A malfunction in Florida's electrical cut caused sporadic power outages to nearly 3 million people in the state on Tuesday, and caused a nuclear plant to automatically shut down. The outages were mostly brief, and no threat was posed by the nuclear plant, authorities said. The problem, as yet unidentified, occurred in a substation near Miami and disabled two power distribution lines, Nuclear Regulatory Commission spokesman Kenneth Clark said. A Florida Power & Light spokesman initially said its nuclear plant caused the outages to about a fifth of Florida's population. But the utility's nuclear spokesman, Dick Winn, later said grid problems caused both reactors at the plant to shut down between 1 p.m. and 1:30 p.m. Power was already restored in some places by early afternoon and was estimated to be fully restored by 6 p.m. Miami-Dade County Mayor Carlos Alvarez said the outages were technical, not criminal. The Homeland Security Department said the outages had no connection to terrorism, and the Nuclear Regulatory Commission said the reactors automatically shut down as designed. An official at the Miami International Airport said the facility was working on a generator backup but that no airline delays were reported.