There are multiple reasons for requiring grid-tied inverter (GTI) shutoff in case of grid outages (i.e. anti-islanding). Lineman safety is one of the reasons but it's not the only reason. GTI's require a common stable "grid signal" to synchronize power production and function properly. So, if GTI's didn't shutoff in grid outages (i.e. unintentional islanding condition) then they would not be able to synchronize properly and would have very unstable behavior, especially with many GTI's, including voltage transients that can damage the GTI's and/or connected device loads.
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Tesla solar panels during power outage
- Thread starter houser2021
- Start date
MrTemple
Member
Not sure if you’re just being argumentative, or if you’re honestly unaware that other inverters can do islanding…
Either way you’re wrong.
Not sure if you’re just being argumentative, or if you’re honestly unaware that other inverters can do islanding…
Either way you’re wrong.
Some Sunny Boy inverter lines have the Secure Power Supply feature, essentially a separate circuit and outlet for up to 2000w of power while the grid is down. They've had it as an option since 2013.
SMA Secure Power Supply Technical Description
SMA Youtube Video on SPS
Just a guess: if you have a Sunny Boy inverter and Powerwall when the grid goes down the Sunny Boy will still consider itself on-grid since technically it is still on the Powerwall formed microgrid. It would only engage the SPS if the Powerwall failed for some reason, leaving it truly gridless. Something catastrophic would have to have happened to the Powerwall as a simple low battery condition would cause the Powerwall to try to reform the microgrid every few minutes using the reserve power.
Not sure what you mean by rapid shutdown
Rapid shutdown is an NEC requirement, at least where I'm at. I think it has to do with being able to quickly shut the system off (perhaps by emergency services?) but am not sure how it works or when.Just a guess: if you have a Sunny Boy inverter and Powerwall when the grid goes down the Sunny Boy will still consider itself on-grid since technically it is still on the Powerwall formed microgrid. It would only engage the SPS if the Powerwall failed for some reason, leaving it truly gridless. Something catastrophic would have to have happened to the Powerwall as a simple low battery condition would cause the Powerwall to try to reform the microgrid every few minutes using the reserve power.
Not sure what you mean by rapid shutdown
Was thinking of the case where PWs get full and raise the frequency to shut off inverters when grid is out. Will SPS still work? Guessing it would as the inverter would just see the PWs as the "grid" as you've indicated, but am unsure whether the high frequency would cause an issue.
I imagine the standard shutoff on the inverter would meet the requirement.
Good question about the frequency change. Not sure.
The rapid shutdown requirement is about de-energizing (or at least reducing the voltage of) the equipment on the roof not the inverter output. For string inverters without optimizers like the Tesla inverter, the issue is that if the inverter is turned off the panel strings could have as much as ~600V on them depending on the number of panels in the string. To address this mid-circuit interrupters are added at least at every 3rd panel in the string. When activated they open isolating the 3 panel sets from one another. The max voltage on the roof is then only whatever 3 panels can generate (~100V).
I don't know any more about SPS then the links posted above. Reading the spec sheet of an SMA inverter that includes SPS it states the SPS will not work with some implementations of rapid shutdown so it depends on how the system is configured.
I really don't see a use case for SPS with powerwalls. SPS is not active when the inverter sees line voltage whether that is from the grid or the powerwalls. SPS also only provides a 120VAC 12 A outlet that you could maybe plug one moderate power device into with an extension cord. Even without powerwalls the use cases seem quite limited.
I am guessing that you are looking to keep solar active when PW's are full but still on. SPS won't help with that
SPS is only active when PW's and grid are both off so there would be no frequency shift involved. Some Tigo RSD models have been used with SPS but apparently they are no longer available. I've seen reports indicating newer RSD models need separate DC supply/battery for the required wireless comm to work during blackouts which makes SPS more complicated to deploy.
Holy crap enphase has started shipping iQ8 micros. About friggin time.
Enphase Energy Introduces IQ8 Microgrid-Forming Microinverter - Solar Industry
Enphase Energy Inc. has announced an all-in-one Enphase Energy System with IQ8 solar microinverters for customers in North America. IQ8 is capable of forming a microgrid during a power outage using only sunlight, providing backup power even without a battery. “Since the company’s inception, we...
solarindustrymag.com
Holy crap enphase has started shipping iQ8 micros. About friggin time.
Enphase Energy Introduces IQ8 Microgrid-Forming Microinverter - Solar Industry
Enphase Energy Inc. has announced an all-in-one Enphase Energy System with IQ8 solar microinverters for customers in North America. IQ8 is capable of forming a microgrid during a power outage using only sunlight, providing backup power even without a battery. “Since the company’s inception, we...solarindustrymag.com
View attachment 725847
This looks a few days old, but supposedly the generator option is coming in November as well:
Enphase Energy Systems Offer Integration With Existing AC Home Standby Generators Further Enhancing Customer Experience
Integration enables homeowners to use clean energy most of the time and allows for a seamless transition to generator only when needed...
This is probably the more flexible long term rain/cloud solution since you can only go so far with batteries with no sun.
It'd be interesting if customers avoid Tesla Solar since it doesn't have a microinverter option at all currently for new installs and the IQ8 sounds like a big positive on no grid, sunny days.
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el-guapin
Trust no One
Nice Find!!Holy crap enphase has started shipping iQ8 micros. About friggin time.
Enphase Energy Introduces IQ8 Microgrid-Forming Microinverter - Solar Industry
Enphase Energy Inc. has announced an all-in-one Enphase Energy System with IQ8 solar microinverters for customers in North America. IQ8 is capable of forming a microgrid during a power outage using only sunlight, providing backup power even without a battery. “Since the company’s inception, we...solarindustrymag.com
View attachment 725847
