Covering half of North America, the U.S. electric grid functions somewhat like a vast, complex organism. Researchers at the Department of Energy’s Oak Ridge National Laboratory have developed a new simulation platform for understanding and predicting the behavior of this modern grid. Using a combination of mathematical tools, automation and analysis, the approach provides highly accurate results with less computing time at a lower cost, increasing the reliability of electricity.

Simulation uses mathematical approaches to reproduce the dynamics of a real-world system. This allows utilities and planners to analyze grid management methods without any risk to safety, equipment or electrical service. ORNL researchers refined a cutting-edge grid modeling approach called Electromagnetic Transient simulation (EMT), which is especially effective for analyzing the split-second reactions of modern power electronics. This capability helps operators prevent cascading blackouts and unsafe operating conditions in modern electric grids brimming with power electronics.

“We are trying to understand electronics and systems in a way that mimics their real behavior with higher fidelity,” said ORNL researcher Phani Marthi. “The challenge today is that high-fidelity EMT simulation is extremely time-consuming to simulate large-scale modern power grid systems.”

The ORNL simulation approach is tackling those challenges, as Marthi and his co-authors explained in a paper that was presented in the best paper session at the July general meeting of the IEEE Power and Energy Society.

Representing the next phase of ORNL’s national leadership in EMT simulation, the ORNL tool is called RE-INTEGRATE for its enhanced speed and accuracy at simulating large-scale power systems that integrate many power electronics.

In the past, the grid relied on the natural momentum of huge rotating mechanical machines and power flowing in a single direction along established paths, like a locomotive on a track. But today, power electronics make the grid respond more like a sports car, with rapid electronic adjustments instead of built-in momentum. Unfortunately, today’s grid is not fully ready for that speed. RE-INTEGRATE helps utilities map the best route for the grid of the future.

Power electronics accommodate generating and moving electricity in different ways. They can also enable both alternating and direct current in long-distance power transmission. This could expand the capacity of the U.S. grid to support a growing population and economy, including new industries such as data centers for AI and cryptocurrency.

Unlike existing EMT models, RE-INTEGRATE is intended as an open-source platform that incorporates features such as numerical simulation techniques, automation and intelligence based on neural networks that function more like the brain for faster computation. These features offer unique advantages over existing tools in analyzing modern grids.

Eventually, the tool will be able to replicate faults—disruptions in the power grid caused by equipment failure, short circuits, or other technical issues—like the one that wiped out power to much of Spain and Portugal in April. “Analysis with the RE-INTEGRATE tool can give us new insights into how to consistently prevent or stop cascading blackouts and brownouts,” Marthi said.

One of the fundamental building blocks of RE-INTEGRATE is differential algebraic equation solvers. These algorithms reduce the degree of manual processing required for an immense volume of data. As a proof of concept, ORNL researchers validated the effectiveness of these solvers on simple power electronics circuits.

The long-term goal is honing the software to simulate all possible circumstances that could arise from fast-acting power electronics systems interacting with grid components in a large-scale power grid, equivalent to the grid of the eastern United States.

This will broaden the accuracy benefits of EMT while enabling greater understanding of how the parts of the broader grid affect each other across service areas and regions.

“Beyond accelerating the EMT simulation, the next major challenge lies in managing and sifting through the huge volumes of data generated by EMT simulations,” Marthi said. ORNL researchers are already developing advanced analysis techniques, including the use of specialized neural networks, so that the RE-INTEGRATE tool can enhance power system operations and support informed decision-making. “We want to create an entire EMT ecosystem with RE-INTEGRATE as the backbone, including all these capabilities so utilities use it more often and with more confidence.”

Researchers who contributed to the development of automation and solvers for RE-INTEGRATE include ORNL researchers Jongchan Choi and Suman Debnath with support from student Soumyajit Gangopadhyay and intern Kuan-Chieh Hsu.

RE-INTEGRATE advances will be presented during an EMT simulation workshop at ORNL, co-hosted by the North American Electric Reliability Corporation Oct. 7-9 in Knoxville, Tennessee.

Compare Our Top Picks

More Sound Machines We Like

Yogasleep Rohm+ Travel White Noise Machine for $50: This is a more refined, adult sound machine option that looks significantly more chic than your standard sound machine (if that matters to you, that is). The timer and white noise options are solid, but for the price and audio quality, Momcozy’s portable option runs circles around the Rohm+.

Baby Brezza Sleep and Soother for $25: This is super light, can run on batteries or be plugged in, and has 18 sleep sounds and three timer options (or it plays continuously). There’s also a night light with three brightness levels. —Medea Giordano

Yogasleep Hushh 2 Portable Sound Machine for $30: The Hushh 2 is another great portable sound machine that you should consider. It has six sounds, three timer options, and a nice night light for softly illuminating your bedside table or guiding your way to the bathroom. The brand says this model is its most durable sound machine. I didn’t fling it down the stairs, but it has held up to falling off my nightstand. —Medea Giordano

Lectrofan Evo for $60: Another solid option from the brand that makes our top pick. The Evo has a few more sound choices (like ocean noises) and looks nicer, but we prefer the buttons on the Classic. They’re better for fiddling with in the dark. This one also jumped in price recently. —Medea Giordano

