Power energy consumption

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1

I am completely new, I would like to install energy consumption measuring elements at home,
I am looking for information which elements will be needed to measure energy consumption by my household, I have a three-phase installation from GRID, additionally a PV installation (SolarEdge) without battery, energy is stored into the public GRID, Could you please advice which items from openmonitorenegry shop will required to measure energy consumption?
Thank you in advance, Kind Regards, Slawek

2

Welcome, Slawek, to the OEM forum.

Is your PV (SolarEdge) single phase or three phase? And what is its power rating?

Because you are on a 3-phase system, the emonPi will not be useful to you.

There are several possibilities, which is the best will depend on several things. Here are the main things to think about:

  1. If you have a generation meter that has a flashing LED, then you can use an optical pulse detector to count the pulses. An emonTx can count those pulses.
  2. If your PV inverter is 3-phase, you can either count pulses from your generation meter, or you can measure the power with an emonTx.
  3. You will need an emonTx with the 3-phase sketch in order to measure the Grid power.
  4. If your PV inverter is single phase and less than 4.5 kW, you can measure that plus the grid power with one emonTx.
  5. The emonTx measures the voltage of one phase only, and assumes the other two are the same. If they are not, there will be an error. If that error is not acceptable to you, then you need 3 Ă— emonTx, one for each phase measuring both grid and PV power.
  6. You will need an emonBase to record the data and create the web pages to view it.

So, depending on what you have, I think you can have:

  1. One emonTx, possibly with an optical pulse sensor, and emonBase. This will work if you can use your generation meter or if your PV inverter is single phase.
  2. 2 Ă— emonTx and emonBase. This will work if your PV inverter is 3-phase and you cannot use your generation meter.
  3. 3 Ă— emonTx and emonBase. This is if you need the best possible accuracy.

You will also need c.t’s, a.c. adapters, USB power supplies, cables and we also recommend a programmer, which will allow you to upload new sketches to the emonTx. But we can deal with those details later.

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3

Many thanks for reply, referring to your questions, I have 3-phases PV installation , part of the produce energy per day is consumed by household and part of is stored in public energy grid, some basic information i can gather with using soleage API which can give me some daily overview,but what I wants to achive I would like to know how much energy daily is consumed my house from PV and public grid,
moreover i have to heat pump (3-phases), would be good to also to covers this thing in scope of energy consumption, rest of the information from Heat Pump is grab by H1 interface from husdata.se
Can you give me some overview if it is technically possible and what kind of items are required, what kind of setup of h/w is required ? Sorry for basic question, but im completly newbe here, with many knowledge gaps with energy metering,

Many thanks, Slawek

4

You need to measure 3 currents on your connection to the electricity grid. Even if your grid meter has a flashing LED, you cannot use the optical pulse sensor on this, because it cannot show the direction of power flow (and you need to know this). You must use current transformers here.

As your PV is 3-phase, then you need to either measure 3 currents from that, or the total generated power recorded by your generation meter. You can do this with an optical pulse sensor if your meter has a LED which flashes to show energy units being generated. If it does not have a flashing LED, then you must also use current transformers for this.
If you use the optical pulse sensor, you cannot know the power/energy for each phase on its own, you will only know the total.

I think your choices remain nearly the same:

  1. One emonTx, with an optical pulse sensor, and emonBase. This will work if you can use the optical sensor on your generation meter, but it will only show you the total generated power (and energy), it will not show you the individual values for each phase. But it will show the nett grid power and energy for each phase. For this, you will need for the emonTx: 3 Ă— current transformer, 1 Ă— a.c. adapter & cable, 1 Ă— optical pulse sensor.
  2. 2 Ă— emonTx and emonBase. This will show you the generated and grid power and energy for each phase. From that you can compute the household consumption per phase and the total power and energy across all three phases. You will have one spare input on each emonTx, which you can use to monitor individual circuits. For this, you will need for each emonTx: 2 Ă— current transformer, 1 Ă— a.c. adapter & cable.
  3. 3 Ă— emonTx and emonBase. This is if you need the best possible accuracy. You will have two spare inputs on each emonTx, which you can use to monitor individual circuits. For this, you will need for each emonTx: 2 Ă— current transformer, 1 Ă— a.c. adapter & cable.

For the emonBase, you will need a 5 V USB power supply & cable, and a SD card with emonCMS (or download it yourself).

Using emonCMS on the emonBase, you will be able to see power and energy updated every 10 s.

I have never used a H1 interface, so I cannot help you with that. If an H1 interface for the Raspberry Pi is available (maybe as a H1 - USB ?), and it does not conflict with our GSM radio interface module, then it might be possible to import the data into emonCMS - and it is most likely that you will need some additional software.

If the electrical feed to the heat pump is accessible, you can use a spare input of the emonTx to measure its electrical power input.

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5

Hi Robert

Thank you for helping me with my doubts and “green questions”, Can you draw a simple a connection diagram which can illustrate scenario 3?
Due to the fact that my PV does not have an optical sensor, if I understand the scenarios well. i guess that I need one emonTX connected to grid cables, another to PV cables and the last emonTX connected to Heat Pump via 3 phase cables? Please correct me if Im wrong ?

Moreover from Heat Pump I can only gather values with temperatures on heats circuits, ie from/to ground, nothing in scope of power energy consumption, H1 interface is connected via GPIO so is not possible is to use with together with emonBase, it would also be good for me to monitor energy consumption by Heat Pump because from my point of view Heap Pump is one of the most consumers of the power energy in my house.

Kind Regards, Slawek

6

I think the best way will be for you to draw a diagram showing where all the relevant items connect into your system, then I can add the monitoring components.

I would assume that your heat pump is what I call a “balanced” load - the current on the three phases will be identical - therefore you only need to measure one current because the other two will be the same.

7

ok, I will prepare small draft,
Kind Regard, Slawek

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