Grid outage. Odd behavior?

[daniel]

Yesterday evening after dark I was watching a streaming show on the internet. Suddenly the dim fluorescent lights in the tv room started to flicker wildly, and then went dark. I don't recall if the tv went dark when the flickering started or when the lights went dark. After maybe ten seconds (not sure at all) all the power came back on, but I had no internet. The local neighborhood remained dark. I tried connecting to the internet again a short while later. I was connected to my wi-fi, but there was no connectivity.

My A/C does not have soft-start so maybe if it tried to start it could have caused the flickering. But the internet outage seemed to coincide exactly with the flickering, and what are the chances the A/C tried to start just at the moment the grid and internet went down? My system is supposed to switch over so quickly that if the A/C were running it would not even notice the grid going down. And anyway, I don't think it was running because when I went to shut it off at the thermostat it was off at the moment.

I'm wondering why the flickering, since the system is supposed to switch so quickly.

I'm also really happy that I have the Powerwalls. I couldn't watch the end of the show or go on-line, but after ten seconds of dark I had power when all my neighbors' houses were dark. This morning my Powerwalls are at 60% which is normal or a bit higher than normal pre-dawn, since the outage shut off my A/C an hour or two earlier than I'd have shut it off normally. Ceiling fans are not as good as A/C but my neighbors would not have had even that. Thank you Tesla. But I'm still wondering about the flickering.

 

[arnolddeleon]

The powerwalls are not UPS. My experience is it can take several seconds for the system to recognize grid down, open the gateway (isolate the system) and the inverters to kick in if the system was not already outputting power. If the system was already putting out power the transition is quick and can be invisible to most devices. You should be able to check your app for backup history.

I suspect the flickering was the grid going down. The powerwalls also can run at a higher frequency when there is no grid and that can affect some devices.

 

[daniel]

The powerwalls are not UPS. My experience is it can take several seconds for the system to recognize grid down, open the gateway (isolate the system) and the inverters to kick in if the system was not already outputting power. If the system was already putting out power the transition is quick and can be invisible to most devices. You should be able to check your app for backup history.

I suspect the flickering was the grid going down. The powerwalls also can run at a higher frequency when there is no grid and that can affect some devices.

It was after sunset, so my house was being run entirely from my Powerwalls. I use grid power only for load balancing. So while a tiny bit of power might have been coming from the grid, at least 99% of my power usage, and more likely 100%, was coming from the Powerwalls when the grid went down.

 

[wwhitney]

But as the grid goes down it may not be an instantaneous drop to zero grid voltage. If there is a brown-out period first, for some of that time the Powerwall inverter will follow the grid voltage, until the Gateway decides to disconnect and the inverter goes into island mode.

Cheers, Wayne

 

[daniel]

But as the grid goes down it may not be an instantaneous drop to zero grid voltage. If there is a brown-out period first, for some of that time the Powerwall inverter will follow the grid voltage, until the Gateway decides to disconnect and the inverter goes into island mode.

Cheers, Wayne

That makes sense. And yet there was a period of maybe ten seconds (maybe 15?) without power to the house at all. The last power outage I remember, my lights never even flickered and the computer didn't even blink.

I guess the system isn't perfect. No biggie. I was just curious, as it seemed to be an anomaly. Power outages without Powerwall are no fun. I once lived through a 4-day outage in a blizzard in North Dakota. And no running water as that required electricity!

 

[Sylvia Else]

The powerwalls also can run at a higher frequency when there is no grid and that can affect some devices.

I was rather surprised to see that my microwave oven's time of day clock ran fast when we had an extended (more than 24 hour) outage. I had thought the practice of using the main's frequency as a timebase was long abandoned, but apparently not completely.

 

[Sylvia Else]

I tried connecting to the internet again a short while later. I was connected to my wi-fi, but there was no connectivity.

My extended outage also took out my Internet access, which was annoying because it is meant to have battery backup. I find it convenient to have a broadband Internet SIM for a prepaid service. Even when I have no credit (which is almost always, given how I use it), I can still use it to access the billing system for the ISP, and add some credit so that I can use it for Internet access. Connect the phone to the PC with a USB cable, and enable tethering on the phone, and I'm all set.

 

[bob_p]

We received PTO on our new solar/PW system last week and are waiting to complete our acceptance testing with an "off grid" test, verifying everything works as expected when losing grid power, operating without any power from the grid, and then returning to grid power.

We want to make sure the transition is smooth (except for the brief milleseconds to seconds transition between on grid-off grid operation) and that all of our processor-based devices and UPS systems work correctly when operating off grid.

This was part of the acceptance testing we specified with out installer - if there is an issue, we want to detect it now (while the installer has us as a high priority) and not discover it later when we are counting on the system to work.

Unfortunately the wiring configuration doesn't include a breaker between the Tesla Backup Gateway and the grid power, so the only way for us to go "off grid" for testing requires an electrician manually disconnecting the cables; if there had been a breaker for the grid power, we would have done this test already.