Dreamegg D1 for $60: This one plays a lot of the same sounds as the D11 portable machine, with a handful more fans and a spectrum of noises. The control panel is matte and soft to the touch, and you can set it to play continuously or for 30, 60, or 90 minutes. I tried the white version, but you can get a few other nice colors on the Dreamegg site. The rim also lights up. —Medea Giordano

Encalife Sound Machine for $46: This little sound machine has a blue light that you can match your breathing to in order to relax. You’ll also likely find it on sale often, which is good because I wouldn’t spend too much on it—there are better options on this list for less. —Medea Giordano

Sound Machines to Avoid

Allway Aqua10 for $120: I love that this looks like a cute Marshall amp and works as a decent-sounding Bluetooth speaker for sleep sounds and anything else you want to listen to the rest of the day. You need the Allway app to access the sounds, which include crackling fires, busy cafes, a spectrum of colored noises, and a wide selection of instrumentals. They’ll play for anywhere from five to 120 minutes. The Aqua10 also has a humidifier function, which looks extremely cool paired with lights that illuminate the vapor like a fire. But I found it to be fussy and leaky, and it seemed to stop even though the reservoir was full. It’s no longer available on Amazon, which might say something about its longevity. —Medea Giordano

Frequently Asked Questions

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From texting on a smart phone to ordering train tickets at a kiosk, touch screens are ubiquitous and, in most cases, relatively reliable. But for people who are blind or visually impaired and use electronic braille devices, the technology can be vulnerable to the elements, easily broken or clogged by dirt, and difficult to repair.

By combining the design principles and materials of soft robotics with microscale combustions, Cornell researchers have now created a high-resolution electronic tactile display that is more robust than other haptic braille systems and can operate in messy, unpredictable environments.

The technology also has potential applications in teleoperation, automation and could bring more tactile experiences to virtual reality.

The research is published in Science Robotics. The paper’s co-first authors are Ronald Heisser, Ph.D. ’23 and postdoctoral researcher Khoi Ly.

“The central premise of this work is two-fold: using energy stored in fluid to reduce the complexity of mass transport, and then thermal control of pressure to remove the requirements of complex valving,” said Rob Shepherd, the John F. Carr Professor of Mechanical Engineering in Cornell Engineering and the paper’s senior author.

“Very small amounts of combustible fuel allow us to create high-pressure actuation for tactile feedback wherever we like using small fluid channels, and cooling the gas during the reaction means this pressure stays localized and does not create pressure where we do not want it,” he said. “This chemical and thermal approach to tactile feedback solves the long-standing “Holy Braille’ challenge.”

The majority of refreshable electronic tactile displays contain dozens of tiny, intricate components in a single braille cell, which has six raised dots. Considering that a page of braille can hold upwards of 6,000 dots, that adds up to a lot of moving parts, all at risk of being jostled or damaged. Also, most refreshable displays only have a single line of braille, with a maximum of roughly 40 characters, which can be extremely limiting for readers, according to Heisser.

“Now people want to have multi-line displays so you can show pictures, or if you want to edit a spreadsheet or write computer code and read it back in braille,” he said.

Rather than relying on electromechanical systems—such as motors, hydraulics or tethered pumps—to power their tactile displays, Shepherd’s Organic Robotics Lab has taken a more explosive approach: micro combustion. In 2021, they unveiled a system in which liquid metal electrodes caused a spark to ignite a microscale volume of premixed methane and oxygen. The rapid combustion forced a haptic array of densely packed, 3-millimeter-wide actuators to cause molded silicone membrane dots—their form determined by a magnetic latching system—to pop up.

For the new iteration, the researchers created a 10-by-10-dot array of 2-millimeter-wide soft actuators, which are eversible—i.e., able to be turned inside out. When triggered by a mini combustion of oxygen and butane, the dots pop up in 0.24 milliseconds and remain fixed in place by virtue of their domed shape until a vacuum sucks them down. The untethered system maintains the elegance of soft robotics, Heisser said, resulting in something that is less bulky, less expensive and more resilient—”far beyond what typical braille displays are like.”

“We opted to have this rubber format where we’re molding separate components together, but because we’re kind of molding it all in one go and adhering everything, you have sheets of rubber,” said Heisser, currently a postdoctoral researcher at the Massachusetts Institute of Technology. “So now, instead of having 1,000 moving parts, we just have a few parts, and these parts aren’t sliding against each other. They’re integrated in this way that makes it simpler from a manufacturing and use standpoint.”

The silicone sheets would be replaceable, extending the lifespan of the device, and could be scaled up to include a larger number of braille characters while still being relatively portable. The hermetically sealed design also keeps out dirt and troublesome liquids.

“From a maintenance standpoint, if you want to give someone the ability to read braille in a public setting, like a museum or restaurant or sports game, we think this sort of display would be much more appropriate, more reliable,” Heisser said. “So someone spills beer on the braille display, is it going to survive? We think, in our case, yes, you can just wipe it down.”

This type of technology has numerous medical and industrial applications in which the sense of touch is important, from mimicking muscle to providing high-resolution haptic feedback during surgery or from automated machines, in addition to increasing accessibility and literacy for people who are blind or visually impaired.

“As technologies become more and more digitized, as we rely more and more on computer access, human-computer interaction becomes essential,” Heisser said. “Reading braille is equivalent to literacy. The workaround has been screen-reading technologies that allow you to interact with the computer, but don’t encourage your cognitive fluency.”