Minor Backfeed Issue with Utility

[RCinFLA]

If they see PV panels and you don't have an interconnect agreement, you are automatically guilty.

Fixing it after the fact is a greater uphill battle.

You apparently have not seen the second shoe drop yet, that will be your homeowners insurance dropping you if you have it.

 

[WaterWiz]

Update:

The utility company is coming by this Friday to see what I have. If they determine I am disconnected from their equipment they have indicated they will let me be. If they find I am interconnected then I will need an interconnect agreement.

Some things are not clear in this discussion so I hope the following clarifies things.

1. Before this post my AIO inverter had the AC input connected to the grid. Nothing on the AIO output has ever been cross-connected.
2. Under heavy AC loads (charging EV vehicles) and I needed extra power the AIO would draw power from the grid. When it did this it would spike and show a momentary backfeed.
3. The utility has AMI meters that log everything, they saw a back feed blip. The utility sent someone out, saw solar, no agreement, investigation.
4. I originally explained to the utility there was no way I was backfeeding.
5. I DO NOT want an interconnect agreement.
6. I posted this post. Asking if anyone else possibly had this backfeed issue.
7. Seven days ago I physically disconnected and air-gapped the connection. No more utility power at all.
8. I talked to the Utility today and they indicated that over the last seven days no backfeed blips at all.
9. This in my opinion eliminates any EV charger scenarios.
10. I 100% suspect the AIO causes some form of backfeeding when connected to the grid in an SBU or supplemental to the AIO configuration. This is not a grid-tied system. It is a parallel system that is now in an EV charging system scenario.
11. This backfeed is a big issue IMO because it is a solar system backfeeding into the grid. Whether it's 1W or 10000 watts the utility has an issue with this. Rightly so.
12. I have resolved to never connect the AC inlet to the utility. I have a utility-only EV charger if needed. If no utility and no solar I can power either (separately) with a gas generator.

New Questions:

Since the solar system is not connected to the utility should it have a rapid shutdown near the utility power? I don't even think I can rapidly shut down an LV6548 short of killing all power.

I have labeled all components but most everything I read concerns cross-connected systems. Should I paint everything solar orange/yellow??

Any other recommendations? I have disconnects at the PV panels and inside the garage before AIO. All wiring is in conduit into the garage, into AIO, I do not see the need for PV disconnect before going into the garage (i.e. outside garage disconnects because this wiring is never exposed)

I am fine with making this about having a solar EV charge station only. My Tesla has a 75-kWh battery and my Lightning has a 131kWh battery. If my wife and I both drive somewhere it takes all the solar I have to charge these vehicles. I was paying $100/wk in gas. Now it's almost zero.

Thanks for all the help everyone

 

[Hedges]

Rapid shutdown for PV panels on the roof, yes.
Maybe any AC from inverter that is in or on the house should shut down.

Of course you want to be able to charge EV from PV, and charge from grid if necessary.
Dual-conversion UPS ought to support that, e.g. Charverter.
Or, transfer switch: If inverter shuts down, charger is fed from the grid.
You might want to switch between level 1 and level 2 charging based on SoC; that could often deliver 100% PV charging.

 

[zanydroid]

Since the solar system is not connected to the utility should it have a rapid shutdown near the utility power? I don't even think I can rapidly shut down an LV6548 short of killing all power.

This is a local question to ask your AHJ/fire marshal.

Here we are supposed to have a system map next to the service entry, and I plan to put all future off switches there so it is visible.

I believe the shutdown needs to nuke both DC side (at module level) and AC side.

 

[zanydroid]

As an example:

 

[OzSolar]

But he is not connected in parallel with the grid at all.

They made up some bs story because they probably felt he was not using enough power or knew about his solar.

Op should stand on the fact his system cannot feed the grid and is not in parallel and then make them prove they are seeing back feed

See the OP's latest post. Exactly what I said was going to happen.