Wonder if Tesla could add an option to the Gateway controls to disconnect the grid, solar panels and PowerWalls (individually) in the Gateway, and allow this level of testing & diagnostics to be done using only the gateway controls...

 

[daniel]

Unfortunately the wiring configuration doesn't include a breaker between the Tesla Backup Gateway and the grid power, so the only way for us to go "off grid" for testing requires an electrician manually disconnecting the cables; if there had been a breaker for the grid power, we would have done this test already.

I'm surprised. I have a shut-off switch that allows me to cut off grid power to the whole house. I believe it's a legal requirement here. Testing off-grid operation is a simple matter of throwing a big switch. This test is a routine procedure for my installer.

I've got Solar Edge panels, a Tesla gateway, and Powerwalls. I have no idea if individual elements can be disconnected from each other, but the main power switches outside let me disconnect the grid or the solar panels or both.

I was rather surprised to see that my microwave oven's time of day clock ran fast when we had an extended (more than 24 hour) outage. I had thought the practice of using the main's frequency as a timebase was long abandoned, but apparently not completely.

I think my system works the same way, but I've not yet had a power outage long enough for me to notice a discrepancy on the M/W clock. I think that is the only clock in my home that's even plugged into the electrical system. All my other clocks are independent of the electrical frequency.

 

[KY-Lonewolf]

Unfortunately the wiring configuration doesn't include a breaker between the Tesla Backup Gateway and the grid power, so the only way for us to go "off grid" for testing requires an electrician manually disconnecting the cables; if there had been a breaker for the grid power, we would have done this test already.

Did you open the door to the backup gateway panel and look for a breaker inside?

 

[SRO-Sean]

Daniel,

May not be the same issue, but we experienced similar behavior (low voltage issues) after a series of long grid outages (3+ days).

Our current install is Powerwalls only. No solar. No whole house generator. The day after Christmas after heavy snow, the grid went down for more than 19 hours. When SCE ‘restored’ the grid, it was in a degraded state (we measured 88v at the main breaker). The gateway wont use the grid that far out of tolerance (+/- 5% according to a Powerwall support rep), so it kept us on battery almost a whole day more until the battery dropped below 10%. At that point, it simply shut us down.

We currently only have a portable generator, so we did a bunch of running around, getting gas, etc. for the next two days. Meanwhile, the grid went up and down a number of times. On several occasions, we had alternating partial power then normal power (seemingly 88v from the grid, then 120v from the Powerwall). This would last somewhere from 5 to 15 minutes, then the gateway would shut down again.

In our cause, it appeared the gateway was going in and out of some kind of maintenance mode where it opened the grid connection and used the degraded grid power just long enough to keep the batteries charged. It's also possible the grid was temporarily reaching normal condition and the gateway was reacting to that. During those periods, it was feeding the house with the same 88v grid power. At some point, the house would start to run off battery again (probably the gateway doing diagnostics/maintenance), then shut us down again a few minutes later.

Being well below freezing most of the time and the Powerwall unable to use 88v, it was a frustrating three days. To their credit, both Edison and Tesla managed to take my after hours calls and entertain my theories, so that was appreciated.

In the end, this was all on Socal Edison. Way out on a limb, I think the surge of 'upgrades' they've been doing in reaction to their equipment starting wildfires may have weakened the grid in some way (at least our local infrastructure). I don't recall seeing these kinds of brownout conditions here in 30 years and definitely not in the last two years we've had Powerwalls.

 

[daniel]

I made a point of looking again at all the stuff on the side of my house: There is a box with an exterior shut-off lever for each of the two solar panel arrays (main house and cottage), and there is a shut-off switch (with a circuit breaker I think) by each of the two electric meters. (The house and cottage have completely separate systems.) So the solar and the grid feed separately into the gateways, and either can be shut off.

The only thing I actually know about any of it is that I really like getting all my energy for the house and the car from the sun. And I'm really privileged to live where this is so easy to do.

 

[Dan123]

Yesterday evening after dark I was watching a streaming show on the internet. Suddenly the dim fluorescent lights in the tv room started to flicker wildly, and then went dark. I don't recall if the tv went dark when the flickering started or when the lights went dark. After maybe ten seconds (not sure at all) all the power came back on, but I had no internet. The local neighborhood remained dark. I tried connecting to the internet again a short while later. I was connected to my wi-fi, but there was no connectivity.

My A/C does not have soft-start so maybe if it tried to start it could have caused the flickering. But the internet outage seemed to coincide exactly with the flickering, and what are the chances the A/C tried to start just at the moment the grid and internet went down? My system is supposed to switch over so quickly that if the A/C were running it would not even notice the grid going down. And anyway, I don't think it was running because when I went to shut it off at the thermostat it was off at the moment.

I'm wondering why the flickering, since the system is supposed to switch so quickly.

