Yeah, I lived the wild voltage swings for a few years at the farm in Maimon until I finally installed my own posts and transformer.Got a little higher voltage problem were the inverters show incoming 135 from time to time and this triggers my UPSs to block the incoming. Now testing a 3500 voltage regulator before the inverter to keep voltage in the correct range and also protects the inverter at the same time.
Still in testing phase week, until now looks good, always something here in this country.
I don't think primary lines ever suffer voltage swings, they're either on or off.