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My grid outage frequency issue is resolved!

Dan123

Member
Jun 19, 2018
451
322
Miami
Doesn't sound right. UL1741 SA is about grid interactivity with the frequency source grid-side

PWs are just pass-through until it islands, so until then Enphase still has to respect grid-rules. The PREPA profile probably allows Enphase to be flexible with the crazy frequencies from the PW in the micro-grid.

I am not an electrical engineer, so I don't know for sure. But this is what Enphase technical brief says:

Point of Common Coupling: When using a Tesla Powerwall, the Backup Gateway becomes the point of common coupling as per standard IEEE 1547. Therefore, it is the Tesla Backup Gateway that must comply with the Utility's interconnection requirements. Any IQ Micros that are connected on the load side of the Backup Gateway do not have to comply with the Utility's interconnection requirements, and their parameters can be set to optimize ESS operation.
 
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L-P-G

Member
Feb 20, 2016
359
350
Orlando, FL
I am not an electrical engineer, so I don't know for sure. But this is what Enphase technical brief says:

Point of Common Coupling: When using a Tesla Powerwall, the Backup Gateway becomes the point of common coupling as per standard IEEE 1547. Therefore, it is the Tesla Backup Gateway that must comply with the Utility's interconnection requirements. Any IQ Micros that are connected on the load side of the Backup Gateway do not have to comply with the Utility's interconnection requirements, and their parameters can be set to optimize ESS operation.

That's correct, it's called AC coupling. The reason for the exception is because per 1741 inverters are not allowed to operate when the grid is out. By adding that clause when the gateway islands the micros can continue operating as they will sync to the PW sinewave.
 

gpez

Member
Apr 25, 2019
776
640
USA
That's correct, it's called AC coupling. The reason for the exception is because per 1741 inverters are not allowed to operate when the grid is out. By adding that clause when the gateway islands the micros can continue operating as they will sync to the PW sinewave.

So does "load side" simply mean "not directly coupled to the utility"? My production panel doesn't reach the utility until the gateway, which I'm guessing that means "load side"?
 

Dan123

Member
Jun 19, 2018
451
322
Miami
So does "load side" simply mean "not directly coupled to the utility"? My production panel doesn't reach the utility until the gateway, which I'm guessing that means "load side"?


Yes, I think by definition, the solar panels will be on the load side. If they are on the other side of the PW, then they will not work during the grid outage, and will be disconnected.
 

ez123

Member
May 19, 2019
21
1
San Diego
I have not been able to get this issue resolved. I called Tesla and after about an hour's wait on hold I was able to speak with someone, and that person was knowledgeable about the issue. He told me that they would address it. It seemed promising. About two weeks later I received a call saying that they would need to do a test outage first before making any changes and we scheduled a time about two weeks later, in the afternoon, when I could take time off from work and be at home. Again, it seemed promising, but it was not what I was originally told. The person I spoke with said he would call at the time we scheduled. When the date/time came, there was no phone call. A half-hour after the time passed, I received an email saying he called twice but my line was busy and to call him back ASAP at the number provided. (I confirmed that my phone (my cell phone), was working. I have great reception at my house. Still, I suppose it's possible two calls didn't go through, even though that's not been an issue previously.) I called back immediately after receiving the email. The number was for the general number. I waited on hold for about two hours, without speaking to anyone, and since it was getting dark (and there would be no solar production), I hung up without actually getting through. I then sent four follow-up emails asking to reschedule and never received a reply. I tried calling again but gave up after about an hour's wait, again without speaking to anyone. I conclude that I have no evidence that the service department for Tesla Powerwalls remains in existence, as they have not been reachable by phone or email, when they once were.
 

gpez

Member
Apr 25, 2019
776
640
USA
Yes, I think by definition, the solar panels will be on the load side. If they are on the other side of the PW, then they will not work during the grid outage, and will be disconnected.

Any chance you know if these Enphase systems are custom configurable? My installer is telling me they can only apply profiles, none of the ones available meet my specific needs. Seems like it would be simple enough to create a custom profile, which the installer agrees, but can't seem to make it happen.
 

Dan123

Member
Jun 19, 2018
451
322
Miami
Any chance you know if these Enphase systems are custom configurable? My installer is telling me they can only apply profiles, none of the ones available meet my specific needs. Seems like it would be simple enough to create a custom profile, which the installer agrees, but can't seem to make it happen.

I think they require Enphase to create a profile for you. Which they should be able to do. Have you tried calling their support line?
 

Dan123

Member
Jun 19, 2018
451
322
Miami
I haven't but my installer has. They've been having difficulty getting Enphase to that point. Thanks for the info.

My installer was fairly clueless about grid profiles. I called Enphase, told the customer service that I have a Powerwall, and that I read that I need to use a special grid profile. He remotely changed it for me to that Puero Rican profile.
 
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gpez

Member
Apr 25, 2019
776
640
USA
My installer was fairly clueless about grid profiles. I called Enphase, told the customer service that I have a Powerwall, and that I read that I need to use a special grid profile. He remotely changed it for me to that Puero Rican profile.

