Right-Sizing the Grid Could Reduce Blackout Risk, According to New Analysis in the Journal "Chaos"
Some 90 years ago, British polymath J.B.S. Haldane proposed that for every animal there is an optimal size -- one which allows it to make best use of its environment and the physical laws that govern its activities, whether hiding, hunting, hoofing or hibernating. Today, three researchers are asking whether there is a "right" size for another type of huge beast: the U.S. power grid.
B.A. Carreras/BACV Solutions
The overall operational "Risk" as a function of the system size (N), showing a decrease at first as the system becomes more efficient with size followed by an increase as the risk of large failures starts to dominate. The optimal size is then the minimum point in the curve.
David Newman, a physicist at the University of Alaska, believes that smaller grids would reduce the likelihood of severe outages, such as the 2003 Northeast blackout that cut power to 50 million people in the United States and Canada for up to two days.
Newman and co-authors Benjamin Carreras, of BACV Solutions in Oak Ridge, Tenn., and Ian Dobson of Iowa State University make their case in the journal Chaos, which is produced by AIP Publishing.
Their investigation began 20 years ago, when Newman and Carreras were studying why stable fusion plasmas turned unstable so quickly. They modeled the problem by comparing the plasma to a sandpile.
"Sandpiles are stable until you get to a certain height. Then you add one more grain and the whole thing starts to avalanche. This is because the pile's grains are already close to the critical angle where they will start rolling down the pile. All it takes is one grain to trigger a cascade," he explained.
While discussing a blackout, Newman and Carreras realized that their sandpile model might help explain grid behavior.
The Structure of the U.S. Power Grid
North America has three power grids, interconnected systems that transmit electricity from hundreds of power plants to millions of consumers. Each grid is huge, because the more power plants and power lines in a grid, the better it can even out local variations in the supply and demand or respond if some part of the grid goes down.
On the other hand, large grids are vulnerable to the rare but significant possibility of a grid-wide blackout like the one in 2003.
"The problem is that grids run close to the edge of their capacity because of economic pressures. Electric companies want to maximize profits, so they don't invest in more equipment than they need," Newman said.
On a hot days, when everyone's air conditioners are on, the grid runs near capacity. If a tree branch knocks down a power line, the grid is usually resilient enough to distribute extra power and make up the difference. But if the grid is already near its critical point and has no extra capacity, there is a small but significant chance that it can collapse like a sandpile.
This is vulnerable to cascading events comes from the fact that the grid's complexity evolved over time. It reflects the tension between economic pressures and government regulations to ensure reliability.
"Over time, the grid evolved in ways that are not pre-engineered," Newman said.
Backup Power Versus Blackout Risk
In their new paper, the researchers ask whether the grid has an optimal size, one large enough to share power efficiently but small enough to prevent enormous blackouts.
The team based its analysis on the Western United States grid, which has more than 16,000 nodes. Nodes include generators, substations, and transformers (which convert high-voltage electricity into low-voltage power for homes and business).
The model started by comparing one 1,000-bus grid with ten 100-bus networks. It then assessed how well the grids shared electricity in response to virtual outages.
"We found that for the best tradeoff between providing backup power and blackout risk, the optimal size was 500 to 700 nodes," Newman said.
Though grid wide blackouts are highly unlikely, they can dominate costs. They are very expensive and take longer to get things back under control. They also require more crews and resources, so utilities can help one another as they do in smaller blackouts.
In smaller grids, the blackouts are smaller and easier to fix because utilities can call for help from surrounding regions. Overall, small grid blackouts have a lower cost to society,” Newman said.
The researchers believe their insights into sizing might apply to other complex, evolved networks like the Internet and financial markets.
"If we reduce the number of connected pieces, maybe we can reduce the societal cost of failures," Newman added.
The article, “Does size matter?” by B. A. Carreras, D. E. Newman, Ian Dobson appears in Chaos: An Interdisciplinary Journal of Nonlinear Science (DOI: 10.1063/1.4868393). It will be published online on April 8, 2014. After that date, it may be accessed at: http://scitation.aip.org/content/aip/journal/chaos/24/2/10.1063/1.4868393
ABOUT THE JOURNAL
Chaos: An Interdisciplinary Journal of Nonlinear Science is devoted to increasing the understanding of nonlinear phenomena and describing the manifestations in a manner comprehensible to researchers from a broad spectrum of disciplines. See: http://chaos.aip.org/
Jason Socrates Bardi | newswise
Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa
Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy