High-temperature power transformers as a part of grid resilience
What we refer to broadly as the “national power grid” is in fact three joined systems: the Eastern, Western, and Texas interconnections. Taken as a whole, the system has 80,000 miles of extra-high voltage transmission lines, through which 90% of our electricity is funneled. The grid comprises more than 7,600 power stations, 20,000 large power transformers and nearly 160,000 miles of high voltage transmission lines, along with hundreds of thousands miles more of overhead and underground transmission lines. The system is operated by more than 3,000 utilities, and, given its complexity, does a remarkable job of distributing power.
But the grid also has its share of weaknesses. The equipment it uses varies widely in age, condition, and capacity, and expansion and upgrades are long overdue. In fact, more than 50% of the U.S. generating capacity is in plants that are at least 36 years old, and 70% of transmission lines and power transformers are 25-plus years old.
Every day across the United States, half a million people on average are impacted by power outages. These outages carry an estimated annual cost of at least $150 billion. And they’re on the rise: up 67% between 2011 and 2014. While roughly two-thirds of U.S. power outages are caused by severe weather such as lightning strikes, hurricanes and blizzards, fully 20% of sustained outages—defined as outages that last more than one minute—are attributable to failing electrical equipment. That’s troubling news, given that 70% of the power transformers in the U.S. are a quarter-century old or older, and well past their expected lifespans. As the equipment that delivers U.S. power continues to age, the number of lengthy outages will likely grow, and the consequences will grow more significant.
A federal priority
In response these threats, in February 2013 President Obama signed a Presidential Policy Directive on Critical Infrastructure Security and Resilience (PPD-21), which identified 16 critical infrastructure sectors, the national grid among them. The directive defined resilience as “the ability to prepare for and adapt to changing conditions and withstand and recover rapidly from disruptions.” It went on to say that resilience “includes the ability to withstand and recover from deliberate attacks, accidents, or naturally occurring threats or incidents.”
The following year, as a result of the president’s directive, the Federal Energy Regulatory Commission (FERC), took action to enhance grid resilience and ordered the creation of physical security standards.