Grid and quattro serve loads in paralel

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mito asked May 1, '23

Grid and quattro serve loads in paralel

I have an instalation where the daily peak loads cannot be served from the grid when power demand is higher than 600 Kw. So I was trying to configure a three phase quattro configuration + battery bank to serve the worst case150 Kw needed during 2 hours a day, to add the energy that loads demand during these hours. It is rather similar to peak shaving scenario.

My question is if there is possible to connect Inverter output in paralel to grid (provided 3 phase compensation). Reason is not to oversize inverters, just for the 2 hours where power assist should be needed

MultiPlus Quattro Inverter Charger ESS powerassist

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Answer 1 · 2023-05-02T08:43:50Z

Michelle Konzack answered · May 02, 2023 at 08:43 AM

No, it does not work this way.

Even if you put 12 Qutros 15kVA together, you do not get more the 180kVA or 144kW out of it.

I have in Estonia with a customer a similar problem, but he can not get from the GRID more the 250A (100kW) and will use (unfortunately) 12 Quatro 48/15000 because the MultiPlus-II 48/15000 can run in 400V but not parallel.

Hence he add 144kW to the 100kW from the Grid and if he has enough solar/wind energy he can go even over 300kW.

"unfortunately" because the Quattros can not sell back the weekend when not use.

(He get at least one windmill 40kW, 2 Fronius 30kW and 4-6 RS45/200)

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Answer 2 · 2023-05-02T13:15:23Z

mito answered · May 02, 2023 at 01:15 PM

Thanks Michelle for replying to my post

My question was regarding to configure 9 Quattros 15K (3Quattro x phase) and Grid in paralel, just for adding to grid power during the couple of hours needed.

My idea was configuring Assistants with an AC current sensor, so keeping quattros inactive until load current demand achieves a certain value. When this current is present we start inverters in Power Assist mode, as that will sync to grid with frequency and voltage, so we can paralel output to grid safely. Power control through Ve-config can keep power from quattros below limits. A simplified view as follows (obvious lot of the details avoided)
The scenario is similar as we do when we connect several 3phase gensets in paralel to achieve load demands.

If this is not possible I assume Quattros cannot be used for peak shaving at these powers.

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Answer 3 · 2023-05-02T14:00:31Z

janieronen answered · May 02, 2023 at 02:00 PM

If understood correctly what you are looking for is energy storage with inverter capacity to cover few daily peak hours load on high demand period?

When adding ESS grid meter at grid side you need to connect only input of your inverters and they will give full capacity to cover your load (over set-point) if you configure grid set-point in example to 600kW.

No need to connect inverter output to anywhere if you are not needing back-up when grid fails. That size of system you definitely should have Victron specialist to do all calculations and make sure that system comply to local regulations.

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Answer 4 · 2023-05-02T17:27:02Z

mito answered · May 02, 2023 at 05:27 PM

Hi Janieronen, thank for your time

I need to setup configuration to "add" energy to grid , when loads demand more than 600 KW (no to replace grid by quattros or oversizing quattros that also is not feasible at that power load).
Load profile shows that need is below 150 Kw during less than 2 hours, so it is mandatory that grid and inverters work in paralel during that period of time. I emphasize that is not feasible at those powers to pass all Energy through quattros. That is the reason for paralel configuration

It is not feasible to size inverters to give themselves full load, or more than 600 KW, so paralel connection is needed (such as happens when you put gensets to work in paralel). So requirement is that when the demand request Grid will spouce 600 KW and Quattro outputs in paralel to Grid, will add the 150 Kw from batteries, sincronized with Grid (that is what Power Assist does)

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janieronen commented · May 02, 2023 at 06:16 PM

Hi. When you link only input to network there is no load side energy flowing through inverter. You parallel inverter with loads (connect input side to your installation) and normally loads are powered from grid. When load exceeds grid set-point your inverters begin to transfer energy to grid connection and it flows to your loads.

Input side can synchronize to grid but output side cannot.

There is mockup from my installation. In my on test system I have nothing connected to AC-OUT and inverters work only as energy storage to charge night&solar and push energy to my loads when Tarif is high or need peak shaving. I use node-RED to add more controlling options. In that example you need multiplusses capable of providing that extra 150kW and grid will provide rest. You do not need inverters capable of passthrough 750kW.

Hope that helps understanding my test setup and you can get useful ideas.

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mito janieronen commented · Jul 20, 2023 at 12:02 AM

Hi Janieronen,

I am planning to test your suggestion in a Lab mockup with Quattros and Cerbo, to test the peak shaving process in a paralel to grid controlled environment.

Question: where do you configure peak shaving Grid power limit to start adding power to loads from Inverters AC-IN ?

Seems easy when you use power assist to grid power using the inverter, channel, but I don´t see how to trigger when loads are being sourced paralel to inverter.

You mentioned that your are using nodered. I guess you think Cerbo parameter progaramming cannot address this kind of external assistance to paralel peak shaving

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Answer 5 · 2023-05-02T18:39:37Z

mito answered · May 02, 2023 at 06:39 PM

Oh, Oh Janieronen.
It is quite simple and I didn´t even considered the possibility to reverse energy to loads from AC-IN
So what you say is that not pushing energy to grid, but to source stored energy from battery bank , in paralel with grid, to serve loads, under configured conditions, using AC-IN.

I never used ESS, as I normaly work with no solar hybrids, I use DVCC and skiped ESS. Would ESS be required to implement the scenario?

Thanks for your value time

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janieronen commented · May 02, 2023 at 06:53 PM

Yes :) Multiplus and Quattro are bi-directional inverters and all you need is design rules for control system. Hand out these to your local Victron installation company so they can plan what needed for system to meet your requirements.

First to be able to feed-in even energy is not going to grid you need to use ESS. And to get ESS working your installation must comply with local feed-in regulations. That can be tricky as not all devices have compliant to all regulations. Also there are some new inverters which cannot yet to be connected in large installations. Be sure that talk with specialist before ordering anything.

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