Which stabilizer to buy if you need an exact voltage range?

Question

Iron

Good afternoon, there are two UPSs on the servers.
They are configured so that if the voltage drops below 202, then they switch to high voltage mode at the expense of batteries.
The problem is that our voltage jumps from 216 to 190 all the time and the UPS is constantly switching and clicking all the time. I read somewhere that this is very bad for the UPS.
Therefore, I decided to buy a voltage stabilizer IEK 1.5 kVA. I didn't bother much, because I don't understand them at all.
The instructions say that the stabilizer maintains an output voltage level of 220 with an accuracy of 8%.
The protection is triggered at 188+-4.
So I can’t understand if 220 is written with an accuracy of 8%, then should it not fall below 202?
By means of the UPS, I monitor the voltage in the network. (Every two seconds the current voltage is written to the log).
And in fact, the voltage still drops below the declared 202 volts, and the UPS continues to click, but it seems less often.
Either I misunderstand the accuracy parameter, or the declared stabilizer characteristic is incorrect.
Are there any stabilizers that are able to keep a constant voltage in the range of 208? It is clear that if the voltage drops too much, then the stabilizer needs some time to operate, but if the voltage does not drop much, but simply jumps within 190-216?

Answer 1

I didn't bother much, because I don't understand them at all.

You seem to understand uninterruptible power supplies in the same way as stabilizers.
If they only click, but do not squeak, then everything is fine, uninterruptibles do not switch to battery operation. They themselves act as a stabilizer. No other additional stabilizer is needed.
You most likely have LineInteractive UPSs.
For a more substantive conversation - the "surnames" of UPS'ov in the studio!

Answer 2

You need at least the simplest relay stabilizer in your country house to adjust the voltage. BUT, before buying, it is advisable to measure the incoming voltage in the network for several days. From the results obtained, the operating frequency range of the voltage stabilizer you need will already be clear . My wife and I bought these devices back in 2015 in VoTO and they still serve. At least, no freezing or burning of the relay contacts has yet been noticed ... Whatever you say, it’s better not to save on our power grids, because there is a proverb: “the miser pays twice”, and in our country it usually climbs sideways. That is why I have models with a margin at home - single-phase 5000 VA SLRs (details of the characteristics below)