In the event your voltage concentrations are unstable (ie: power stays on, but the particular voltage level differs a whole lot with the 220V normal), then I believe that's the kind of scenario wherever an AVR is useful. For giant power models, dynamic uninterruptible power materials (DUPS) are occasionally employed. https://riverzdcby.anchor-blog.com/14100199/the-smart-trick-of-uninterruptible-power-supply-pronunciation-that-nobody-is-discussing