 3 phase power so its simplified.

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#2

Net data upload is supported.

See Net Data section under - https://pvoutput.org/help.html#api-addstatus

Import 100W

  • addstatus.jsp?n=1&v4=150

Export 100W

  • addstatus.jsp?n=1&v4=-150
#3

Thanks I did see net was supported but I didnt realize I could provide negative numbers, it makes sense though.

I ended up getting this to work by calculating daily consumption using the below formula localy and uploading the energy consumption (v3), v4 seem to be derived automatticly. I did notice however when the page refreshes automatticly the v4 derived values disapear.

consumption = (generation - export) + import

At first this was not working because I was using the parrent SID to upload the energy consumption which the two inverter systems aggregate into, it apeared as tho the energy consumption was getting removed for some reason. I mananged to get it working by creating another system to hold the energy consumption values, upload into the child sid and aggregate into the same parrent system of the inverters.

#4

hi @bankstownbloke ,

Using his drawings, if I provide v2 from the inverter (gross generation, am I right?) and v4 from the meter (net consumption). I do need to send v2 and v4 in two separate requests. Am I right?

If so, wouldn’t make sense to allow a negative v4 for n=0? Like this, if I am not too confused, the v4 becomes export/import and consumption could be derived from there without needing for two separate requests. Does it make any sense?

Thanks

#5

Yes, this would need to be two separate requests.

  • The first v2=100, gross 100W generation from inverter
  • Second v4=50&n=1, net import 50 from meter

This is the same as a single v2=100&v4=150 request.

Negative values are ignored for any gross generation/consumption request.

#6

Not exactly ignored, it generates a “bad request” error.

#7

Hi @bankstownbloke ,

I still did not get it right. Could you please help?

Take today as example (2021-05-18), and system 56722. I am sending two measurements every 5 minutes, one with v2 and other parameters (v1, voltage, and some extended parameters), another with v4 and n=1. However, in daily page, system shows up as exporting exactly the same amount it generated. Per my understand, the second measurement with n=1 would signal import/export and consumption would be calculated. What I see is that consumption being taken from v4 and export from v2 anyway.

What am I doing wrong?

thanks,
José

#8

Answering to my own question: the system tariff configuration was configured to gross instead of net. Changed that and it seems to have solved the issue.

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