7. Seven days ago I physically disconnected and air-gapped the connection. No more utility power at all.
8. I talked to the Utility today and they indicated that over the last seven days no backfeed blips at all.
9. This in my opinion eliminates any EV charger scenarios.
10. I 100% suspect the AIO causes some form of backfeeding when connected to the grid in an SBU or supplemental to the AIO configuration. This is not a grid-tied system. It is a parallel system that is now in an EV charging system scenario.
11. This backfeed is a big issue IMO because it is a solar system backfeeding into the grid. Whether it's 1W or 10000 watts the utility has an issue with this. Rightly so.

 

[solar8484]

Update:

The utility company is coming by this Friday to see what I have. If they determine I am disconnected from their equipment they have indicated they will let me be. If they find I am interconnected then I will need an interconnect agreement.

Some things are not clear in this discussion so I hope the following clarifies things.

1. Before this post my AIO inverter had the AC input connected to the grid. Nothing on the AIO output has ever been cross-connected.
2. Under heavy AC loads (charging EV vehicles) and I needed extra power the AIO would draw power from the grid. When it did this it would spike and show a momentary backfeed.
3. The utility has AMI meters that log everything, they saw a back feed blip. The utility sent someone out, saw solar, no agreement, investigation.
4. I originally explained to the utility there was no way I was backfeeding.
5. I DO NOT want an interconnect agreement.
6. I posted this post. Asking if anyone else possibly had this backfeed issue.
7. Seven days ago I physically disconnected and air-gapped the connection. No more utility power at all.
8. I talked to the Utility today and they indicated that over the last seven days no backfeed blips at all.
9. This in my opinion eliminates any EV charger scenarios.
10. I 100% suspect the AIO causes some form of backfeeding when connected to the grid in an SBU or supplemental to the AIO configuration. This is not a grid-tied system. It is a parallel system that is now in an EV charging system scenario.
11. This backfeed is a big issue IMO because it is a solar system backfeeding into the grid. Whether it's 1W or 10000 watts the utility has an issue with this. Rightly so.
12. I have resolved to never connect the AC inlet to the utility. I have a utility-only EV charger if needed. If no utility and no solar I can power either (separately) with a gas generator.

New Questions:

Since the solar system is not connected to the utility should it have a rapid shutdown near the utility power? I don't even think I can rapidly shut down an LV6548 short of killing all power.

I have labeled all components but most everything I read concerns cross-connected systems. Should I paint everything solar orange/yellow??

Any other recommendations? I have disconnects at the PV panels and inside the garage before AIO. All wiring is in conduit into the garage, into AIO, I do not see the need for PV disconnect before going into the garage (i.e. outside garage disconnects because this wiring is never exposed)

I am fine with making this about having a solar EV charge station only. My Tesla has a 75-kWh battery and my Lightning has a 131kWh battery. If my wife and I both drive somewhere it takes all the solar I have to charge these vehicles. I was paying $100/wk in gas. Now it's almost zero.

Thanks for all the help everyone

This is the first time I see someone actually caught by a POCO for using the AC input on an off-grid inverter that is actually in parallel with the grid. I first raised this issue awhile back (https://diysolarforum.com/threads/h...k-batteries-off-grid.50433/page-8#post-793018). Looks like POCO's are catching on. Your downfall appears to be not maintaining a minimum grid load.

 

[k490]

Friend works for a utility servicing meters he said the AMI system they use does look for illegal solar systems. He told me they report it to renewable department who sends someone to investigate. If they confirm an unpermitted system has been installed they report it to the AHJ for investigation, and possible fines. He said they consider any solar system directly connected no matter what type it is to them it's considered "Grid-tied" requires the system to be fully permitted and an interconnect agreement. The only way they might consider it not is if you used an outlet like an RV with solar on it portable solar system. They leave it up to the AHJ to figure it out he was told the reason was safety don't want someone back feeding during a power outage.

This is why I went with the EG4-6000XP I could not risk the scenario above.

The OP is at least able to work with hi POCO not involve the AHJ who likely fine him.

 

[Texas-Mark]

he was told the reason was safety don't want someone back feeding during a power outage.

I would bet the number of mechanical generators that are not using proper transfer switches outnumber the number of "dangerous" solar systems 1000:1

 

[rhino]

I would bet the number of mechanical generators that are not using proper transfer switches outnumber the number of "dangerous" solar systems 1000:1

This is why they always assume the line is energized unless they've manually disconnected it at a pole. Would you ASSUME a line is non-energized when you have no idea if someone might start up a generator wired incorrectly somewhere down the line?

