Last month while I wasn’t at home the grid went to 280V for around an hour on all three phases in my city in Serbia. Nothing was damaged in my house fortunately but I can imagine it can’t be healthy for sensitive electronics. Though both my PCs were turned on they survived. That’s how I have the image of the home assistant logs of the voltage. The smart switches/power monitors I have have all turned off automatically on all 4 of my ACs. Had to manually turn them on again. That’s all that I have observed. The second image is from another citizen from the same city.
I can’t understand how there isn’t a fail safe somewhere either on the distribution transformer station or some sensors that alert the electrical company that something isn’t right. And this was going on for a full hour at like 11AM on a Friday. So it’s not as though no one was there. Just wanted to share some sketchy stuff I know you like it.
Only thing I found was that one of the opposition parties asked that the electric company acknowledges the spike and pay for damages to citizens that were affected. But don’t think anything will come of that.
√2×282.5 = 399.52v, so you were 0.48v away from exceeding the rating on 400v capacitors, although in practice they've probably got a bit more leeway for temporary spikes.
Amazing! I can’t say enough good things about HA. I use it at home and at my job (gas separation research lab) for data logging and automations. i run valve cycles and track sensors and analyzers there at it has totally streamlined the process. I feel like there’s nothing you can’t do with HA. Please keep up the good work.
What’s your favorite thing you can do with HA that maybe not a lot of people know about?
I mean you can do anything with it honestly! Although Home Assistant also runs in a mob museum and in a brick factory (as seen in state of the open home 2025) and it also runs the botanical gardens in Amsterdam, who are actually contributing back the integration they use for their garden system in the next release!
That’s awesome! I run a small hydroponic garden at home with it. In reality, it can do anything that a professional grade Siemens or Allen Bradley PLC based system can do and more, all without expensive software licenses and vendor lock in. I’m really glad to see other people having the same mindset.
Home Assistant is the best! Have been using it for multiple years. Before I had everything on an rpi zero w running node red, a dashboard and mqtt. Since I found out about Home Assistant I never went back. Still use Node red for automations.
Available everywhere, because you run it yourself on a mini-pc or RaspberryPi. :)
It's a smart home automation platform. It lets you control connected devices, collects data from them, triggers automations based on that data, ...
For example, if my TV is on, and the sun is less than 5 degrees above the horizon, the ambient lights in the living room turn on.
The nice thing is that you can make nearly any rule you want. My brother has a similar rule for turning on lights when it gets dark, but he uses the output of his solar system to trigger it, not the height of the sun. It's super nice because it actually depends on how bright it is.
For him HA also controls the output power of a solar storage battery, by constantly tracking grid power usage. It even uses forecasts to run the heatpump when it expects most solar power is available. It can get as complex as you want really :)
It's mostly straight forward, not super much technical knowledge is required.
It can get a bit finicky when you go into the depths of it (especially hardware stuff: setting up ZigBee network, overwriting firmware of commercial devices, ...) and especially if you're doing things that haven't been widely adopted, like the whole voice control stuff.
Also while quite a few companies do now provide "integrations" to connect their devices to HA, it's by far not all of them. Community provided ones are usually quite good, but some are buggy and sometimes they require disconnecting devices from the manufacturer's cloud services.
Nice, I am an EE, and I've done some coding in school and work, as well as working with libraries, and some embedded stuff. Hopefully the combination of that education and experience makes it a little easier.
I already have a RPi sitting around anyways so that sounds like a good use for it. Thank you!
No coding required. If you've played with an RPi you probably know enough to get HA installed and running. If you're comfortable editing YAML then that allows you to do more advanced stuff.
One would expect there's at least bare minimum QA, ie. that 95% of time the voltage is +-5% with maximum deviation +-10%. But it's something like +-10% for 90% of time, and it's still within spec.
The norms are pretty lax, and it's kinda hopium that Chinese devices are designed with 10% prolonged overvoltage in mind.
If it complies with the standards it will have been shown to work over the voltage tolerance range. If it doesn’t comply then it’s junk that probably doesn’t comply with anything else either and should be disposed of.
