"Possible damage to large power transformers was found to be minimal."
The Electric Power Research Institute (EPRI) released findings from its three-year study of potential impacts of high-altitude electromagnetic pulses (EMP) on the electric transmission system, along with options to mitigate those impacts.
The report includes results from extensive laboratory testing and analysis of potential EMP impacts on the electric transmission system.
The key findings are that transmission electronic equipment damage or disruption can result from induced voltage surges in connecting cables, as well as by direct exposure to the initial pulse, and that digital protective relays were generally resilient to direct exposure to the initial pulse but were found to be vulnerable to the surges induced on control and communication cables.
The research indicated that initial pulse impacts could be mitigated through various options including shielded cables with proper grounding; low-voltage surge protection devices and/or filters; use of fiber optics-based communications; enhanced electromagnetic shielding of electric substation control houses; and grounding and bonding enhancements.
The research also showed that the combined effects of the initial and late pulses could trigger a regional service interruption but would not trigger a nationwide grid failure.
Possible damage to large power transformers was found to be minimal.
The report is EPRI’s most significant collaborative research in this area to date, with funding and active support from more than 60 U.S. utilities, and collaboration with the Defense Threat Reduction Agency, the U.S. Department of Energy (including the three nuclear weapons laboratories), and the Electricity Subsector Coordinating Council (ESCC).
“This groundbreaking research greatly enhances our understanding of the potential impacts EMPs could have on our national energy grid,” said Thomas A. Fanning, chairman, president and CEO of Southern Company and co-chair of the ESCC. “In the interest of national security, protecting the grid and preserving our American way of life, the ESCC and the electric power industry will use these findings to continue our work with the federal government to develop the optimal strategies to prepare for, and respond to, security threats.”
Source: EPRI