power interuption

I'm not sure if it is the best device, but the backup power supplies for personal computers work well. They are a little pricey, depending on how many you need, but are great for intermittent short breaks in power.

For example,

http://logicbox.zoovy.com/category/upsbatterybackupunits/

I would complain to your Electric company. Unless its just a problem due to a bad {hot} summer, that is unacceptable

I can't determine from your question if you actually want to keep the system *running* during those line-dropouts, or are you simply concerned with transient protection? In order to maintain constant system operation then yes you'll need a small UPS, but NOT the computer-type; those do not output clean undistorted sinewaves so they are potentially damaging to audio gear & would likely be very noisy as well.

I would be more concerned about protecting the equipment from electrical damage during these glitches. This is readily accomplished by installing an AC line conditioner which includes a line-transient protection feature, as many of them do. Products from Chang Lightspeed or Audio Magic both have this type of protection, as do many others. Monster offers several home-theater grade units that will also do the job.