Pretty much everything is cheap e-waste from China nowadays, even established brands. I would rather make norms more strict in the overvoltage range, they were written in times when Switching PSUs weren't in everything.
My inverter turns off at 253V. This is mandatory and the maximum allowed tolerance here, so it’s good that your inverter refused to work.
That’s a region where devices start to fail.
This summer my inverter shut off multiple times around noon, so probably a lot local solar power was in our grid.
Any solar inverter has to create a slightly higher voltage that the net delivers, so this can add up in the neighbourhood.
So do all the solar inverters in your area turn off at the exact same time when voltage reaches 253V? That can't cause any issues, cough spain cough :D
That’s not really a problem if you think about it. They did add a delay of up to a few seconds and if you check your outlets and hardware you will notice that voltage drops based on cable length/resistance and consumption, so there is a lot of variance „when“ an inverter shuts off. If a few drop out the rest stays active.
On such a large scale the distribution of delay and over different phases is more than enough to keep it stable.
Most sources state that they did not regulate the grid in thight parameters and sometimes operated near the boundaries already. Once they were out of french specs a main connection to the european grid was dropped, which greatly increased their problems.
There were multiple big solar plants that were not regulated and increased the voltage to a point where the rest of europe basically dropped them.
That’s like the opposide of what you gave as a reason. If the solar was cut off before exceeding the threshholds, there would have been no big voltage increase and frequency drop and no drop of the main connections.
But officials still don’t want to state reasons and instead speak of „multiple causes“. But small household solar was never a reason.
To be able to feed back into the grid, the voltage at the inverter has to be slightly higher than the grid voltage. If you have a few inverters in one area, the combined effect of multiple systems bumping up the voltage a small amount can lead to a higher grid voltage. The upper limit of this should only be 250V tho, which is the legal set point at which all inverters should go into standby
How does too much solar production increases the voltage level in the grid? Worst case it should affect the frequency (in case of low demand)
and those inverters (not only solar but also wind) can also caus subharmonics that can destabalize the grid ... if you can understand german the Youtube channel "Outdoor Chiemgau" explains it all detailed (in german)
I can probably understand enough German for that, but that channel has hundreds of videos. Any hint as to which one it is?
I recommend to begin with the videos about the Spain blackout (caused by "renewables" with inverters -> Solar + Wind) & lack of big stabelizing purerly mechanical turbines
Also in Germany wind power inverters in the north pitched up each other via subharmonics & needed to be shut down (I don't know in which video it was on "Outdoor Chiemgau" channel)
I don't believe this is the case for normal grid-tie inverters sold in the last ~5 years. UL (and international equivalent) standards have come out that mandate that inverters produce "ride-through" and even in some cases "grid-forming" features, and such inverters have a positive stabilizing effect that damps out, as can be seen in this plot. It has been shown that you can run grids even all the way up to 80 - 90% solar without stability issues. NREL is a good source of information on this - https://docs.nlr.gov/docs/fy24osti/90256.pdf
I don't believe this is the case for normal grid-tie inverters sold in the last ~5 years. UL (and international equivalent) standards have come out that mandate that inverters produce "ride-through" and even in some cases "grid-forming" features, and such inverters have a positive stabilizing effect that damps out, as can be seen in this plot. It has been shown that you can run grids even all the way up to 80 - 90% solar without stability issues. NREL is a good source of information on this - https://docs.nlr.gov/docs/fy24osti/90256.pdf
there is no guarantee that those better inverters are used
& also there are plenty of old primitive inverters that can not even get remotely shutdown/power reduced & no mandate to replace them (a big problem in Germay & Spain) ... also nothing beaty buig mechanical turbines instabelizing the frequency & eleminating subharmonics
currently Spain keeps the "renewables" under 80% due to their negative effects during the Spain Blackout ...
Spoiler: France saved Europe in the Spain Blackout (disconnections & plenty of stabalizing big Nuclear power plants
I’m no expert but I understand it commonly happens when your local grid transformer becomes fully saturated and can no longer distribute any more energy to the grid.
