When storms attack, Smart Grid could reduce outages, speed recovery
It’s been a bad 12 months for electric utilities and the customers who depend on them. Hurricane Irene in August 2011 knocked out power to more than 4 million homes and businesses in the eastern United States, some for more than a week, and two months later a freak October snow storm left 3 million customers without power in the Northeast.
And last month a suddenly notorious type of storm — the fast-moving derecho — cut power to 5 million customers across six states from the Midwest to the Mid Atlantic. Some customers in the Washington, D.C., stayed without power for a week during the area’s hottest stretch of weather on record.
Forecasters predict that global climate change will make severe weather events more common, but a nationwide program to develop an intelligent power grid could help ease the pain of extended outages.
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“There are a number of ways Smart Grid technology would help,” said George Arnold of the National Institute of Standards and Technology.
At the distribution level, smart meter technology for customers can provide better visibility of the problems to utilities. At the transmission level, sensors can help identify unstable conditions in high-voltage transmission lines so that cascading failures can be avoided.
And the ability to handle two-way power flow will enable microgrids to generate power locally for campuses or neighborhoods, giving a degree of independence from the larger grid.
The improvements might not be apparent to those who sweltered without power through triple-digit temperatures last week, but the technology has begun making its way into power systems and homes.
“It will be a decades-long process,” said Arnold, who is the national coordinator for Smart Grid interoperability for NIST. “But we have a very significant start.”
The electric grid is a backbone of the nation’s critical infrastructure, providing the power the rest of the systems need to operate. With the current program of updating the grid with automated networking technology, there is a growing concern about the possibility of cyber attacks on this infrastructure. But most cyberattacks against the grid are unlikely to produce effects worse than those already produced by Mother Nature.
“The sorts of cyber attacks that are easy to do would simply trigger breakers, causing only brief outages,” said Scott Borg, director of the U.S. Cyber Consequences Unit, an independent research institute. “These would be less destructive than many storm outages.”
Attacks against the physical components at the core of the grid — the generators, large transformers and cross-country transmission lines — would be much more destructive but also more difficult to carry out.
“Highly sophisticated cyberattacks, prepared by considerable numbers of highly skilled experts, could cause damage that would make the worst storm damage seem trivial,” Borg said. “This is because such attacks could physically destroy large quantities of large, hard-to-replace equipment. The consequences of this could be almost unbelievably bad.”
Borg said utilities actually respond well to power outages caused by weather. They have plenty of experience, and the components being repaired and replaced are relatively easy to work with.
“What gets damaged by storms are mainly local distribution lines, local relays, and smaller transformers,” he said. “When storms cause lots of people to lose power for longer periods, this is usually because lots of things have been damaged in lots of locations.”
But even in these cases, power usually is restored to most homes and business within four days, Borg said. “Outages of three-and-a-half days or less are inconvenient and dangerous in extreme temperatures, but they normally cause remarkably little economic damage.”
One of the challenges of widespread outage that last for a week or more is simply identifying the scope and location of the problems, Arnold said. Today, utilities rely on customer reports to identify outages. “In most cases, they don’t know when people are without power,” he said.
At the distribution level, where most storm damage occurs, smart meters could provide this information. “They can more rapidly get a picture of where the damage is without spending a day driving around,” Arnold said. “They could be much more effective in dispatching crews.”
If the grid is enabled to handle two-way power flow, local generating sources could be used to help supply power to microgrids. These local generators could supply local customers, and feed excess power into the grid when demand is low. If the grid is damaged, the local generators could help take care of local demand.
“It wouldn’t necessarily provide all of the power needed all of the time,” Arnold said, but local generators could be more economical than static back-up generators that are used only during emergencies.
In the transmission system, phasor measurement units can provide a more granular way to measure and manage loads, so that problems can be spotted and dealt with before a cascading failure causes a widespread blackout.
The Energy Department has made $4.5 billion available through the Smart Grid Investment Grant program, part of the American Recovery and Reinvestment Act. Under the program, more than 11 million smart meters have been installed, a little more than 7 percent of the customer meters in the country, and 313 phasor measurement units have been installed out of a projected 800. Also, 5,741 automated feeder switches and 13,697 substation monitors have been installed.
While this deployment is under way, NIST is spearheading the job of developing technical standards for the new infrastructure. In February it released version two of its Framework and Roadmap for Smart Grid Interoperability Standards, and later this year will update its Guidelines for Smart Grid Cyber Security.
Also later this year, the government and industry Smart Grid Interoperability Panel, which has helped develop the guidelines, will be relaunched as a government-funded non-profit organization.