Extreme weather continues to be identified by the ERO Enterprise as a potential risk to grid reliability and geomagnetic disturbance events (GMDs) are one example of this risk that continue to be a rising concern facing the electric grid, as exemplified by the storm experienced across much of the ReliabilityFirst (RF) footprint in May 2024.  

During a geomagnetic storm, the sun hurls coronial mass ejections toward the Earth, causing weak power grid fluctuations that can damage equipment if not monitored. System operators must monitor flows across transmission elements, and when needed, take actions ranging from taking a transformer out of service to re-dispatching generation to limit the flows on the elements, in order to safeguard the reliability of the bulk power system.

While GMDs happen on a semi-regular basis, the last time there was a storm of this magnitude in the U.S. was back in January 2005, so there are now many system operators that haven’t dealt with situations like this before, adding to the potential reliability concern.

The North American Electric Reliability Corporation (NERC) enforces compliance with two Reliability Standards to mitigate this risk:  EOP-010-1 (Geomagnetic Disturbance Operations) and TPL-007-4 (Transmission System Planned Performance for Geomagnetic Disturbance Events).

While not frequently included in spot check or audit related engagement scopes, entities should strive to always be audit-ready, which includes understanding and having controls in place to manage Geomagnetic Disturbance Operations standard requirements.

EOP-010-1 (Geomagnetic Disturbance Operations)

The purpose of EOP-010-1 is to mitigate the impacts of GMDs through effective operating plans, processes and procedures. GMDs can increase risk in areas with an already sensitive voltage control environment, such as areas with a higher-than-average influx of inverter-based resources connected to the Bulk Electric System.

TPL-007-4 (Transmission System Planned Performance for Geomagnetic Disturbance Events)

The purpose of TPL-007-4 is to establish requirements for planned performance on the transmission system during a GMD. This proactive measure is to ensure individual and joint areas of responsibility are known and documented for modeling, GMD vulnerability assessments, and thorough procedures to measure GMD data as stated in the standard.

How RF monitors this risk

RF’s Operational Analysis & Awareness team monitors storms as they occur, and the actions being taken by the system operators in our footprint. For example, many of our Reliability Coordinators and Transmission Operators declare conservative operations (delaying outages or asking for any equipment to be put back into service, if possible, prior to the event).

For more information on how RF’s OAA team monitors impacts from these storms or for more information on compliance with the standards above, use the form on the Contact Us page on the RF website and select the department you would like to contact via the dropdown.