 

[Texas-Mark]

This is why they always assume the line is energized unless they've manually disconnected it at a pole. Would you ASSUME a line is non-energized when you have no idea if someone might start up a generator wired incorrectly somewhere down the line?

If they always assume this, then what's the issue? Point being a "true" grid-tie inverter won't/can't operate without the grid, but yet the electric company makes a big deal out having a "non-approved" one. And they don't seem to care about how many mechanical generators are sitting in your yard, even though they are more likely to be problematic.

 

[k490]

I would bet the number of mechanical generators that are not using proper transfer switches outnumber the number of "dangerous" solar systems 1000:1

I could see situation where they check and find no power then someone fires up a generator in the morning and someone gets injured. He said the meter system discovered an underground bunker used for illegal drugs possibly other crimes although. They were tapping into power of a neighboring business the system noticed sudden jump in power usage so they went to investigate. They should have connected the bunker to a solar system would never been discovered. Reminded me of TV show breaking bad.

https://kjzz.org/content/1820926/underground-bunker-discovered-waddell-had-guns-and-drugs-msco-says

 

[WaterWiz]

Update: I have been running the system for several weeks, and there have been no further issues with the Utility Provider. I strictly use solar for EV charging, which, to be honest, is a much better ROI than home power.

 

[Brucey]

So how did the home visit by utility go?

 

[Brucey]

Friend works for a utility servicing meters he said the AMI system they use does look for illegal solar systems. He told me they report it to renewable department who sends someone to investigate. If they confirm an unpermitted system has been installed they report it to the AHJ for investigation, and possible fines. He said they consider any solar system directly connected no matter what type it is to them it's considered "Grid-tied" requires the system to be fully permitted and an interconnect agreement. The only way they might consider it not is if you used an outlet like an RV with solar on it portable solar system. They leave it up to the AHJ to figure it out he was told the reason was safety don't want someone back feeding during a power outage.

This is why I went with the EG4-6000XP I could not risk the scenario above.

The OP is at least able to work with hi POCO not involve the AHJ who likely fine him.

Is the 6000XP a double conversion unit?

 

[zanydroid]

Is the 6000XP a double conversion unit?

It is not. I am not aware of any commonly discussed double conversion AIO.

 

[Brucey]

It is not. I am not aware of any commonly discussed double conversion AIO.

I didn't think it was, but he mentioned going to the 6000XP to avoid the issue, isn't it basically the same design in terms of charging and inverting?...wondering if something like a Victron multiplus/Quattro would have the same issue with tiny unwanted exports.

 

[zanydroid]

I didn't think it was, but he mentioned going to the 6000XP to avoid the issue, isn't it basically the same design in terms of charging and inverting?...wondering if something like a Victron multiplus/Quattro would have the same issue with tiny unwanted exports.

Two things to unpack here
1) Correct SBU/SUB/etc off-grid behavior. The problem here is that whatever inverter this was, it bridged grid and inverter output. That is not supposed to happen for off grid inverters. But it is not clear how well policed that is. In principle since 6000XP is listed as off grid inverter and has US company backing it, there is some stronger guarantee. However that bakes in an assumption about what exactly 1741 guarantees for off-grid inverters. If it only guarantees momentary parallel or better, then there are POCOs that will still beat you down if they find out. I have yet to see a thread here that lawyers the 1741 (IE down to sentence diagramming and quoting of the book) to the point of establishing that it guarantees full air-gapping between grid and inverter. Rather, it is just accepted that it is the case.

If you double convert, physics and your own hands of constructing the double conversion, is the proof. Instead of lawyering, disassembling the AIO to confirm, or using social infrastructure (buying listed from domestic supplier) to gain confidence.

2) Unwanted exports. Depends on what you mean.

Zero export when operating in parallel? Physically impossible to prevent without doing things like setting minimum import amount, and still taking a risk (though probably reduced if you do that, and the size of import needs to be modeled for your house).

Zero export from unexpected momentary parallel? See (1)

MultiPlus and Quattro can be used in both on-grid and off-grid cases, so you need to have the settings right, or use external disconnecting relay. In the latter case you may not have proper SBU capability.

