[morzh]

Addition:

A simplest way of timing voltages is using a small semiconductor rectifier, RC circuits and electromechanical relays or simistors. This way you can create an exact timing of what you want. Again, it is a whole lot of trouble for a result that is not very useful.

As for the voltage limiting, MOV will protect you from a surge, but they are not used for a very tight voltage limiting: what they do is limit the voltage to a safety acceptable level of the equipment behind it, such as 220V may be limited to, say, 600V as it is a short surge and the elements after it will likely withstand it.

Now if you want to address a serious lasting voltage deviations (not surges) in your MAINs, like in India where what they call 220V can be 340V (and I am dealing with a project addressing exactly that right now designing a power supply for that region) then for old tube equipment in the olden times we used ferroresonant stabilizers which I think could still be found. They limit the voltage deviation quite well