Should your voltage stages are unstable (ie: power stays on, but the actual voltage amount may differ a great deal from the 220V standard), then I think that's the type of circumstance exactly where an AVR is useful. Though that is a good deal better than the output we are https://bodyguard50471.blogkoo.com/the-fact-about-ups-uninterruptible-power-supply-that-no-one-is-suggesting-53254859