I'm not entirely convinced the PR profile is exactly what I need, but perhaps I just need more education as to what the values actually mean. For example why is "Start Frequency" 60.20hz while "Ramp up Frequency (Max)" is lower at 60.10hz? Are we sure these values match how the Powerwall is newly configured for backups as per this thread? Another consideration for me is I have a system that's plated at over 8kW and the Powerwall inverter max is 5kW. I think I have to ensure the Enphase settings are configured so that they don't overload the Powerwall during a grid outage and max sun.
 

miimura

Well-Known Member
Aug 21, 2013
6,827
6,710
Los Altos, CA
I'm not entirely convinced the PR profile is exactly what I need, but perhaps I just need more education as to what the values actually mean. For example why is "Start Frequency" 60.20hz while "Ramp up Frequency (Max)" is lower at 60.10hz? Are we sure these values match how the Powerwall is newly configured for backups as per this thread? Another consideration for me is I have a system that's plated at over 8kW and the Powerwall inverter max is 5kW. I think I have to ensure the Enphase settings are configured so that they don't overload the Powerwall during a grid outage and max sun.
In an ideal case, with the profile properly configured, the Powerwall frequency shifting should proportionally curtail the solar to stay below the 5kW max charging rate on the Powerwall. Worst case, if the grid is down and your solar output is repeatedly causing the Powerwall to force the solar offline with frequency shifting, turn off one or more of the solar circuit breakers until the output can be accepted by the Powerwall. If you have 8kW of Enphase solar, you must have more than one solar circuit breaker unless Enphase dramatically increased their AC wiring sizes for product more recent than mine.
 

Dan123

Member
Jun 19, 2018
451
322
Miami
I'm not entirely convinced the PR profile is exactly what I need, but perhaps I just need more education as to what the values actually mean. For example why is "Start Frequency" 60.20hz while "Ramp up Frequency (Max)" is lower at 60.10hz? Are we sure these values match how the Powerwall is newly configured for backups as per this thread? Another consideration for me is I have a system that's plated at over 8kW and the Powerwall inverter max is 5kW. I think I have to ensure the Enphase settings are configured so that they don't overload the Powerwall during a grid outage and max sun.

The way I understand is that if the inverters are off, they will wait until 60.2 to start again. I don't know if they start at full power or reduced power at that point.

My powerwall, when it starts to reach its full capacity 92-95%, starts to slowly increase the frequency. And the microinverters start to slowly decrease the power, until they close to the demand of the house.

If the power goes off while the PW is about 95%, then the PW increases the frequence to 62.5, and the inverters turn off immediately. Then, after the PW gets discharged a bit, it starts reducing the frequency, and the inverters come back on.

If your inverters start producing more than 5kw, then I think the PW will increase the frequency to 62.5 or higher, and the inverters should shut down, until the PW reduces the frequency below 60.2. I am not sure that they can deal with this situation in a gradual manner. That would be a Powerwall setting.
 

gpez

Member
Apr 25, 2019
776
640
USA
@Dan123 my installer is saying that the "5s reconnect time is married to a 3kW export limitation" and "The Envoy measures export limitations via consumption CTs at the service entrance" (meaning I'd need new CTs). I can't possibly believe either of those are true. Do you sell your power back to the grid? If so, with the PREPA profile are you limited to 3kW?
 
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Dan123

Member
Jun 19, 2018
451
322
Miami
There may be some local export limitation. In my case, I don't have any export limitations, and the solar routinely exports more than 3KW to the grid.

I don't see how the 5s reconnected is related to that. All that the 5s reconnect does - if the powerwall is discharged, and it tries to restart, the solar panels will kick in within 5 seconds, and will not wait for 305 seconds. If they wait for 305 seconds, the PW may get discharged even more and shut down again.


The powerwall, however, doesn't export to the grid, and does not charge from the grid. it only charges from the solar, and it only discharges when there is a home load.
 

gpez

Member
Apr 25, 2019
776
640
USA
There may be some local export limitation. In my case, I don't have any export limitations, and the solar routinely exports more than 3KW to the grid.

I don't see how the 5s reconnected is related to that. All that the 5s reconnect does - if the powerwall is discharged, and it tries to restart, the solar panels will kick in within 5 seconds, and will not wait for 305 seconds. If they wait for 305 seconds, the PW may get discharged even more and shut down again.


The powerwall, however, doesn't export to the grid, and does not charge from the grid. it only charges from the solar, and it only discharges when there is a home load.

My configuration is the same - Powerwall charges from solar, doesn't export to grid, and our utility has no export limitation from solar. And my installer says Enphase says configuring a 5s reconnect will require a 3kW export limit. I'm going to call Enphase directly today.
 

Dan123

Member
Jun 19, 2018
451
322
Miami
Called Enphase, they didn't even blink applying the PREPA 83 profile. I'm going to keep an eye on things and make sure it's all working. Perhaps I'll run an outage test this weekend.
Good news!

I also had to ask Tesla to reduce their frequency to 62.5 when the power goes out with the battery near full (you may already have it)

With PREPA 83 and 62.5 everything works beautifully.
 

Jaidmaster

New Member
Feb 18, 2020
4
6
Colorado
Good info in various threads on this topic. Thanks!
I applied the PREPA Off Grid 83 yesterday via the Installer Toolkit, and noticed there is a PREPA Off Grid 60 in my list as well. I have not looked, but assume this would be 60% / Hz with slightly higher Slow Freq Cutoff since 60% would take about 1.7Hz increase to fully curtail. I can't see the info on the profiles until AFTER I apply and propagate them to my micros (Then hit the info / i button but will probably take a look.
I suppose the next step is to call Tesla and get them to reduce the max frequency. 62.5Hz max should allow my UPS to continue to pass through and hopefully not affect LED lights and pumps too badly? I suppose Tesla will ultimately decide?
Does this frequency change get overwritten once new firmware is pushed to the TEG?

For reference, I have 11.4 kW array with 30x IQ7+ micros and 3x PW2's, installed Oct 2019.
 

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