Physical Security of the U.S. Power Grid: High-Voltage Transformer Substations [June 17, 2014]   [open pdf - 528KB]

"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. For more than 10 years, the electric utility industry and government agencies have engaged in a number of initiatives to secure HV transformers from physical attack and to improve recovery in the event of a successful attack. These initiatives include coordination and information sharing, spare equipment programs, security standards, grid security exercises, and other measures. There has been some level of physical security investment and an increasing refinement of voluntary grid security practices across the electric power sector for at least the last 15 years. Several major transmission owners have recently announced significant new initiatives specifically to improve the physical security of critical transformer substations in light of the Metcalf attack."

Report Number:
CRS Report for Congress, R43604
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