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bjorn-n asked

MultiPlus II ESS without neutral in Belgium

I have a MultiPlus-II configured as an Energy Storage System. The charge/discharge cycle is done via ModBus-TCP. Here's how the power/voltage graph looks over time:

screenshot-at-2021-05-02-09-45-32.png

As you can see above, all was working fine, until the utility company decided to do (unannounced) work and all grid power went down. After power was restored, I no longer had a Neutral wire.

The MultiPlus-II is connected to a "monofase" connection. Below is a measurement on my "monofase" connection with 2 wires coming in from the grid. As you see, in stead of 1F+1N, I now have 2F wires (120° out of phase of each other) coming in.

screenshot-at-2021-05-02-10-26-57.png

There is still 230V between both wires. However, some devices, including the MultiPlus-II ESS stopped working... Can the MultiPlus-II handle this kind of (old-school) 2 phase (no neutral) grid connection? If yes, how to (re)configure?



Side information: I also measured at a neighbouring grid connection with 3 wires coming in from the grid. It look like this:

screenshot-at-2021-05-02-10-34-39.png

It clearly shows 3 phases on prove #1, #2 and #3. Probe #4 is connected to a 4th wire, but that 4th wire is not connected inside the (sealed) box of the grid company.

Multiplus-II
screenshot-at-2021-05-02-09-45-32.png (97.9 KiB)
screenshot-at-2021-05-02-10-26-57.png (819.0 KiB)
screenshot-at-2021-05-02-10-34-39.png (990.4 KiB)
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bjorn-n avatar image bjorn-n commented ·

Quick update: a few weeks after the utility company "fixed" the issue (by connecting one fase to ground in the transformer substation nearby), they replaced the transformer in that substation with a "7 point" transformer. I'm no expert at this but I guess this is a combination of a "Whye" Y and Delta transformer. Anyway, because of this, they could no longer connect one phase to ground and I am now stuck with 2 phases again. Each phase has a potential of approx. 135V AC @50Hz compared to Earth. Between phases there's 230V.

Strangely enough, this time the MultiPlus-II seems to do fine for now. At least it's charging and discharging. Which it wasn't when I first posted this. I have not thoroughly tested failover and failback though. So it remains to be seen if it really works this way.

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sergi avatar image sergi bjorn-n commented ·
Hello, i have 2 lines and 230v between lines with no neutral, did the multiplus II work correctly for you? are you in ESS? thanks
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bjorn-n answered ·

Problem solved it seems. The utility company fixed a fault in the cabin nearby. I now have 1F+1N again.

Though I still wonder if such a "2 fase" setup is (officially) supported?

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Alexandra avatar image Alexandra ♦ commented ·

Not without a neutral.

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