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marekp avatar image
marekp asked

Can I go from AC coupled PV to not AC coupled PV and back with the switch?

At the moment my on-grid inverter is connected in front of Victron system.

This on-grid inverter is not on the list of inverters recognized by Victron and does not react to frequency shifting used by Victron.

I would like to be able to move this inverter from not AC coupled to AC coupled and back with the switch.

Can it be done?

The reason for it is that, when inverter is AC coupled and Victron fails, I can use a bypass switch to bring power my loads. When it happens my PV inverter is also disconnected from my loads.

In this situation I would like to "move" my PV inverter to AC input side and be able to use its production when grid is present.

The other reason has to do with my grid operator.

They are preparing to force the owners of PV systems, connected to the grid, to turn the PV system off on their request, or even do it automatically by the signal from the grid.

In that situation I want to have an option to go off-grid rather that turn my PV off.

AC PV Coupling
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basil katakuzinos avatar image
basil katakuzinos answered ·

I guess a transfer switch can accomplish this, not sure if it is to code and it is definitely not a good idea at all as you could end up providing too much power to the Inverter side while you are not home to flip the switch. I think this will probably just collapse the local grid if you are off grid, but i am not sure if it has the potential to cause equipment failure. What PV inverter do you have and does it not have some sort of zero feed in setting. If it is not feeding back into the grid then your utility should not have a problem with it.

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marekp avatar image marekp commented ·

Since I asked that question 11 months ago, I tested it using transfer switch to move my inverter back and forth between AC-in and AC-out.

It can be done.

My utility has no problem with me feeding energy back to the grid and I can do it from either inverter position.


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emmanuel-allaud avatar image emmanuel-allaud marekp commented ·

Hi,

I would like to do something similar: I have a PV inverter that feeds the grid (total sale contract) and I would like to automatically switch to AC-coupling (so tied to the multiplus AC-output) for this inverter when grid is down to use the PV power for my house.

Can you tell me what switch you used and how you wired it please? Also how do you control it to switch depending on grid status?

Thanks in advance.
Emmanuel

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marekp avatar image marekp emmanuel-allaud commented ·

@Emmanuel Allaud

I use manual 4 pole changeover switch SF463 made by Hager

https://www.hager.sg/energy-distribution/control-signaling/modular-changeover-switches/3298.htm

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Automatic changeover is not easy because after changing PV inverter connection you have to change settings in GX.

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emmanuel-allaud avatar image emmanuel-allaud marekp commented ·

Thanks for the info. I thought the multiplus would produce a CA that would enable the PV inverter to sync as if it was connected to the grid.

Your solution is OK if it is a long grid failure AND you are home, otherwise for me it is not practical.

So what you do in case of grid failure: you manually switch the PV inverter output to the multiplus AC output and what setting do you have to change in the GX?

Thanks again.

Emmanuel


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marekp avatar image marekp emmanuel-allaud commented ·

@Emmanuel Allaud

Today I keep my PV inverter connected at AC-out, because as long as Victron is working, I do not need to change it over to AC-in. Excess power from PV is fed to the grid.

The only times when that changeover switch is used is when Victron is down and bypassed. When Sun is shining than I move my PV inverter to AC-in (grid) to get Sun power for house loads.

P.S.

Today I have Fronius Symo, so I have no problem with an incompatible inverter I had back then.

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emmanuel-allaud avatar image emmanuel-allaud marekp commented ·
OK I get it thanks!
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