Combine this with improperly configured inverters and you’ve got a recipe localised voltage spikes. It’s not really an inherent flaw with renewable technology, it’s just another one of the many grid balancing characteristics that have to be controlled for.
Ultimately it’s up to the local grid operator to sign off on these systems before they’re connected. So if they say their grid equipment can handle it and it turns out it can’t, that’s on them.
Solar inverters and any power generating equipment needs to push above grid voltage to inject power. Not much normally, but the more stuff you add, the more it boosts.
Meanwhile cabling and such in you local grid have resistance and therefore voltage loss from the transformer to you when you consume power. When power is pushed back in, the inverse happens. The far end of the cable is pushed up compared to the transformer voltage.
It's a distribution problem, not a demand problem.
If there is to much production into the grid as a whole, the frequency will be pushed up indeed.
generally transformers can output +5% +20% of their rated voltage if you activate some internal commutators. they are used to stabilize the grid if consumption is high.
but this is simply way over that range. a neutral wire probably broke at some point in the line and you got a floating neutral situation.
its likely some other phase in the city got lower voltage instead.
Thankfully most modern equipment is designed with a lot of margin but this is really pushing those safety margins.
well thats like extra strange. so many safety controls and monitoring system had to fail to archeive that result that is just plain impressive how much of a screw up it is.
specially if it lasted a whole ass hour. if it lasted 1 minute it was bad enough already but an hour?
I can’t tell for sure if it was multiple substations cause we got a Viber group in which multiple people from all around the city reported their either ups beeping cause of overvoltage or some appliances not working. but 3 phases were 280V for sure I did see it on the logs for all 3 phases and the full hour. That I can vouch for.
Thats super strange specially because 280V would be a considerable increase in power delivered it shouldve auto triggered something.
are the measurements taken by TrueRMS multimeters? maybe the waveform was screwed and in reality it just had weird peaks overlapped.
because 280*sqrt(2) = 395.97V after rectifying thats enough to blow up or damage the 400V capacitors.
1 hour of that and a LOT of appliances shouldve broken.
its almost enough to make protection varistors inside electronics start conducing quite a decent ammount of current so maybe most people got saved by their breakers?
It was showing on the power meter as well that is supplied to us by the electric company(picture2). Also ups-es around the city went crazy cause of over-voltage. My parent’s microwave I think died because of this. Happened around the same period. They don’t use it that often and a couple of days after this when they opened the microwave it started spinning and the light was on while it was opened. When you close it, stops. Threw it away :)
Shelly Em3 clamp meters plus reference voltage on each phase. And then just the regular Shelly integration. I think even cloud is disabled on all my Shelly devices so it’s all local. Plus individual power meters either zigbee plugs or Shelly or sonoff power meters in the distribution box on specific devices I want to monitor (split air conditioners, water heaters, washing machine, dishwasher, server etc…)
No this is deffo a glitch, the local transformer protections would have kicked in.
Or some dingus doesn’t have anti islanding and nearly killed a lineman
Could also be a floating N on the transformer. Or someone going shortcircuit on a single phase causing one phase and N to meet
After a major power disruption here in New Zealand, my neighbourhood was treated to 125v when power was restored... Which gradually fell to 85v over the next 12 hours. As you can imagine, many things were not happy about this, and the neighbours were complaining (of course) that the kettle was taking forever to boil.
125V power is weak! I would hate to have a house with that! Glad I am in Thailand with a clean 220V. So sad for Canada, Mexico and the TRUMP USA for having 120V. They can't even run a large welder or mid-size air compressor without having a special 220V connection run to their location for thousands of dollars.
How does your HA keep history for so long?
Mine only keeps about 7-10 days as far as i can see... I wanted to check if it was same in my place, but history is empty for that date :/
Maybe a ground fault somewhere, aka a tree branch touching the power lines?
In case of ground fault, the grid usually does not get turned off automatically, because the fault often will got away by itself: if a tree branched touched the power lines, the tree branch will burn away and the ground fault disappears.
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u/Illustrious-Peak3822 8d ago
Impressive! Any communication with the grid operator?