If it's happened twice, I suppose you can expect it a third time!! And I completely understand your worries. I often contemplate what ifs and how my animals will cope.
Just off the top of my head as I write this, but may an inverter with a change over switch and an external power supply be more suitable for your concerns?
If an excessive current, or cut to supply be detected, it should be able to alternate between the most appropriate power supply based on your requirements!
Obviously going to be more expensive, but may offer a greater peace of mind.
But also, I could be talking total horse waddle as this has literally just popped into my brain and it may not be plausible. But my initial thought is mains supply to trip switch, to change over switch to inverter.