I'm also really happy that I have the Powerwalls. I couldn't watch the end of the show or go on-line, but after ten seconds of dark I had power when all my neighbors' houses were dark. This morning my Powerwalls are at 60% which is normal or a bit higher than normal pre-dawn, since the outage shut off my A/C an hour or two earlier than I'd have shut it off normally. Ceiling fans are not as good as A/C but my neighbors would not have had even that. Thank you Tesla. But I'm still wondering about the flickering.

The flickering and the lights off was because the Powerwall raised the electrical frequency. It does it when it is nearly full to prevent the solar panels from producing more energy. When the frequency is high, many things, like newer lights and AC compressors, will not work.

The internet did not work because probably the power was cut off for the internet switch somewhere outside of your house.

 

[bob_p]

There is a breaker in the Backup Gateway panel - but that controls the Backup Gateway and power to the two house panels that are connected to the gateway - it doesn't disconnect just the grid power.

 

[wwhitney]

There is a breaker in the Backup Gateway panel - but that controls the Backup Gateway and power to the two house panels that are connected to the gateway - it doesn't disconnect just the grid power.

My understanding of the wiring of the (optional) breaker in the Backup Gateway is that it is directly on the line side of the disconnect relay. So turning it off would precisely just disconnect grid power downstream.

The original design purpose of this breaker was to be the service disconnect, when the Backup Gateway is installed between a standalone meter and the previous service disconnect. In this configuration turning off the Backup Gateway's internal breaker would disconnect everything from the grid, but other configurations are possible.

Cheers, Wayne

 

[daniel]

The flickering and the lights off was because the Powerwall raised the electrical frequency. It does it when it is nearly full to prevent the solar panels from producing more energy. When the frequency is high, many things, like newer lights and AC compressors, will not work.

The internet did not work because probably the power was cut off for the internet switch somewhere outside of your house.

Okay. But it was already dark outside so the house (including A/C) had been getting its power from the Powerwall for an hour or two, and should not have been so full as to cause it to raise the line frequency.

It never occurred to me that the cable (internet) would have a local switch that would shut off service when the local grid went down. I imagined the internet would go down only if the local node went down. But I can see that this is possible.

Nothing like this happened (the flickering and the loss of power for several seconds) that last time I was at home during a power failure. On that occasion I didn't even know anything had happened. But I don't remember if I was on the internet at the time.

There is a breaker in the Backup Gateway panel - but that controls the Backup Gateway and power to the two house panels that are connected to the gateway - it doesn't disconnect just the grid power.

Don't you have a breaker right at the service meter? I'm sure that's required by law here.

 

[jboy210]

The powerwalls are not UPS. My experience is it can take several seconds for the system to recognize grid down, open the gateway (isolate the system) and the inverters to kick in if the system was not already outputting power. If the system was already putting out power the transition is quick and can be invisible to most devices. You should be able to check your app for backup history.

I suspect the flickering was the grid going down. The powerwalls also can run at a higher frequency when there is no grid and that can affect some devices.

That is why I am still keeping UPS units on my computers and network gear. No matter how fast they are I know that our Powerwalls will never react quick enough to ensure computers or networks do not go offline. The UPSes saw us through the PG&E shutoffs until they ran out of battery and they we had no choice but to gracefully power down our systems and network.

 

[Patrick66]

Sounds like a typical power outage starting with utility instability; sometimes the router will take up to 3 minutes to complete boot. You really need a UPS for the electronics, even if the PowerWall is supposed to be fast enough.

 

[daniel]

Sounds like a typical power outage starting with utility instability; sometimes the router will take up to 3 minutes to complete boot. You really need a UPS for the electronics, even if the PowerWall is supposed to be fast enough.

My internet remained down long after the router had rebooted. Quite a bit later when I tried to get on-line, I was connected and logged into the router but there was no internet.

My computer and printer are plugged into surge protectors and I have a whole-house surge protector as well. But I don't really need a USP because nothing I do is that important. I might lose a chat-board post or the last minute or two of an email I was writing (gmail automatically saves frequently). Or as happened a movie was interrupted. No biggie. Back in the old days losing power to a computer was a sh!t show, but my iMac doesn't seem to suffer and Chrome will even re-open the same tabs if I want it to.

 

[jboy210]

My internet remained down long after the router had rebooted. Quite a bit later when I tried to get on-line, I was connected and logged into the router but there was no internet.

My computer and printer are plugged into surge protectors and I have a whole-house surge protector as well. But I don't really need a USP because nothing I do is that important. I might lose a chat-board post or the last minute or two of an email I was writing (gmail automatically saves frequently). Or as happened a movie was interrupted. No biggie. Back in the old days losing power to a computer was a sh!t show, but my iMac doesn't seem to suffer and Chrome will even re-open the same tabs if I want it to.

If the power was out in a wide area it is likely some of your ISPs equipment upstream was down.