3 Phase Summary Power Feed - how to configure kWh in emonCMS?

Bielefeldt · 2016-06-06T14:56:31.213Z

I use a 3 phase system (Denmark).
How do I set up a feed showing the total power without changing the 3 individual Power feeds?

I do not get summed the 3 phases, as I want it?

Feed_setup2.JPG1015×336 46.9 KB

Robert.Wall · 2016-06-06T15:03:42.692Z

How are your obtaining the “power” values from your emonTx?
Remember that almost all UK houses have only a single phase supply, so all the OEM sketches are for single phase unless the name says differently.
So unless you have downloaded the 3-phase sketch, you will be reading the “power” of phases 2 & 3 with a 120° phase shift, which is definitely not ‘real power’. Apparent power (VA) will however be correct, assuming that the phase voltages are equal.

I don’t know the workings of emonCMS in detail, but what you have looks OK to me. If you want to display total power (as distinct from energy), you need to add a second “log to feed” after the second “+ input”.

Bielefeldt · 2016-06-09T14:12:22.907Z

It works fine with measuring the total output from 3 feeds, thank you.
Now, I want similar measure Power to kWh and Wh Acc. for all 3 phases.
I can not figure out how I do it?

Can you help me a little bit on the road with 3-phase sketch
Is it emontx3 I need to upload a new sketch?
I use 1 x emontx3 to measure the 3 phases.
There are only very small fluctuations in voltages from the 3 phases, so I accept the miscalculations I have to get there.

Can you give me a link to where I can find 3PHASE sketch.

3 phase Power.JPG1267×854 107 KB

Robert.Wall · 2016-06-09T18:16:21.237Z

You will find the 3-phase sketch on GitHub (Resources > emonTx firmware). The same sketch is used for all versions - you configure it to suit the version (Shield or emonTx, radio version, etc) inside the sketch.
You must follow the calibration procedure in the comments, because there are significant differences from the single-phase sketches.

Bielefeldt:

Now, I want similar measure Power to kWh and Wh Acc. for all 3 phases.I can not figure out how I do it?

I cannot help you with that. Hopefully, Paul @pb66 will be able to tell you.

Bielefeldt · 2016-06-09T23:58:30.732Z

I have a feed that sum effect from 3 phases.
Line 2 + 3 + 4 = Total power

I also want Power to KWh summed,

In the same way, I want Wh Accumulator summed.

how do I do it ?

Summed KWh.JPG1092×840 90.8 KB

MikeSims · 2016-06-09T21:04:19.903Z

I’m puzzled, I may be misunderstanding what you want to do, but I note you have called the Power to kWh feed in step 5 “power1 kWh”, but it is actually already getting the summed powers of your three power inputs, so a more proper name would be “power1 2 3 kWh”, and it is accumulating a Wh total, but in kWh.

If you want to forward that to Wh Accumulator, you need a “x 1000” after step 5 to convert the accumulated kWh to accumulated Wh for the Wh Accumulator.

Bielefeldt · 2016-06-10T13:53:26.886Z

Thank MikeSims

I am still quite inexperienced in the use of emonPi and EmonCMS, so there will be many stupid questions from me

I miss a deeper description of how EmonCMS system works found it somewhere?

Have tried to set up feeds as you have described.

Does it look correct?

Good weekend

emontx3 Feeds2.JPG1043×654 79.5 KB

pb66 · 2016-06-11T07:54:47.444Z

As Mike points out the values are summed by using the +input processes, So line 4 log to feed is the sum of the powers, therefore the Power to kWh in line 5 is a total kWh derived from the total power and is an ever increasing accumulating total kWh for all 3 power’s.

I cannot see any reason for the Wh Accumulator, that is a process is a special tool for processing Wh total values as they arrive from a device so that any reset/rollover of the device doesn’t reset the total in emoncms eg if you are using 10w every 10s reporting period and the values received were 3100, 3110, 3120, 10, 20, 30 because of a reset. The Wh accumulator would continue to increase by the difference between “this” and “the last” value rather than record the actual value received, eg 3100, 3110, 3120, 3130, 3140, 3150.

The resets or rollovers will not happen the way you are collecting data.

If you are just wanting to record the kWh total in Watts then keep the “x1000” and replace the Wh accumulator with a simple log to feed otherwise just remove both line 6 and 7.

Robert.Wall · 2017-06-12T19:09:56.201Z

5 posts were split to a new topic: Understanding 3-phase measurements