[EU] Powerwall and 3-phase 400VAC

[widodh]

So you have a 3 phase electrical supply at your house, and that is a common arrangement in the Netherlands? That supply would support loads that are 230V single phase (line to neutral), 400V single phase (line to line) or 400V 3 phase. Are all of your household loads 230V single phase, or are there common loads that operate on 400V single phase or 3 phase?

Cheers, Wayne

Yes, that's common in the Netherlands, but also in Germany, Switzerland, Austria, Belgium, Sweden, Denmark, many European countries.

The voltage single phase is 230V and the 3-phase voltage is 400V.

Most appliances are rated for 110 - 250VAC, but some like electrical ovens, cooking appliances, heatpumps, AC and garage doors are 3-phase.

And ofcourse my Model S charges on 3-phase 32A (22kW) at home.

So I would like a PowerWall (or more) with a 3-phase Inverter because my PV-array has a 10kW 3-phase inverter (SolarEdge) and I want my PW to supply power on all 3-phases.

Tesla says they are working on it to release it and of this year.

 

[fresnoboy]

Interesting. is this via adding a 3 phase inverter, or making a DC version that can be more easily integrated?

thx
mike

 

[widodh]

Interesting. is this via adding a 3 phase inverter, or making a DC version that can be more easily integrated?

thx
mike

The DC version isn't sold here. So it would be a integrated 3-phase inverter in the PowerWall 2 instead of the standard 1-phase inverter in the PW right now.

The AU market also wants the 3-phase version badly and the same goes for Austria and Switzerland as they have rules for a maximum single-phase load which is somewhere around 20A.

 

[NicoV]

So you have a 3 phase electrical supply at your house, and that is a common arrangement in the Netherlands? That supply would support loads that are 230V single phase (line to neutral), 400V single phase (line to line) or 400V 3 phase. Are all of your household loads 230V single phase, or are there common loads that operate on 400V single phase or 3 phase?

Cheers, Wayne

In Belgium we have the same 3 phase connection. Typically, when you build a new house you get 3 phase from the public network to the electricity meter. Depending on what kind of subscription you agreed to with the electric network operator, you will either get a single phase meter (internally only connecting 1 phase), or a 3 phase meter, outputting (and metering) all 3 phases. It is the job of the electrician to distribute all connections evenly over the three phases.
Upgrading from one phase to three phase is fairly simple: first the electrician rewires the switchboard to support 3 different phases, and then the network operator just has to replace the one phase meter with a 3 phase meter.
This switch actually happened in my house a couple of years ago when I wanted to install a geothermic heat pump and prepare myself for getting an electric car.
Iirc Belgian regulations are such that if you want to install more than 6kW solar, you need to convert to 3 phase.

 

[WannabeOwner]

Somewhat related:

3-Phase domestic rare here in UK, and usually incredibly expensive to have connected (utility monopoly ...)

We have 3-Phase at work, and have suffered with one of the phases dropping out with the fault reoccurring periodically over the course of many months. We wanted to put PowerWall on one of the phases, and make sure that the computer rooms were running off that Phase, to use Powerwall as a better/bigger backup than the toy UPS connected to each server Also a manual switch-over so that we could Supply the Powerwall from a different (operating) phase

At the time (a year or so ago) our Sparky didn't think that could be done very easily.

 

[widodh]

I called Tesla Energy in Amsterdam this morning and asked again.

They confirmed that in 2018 there will be a 3-phase Powerwall but suggested to call back this summer.

 

[jmorrison]

I called Tesla Energy in Amsterdam this morning and asked again.

They confirmed that in 2018 there will be a 3-phase Powerwall but suggested to call back this summer.

So with 3 phase 400V line-to-line that's 230V line to neutral.

Just install three Powerwalls, one for each phase. Do they come in three-packs for a discount?

Three times the cost and space, but also three times the capacity

I don't know if there would be any special code or special installation requirements for this (should check) but I can't think why.

In single phase North America, three houses could be fed by separate phases and they could each have their own Powerwall/Grid tie with no issues. Perhaps if the inverter controls are linked they could optimize power factor etc?

 

[wwhitney]

So with 3 phase 400V line-to-line that's 230V line to neutral.

