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Master’s Student Works to Protect Grids from EMPs

Between August 28 and September 2, 1859, telegraph lines across the globe sputtered and surged. Conducting wires threw sparks, shocking operators and igniting a few fires. Many communication lines cut out entirely, while others were inoperable for hours after being disconnected from their batteries.

This disturbance, known as the Carrington Event, was caused by an enormous electromagnetic pulse (EMP), a sudden burst of electromagnetic energy. This EMP arose when a large amount of ejected solar mass interacted with the Earth’s magnetic field, but such pulses can occur after many types of extreme events, like lightning storms or hurricanes.

Or the detonation of an atomic bomb.

“High-altitude electromagnetic pulse (HEMP) is a byproduct of detonating nuclear weapons in the higher regions of the atmosphere,” said David Mignardot, a master’s candidate working with UT-Oak Ridge National Laboratory (ORNL) Governor’s Chair Yilu Liu. “Unfortunately, we don’t yet fully understand the threat of HEMP towards power system infrastructure.”

A large EMP in 2023 would threaten the operation of not only cell and internet access, but medical equipment, freshwater and sewer infrastructure, gas pumps, and even some vehicles near the source of the pulse. Damage to power stations would cause additional downstream failures.

David Mignardot

“An EMP induces electric and magnetic energy inside power generation facilities,” Mignardot explained. “If this induced energy is strong enough, it could couple onto equipment, leading to plant shutdowns and possibly even grid blackouts.”

While completing his mechanical engineering degree at New Mexico State University, Mignardot found himself drawn to electrical engineering as well. Inspired by the complexity, scale, and importance of the power grid, he studied power systems and decided to pursue a master’s degree in electrical engineering.

In his search for a graduate program, Mignardot was intrigued by UT’s Center for Ultra-Wide-Area Resilient Electric Energy Transmission Networks (CURENT), which is devoted to creating a reliable, unified US energy grid.

“Professor Liu was very responsive and welcoming when I reached out,” Mignardot recalled. “Her friendliness, along with CURENT and UT’s renowned power system program, made my decision to come to Knoxville easy.”

Once Mignardot arrived at UT, he began investigating factors that improve power plant resilience to EMPs.

Conducting experimental research on this problem is difficult. Radio frequency antenna systems could be used to generate continuous waves akin to an EMP, but utility companies are not eager to expose their power plants to high-powered electromagnetic radiation. HEMP tests would obviously be even less desirable, even if nuclear test detonations were not globally banned.

Instead, Mignardot is constructing and studying simulations of the problem.

“I have studied many variables relating to the radiation incidence parameters, structure design characteristics, and cable coupling,” he said. “These simulations allow me to investigate the interaction of plane wave electromagnetic radiation and building structures, providing insight towards the behavior of HEMP-power plant interactions.”

Mignardot’s simulations and analysis are bolstered with assistance from Liu and several researchers at ORNL, including Larry Markel, Ben McConnell, and DaHan Liao.

“My experience at UT has been phenomenal,” said Mignardot. “The amount I have learned in the past year and a half has truly surpassed my expectations. My collaborators in Professor Liu’s group, and at ORNL, are serving as subject matter experts, mentors, and guides for my research. Their influence and expertise have been invaluable.”

Mignardot is excited to become involved in more power system research, exploring the opportunities he has discovered while working with Liu and her colleagues at ORNL and CURENT.

He hopes his discoveries will keep blackouts like the Carrington Event in the past, ensuring that the grid stays on no matter what comes our way—lightning, a HEMP, or more mass spewing from the surface of our sun.

“The overall goal of my research is to increase energy security, which is a large component of national security,” he said. “Although a HEMP event will hopefully never occur, being prepared could determine the availability of energy to citizens across the globe during a crisis.”


Izzie Gall (865-974-7203,