Artificially limited solar production during PG&E PSPS outage

[barely]

I have ~ 8KWh solar + 2 Powerwalls. The inverter is a SolarEdge 7600H-US with optimizers, The weekend before last, we got hit with a PG&E PSPS outage. It started at 8pm on Sunday. The Powerwalls were full when the outage hit. By the morning, when the sun starting hitting the panels, the Powerwalls were down to ~30%. That should have been fine. The panels should have supported the house and the excess should have gone into the batteries. At this time of year, we produce ~25KWh. It might not have gotten us back to 100% with the house usage, but would have brought us to at least 80-85%. Instead, The system was artificially limiting production from the panels.

Here is the solar production.

During the outage

Day after the outage

The sky was identical between the two days -- full sun, no clouds. In 2019, the system worked flawlessly during that 36 hour outage event. In the morning, the panels ran the house and charged the batteries as expected.

On the SolarEdge display during the outage in the Power Control menu, it showed:

PWR CTRL: LOCAL
PWR Limit: (around 1.4 kW)
CosPhi: 1.0
Power Prod: (never more than 1.4 - 1.5 kW)

The next day, that same menu showed:
PWR CTRL: LOCAL
PWR Limit: 7.6 kW (though occasionally would drop to around the level of Power Prod
for a couple of moments and then back to 7.6 kW)
CosPhi: 1.0
Power Prod: XXX

Something changed in the configuration of the SolarEdge. Nobody from Tesla was ever at the house after the initial installation, so the change must have been done remotely. Has anyone seen this kind of behavior from their system? I've been waiting over a week for an answer from Tesla support without a peep from them. I've made multiple calls and get their first tier people telling me the same thing, it's with tier 2.

Fortunately, we don't have any more wind events in the near forecast, but I really don't like being left with a system that isn't going to function during an outage.

 

[sorka]

I've been testing my system off grid since I don't yet have PTO and my solar production has been full bore right up to 98% when the inverter shuts off after hitting 60.5Hz.

Are you sure that isn't just clouds? I know you said no, but I've seen some days look like yours because of smoke or light whispy clouds that were a little hard to make out because they had no sharp boundaries.

 

[barely]

I can guaranteed it was not clouds. The sky was crystal clear on both days. Even with a few wispy clouds, a drop of 60%+ is not expect. You can see in the first graph that production seems to have a cap of just under 1.5kW. I checked some more of my data. During the course of the outage, the PWs were putting out 59.60 - 59.71Hz. I wondering if this was badly interacting with the Rule 21 settings in the SolarEdge.

 

[sorka]

Interesting. When I'm running off grid, my PWs are outputting a steady 59.99 Hz.

 

[barely]

What inverter do you have and do you know if it is set for Rule 21? In my area PG&E, you set a SolarEdge to USA34 (240V with neutral).

 

[wjgjr]

I can guaranteed it was not clouds. The sky was crystal clear on both days. Even with a few wispy clouds, a drop of 60%+ is not expect. You can see in the first graph that production seems to have a cap of just under 1.5kW. I checked some more of my data. During the course of the outage, the PWs were putting out 59.60 - 59.71Hz. I wondering if this was badly interacting with the Rule 21 settings in the SolarEdge.

View attachment 605215

I have seen the same behavior of 59.7 Hz frequency when the PWs were running the house off-grid. It did not seem to have any obvious impact on production, but I have a Delta Solivia inverter, so it may behave differently with that lower frequency.

 

[sorka]

I thought Rule 21 required inverters to operate with a larger range of frequencies?

 

[barely]

I'm trying to figure out from SolarEdge's documentation what its behavior is when down at 59.7. I checked my data from last year's PG&E outages. The PW kept a 60Hz baseline with spikes upwards to throttle the PV when the battery was near full. I have no idea why the PW went low frequency this year. Clearly there were changes in the PW/TEG firmware between then and now.

 

[barely]

I thought Rule 21 required inverters to operate with a larger range of frequencies?

It does, but from the SolarEdge docs, it looks like it added various "slow start" modes based on voltage and frequency.

 

[sorka]

My PWs better not ever go down to 59.7 hz as it will ruin my home automation powerline coms.

 

[Kodemonkey]

My PWs better not ever go down to 59.7 hz as it will ruin my home automation powerline coms.

What home automation system are you using? I have a mix of Insteon, zwave and zigbee.

 

[sorka]

What home automation system are you using? I have a mix of Insteon, zwave and zigbee.

I have over 200 Insteon devices about half of which are dual mode(powerline and wireless). When I tested filling up the PWs off grid, I was still able to get status from all but two but the time required to query statuses shot up ten fold.

 

[Kodemonkey]

I have over 200 Insteon devices about half of which are dual mode(powerline and wireless). When I tested filling up the PWs off grid, I was still able to get status from all but two but the time required to query statuses shot up ten fold.

All my insteon switches are dual band so maybe I will luck out. I have about 30 in my house, but I am slowly moving to Zwave. I have tried them all; insteon, ISY, homeseer (returned), vera, wink, Hue, smarthings, home assistant on RPi, and starting to play with Hubitat. We lost wifi and our Amazon Echo and the other cloud based hubs obviously went offline too. One of my kids asked how to turn the living room light on. Son, let me introduce you to something called a "light switch". They have been using Echo for so long he literally forgot - and he's in advanced math lol.

 

[gcsutton]