Just install three Powerwalls, one for each phase

That should work when the Powerwalls are operating in grid-tie mode. But it can't work in the event of a power failure, as there would be no 3 phase source to sync to.

Cheers, Wayne

 

[widodh]

That should work when the Powerwalls are operating in grid-tie mode. But it can't work in the event of a power failure, as there would be no 3 phase source to sync to.

Cheers, Wayne

Indeed. You will need to sync all three phases.

So you will neer a true three phase inverter to make this work in Europe.

I’ll wait patiently until the end of this year

 

[jmorrison]

That should work when the Powerwalls are operating in grid-tie mode. But it can't work in the event of a power failure, as there would be no 3 phase source to sync to.

Cheers, Wayne

Indeed. You will need to sync all three phases.

So you will neer a true three phase inverter to make this work in Europe.

I’ll wait patiently until the end of this year

That doesn't make a lot sense to me as an EE but I may have missed something - it's been a while and I don't work with 3 phase professionally.

I was mostly being facetious because it seems like a very expensive approach for a household.

But I found this technical note for connecting multiple single phase grid-tie inverters to the three phase distribution system.
It looks like what I'd expect it to look. Anyway, it's for NEC and another manufacturer, so don't try this at home!

http://files.sma.de/dl/4307/Multiple SB Installation on 3 Phase Utility Tech Note V21.pdf

 

[wwhitney]

3 single phase grid-tie inverters in a wye configuration should work fine when the grid is up.

But if the grid goes down, 3 single phase stand-alone inverters in a wye configuration will not give you 3-phase power. There is no mechanism to ensure that the voltage waveforms produced by the individual inverters will be 120 degrees out of phase. I'm not sure what would happen to a L-L connected load in that scenario, but nothing good. If you only had L-N connected loads, then the system would work OK, it just wouldn't be a 3-phase system.

Cheers, Wayne

 

[Drewflux]

Currently holding out for a 3 phase compatible power wall here in Australia. Hopeful that Australia will get them around tge same time as the Euro market

 

[widodh]

Currently holding out for a 3 phase compatible power wall here in Australia. Hopeful that Australia will get them around tge same time as the Euro market

Understandable! I would call Tesla Energy in AU and ask them.

As I mentioned before I had two people from Tesla Energy in Amsterdam confirming it to me.

That doesn't make a lot sense to me as an EE but I may have missed something - it's been a while and I don't work with 3 phase professionally.

I was mostly being facetious because it seems like a very expensive approach for a household.

But I found this technical note for connecting multiple single phase grid-tie inverters to the three phase distribution system.
It looks like what I'd expect it to look. Anyway, it's for NEC and another manufacturer, so don't try this at home!

http://files.sma.de/dl/4307/Multiple SB Installation on 3 Phase Utility Tech Note V21.pdf

With 3-phase all the phases need to be 120 degrees from each other. You can't just have three inverters on each phase when the grid goes down.

Or you need a inverter which some kind of communication between them to sync the phases.

But I'll just wait for a 3-phase inverter from Tesla so that I can install two or three powerwalls in my still to build house.

 

[wwhitney]

But if the grid goes down, 3 single phase stand-alone inverters in a wye configuration will not give you 3-phase power. [. . .]If you only had L-N connected loads, then the system would work OK, it just wouldn't be a 3-phase system.

An important correction to the above: If all the loads are L-N and each circuit has a dedicated neutral circuit conductor, then the system would work OK while the grid is down. If a neutral conductor is shared between two circuits on different phases (called a multi-wire branch circuit, or MWBC, here in the US), then the system would not work OK, as the loss of a fixed phase relationship between two different phases would lead to the common neutral having higher than normal current and likely overloading it. I'm not sure if this MWBC wiring arrangement is used in other parts of the world.

Cheers, Wayne

 

[miimura]

An important correction to the above: If all the loads are L-N and each circuit has a dedicated neutral circuit conductor, then the system would work OK while the grid is down. If a neutral conductor is shared between two circuits on different phases (called a multi-wire branch circuit, or MWBC, here in the US), then the system would not work OK, as the loss of a fixed phase relationship between two different phases would lead to the common neutral having higher than normal current and likely overloading it. I'm not sure if this MWBC wiring arrangement is used in other parts of the world.

