Led by Dr. Thomas Overbye, this Texas A&M research group consisting of graduate students, faculty, and staff is working on the modeling the impacts of geomagnetic disturbances on the power grid. This work began in 2011 at University of Illinois, continuing at A&M since 2017. A key aspect has been the collaboration with inter-disciplinary teams from other universities and industry to address 1) model validation (ground conductivity, models of grid components such as transformers, substation grounding resistance), 2) developing mitigation measures, 3) modeling enhancements or feature additions, 4) system impact assessments, and 5) GMD monitoring. Work has been focused on leveraging and developing state-of-the-art models, data, and tools to predict, simulate, and assess impacts. The guiding principle is that space scientists, geophysicists, and power engineers should be working together, as some of the key challenges of the GMD impact problem lie at the interfaces between these areas, i.e. starting from the sun to the earth’s magnetosphere and surface, to the deep earth and finally to the grid.
The driver of GMDs is space weather, which is caused by changes occurring at the Sun. Coronal mass ejections and solar flares caused by solar wind can emit highly energized charged particles, at times directed towards the earth. In case of a large solar event, these can potentially affect the earth’s magnetic field significantly, inducing electric fields at the surface of the earth. This induces low frequency geomagnetically induced currents (GICs) which flow through low resistance paths from the ground such as power transmission lines, telegraph lines, and even pipelines and railway tracks. The effects of geomagnetic disturbances on ground-based electrical systems have been known for over 170 years. GMD-induced blackouts and other impacts were experienced later in the 20th century.
While research on GIC impacts on the power grid has been happening for several decades, the issue gained prominence more recently in the early 2010s following a joint report by the North American Electric Reliability Corporation (NERC) and the Department of Energy (DOE) on the “High Impact, Low Frequency (HILF) Event Risk to the North American Bulk Power System”. Electromagnetic events manifesting naturally such as geomagnetic disturbances or man-made attacks such as electromagnetic pulses (EMPs), were included as one of the three types of HILF events that pose a major threat to power systems.
This was followed by a special NERC assessment focusing on just the impacts of GMDs. This report determined that voltage collapse was more likely to be the cause of a blackout rather than transformer damage due to overheating. In fact, voltage collapse caused by tripping of reactive power support devices known as static var compensators (SVCs) was the cause of the March 1989 in Hydro-Quebec blackout.
Following the 2012 report, the Federal Energy Regulatory Commission (FERC) issued orders to NERC to develop reliability standards for planning and operating the grid under a GMD. These standards can be related to planning (i.e. offline studies), operating, and modeling, among other topics. According to the planning standards developed (TPL-007-1 (now obsolete), TPL-007-2, and TPL-007-3), utilities are required to collect data to aid research and validation and maintain system models required to perform GMD assessments. At A&M, we are working on cutting edge GMD research funded by the National Science Foundation and the State of Texas, as well as performing GMD assessments for major utilities