Home power line filter?

[Gytis]

Hi,
I would like to preface this question with a story of my troubles:

I have noticed that in the evening when I have my dimmable LED lights on, I notice a slight change in brightness (flicker). It's not really periodic, but consistent.
Almost all of my lights in my home are LED and dimmable, and all show the same behavior. Same with LED non-dimmable bulbs.

I didn't bother with the flicker until I noticed that when I am running my washing machine (which has a very clear periodic wash cycle which can simply be described as 1sec motor on, 1sec motor off, and repeat for 15 minutes) that I can see the wash motor pattern in the flickering.
This find lead me to believe that different power draws around my house may be causing the flicker. So I set up an experiment to see if the flicker wouldn't show up if I were to unplug as much as I thought was reasonable. I unplugged my wifi router, refrigerator, smart-home devices. And still I was seeing the occasional flickers.
Just today, I set up my scope in roll mode to view the AC voltage from one of my outlets. I see random and some periodic voltage drops (on the order of 2 to 6Vrms). I'm assuming this is somehow caused by neighbors? One of the more curious ones is a drop of approximately 3.5Vrms which lasts exactly 10 seconds, and occurs periodically with 200 to 400 second delays.

Before I get a chance to observe the supply this evening to see how low voltage drops must be to show observable flickers, I was wondering if anyone else has encountered such an issue, and is there a fix to it? I don't have solar, but would a solar battery help alleviate this issue? Or is there a filter for such cases? I'm assuming if the transition between higher/lower and lower/higher voltage wasn't so sudden, the flicker would be much less noticeable.

[Someone]

A filter alone won't fix this:
https://en.wikipedia.org/wiki/Electric_power_quality
http://www.powerlines.com/clips/pq2kdoc.pdf

... get better LED lamps (way cheaper than any other option)

[bob91343]

Don't waste your time trying to fix this.  Call the power company and complain.  They have the experience and the equipment to fix it.

[HB9EVI]

no way to fix that by yourself

I once had a server room in a new building in the middle of town; random outages and undervoltages occured over a long time, till some clever guy found out, that the connection to the grid was far too small dimensioned to cover the needs of the whole building; so they had quite some work to fix that, but afterward, everything was fine

[Psi]

You don't happen to live next door to photonic induction ?

[Gytis]

Sure enough during the evening, when I noticed a flicker, I would run back to my scope... there was like few hundred millisecond intervals where the voltage drops by about 5Vrms or so. I will continue monitoring tonight. I think if it persists, I will log it, and I will call up the electric co.

I am located in the U.S. so I think photonic induction could not be my neighbor :-)

@HB9EVI, did anyone have to pay for it, or did the electric company do that for free?

[HB9EVI]

it was obviously a mistake by the electric company about the necessary current rating of the interconnection between the house and the grid, so they had so fix; this is at least what I got to know at that time; but it was a long way to go, and for me, even with UPS many crashed servers and unhappy customers

In your place I'd get the electric company to install a long term measurement to evaluate voltage/current; they have those devices; it's not up to you to find the trick, if you can exclude malfunctioning hardware on your side

[David Hess]

Short of installing non-dimmable lamps or putting your lighting circuits on an online UPS, the only thing you can do it complain to the power company.  The variation in line voltage is caused by switching of heavy loads by you and your neighbors that are on the same distribution line.

[TimFox]

I posted some of my experience along similar lines in 2017:  https://www.eevblog.com/forum/projects/ac-line-fluctuations/msg1265692/#msg1265692
In a design for an audio preamplifier, I naively thought that I only had to worry about 60 and 120 Hz variations on the DC power supplies, so I did not stabilize them with appropriate voltage regulators.
However, since the subsections were internally DC-coupled, I found fluctuations on the signal lines that interfered with good oscilloscope measurements.  They were at surprising (to me) fast rates.
I had to change the design to include voltage regulation in order to get decent measurements, although the sub-audio voltage transients probably were not audible.