Cheers, Wayne

It's hard for me to imagine any home or business that had 3-phase service and no 3-phase loads. Provisioning a system for three phase power that does not guarantee that the three phases maintain the correct phase relationship is nonsense.

 

[wwhitney]

An important correction to the above: If all the loads are L-N and each circuit has a dedicated neutral circuit conductor, then the system would work OK while the grid is down.

Well, there is still another potential problem that occurs to me, namely the shared neutral in any feeders or in a panelboard. So the set of circumstances where this would actually work out OK is pretty limited. Still, it depends on the details of European wiring practices in countries where residences have 3-phase services.

Cheers, Wayne

 

[widodh]

Well, there is still another potential problem that occurs to me, namely the shared neutral in any feeders or in a panelboard. So the set of circumstances where this would actually work out OK is pretty limited. Still, it depends on the details of European wiring practices in countries where residences have 3-phase services.

Cheers, Wayne

In Europe the ground is always shared.

Voltage between phases is 400V and between L and N it’s 230V. All at 50Hz

My house has 4 wires coming in: L1, L2, L3 and N. All three phases have a 40A breaker between them. So my connection can provide 40A x 400V x 1,73 = 27,5kW at maximum.

So still, we need a 3-phase inverter in the PW. SolarEdge said they are also working on it with their StorEdge product, so we will probably get it in a few months.

 

[wwhitney]

In Europe the ground is always shared.

Voltage between phases is 400V and between L and N it’s 230V. All at 50Hz

My house has 4 wires coming in: L1, L2, L3 and N. All three phases have a 40A breaker between them. So my connection can provide 40A x 400V x 1,73 = 27,5kW at maximum.

Right, I got that part. So there's 4 wires (or 5, with PE?) coming into your house, and they go to a panel (breaker enclosure), and each of the ungrounded conductors L1 to L3 has a 40A breaker protecting it. Then what happens?

1) Is every circuit leaving this panel (to a load or to another panel) just 2 wires L-N (single phase 230V)? [Versus some circuit leaving the panel is 2 wires L-L (single phase 400V) or 3 or 4 wires.]
2) What is the rating of the neutral bus?

If the answers are (1) Yes and (2) at least 90A (3 * the 30A breaker protecting a Powerwall), then 3 single phase Powerwalls installed on the 3 phases would work OK in stand-alone mode when the grid is down.

Cheers, Wayne

 

[widodh]

Right, I got that part. So there's 4 wires (or 5, with PE?) coming into your house, and they go to a panel (breaker enclosure), and each of the ungrounded conductors L1 to L3 has a 40A breaker protecting it. Then what happens?

1) Is every circuit leaving this panel (to a load or to another panel) just 2 wires L-N (single phase 230V)? [Versus some circuit leaving the panel is 2 wires L-L (single phase 400V) or 3 or 4 wires.]
2) What is the rating of the neutral bus?

If the answers are (1) Yes and (2) at least 90A (3 * the 30A breaker protecting a Powerwall), then 3 single phase Powerwalls installed on the 3 phases would work OK in stand-alone mode when the grid is down.

Cheers, Wayne

4 wires, the PE is a copper pin going into the ground under my house.

Each phase has a 40A breaker and then goes through a CFGI.

Afterwards some circuits (16A) might be L1+N, the other L2+N and another L3+N. Balancing the loads over the phases. This way you have 230V on those circuits.

Other circuits, like my 3x32A/22kW charger for my Tesla are connected with L1+L2+L3+N to provide true 3-phase power to my Model S.

The same goes for my SolarEdge PV 10kW inverter, it's connected using a 16A breaker with L1+L2+L3+N

3 PWs each on their own phase wouldn't work as the phases aren't synced and some loads are actually truly 3-phase and need those phases to be in sync.

Other loads (which I don't have) are for example heatpumps for heating.

The best would still be to wait for a PW with a true 3-phase inverter.

 

[wwhitney]

Thanks for clarifying the details of a typical residential wiring system in your part of Europe.

Cheers, Wayne