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ESS system with grid attached Solar PV running in 'micro grid' mode during Grid power failure

Hi All,

Scenario as follows. Grid attached Solar PV (SMA 3kw) installed 12 years ago. Quattro ESS system recently installed. Testing Grid failure when batteries are full and excess PV being generated. What should happen?

My understanding is that the SMA inverter was configured as grid attached (correctly) when it was installed i.e. frequency shifting will not work. This cannot be changed since my system has a bypass switch for the Quattro so the SMA inverter must always be configured as 'grid attached'.

What appeared to actually happen was the system tried to frequency shift (per the ESS parameters) and the SMA inverter noted the frequency was outside the acceptable 'grid-attached' range and decided the grid was faulty and stopped inverting. A few minutes later (i think there is a minimum wait time in the SMA config) , the system had restored normal frequency and the SMA inverter restarted. This cycle repeated many times - it did avoid overheating the system (not least because eventually somehow it caused the PV RCD trip). So, was this just lucky? I've seen other forum entries for similar scenarios where systems have overheated and shut down.

Colin

colj asked
bassman commented ·

4 Answers

AC coupling on Multiplus II with micro Inverter

Hi Guys,

I am googling for long time now and maybe I just use the wrong key words or dont understand what I am reading, so I try to ask here. Maybe someone can help.


We have an Offgrid PV System based on Multiplus II, 3kWp Solar panels (DC coupled with Victron MPPT) and 10kWh battery from pylontech.

The setup works very good, but we want to increase the photovoltaik power.

The setup is installed in an old farm and the orientation towards the sun is not optimal, so we think about installing PV modules all around the area to get good energy all over the day...

Now the question:

It would be ideal if I could just take micro inverter for every PV module and couple them via AC coupling to the system. I know the 1:1 rules and so on. But I dont find micro inverters which support frequency shifting as SolarEdge, ABB or Fronius do.

Is there a working and tested combination of Multiplus II together with microinverters which supports frequency shift for this setup?

Which microinverters can be used here?

I am very thankfull for ideas or help so

Thanks an best regards

Richard

richard-offgrid asked
Michelle Konzack answered ·

1 Answer

Can I use a PLC to control the Victron Energie Multiplus ?

Hello, I have questions about the Multiplus Victron Energy. In the case of Victron Energy, the grid (backup source) and the battery pack are connected to the Multiplus. And the latter is who will manage this is two sources, that is to say, for example, if the state of charge of the battery reaches its minimum and the PV system can not feed the load, the Multiplus will feed the load with the grid. In my case (I work on microgrid systems and energy management systems) I have to do this management with an independent control system, that is the control station that has to start the battery charging and connect the system to the grid to feed the load. For this I have two questions:

Q1. Can I use a PLC to control the Victron Energie Multiplus so that it works either in charger mode or as an inverter?

Q2. Can I connect the grid directly to the AC bus to be able to control the grid relay directly with the PLC? I don't think I can control the relay inside the Multiplus directly with the PLC (please confirm this if possible).

ayoub-rahmouni asked
djsmiley answered ·

1 Answer

Can I use a PLC to control the Victron Energie Multiplus ?

Hello, I have questions about the Multiplus Victron Energy. In the case of Victron Energy, the grid (backup source) and the battery pack are connected to the Multiplus. And the latter is who will manage this is two sources, that is to say, for example, if the state of charge of the battery reaches its minimum and the PV system can not feed the load, the Multiplus will feed the load with the grid. In my case (I work on microgrid systems and energy management systems) I have to do this management with an independent control system, that is the control station that has to start the battery charging and connect the system to the grid to feed the load. For this I have two questions:

Q1. Can I use a PLC to control the Victron Energie Multiplus so that it works either in charger mode or as an inverter?

Q2. Can I connect the grid directly to the AC bus to be able to control the grid relay directly with the PLC? I don't think I can control the relay inside the Multiplus directly with the PLC (please confirm this if possible).

ayoub-rahmouni asked

0 Answers

Is there a minimum power of the battery bank for a Victron Energy Multiplus inverter/charger?

