Even though the report “High-Impact, Low-Frequency Event Risk to the North American Bulk Power System” from the North American Electric Reliability Corporation (NERC) and the U.S. Department of Energy (DOE) was released in 2010, its content is still valuable in 2014 as the utility sector is well determined to strengthen its electric infrastructure against high-impact events. The NERC and DOE have given guidelines which are slowly being implemented.
All the quotes are from the report.The full report can be accessed here.
Do not miss our resources blog section to find other relevant reports from the electric utility industry: 
Definition
High-Impact, Low-Frequency (HILF) events are “coordinated cyber, physical […] attacks, […] nuclear weapon, and major natural disasters” such as hurricanes, earthquakes, tsunami, pandemics and geomagnetic disturbances.
Their frequency is extremely low, but they have an impact at the regional, national or international level. Power generation, transmission and distribution, as well as health, transportation and other key sectors can easily be paralyzed.
The U.S. Department of Energy and the North American Electric Reliability Corporation have made grid resiliency a priority, with a focus on large equipment, such as power transformers.
“Today, the government and industry must recommit themselves to supporting one another to enhance the protection, resiliency, and response capabilities for the North American bulk power system in the face of these rare events.”
Mitigating such risks requires balanced investments between protection of the facilities, restoration plans and resilience efforts, as well as simply raising utilities’, industry partners’ and end users’ awareness.
Common Characteristics
- Can occur very quickly with little warning;
- Cause widespread impact to the sector (human and/or physical);
- Originate from external sources outside of control;
- Limits the extent of proactive measure;
- Operational experience is still little.
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3 types of High-Impact Low-Frequency risks
- Coordinated Attack Risk such as cyber and/or physical attack: “The specific concern with respect to these threats is the targeting of multiple key nodes on the system that, if damaged, destroyed, or interrupted in a coordinated fashion, could bring the system outside the protection provided by traditional planning and operating criteria.” Thus the NERC has developed Critical Infrastructure Protection standards.
- Pandemic Risk: “The principal vulnerability with respect to a pandemic is the loss of staff critical to operating the electric power system.” The lack of qualified personnel would slow down operations and increase risks of failure. But the impact on the power supply is recognized as minor, as the resolution of this type of issues mainly relies on health authorities.
- Geomagnetic/Electromagnetic Disturbances: caused by the solar weather, they can affect the transmission lines and large transformers. Certain areas are more affected than others. (MAP) The 1989 blackout of Hydro Québec was due to such a electromagnetic disturbance. This event led to new operational procedures for utilities whose substations are located in areas at risk.
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Guidelines
The North American Electric Reliability Corporation and the U.S. Department of Energy have given guidelines to face such events:
| Coordinated Attack Risk |
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Pandemic Risk |
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Geomagnetic Disturbances, High Altitude Electromagnetic Pulse Events, Intentional Electromagnetic Interference Threats |
|
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Questions
This report brings up the following questions:
- How much risk is the private sector willing to accept?
- How much risk is the public sector willing to accept?
- How much are consumers (or society at large) willing to pay to reduce this risk?
- Who makes the determination for society’s tolerance for risk and the cost of employing protections?
- How should the costs of employing protections be paid for?
- How is damage measured: cost to replace damaged equipment, number of people-hours without power, number of other critical infrastructure nodes affected?
- Where are interdependencies most critical?
Go further
The following blog posts can help you learn more about critical equipment and grid resilience:
Transformers: An Essential Link of the Electrical Grid
Key points from “Economic Benefits of Increasing Electric Grid Resilience to Weather Outages”
9 Key Facts from the “Large Power Transformers and the U.S. Electric Grid” Study
Your Veracity Connect Newsletter – Volume 6
Learn more about our Critical Spares Management Solution for Utilities: 
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