The Metroplex's Secret Power Hub

By JACK Z. SMITH
|  Saturday, Dec 5, 2009  |  Updated 11:30 AM CDT
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The Metroplex's Secret Power Hub

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In one location in North Texas, uninterrupted power is never taken for granted.

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People take electricity for granted -- until the lights fail to come on in the morning or there's no air conditioning on a scorching July afternoon.

But in one location in North Texas, uninterrupted power is never taken for granted.

That's Oncor Electric Delivery's Transmission Grid Management Center, tucked away in a remote Metroplex location that company officials don't want publicly divulged for security reasons. It's the nerve center for the biggest electric transmission and distribution system in Texas --Oncor's 14,000 miles of transmission lines, 102,000 miles of distribution lines, and 1,000 switching stations and substations. The system serves most of North Texas as well as large chunks of East, West and Central Texas.

The center is staffed with certified, highly experienced controllers and supervisors, 24/7, year-round. A remote backup facility 30 miles away can take over if the center is disabled, said Michael Quinn, Oncor's director of transmission system operations. Oncor recently allowed a Star-Telegram reporter and photographer to tour the center provided they not disclose the location.

The center's most-striking feature is an 86-foot-long wall filled with video screens in a large control room that monitors everything from Oncor's maze of power lines to weather reports warning of impending high winds, thunderstorms or lightning that could cause power outages in the company's far-flung service territory, which Quinn dubs its "electrical footprint."

The center even monitors national news networks. When 9/11 occurred, the Oncor center undertook "some very specific activities" to help ensure the safety and reliability of its transmission system, Quinn said without elaboration.

The control-room video board "is not Jerry World-big, but it's pretty big," Quinn joked in reference to the monstrous video board in Cowboys Stadium, commissioned by team owner Jerry Jones.

The center monitors not only its bigger transmission lines -- 345, 138 and 69 kilovolts -- but also the smaller 25 and 13 kilovolt distribution lines typically serving residential neighborhoods.

"Every transmission line, every substation, everything we have electrically, these folks can see remotely and have it represented on their computer screens," Quinn said of the 24 controllers, who average 26 years' experience with Oncor. The six shift supervisors average 28 years.

Because electricity cannot be stored -- and because usage levels vary greatly -- providing power requires a continual balancing of supply and demand. That means that the center is constantly communicating with everyone from company field personnel to the staff of the Electric Reliability Council of Texas, which manages the power grid serving most of Texas.

Pointing to one screen, Quinn said, "The green tells me that is a 345 kilovolt transmission line; the blue tells me it's a 138 kilovolt" line. In the event of an outage somewhere, "we get both an audible alarm in here as well as a color change on our screens, so we know that something has changed." The center will then coordinate with field personnel to begin restoring power at the trouble spot.

One monitoring device, dubbed the pizza wheel because of its circular shape, includes a color-coded pie chart showing how much surplus power is available in the ERCOT system at any given time.

Shortly before noon on a Wednesday when the Star-Telegram visited the center, the wheel showed 3,400 surplus megawatts available, a level in the green zone: no cause for alarm. But if the surplus dips below 2,250 megawatts, the wheel notifies the control room with an Energy Emergency Alert in red.

Rain rarely threatens Oncor's transmission system, but lightning is "really challenging," Quinn said. Some of Texas' 345 kilovolt lines are potentially vulnerable because they are strung along steel towers that might be 100 feet high.

"Typically, especially out west, we're the tallest thing in the air, and lightning likes to hit the tall things," Quinn said. "The higher the voltage, the taller the line."

"From this facility, we have the ability to track lightning," he said.

"So we know when a storm is incredibly intense, especially with lightning ... and know when we're more subject to have issues."

He said Oncor attempts to make its system as efficient as possible by sending the most power it can through lines without overloading them. A sagging power line can indicate problems, he said.

"It's actually the sag you're concerned about as transmission lines heat up. ... The more energy that goes through them, the more they sag," Quinn said.

Failing to adequately monitor lines and electricity flows can have painful consequences, as illustrated by the massive 2003 power blackout that cut off electricity to 50 million people in eight states and part of Canada.

A three-month investigation by a U.S.-Canada task force concluded that the blackout began with three power-line failures in Ohio and that it should have been contained by operators at Akron-based FirstEnergy Corp. The utility was also faulted for failing to adequately trim trees along power lines, which the task force said contributed to the blackout.

Oncor's system makes up 37 percent of the huge grid managed by ERCOT, which must coordinate electricity flows between utilities' transmission and distribution systems.

During times of heavy power demand, congestion can occur on transmission lines. Utilities might then have to draw more power from little-used generating units with higher operating costs, raising the wholesale price of electricity. That can result in higher retail costs for consumers.

Oncor is continually expanding its system to accommodate population growth. It's already spent $90 million this year on a $1.3 billion project, scheduled for completion in 2012, to build 345-kilovolt lines in state-designated Competitive Renewable Energy Zone areas that will transport power from expanding West Texas wind farms to population centers such as Dallas-Fort Worth. Oncor plans $3.6 billion in capital expenditures on projects from 2008 through 2012, company spokeswoman Carol Peters said.

As the number of plug-in hybrid and totally electric vehicles grows, the West Texas wind power generated at night can be used by consumers to recharge their vehicles at home.

"To make electric vehicles really viable and economical, they need to charge off-peak at night to take advantage of the abundant wind power that will be available," Peters said.

Regardless of where the power comes from and when it is generated, the Oncor grid center will need to maintain a smooth flow of electricity and help restore it promptly during outages, Quinn said in an interview in a center office.

"Energy -- electricity -- is just expected," he said.

"It's like when I walked in this room. I just knew the lights would come on because I hit the switch. And to the extent it's not available, it's like, wow, this is really problematic."

Every transmission line, every substation, everything we have electrically, these folks can see remotely and have it represented on their computer screens."

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