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andrewb avatar image
andrewb asked

SMA on-grid + quattros ESS? AC Current sensor - single phase - max 40A in 3-phase ESS

Good day.

I was asked to help with victron system startup. But noticed some strange moments.

System configured as ESS with PV on AC-input (former hub-4) and consist's of:

1. quattro 48/15 - 3 pcs

2. SMA 20TL grid inverter -4 pcs

3. BYD B.Box 13.8

4. AC Current sensor - single phase - max 40A - 3pcs

5. CCGX

And there is no load on AC-output of quattros.

So the list of questions:

1. AC Current sensor - single phase - max 40A will may work with 100-115 A from PV-inverters. Is it safe? May it damage the quattro for some reason?

2. Will the current sensor show anything as the pv-inverters connected to the quattro AC-input not c-output? May be it is better to disconnect AC Current sensors? or even remove?

3. Also there is no energy meter installed at AC-input of the whole system. And no loads at AC-output of the quattros. As I remember in such case ESS will not work properly. CCGX doesn't see pv energy production and energy consumption.

4. One b.box 13.8 for 3 x 48/15000 quattros! It'a not enough. BYD recomend's 3 B.box-13 for quattro 48/15 000 3 phase. May there be any problems?

I was asked to help because it is very hard to communicate with the firm sold the victron equipment. And as I see this set of equipment compiled with errors and will not work in ESS mode. Now we have top priority task - to show the client that all is work. I set it as an UPS.

So we have 4 SMA 3 phase on-grid inverters, 3 quattros 15 kVA. pv Inverters connected to AC-in of quattros (hub-4). What do I need to make it work in ESS mode with zero balance (power supply to the network is prohibited)?

ESS
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5 Answers
byd-service avatar image
byd-service answered ·

Hello Andrew,

I can answer question 3.

As the system is using ESS, I guess it is grid connected. For self-consumption will work without problems as all the excess will go to the grid and all the extra load will be covered by the grid. However, once you have it in backup mode, you have the risk that a big load will shut down the batteries. If that´s the case make sure to only leave loads of maximum 175A during backup.

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andrewb avatar image andrewb commented ·

Update the question. Please look the video above. Seеms b.box doesn't work

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wkirby avatar image
wkirby answered ·

Hello.
This setup is not making a lot of sense. From what I understand, there are three Quattro's set in a three phase configuration. That makes sense so far.
Now there are four SMA PV Inverters. How hare these arranged? All on one phase or two on one phase and one on the other two phases?

1. Which phase or set of PV Inverters is the current sensor connected to?
2. Likewise, I don't know how useful this will be on it's own in a three phase system. Seems useless to me.
3. To me, the Quattro's will be completely lost in ESS, they will have no idea how much to charge and I can't see how they will ever discharge without anything on AC-OUT. The only way the Quattro can discharge via AC-IN with ESS is if there is an energy meter.
Ideally two three phase energy meters one to measure PV power and the other one at the incoming grid supply (loads in-between grid meter and Quattros). ET340 / EM340 should just about be OK @ 65A per phase.
4, That B.Box seems way to small for that system. It can discharge @ 12.8KW max (13.3KW for 60s). Minimum I would think is 3x B.Box 13.8 together for the 3x 15KVA Quattros.

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andrewb avatar image andrewb commented ·

There are four 20 kW 3 phase on-grid SMA inverters. It's 3 phase system. It's a little plant with 80kW on-grid self-consumption pv system (but without energy-meter).

And AC Current sensor - single phase - max 40A measures the current of 1 phase of 4 pv inverters (120A max).



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andrewb avatar image andrewb commented ·

update the question. please look above

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boekel avatar image
boekel answered ·

I strongly suggest you let an installer take care of this system.

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andrewb avatar image andrewb commented ·

now this is a matter of principle.

Installer don't know what to do either. It's our common questions)

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boekel avatar image
boekel answered ·

there are things wrong with the system, for one: 13,8 kWh of battery on 45 kVA of inverters, that's much too small, read the specs

http://en.byd.com/energy/download/low-voltage/B-Box%20Low%20Voltage%20Specification.pdf

manual for the fault codes (could be too much inrush current to charge the capacitors of the Quattro's, is there a precharge resistor in the byd box? or externally?
http://en.byd.com/energy/download/low-voltage/B-BOX%20Pro%2013.8-8S%20Installation%20Guidance.pdf

Andrew, what's your role in this system? are you the client?
If your installer doesn't know, he's the one that should step up to escalate things, but the first role as installer is to specify and install a correctly engineered system.

Do you have pictures of the installation? DC wiring, etc.

also the questions about energy meters is very basic stuff any installer should know, and is also available online:
https://www.victronenergy.com/live/ess:design-installation-manual

Please also read this page:
https://www.victronenergy.com/live/community_guidelines

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andrewb avatar image andrewb commented ·

this installer is not the victron distributor. And the victron distributor who offered and sold this set of equipment .... well isn't enough professional as you see and as it turned out hard to communicate. I just try to help the installer because off dead-line and client's bad mood.

Or! I see. 1 post - 1 question. I got it. thanks.

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boekel avatar image
boekel answered ·

in this case it's not the 1 post / 1 question thing. it's this thing:

Not the place for System Design

Long, multifaceted issues involving system design, multiple questions with very specific installation and nuanced details are not appropriate for this community. Those questions must be directed towards your distributor.

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now I think there has to be a place to ask those questions, but I think the one asking those questions must have good electrical knowledge, and preferably also Victron training.

Victron also states: don't start with complicated 3 phase systems before you have experience with smaller systems.
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But as I wrote you sum up equipment, but not an installation diagram, not pictures, etc.

For such complicated systems -many- things can be wrong, therefore you'll need to provide as much information as possibel, people might try to answer regardless, but these answers can be wrong because they are partly based on assumptions.

you -must- have been given a diagram of the installation? it should be available with the sytem.
and if the installer isn't up to the task...he might have to get the distributor to provide assistance. As much as I and others like to help, it's an expensive installation and lot's of things can be wrong. you -really- need a good installer to check and if needed correct things.

tree 15kVA units can draw 900 A continuous! that is not something for inexperienced installers, and needs to be well planned and well installed, followed by a series of tests (thermal camera needed) and after a couple of weeks a check if nothing has changed.
This is not something to think lightly about.

so please: find a competent installer before things break or catch fire...

And if you want good answers here: post the appropriate information, pictures, etc.

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andrewb avatar image andrewb commented ·

thanks for answer

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