NEW ORLEANS -- Sunday's power outage that delayed part of the Super Bowl's second half for 34 minutes, darkened parts of the Superdome and silenced CBS announcers appeared to be caused by a failure of stadium equipment, Entergy New Orleans spokesman Philip Allison said.Power flowing into the Superdome did not stop before the lights failed, Allison said. Power in the area around the stadium never failed.He said the outage appeared to originate internally, occurring shortly after Beyonce's halftime show that featured extravagant lighting and video effects."All of our distribution and transmission feeds going into the Superdome were operating as expected," Allison said.CBS play-by-play announcer Jim Nantz and color man Phil Simms were off air for most of the 34 minutes after power was lost on the press box level. Host James Brown and CBS's pregame and halftime crews filled much of the time. Brown blamed a power surge.The NFL said stadium officials were investigating but had no immediate cause for the outage."We sincerely apologize for the incident," Superdome spokesman Eric Eagan said.Beyonce electrifiesIf naysayers still doubted Beyonce's singing talents, the singer proved she is an exceptional performer at the Super Bowl halftime show.Beyonce opened and closed her 13-minute set belting songs -- presumably live -- and danced with her usual confidence.She wore all black, singing part of her hit Love on Top amid a fire and light show before going into Crazy in Love.Later, Beyonce was joined by former Destiny's Child bandmates Kelly Rowland and Michelle Williams for Bootylicious.Before ending the set with Halo, Beyonce ripped off part of her shirt and skirt.BrieflyAn emotional pregame included a chorus from Sandy Hook Elementary School, site of the Dec. 14 shooting rampage in Newtown, Conn., performing America the Beautiful with singer Jennifer Hudson, whose mother, brother and nephew were shot to death five years ago.Cornerback Chris Johnson, a native of Gladewater who now resides in the Fort Worth area, was among the Ravens' seven inactive players on Sunday. Among the 49ers' seven inactives was former Texas A&M defensive tackle Tony Jerod-Eddie.