Large Transformer Criticality, Threats, and Opportunities

Large power transformers (LPTs) represent a critical “tent‐pole” in national electric power grid, and national resiliency. They are essential to both the generation and transmission sectors of our electric power grid. They are known to be targets in adversaries' plans to debilitate our critical infrastructures. Their high cost and supply chain issues involving months to years of replacement times dictate the importance of survivability assurance. Transformer vulnerability and protection are addressed for physical attacks, cyber, and electromagnetic effects, including solar weather geomagnetic disturbance (GMD) and high altitude burst nuclear electromagnetic pulse (EMP) effects. Programs have been underway to improve transformer and transformer substation cyber and physical resiliency. Similar programs are lagging for electromagnetic threats. Transformer vulnerability to EMP remains a subject of conjecture since no large power transformer has undergone threat‐level EMP testing. Prevalent claims that LPTs are immune to EMP are premature. The Savannah River National Laboratory has developed a test program and designed a test bed to complete testing on LPTs including physical set‐up, injection sources, and measurement equipment to enable transformer testing under real load conditions without harming the larger power grid. The SNRL test bed will enable tests to determine both transformer vulnerability thresholds and the effectiveness of protection devices. A concerted national effort is needed to determine LPT vulnerabilities and to expeditiously develop and certify effective EMP and GMD protection approaches.