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.

I agree with Darryl
A while back we were having similar problems with power drops. I measured the voltage, and it was down to 110.
We called FPL. They were very responsive, even assigning a customer rep.

First they changed the drop to the house from the pole to a higher gauge.
When the low voltage continued, they sent more techs over and installed a device on the panel to measure voltage over a few days.
When they looked at the graphs, it showed the voltage coming into the house was indeed fluctuating.

I was informed this had something to do with the substation, but didn't give me any real details.
A few days later, the voltage was at 120 and it has been steady since.

KP

ANSI C84.1 specifies that at your meter connection, you should get between 114-126VAC and 228-252VAC across the 2 phases. I'm not aware of any duration or continuity of service spec.

I'd (calmly) yell at your utility. Strongly request they put a recording meter on your service for at least 7 days. Strongly request they share the results with you, and rectify the situation. Tell 'em you got life-support equipment in the house (grin).