If the voltage degrees are unstable (ie: power stays on, but the particular voltage level differs a great deal in the 220V typical), then I think that's the type of situation wherever an AVR is useful. For big power models, dynamic uninterruptible power materials (DUPS) are sometimes applied. A synchronous https://damien9y24j.alltdesign.com/the-basic-principles-of-ups-uninterrupted-power-supply-53049640