GREENVILLE, S.C. -- Nearly 17,000 people in northern Greenville County woke up without electricity on Thursday morning.

Traffic lights were darkened in the Travelers Rest area during the outage, leading to some confusion at busy intersections during the morning commute.

Oby Lyles, spokesman for Greenville County Schools, said that Slater-Marietta Elementary School, Mountain View Elementary School and Tigerville Elementary School were all without power on Thursday morning. He said that the schools are still open. He said that power was expected to be restored by 10 a.m.

Duke Energy's Web site reported that the majority of customers without power were in the Travelers Rest area and the Slater-Marietta area.

A spokesperson for Blue Ridge Electric Cooperative said that about 12,000 of its customers were without power, as well. The representative said that one of Duke Energy's transmission lines went down, causing all of the outages.

Duke Energy said crews are still searching for the source of the blackout.