Sandy, meet RecX. No, it’s not a battle of Transformers action figures. It’s a recognition that extreme weather events like Superstorm Sandy may become more common, and our power system needs to be better prepared to recover and survive such events.
Power system resilience took on added relevance and importance in the aftermath of October 2012’s Superstorm Sandy. Approaching the two-year anniversary of that industry-shaping event, all parties affected – from the utilities to the system operators to the individual consumers – have taken steps to boost readiness for a future event.
To transition to a more resilient power system, technologies will be needed that can respond to a larger array of events that may occur more frequently. The Electric Power Research Institute (EPRI) has focused research efforts on technologies that offer enhanced resilience in three areas: damage prevention, system recovery, and survivability. Damage prevention refers to the application of engineering designs and advanced technologies that harden the power system to limit damage. System recovery refers to the use of tools and techniques to quickly restore service as soon as practical. Survivability refers to the use of innovative technologies to aid consumers, communities, and institutions in continuing some level of function without complete access to normal power sources.
Several of the more prominent technology efforts are described below.
- Field Force Data Visualization – EPRI is developing data visualization technology for utility engineering and field operations. Using tablet and smart phone technologies, these systems would allow real-time data retrieval by pointing the mobile device at a distribution pole or at transmission and distribution conductors. A field technician would aim the hand-held device at a pole structure and the screen would display the camera image, the one-line circuit drawing, and all of the pertinent asset data. Recovery crews could use such tools to retrieve detailed information on assets in the field, and to determine quickly what should be dispatched for repair and replacement.
- Outage Communications – EPRI is working with utilities and vendors to develop a set of common messages to disseminate outage information to multiple channels simultaneously, including radio, TV, social media, web sites, and state and local governments. These messages will be submitted to the International Electrotechnical Commission (IEC) for potential inclusion in a forthcoming standard (IEC 61968) addressing information exchange between electrical distribution systems.
- Damage Prediction – EPRI is conducting several demonstration projects related to distribution modernization. One of these involves the development of more granular, accurate weather information as an input to grid damage prediction algorithms. Utilities could then use the results from these algorithms to optimize crew and asset placement prior to a weather event. Previous experience indicates that this practice greatly improves restoration times.
- Dynamic Circuit Reconfiguration – Advances in information technology, communications, and sensors can be combined with innovations in restoration practices to optimize network reconfiguration and speed service restoration. These systems involve the deployment of equipment such as automated distribution switches, sensors, communications, control systems, and data analytics to automatically reconfigure circuit connections. Once deployed, these systems limit the number of customers affected by faults on the feeder mains by directly tripping or sectionalizing, and once the fault is isolated to one section of the feeder, the systems enable service restoration to unaffected sections from adjacent feeders.
- Recovery Transformer – EPRI has collaborated with the U.S. Department of Homeland Security, ABB Inc., and CenterPoint Energy Inc. to develop a prototype transformer that could be deployed to replace a damaged or destroyed transformer within a week instead of the several months that might be required to order and ship a full-scale replacement. In a worst-case scenario where a city was without power for months, the “recovery transformer” or RecX, could restore power quickly to critical services until permanent replacements were in place. While spare transformers are available in some locations, they typically aren’t designed to facilitate shipping over highway in three modules and to be reconnected on arrival like the RecX. The RecX transformer was installed at a CenterPoint Energy substation in 2012 and has performed as designed over more than one year of testing.
- Microgrids – The use of distributed energy resources could make the power system more resilient to severe weather. When used to enhance resilience, microgrids can be configured to operate in tandem with the bulk supply system during normal conditions, but disconnect and operate as an independent island in the event of a bulk supply failure or emergency. This capability requires the highest level of communication among generation devices and an adaptive grid command and control structure that can shift from one controller to the next as the system changes state. EPRI received an award from the U.S. Department of Energy in September to develop a commercially viable standardized microgrid controller that can enable a community to provide continuous power for critical loads. Target communities have been identified in New York and Connecticut to serve as test beds for this controller.
- Hydrophobic Coatings – Ice can accumulate on transmission and distribution lines and on other system components during storms and cold-weather events. If the buildup is severe, components can fail. EPRI is developing hydrophobic (water-fearing) coatings that can be applied to various components to help “shed” precipitation. For example, these coatings could mitigate water damage on non-ceramic insulators. EPRI is testing an array of advanced coatings to gauge their usefulness in utility applications with respect to performance and reliability.
These are just a sampling of the resilience-focused research activities underway at EPRI. Additional areas of research include cyber and physical security, on-line monitoring of load-tap changers, vegetation inspection, unmanned aerial vehicles for storm damage assessment, community energy storage, and using photovoltaics as a backup energy source. For a more detailed look at EPRI’s grid resilience research efforts focused on transmission and distribution systems, a video is available on our YouTube channel; the video highlights a series of tests conducted at EPRI's laboratory in Lenox, Massachusetts, to evaluate scenarios such as a tree falling across power lines.