Hello, I hope you are well. I am Rahmouni Ayoub a PhD student engineer and I work on microgrid systems. One of our objectives is to realize a laboratory prototype that will contain a photovoltaic emulator that will produce a power of 3kWp connected to the AC bus via a photovoltaic inverter brand "Fronius", a group of batteries with an inverter charger "Victron energy" and other backup sources. According to the rule of the factor 1.0, the inverter charger must have a minimum power of 3kW because our photovoltaic source is 3kWp. but in our case since we use a photovoltaic emulator and even the load is a programmable load so we can simulate our day in some minutes. For this we don't need a battery capacity equal to the one used in a real model (that is to say we need a capacity of about 100ah maximum for our prototype). So my question is, is there a problem if I use a low capacity compared to the one used in real conditions with a 3kW inverter charger? (the capacity in real conditions is about 400Ah/24V).

Thank you very much!

ayoub-rahmouni asked
ayoub-rahmouni commented ·

1 Answer

Unstable Microgrid Multiplus II - Fronius

Setup:

Multiplus II 48 5000, Cerbo, Fronius 501 @ ACOut, no feed in,

Settings:

Fronius: - set to MG50,

Multiplus II:

* programmable relay and general flag assistants are used to ignore AC In1 if SOC >50% not ignore if SOC <30%;

* PV inverter support at last position in assistant list.

Fronius is connected via WIFI to Cerbo and it looks as it should.


Behavior:

Cerbo is showing: Fronius 350W, AC Load 105W.

The issue is that the battery state changes from charging with 900W to discharging with 700W couple of times per second. BMS shows similar values.

In this stage ESS assistant is not an option.

Somebody has this issue before, is there a fix for it ?




popnic asked
Dave Rae commented ·

37 Answers

Micro-grid with MultiPlus II and Fronius Primo - causing flickering lights

Hi,

We built a new single-phase installation recently with the following components:

  • MultiPlus II 48/5000
  • Cerbo GX
  • 4x Pylontech US2000C
  • PV inverter Fronius Primo 4.0

Grid is connected to MultiPlus AC in, all loads and the PV inverter are connected to AC out 1, like so:

[image]

Grid metering is done by the internal meter of the MultiPlus, Fronius is connected via ethernet (zero feed-in with ModBus via TCP).

Generally speaking, this setup works really great, now we're getting to the last 10% of optimization, and the current issue is the transition from grid-parallel to micro-grid, which causes the following:

  • Error 105 on Fronius (AC frequency too high) when switching off the connection to the grid (Fronius restarts/recovers quite quickly though)
  • Flickering lights at certain load constellations while operating on micro-grid (e.g. Fronius delivering 2.5 kW and loads around the same value (oven + small toaster)

The flickering can be described as brightness oscillation around 1-2 Hz, as if MultiPlus competed with Fronius for the voltage regulation. If useful, I can upload a video later.

Parameters are set as recommended by the documentation (MG50 on Fronius, Frequencies set in the ESS assistand according to https://www.victronenergy.com/live/ac_coupling:fronius). Native Fronius zero feed-in works fine also. The documentation mentions "Q5 How can I get the Fronius firmware that improves flickering?", but the Fronius is brand-new and all firmwares have been updated, so this shouldn't be the point.


Any ideas and help is much appreciated :-)

Thanks

ips-ad asked
Rob Duthie edited ·

2 Answers

Which battery technology is most suitable for use in microgrid systems ?

Hello, I hope everyone is well. From a literature search, I found that people are using lead acid batteries as an energy storage source. but from other battery researchers, they suggest using li-ion batteries for microgrid applications. so my question is what type of batteries are most used in microgrid applications?

ayoub-rahmouni asked
Alexandra answered ·

1 Answer

plc-controllable inverter (micro grid)

We want to dimension a PV + Batteries installation a little more complex than usual in order to be able to carry out microgrid tests in our installations, we are interested in the added value of being able to carry out different tests in our installations.


To do this, we would need an inverter with remote management capacity, we want to monitor the status and send remote orders to the inverter via a PLC/ IoT device in our energy management system to carry out operations such as selecting the supply source (grid, battery, panels), limiting the power of the panels, etc... all this under a criterion that sometimes may not be economically optimal but, as mentioned, we value from the point of view of microgrid testing.


which inverter allows me to control the parameters with a plc and what connections should I make, I suppose that the best protocol is modbus tcp, the power of the inverter charger should be around 50-60 kWp three-phase output.


