Physical Security of the U.S. Power Grid: High-Voltage Transformer Substations

• Published in: Policy File 2014
• Main Author: Parfomak, Paul W
• Format: Report
• Language: English
• Subjects: Energy; Federation of American Scientists; National security

In the United States, the electric power grid consists of over 200,000 miles of high-voltage transmission lines interspersed with hundreds of large electric power transformers. High voltage (HV) transformer units make up less than 3% of transformers in U.S. power substations, but they carry 60%-70% of the nation's electricity. Because they serve as vital nodes and carry bulk volumes of electricity, HV transformers are critical elements of the nation's electric power grid. HV transformers are also the most vulnerable to intentional damage from malicious acts. Recent security exercises, together with a 2013 physical attack on transformers in Metcalf, CA, have focused congressional interest on the physical security of HV transformers. They have also prompted new grid security initiatives by utilities and federal regulators. Legislative proposals, notably the Grid Reliability and Infrastructure Defense Act (H.R. 4298 and S. 2158), would expand these efforts by strengthening federal authority to secure the U.S. grid. As the electric power industry and federal agencies continue their efforts to improve the physical security of critical HV transformer substations, Congress may consider several key issues as part of its oversight of the sector: identifying critical transformers, confidentiality of critical transformer information, adequacy of HV transformer protection, quality of federal threat information, and recovery from HV transformer attacks.