Protecting the Power Grid

Larry Pileggi and his graduate students have developed a toolkit that could help model and simulate the power grid more reliably to better protect it from cybersecurity threats.

As a Carnegie Mellon University electrical and computer engineering professor, Pileggi has deep knowledge of working with semiconductors, integrated circuits and circuit simulation methods. But, it wasn't until recently that he started researching topics related to the power field.

Pileggi and his colleagues discovered the methods used to model integrated circuits were different from the methods used to model the power grid, so they found a way to simulate the grid by using techniques derived from the integrated circuit community.

Unlike other simulation approaches, which model the electric grid in terms of power flow and voltage, Pileggi's approach is founded on the equivalent circuit modeling framework, a framework that focuses on calculating power from the flow of current and voltage.

"It's a small distinction, but it's an important one," Pileggi said. "In the past, researchers have modeled the power grid by representing the flow of power directly and then analyzing the voltage from the flow of power. We were able come up with an approach that enables us to simulate the electric power grid in terms of currents and voltages."

Pileggi said the answer to simulating a system comprised of thousands or millions of elements lies within the integrated circuit community.

"Because of the research dollars that have been poured into the integrated circuit field for the past several decades, we're able to simulate the chips that are in all of our electronic gadgets in a very reliable way that provides the correct solution," he said. "Power systems haven't benefited from such robustness or ease of simulation, so what we did was come up with circuit simulation techniques for the power-system framework that are analogous to the simulation techniques that we use for integrated circuits. Now, we can simulate the grid and be assured that we get the right answer."

To get the right answer, Pileggi said researchers must have the means to simulate and model the power grid to track the flow of power. This will help them ensure the grid continues to operate reliably and securely. Such capabilities are critical to optimize the flow of electric power in the most efficient and cost effective manner possible.

"The electric power grid is structured so that we generate power based on what we're going to consume," Pileggi said. "When we wake up in the morning, the utilities have already decided how much power they're going to need for the day and where they're going to get it from — whether it's a nuclear plant in Massachusetts or a wind farm in Kansas. It's really important that utilities can simulate and model the grid so that they can do that kind of planning."

The power grid is one of the most critical infrastructures in the United States, constantly transmitting and distributing power to millions of people across the nation. Modeling and simulation techniques help ensure the efficiency of the U.S. power grid because they help to explain the flow of power and how different disruptions (like a tree crushing a power line) might affect the overall functionality of the grid.

Pileggi and his colleagues believe their simulation method could help protect the grid from potentially crippling disruptions like cybersecurity threats, while also enabling more renewable energy to be brought into the grid. Pileggi's research team is funded by a DARPA program called Rapid Attack Detection, Isolation and Characterization Systems (RADICS), a program that encourages researchers to design technologies capable of detecting and responding to attacks on critical U.S. infrastructure.

"There's always concern about hackers bringing down the grid," Pileggi said. "With funding from the RADICS program, we have the opportunity to develop better modeling and simulation techniques. Better modeling will help us to better represent the grid, which will allow us to better protect against security breaches like cyberattacks."

The research is documented in "Improving Power Flow Robustness via Circuit Simulation Methods," which received the Prize Paper Award in the Best Conference Papers Session on Power System Planning, Operation, and Electricity Markets at the 2017 IEEE Power and Energy Society General Meeting. The paper was written by Pileggi and his students, Amritanshu Pandey and Marko Jereminov, along with his ECE Adjunct Faculty Member Gabriela Hug.