Friday, February 08, 2013

Super Bowl blackout was caused by electrical relay

San Francisco Chronicle 8 February 2013 by Kevin McGill

The power failure cut lights to about half of the stadium, halting play and interrupting the nation's most-watched sporting event for 34 minutes.

The company that supplied electricity to the Super Bowl says the blackout that halted the big game was caused by a device it installed specially to prevent a power failure.

But the utility stopped short of taking all the blame and said Friday that it was looking into whether the electrical relay at fault had a design flaw or a manufacturing defect.

The relay had been installed as part of a project begun in 2011 to upgrade the electrical system serving the Superdome in anticipation of the championship game. The equipment was supposed to guard against problems in the cable that links the power grid with lines that go into the stadium.

"The purpose of it was to provide a newer, more advanced type of protection for the Superdome," Dennis Dawsey, an executive with Entergy Corp., told members of the City Council. Entergy is the parent company of Entergy New Orleans, the city's main electric utility.

"If higher settings had been applied, the equipment would not have disconnected the power," said Michael J.S. Edmonds, vice president of strategic solutions for S&C.

In a follow-up statement, Entergy said that tests conducted by S&C and Entergy on the two relays at the Superdome showed that one worked as expected, the other did not.

Shabab Mehraeen, an assistant professor of electrical engineering at Louisiana State University, said relays are common electrical fixtures in businesses and massive facilities such as the Superdome.

"They are designed to keep a problem they sense from becoming something bigger, like a fire or catastrophic event," he said.

"It's not unusual for them to have problems," Mehraeen said. "They can be unpredictable, despite national testing standards recommended by manufacturers."

It was reported that that the power being drawn at the time of the failure was only two-thirds of capacity.

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