Resilient and Self-healing Grid

Extreme weather and other natural disasters can threaten lives, disable communities, and devastate electric utilities’ generation, transmission, and distribution systems. The majority of outages result from damage to the millions of miles of distribution lines. Utilities and their crews have continued to improve disaster response, focusing on upgraded equipment, advanced communications, rapid deployment of staged resources from their own and other utilities, and the systematic application of lessons learned. However, customers’ expectations of service reliability have changed dramatically with the evolution of the 24/7, digitally connected society. Even with enhanced response and heroic efforts by crews, restoration that stretches to days, and in some cases weeks, is no longer acceptable.

The resilience of the grid is based on three elements: prevention, recovery, and survivability.

1.	Damage prevention refers to the application of engineering designs and advanced technologies that harden the distribution system to limit damage.
2.	System recovery refers to the use of tools and techniques to quickly restore service to as many affected customers as practical.
3.	Survivability refers to the ability to maintain some basic level of electrical functionality to individual consumers or communities in the event of grid disturbance without complete access to the grid.

Improving the distribution system’s resiliency requires advances in all three aspects.

Resilient Electric Grid (REG) is an effort to “keep the lights on” in the event of a power outage by enabling distribution level power substations to share power with one another. The primary goal of REG is to develop and demonstrate an inherently fault current limiting, high-temperature, superconducting cable for increased electric grid resiliency. This technology offers several benefits, most significantly allowing substations to interconnect to share power and assets without the risk of fault currents cascading through the grid and causing damage.

A self-healing grid is a power system that could identify and fix its own problems, without direct human intervention. A self-healing grid uses digital components and real-time secure communications technologies installed throughout to monitor its electrical characteristics at all times and constantly tune itself so it operates at an optimum state. It has the intelligence to constantly look for potential problems caused by storms, catastrophes, human error or even sabotage. It will react to real or potential abnormalities within a fraction of a second, just as a military fighter jet reconfigures itself to stay aloft after it is damaged. The self-healing grid isolates problems immediately as they occur, before they cascade into major blackouts, and reorganizes the grid and reroutes energy transmissions so services continue for all customers while the problem is physically repaired by line crews.

A smart self-healing grid can provide a number of benefits that lead to a more stable and efficient system. Three of its primary functions include:

1.	Real-time monitoring and reaction, which allows the system to constantly tune itself to an optimal state;
2.	Anticipation, which enables the system to automatically look for problems that could trigger larger disturbances; and
3.	Rapid isolation, which allows the system to isolate parts of the network that experience failure from the rest of the system, to avoid the spread of disruption and enable a more rapid restoration.

As a result of these functions, a self-healing smart grid system is able to reduce power outages and minimize their length when they do occur. The smart grid is able to detect abnormal signals, make adaptive reconfigurations and isolate disturbances, eliminating or minimizing electrical disturbances during storms or other catastrophes. And, because the system is self-healing, it has an end-to-end resilience that detects and overrides human errors that result in some of the power outages, such as when a worker error left millions of California residents without electricity in September 2011.