1-2 second home power loss: some circuits stay powered - computer doesn't turn off. How is this possible?
its related to the (internal energy storage) power supply of the computer that remains functioning.
A load of 20 watts and energy storage of 200 watt-seconds would (at best) allow 10 seconds of operation.
If the power line voltage were 10% higher, just before the dropout, you'd get an extra 20% time.
Energy storage in a capacitor is

energy = 0.5 * C * V^2

Thus 180 volts on the cap, and 500uF, stores 0.5 * 0.0005 * 180 * 180 == 8 watt seconds.