Program Sisko 197 was a special computer command designed to sabotage and disable all major systems on Deep Space 9. In late 2373, shortly before the Dominion War began, Captain Benjamin Sisko prepared this program when it appeared likely that the station would be captured by Dominion forces. The program manifested it's function as numerous visible large electrical discharges surging across equipment.
Major Kira Nerys activated the program after Starfleet was forced to abandon the station following the Second Battle of Deep Space 9. The program rendered the station a lifeless hulk and made it almost useless to the Dominion until repairs were made. (DS9: "Call to Arms")