The Western electrical grid is in the midst of a major modernization using an old technology—the synchrophasor. The sci-fi sounding device can help smooth out the peaks and dips in renewable power and avoid regional blackouts.
Fueled by millions in smart grid stimulus funding, the 30-year-old technology is only now experiencing a major uptake, advocates say.
Synchrophasors are, technically, measurements of electricity waves; phasor measurement units, or PMUs, are the machines doing the measuring. Resembling desktop PC units, PMUs sit in electrical substations and record electricity flows on transmissions lines up to 120 times per second and report the results to grid control centers.
The belief is that deploying hundreds at a time would allow an electrical grid to absorb more intermittent power sources, like solar and wind, and keep the grid stable, by providing operators a more precise picture of grid conditions and early warning of problems that lead to blackouts.
Within a year and a half, 18 utilities and power authorities in 14 Western states and two Canadian provinces will deploy 300 units, more than double the current number in the United States. It will be North America’s single largest network of PMUs. The Salt Lake City-based Western Electricity Coordinating Council (WECC), which oversees the reliability of electricity transmission in areas of the Western States, Canada and Mexico, is organizing the effort.
A project like this has been a long time coming.
In 2003, electric utilities and grid operators first pushed for synchrophasor technologies—to no avail—after the Northeast blackout left around 45 million people in eight states and 10 million people in Ontario without power.
Experts say that had the Western region acted earlier to install PMUs, grid operators could have avoided the Sept. 8 blackout that began in Arizona and spread rapidly to California and parts of Mexico, cutting electricity to up to 5 million customers in the summer heat. California’s three biggest utilities—Pacific Gas & Electric, San Diego Gas & Electric and Southern California Edison—are all participating in the PMU rollout.
“One of the things that these PMU networks will help avoid is those kinds of blackouts,” said Jeff Taft, the chief smart grid architect for Cisco Systems, the world’s largest maker of computer networking equipment. The firm is helping WECC develop a vast communications network that will allow utilities to share their synchrophasor data in real time.
“The information produced by these sensors will help system operators see those conditions build up in advance of an actual event. We haven’t had that kind of visibility until now,” he said.
The WECC initiative, called the Western Interconnection Synchrophasor Program, or WISP, received $54 million in grants from the U.S. Department of Energy and $54 million in private funding from participating power companies.
It’s “the biggest such project in the United States … in terms of the ambitious nature of the applications that are being deployed,” said Alison Silverstein, project manager for the North American Synchrophasor Initiative (NASPI), an industry initiative for utilities, technology vendors and system operators to develop voluntary standards for synchrophasor technologies.
There are only about 250 PMUs dispersed throughout the Western and Eastern interconnections, the two major power grids in North America. To monitor electricity systems most grid operators use computer and data processors that collect and review measurements from key substations and generators every four to six seconds—a slow crawl by synchrophasor standards.
As more and more states require utilities to provide increasing amounts of clean electricity and make grid operations more efficient, speedier monitoring tools are needed, advocates say. “Part of easing the integration of renewables is being able to see what’s happening,” said Vickie Van Zandt, program manager of WISP.
Because of poor visibility, utilities have to leave spare room on the grid in the case of unforeseen spikes in demand or surges in renewable energy supplies, costing them money.
Generally they prefer easier-to-install PMUs than building out new infrastructure, such as transmission lines. According to Silverstein, each PMU costs about $20,000 to buy and $50,000 to fully install with communications links and physical security.
The Western Grid
Taft of Cisco said that a real-time picture of the power system will help Western utilities “speed up the integration of large-scale renewables into the grid.”
The Western grid accounts for one quarter of the nation’s electricity use but generates one-third of its renewable power. Half of that came from California alone in 2010, according to U.S. Energy Information Administration statistics.
Wind and solar power cannot be dispatched at will like coal-fired or nuclear generation, which produce power 24-7. That unpredictability makes it difficult for system operators to know when clean power can deliver.
“We need a lot more ability to see what’s happening than we did in the past, so that [operators] can properly coordinate the variable energy sources with the dispatchable ones,” said Taft.
Silverstein noted that the Western grid is better suited for a PMU rollout of this scale than the Eastern system. The West has a handful of grid operators and dozens of utility companies that channel electricity from remotely located power plants along far-reaching transmission lines.
By contrast, the Eastern grid, which encompasses nearly three-fourths of the United States, has many more grid operators and hundreds of power companies that light up densely populated areas with thousands of power plants and transmission lines. The Eastern grid is so large and diverse that region-wide coordination is more complex and costly than in the West, Silverstein said.
How It Will Work
Western grid operators, however, will have to rely on more than just PMUs to improve visibility across the electricity system.
So this summer WISP awarded a five-year contract to Melbourne, Fla.-based Harris Corporation, a global information technology firm, which in turn partnered with Cisco Systems for the project. The team will build a telecommunications network that can instantly gather figures from the data concentrators and send the information at high speeds across the Western network for processing and analysis.
The measurements will continuously flow to 60 local data concentrators owned by participating members. From there they will stream to two of the WECC’s large data centers in Vancouver, Wash., and Loveland, Colo.
“Every single control room will see the same information at the same second,” said Silverstein.
She noted that while the advantages of PMUs are widely recognized, adoption levels stayed relatively flat until 2010, when the Obama administration targeted the technology with $300 million in stimulus grants from a $4.5 billion pool of smart grid funding.
Taft of Cisco said that PMUs perform a function similar to residential smart meters, but on the electricity distribution side. Smart meters attach to the wall of a home and monitor how a household consumes energy. Synchrophasor technologies, which most consumers will never see, monitor how a power plant transmits energy supplied from power plants.
“The smart grid is about improving observability,” he said. “[PMUs] are not as visible to consumers, but they still have a big impact on them.”
Silverstein optimistically predicted that the increasing use of synchrophasors will be “like the growth of Facebook.
“When all of a sudden everybody gets on it, it becomes better known and more valuable and more desirable overnight,” she said, adding that 550 new and upgraded PMUs from additional projects could be installed across the United States and Canada within three years.
“We are finally reaching the point … in this technology where it is turning into a real network. There are enough players who are going to be collecting data and sharing it that we can learn something from it.”
While the full promise of synchrophasor technology is not yet known, Silverstein said that the power industry, especially WISP participants, “are certain that this technology investment will make the Western grid more reliable, lower some operating costs and improve [utilities’] ability to use growing levels of clean, low-cost wind and solar generation.”