Infinisolar and 3 phase rotation issue

[SilverNodashi]

Has anyone ran into an issue with the InfiniSolar 3 phase inverter giving an error with 3 phase incoming power? The Grid icon on the screen is on, but there's no link to the Load side, and in the logs I got an error "phase out of sync". This basically means the that 3 phases are not in the correct / expected sequence of RST (Red-Yellow-Blue). And this then cause the Infinisolar to not use the 3phase power at all. 

 

I suspect it has to do with municipality rotating the phases to balance them, but it seems the Infinisolar doesn't like it. And I can't find a setting to override or bypass it. 

[___]

1 hour ago, SilverNodashi said:

phase out of sync

Victrons also don't like that. Simply swap L2 and L3 and you will be fine (should be able to do this in config... if you can live with the OCD-triggering issue of the inverters no longer being in order on the wall). What's actually funny is that this is such a common problem that a changeover switch is sometimes used. For example, this system that is designed to be moved and used for outdoor events have such switch so you don't have to rewire things because the generator is wired wrong.

Edited June 10, 2018 by plonkster

[SilverNodashi]

9 minutes ago, plonkster said:

Victrons also don't like that. Simply swap L2 and L3 and you will be fine (should be able to do this in config... if you can live with the OCD-triggering issue of the inverters no longer being in order on the wall).

The installation is 4 hour's drive, so it's not a cheap fix everytime council decides to balance the phases - though I don't know how often they do do that, but it happened recently. 

 

9 minutes ago, plonkster said:

 What's actually funny is that this is such a common problem that a changeover switch is sometimes used. For example, this system that is designed to be moved and used for outdoor events have such switch so you don't have to rewire things because the generator is wired wrong.Do 

Do you know of a changeover switch which can be controlled from an MCU, with a way to monitor the phases and do an auto-changeover?

[___]

2 minutes ago, SilverNodashi said:

The installation is 4 hour's drive, so it's not a cheap fix everytime council decides to balance the phases

The ability to do remote configuration changes really is invaluable. But if you cannot do that, sending an electrician to swap two wires would cost much less than driving there, probably only about an hour's work. Is this a customer's home, or is there at least someone around?

4 minutes ago, SilverNodashi said:

everytime council decides to balance the phases

It makes sense to me that to balance the phases you might move some single-phase-connected houses to a different phase, but to swap the phases and potentially affect every three-phase customer in the street is just sloppy.

7 minutes ago, SilverNodashi said:

Do you know of a changeover switch which can be controlled from an MCU, with a way to monitor the phases and do an auto-changeover?

No, which is why I also asked if there is someone around you can send to go and pull a lever. Again, remote monitoring is invaluable, it means you can remotely see what the problem is before you send someone to pull the lever.

I cannot imagine they'd do this sort of thing very often?

[Chris Hobson]

13 hours ago, SilverNodashi said:

I suspect it has to do with municipality rotating the phases to balance them, but it seems the Infinisolar doesn't like it. And I can't find a setting to override or bypass it. 

I suspect it is sloppy workmanship. One cannot willy-nilly change phases. Probably a residential area otherwise every factory/plant's motors are now going to turn in the wrong direction. Charge you customer and get him to take it up with the municipality.

[___]

7 minutes ago, Chris Hobson said:

One cannot willy-nilly change phases. Probably a residential area otherwise every factory/plant's motors are now going to turn in the wrong direction.

Exactly. They'd be open to massive liability for damages.

[___]

12 hours ago, SilverNodashi said:

controlled from an MCU

This actually makes me wonder. How hard would it be to detect? I'm thinking not very hard at all.

Last week's post about the Conlog meters and avoiding feed-in led to the discovery that the emontx could potentially do such a thing, so now I'm thinking it should be easily adaptable to identify phases as well. Your phases has to be 2π/3 radians apart.

So mathematically, you'd take the voltage of L1, and take arcsin of that, which will give you a phase angle. You'd then add 2π/3 to that, and calculate the sine of that, and that will tell you at what voltage the next phase should be.

MCUs are notoriously slow in computing trig functions, so the simplest might be to precompute 50 values or so at 5V intervals, lookup L1 to the nearest 5V, look at what the corresponding L2 and L3 should be, and whichever of the other is closest (within 10V or so) is that phase.

Fun project for someone maybe. Or maybe there is a commercial thing for it already :-)

[pilotfish]

7 hours ago, plonkster said:

This actually makes me wonder. How hard would it be to detect? I'm thinking not very hard at all.

A [phase failure/sequence relay] and a [3ph over/under voltage relay] are commonly available at any electrical wholesaler. You would need both connected to 2x contactors, one wired straight through and one wired to reverse rotation.

If [phase failure/sequence relay] registers an anomaly then it will switch contactors from direct to reverse rotation, but if [over/under relay] also registers an anomaly then it will cut both relays.

Not cheap!

[Coulomb]

9 hours ago, pilotfish said:

You would need both connected to 2x contactors, one wired straight through and one wired to reverse rotation.

And you'd want to make triple sure that the two contactors never ever come on at once 

[___]

4 hours ago, Coulomb said:

And you'd want to make triple sure that the two contactors never ever come on at once 

That's probably a non-issue. Star-Delta starters have a similar two-contactors-that-must-never-be-on-at-the-same-time nature. They use a timer in those setups to ensure there is no overlap. Of course if a contactor does fail... :-)

Edited June 12, 2018 by plonkster

[pilotfish]

4 hours ago, Coulomb said:

And you'd want to make triple sure that the two contactors never ever come on at once

Normally you would use a mechanical interlock - so contactor 1 must have opened before contactor 2 can close and vice-versa. This is normally accomplished with an auxiliary contact.

[SilverNodashi]

On 2018/06/10 at 8:43 PM, plonkster said:

The ability to do remote configuration changes really is invaluable. But if you cannot do that, sending an electrician to swap two wires would cost much less than driving there, probably only about an hour's work. Is this a customer's home, or is there at least someone around?

It makes sense to me that to balance the phases you might move some single-phase-connected houses to a different phase, but to swap the phases and potentially affect every three-phase customer in the street is just sloppy.

No, which is why I also asked if there is someone around you can send to go and pull a lever. Again, remote monitoring is invaluable, it means you can remotely see what the problem is before you send someone to pull the lever.

I cannot imagine they'd do this sort of thing very often?

It's a client's lodge, so only visitors come there. 

 

The client has spoken to one of the city engineers about the matter, but somehow came to the conclusion that 3x single phase inverters would be better in the long run so this wouldn't cause a problem anymore, and if one phase's load is too high it wouldn't drain the batteries of the other two phases unnecessarily. 

[Chris Hobson]

Just as an aside  The 3P GTIs I have worked with are quite happy to receive the phases in any order. I know that this is not the case with the Infinisolar. 

[SilverNodashi]

36 minutes ago, Chris Hobson said:

Just as an aside  The 3P GTIs I have worked with are quite happy to receive the phases in any order. I know that this is not the case with the Infinisolar. 

which do you use that don't care about the sequence? SMA?

[Chris Hobson]

8 minutes ago, SilverNodashi said:

which do you use that don't care about the sequence? SMA?

..and Huawei.

Addition: I did however connect L1, L2 and L3. During that particular install I discovered that the phases on one of the sub breakers was switched. I decided not to correct it as I was not sure what was being powered and let sleeping dogs lie. I tapped off power via  a 1A 3P carefully correcting the phases for the Solar Log meter.