 

[Chris30559]

Wow. This just happened to me, Although my case is slightly different and wondering what everyone's opinion is. Just got a visit from Poco saying I backfed. My first response was impossible....I have a 3pole contactor that is manually activated to connect grid to my ac input of my xantrex xw6048 inverter. This contactor which switches L1,L2, and N was not active it is also normally open state. So couldn't have accidentally closed with loss of power . The Poco couldn't tell me how much or for how long I apparently backfed. But the day range they gave me the contactor was never engaged.

Ive been racking my brain trying to figure out how they could have recorded a back feed. This is what I've come up with.

1. My actual grid consumption was so low, near zero that they just assumed I back fed after they noticed my solar panels. I've brought this up and they assure me that isn't the case.

2. This is far fetched to me but I do believe possible. Some of my off grid load wires actually pass through my original grid connected panel, they were extended and routed to my off grid panel next to it. Nothing electrically connected except the ground wire. However I did notice several of the N wires ran parallel with one of the Lines from the grid. Probably about 12inches worth. And further one was actually wrapped 1 turn worth around it. I wonder if my grid tie loads were so low at a point, Maybe zero, That current was induced through the wires from my off grid loads that recorded as a back feed.

After seeing how little it appears to take for them to register it, I'm guess it's in the single digit watts like you. I'm starting to think scenario 2 has merit.

Also The day in question I did notice a power surge/dip on my on grid panel loads. (Lights dimmed for maybe 1-2seconds. ) I'm almost wondering if that had anything to do with the meter reading backwards also in combination with scenario 2. Again the only physical connection to the grid I had was through a contactor that was off.

Needless to say I was perplexed when they told me. Hopefully my outcome is similar to yours. So far they have just told me to disconnect and all will be ok, but not knowing how it detected backfed to begin with doesn't help me fix the problem.

In any case I've removed all wires that traveled through the grid panel, and removed the contactor. So I have ZERO physical connection what so ever except the ground, And also no wires running parallel anywhere near each other. If I get another call it would have to be scenero 1 at that point. Right..?

 

[k490]

Two things to unpack here
1) Correct SBU/SUB/etc off-grid behavior. The problem here is that whatever inverter this was, it bridged grid and inverter output. That is not supposed to happen for off grid inverters. But it is not clear how well policed that is. In principle since 6000XP is listed as off grid inverter and has US company backing it, there is some stronger guarantee. However that bakes in an assumption about what exactly 1741 guarantees for off-grid inverters. If it only guarantees momentary parallel or better, then there are POCOs that will still beat you down if they find out. I have yet to see a thread here that lawyers the 1741 (IE down to sentence diagramming and quoting of the book) to the point of establishing that it guarantees full air-gapping between grid and inverter. Rather, it is just accepted that it is the case.

If you double convert, physics and your own hands of constructing the double conversion, is the proof. Instead of lawyering, disassembling the AIO to confirm, or using social infrastructure (buying listed from domestic supplier) to gain confidence.

2) Unwanted exports. Depends on what you mean.

Zero export when operating in parallel? Physically impossible to prevent without doing things like setting minimum import amount, and still taking a risk (though probably reduced if you do that, and the size of import needs to be modeled for your house).

Zero export from unexpected momentary parallel? See (1)

MultiPlus and Quattro can be used in both on-grid and off-grid cases, so you need to have the settings right, or use external disconnecting relay. In the latter case you may not have proper SBU capability.

I'm no inverter expert but speculating the way these are designed hybrid VS Off-grid the hybrid always going have a parallel path with some kind of power circuit between the input side, and output side. Where the off grid has air gapped relays that direct power to the battery charger, or bypass the inverter go direct to the loads. It would help if we had block diagrams, and circuit design. I have read several posts about different model hybrid inverters back feeding a little. I'm not sure it's even possible with a hybrid inverter not to back feed little. I know several post here have DIY hybrids connected to their grid are not receiving letters I'm guessing their utility isn't all that sensitive to it. If your utility already doesn't like solar because it's cutting into their profits they are going to do everything they can to shut down solar usage.