New modeling tool advances grid reliability

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-INTEGATE 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. The project was funded by the DOE Office of Electricity.

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.

UT-Battelle manages ORNL for the Department of Energy's Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

Learn more about related grid modeling research:

• New software provides advanced grid simulation capabilities
• ORNL demonstrates power of new modeling approach to understand faults in the modern electric grid