Thank you very much


Translated with www.DeepL.com/Translator (free version)

alvaroitcl asked

0 Answers

Victron Multiplus 12/1200/50-16,230v - AC Grid feed-in based on Battery Voltage

I would like to be able to feed-in to the AC grid when the battery voltage exceeds a certain voltage (10.0V), the battery has an external charge source and the inverter will maintain this desired battery voltage by feeding the excess energy into the grid. Please advise on how to set this up. I have all the necessary protocol equipment such as the CerboGX modules, MK-USB3 cable, GX Touch, BMV etc but looking for advise on how to configure the inverter for the desired operation. Please advise.

solshare2022 asked

0 Answers

Moving load from grid to inverter when the load goes too high

I want to change my grid connection from 150A 3 phase to 80A 3 phase to save costs. The problem is I need to provision for load spikes that exceed the 80A supply and I do not have control over the loads (Commercial tenants). I am planning to add 3 x 15Kw Quatro inverters to the supply, but I want to know if there is a way to allow and control feedback from the battery bank / charge controllers to negate / mitigate load spikes when the loads reaches 70A or higher on a phase or more. So if a phase needs 100A, I want to supply 30A from the inverter / battery bank instead of causing the grid to trip.

Can this be done in ESS, MQQT or Modbus if I add a 3 phase CT meter to monitor the loads? How would one program this and what equipment is needed?

mcwidowmaker asked
Kevin Windrem answered ·

4 Answers

Grid Tied Inverter on existing Quattro Inverter

Hello,


I have 2 Victron Quattro inverters of 15 kVA dc coupled with a 48 V Lead Acid Battery bank.

We wish to synchronize 3 x Huawei SUN2000-5KTL-L1 with the Victron system. The Victron system will act as grid and the Huawei inverters will be configured for net zero export. However from the response time of the net zero export, for a brief time of 5s, power is exported (as shown in figure).


Can someone please confirm if such a system will work without damaging the Victron inverter?

[image]

[image]


yashtir asked
Paul B answered ·

1 Answer

Fronius Primo 3.0-1 alternative?

Hi all,

I have an EasySolar 24/3000/70 (with batt, bms etc.) already installed and with some extra solar panels (3330 Wp) I'd like to have the possibility of a microgrid. Fronius Primo 3.0-1 with MG50 fw seemed to be a good choice AC coupled inverter for these extra panels (complies with the 1:1 rule). Unfortunaltely the Primo is no longer available. Now I'm looking for a good alternative AC coupled inverter, suitable for microgrid, for this 3kVA system. Any suggestions? Thanks in advance!

Dennis asked
Alexandra answered ·

1 Answer

Replace APS YC500I ?

Hi,

I currently have two PV arrays at home:

- 6,7 kWc with Fronius Primo 6 kVA

- 1,2 kWc with two APS YC500I micro-inverters

I try to add AC-coupling ESS functionnalities with a Multiplus II 8 kVA + Pylontech US2000C batteries...

System works with Fronius (MG50 profile) but not with APS micro-inverters. APS micro-inverters are not injecting power correctly...

It seems that they are not compatible with micro-grid mode.

Do you have advice/recommendation if I decide to replace the APS micro inverters ? Enphase ? Other model ?

Thanks

positron asked
positron answered ·

2 Answers

How to connect Multiplus II and Microinverters

My Setup:

12 x panels (a 400 Watt)

3 x Microinverter (Hoymiles HM-1500)

1 x DIY Lifepo4 battery (16 cells a 280ah)


I would like to buy 3 x Multiplus II 48/3000/35-32 and connect them to L1, L2 and L3. Using a current sensor I’d like to achieve zero feed in.


For the sake of simplicity lets just look a one phase:

mp2.png


So in my image this would be:

(A) connected to (B) : power grid and microinverter

(A) connected to (2) : power grid to ACin

(3) connected to (A) : ACout2 to power grid


So I have a direct connection between ACin and ACout2, no?

markus32 asked
marekp edited ·

2 Answers

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