![]() ![]() "Our models predict fields and currents in Earth's upper atmosphere and propagate these currents down to the ground." With less than 30 minutes to go, Solar Shield can issue an alert to utilities with detailed information about GICs. "We quickly feed the data into CCMC computers," says Pulkkinen. These data are transmitted to Earth and the waiting Solar Shield team. Sensors onboard ACE make in situ measurements of the CME's speed, density, and magnetic field. The crucial moment comes about 30 minutes before impact when the cloud sweeps past ACE, a spacecraft stationed 1.5 million km upstream from Earth. The CCMC is a place where leading researchers from around the world have gathered their best physics-based computer programs for modeling space weather events. "We work at Goddard's Community Coordinated Modeling Center (CCMC)," says Pulkkinen. While the CME is crossing the sun-Earth divide, a trip that typically takes 24 to 48 hours, the Solar Shield team prepares to calculate ground currents. Images from SOHO and NASA's twin STEREO spacecraft show us the cloud from as many as three points of view, allowing us to make a 3D model of the CME, and predict when it will arrive." "Solar Shield springs into action when we see a coronal mass ejection (CME) billowing away from the sun. The innovation of Solar Shield is its ability to deliver transformer-level predictions. Transformers protected in this way would be available again for normal operations when the storm is over. That itself could cause a blackout, but only temporarily. During extreme storms, engineers could safeguard the most endangered transformers by disconnecting them from the grid. That is why a node-by-node forecast of geomagnetic currents is potentially so valuable. Permanent damage to the Salem New Jersey Nuclear Plant GSU Transformer caused by the Mageomagnetic storm. As the National Academy report notes, "these multi-ton apparatus cannot be repaired in the field, and if damaged in this manner they need to be replaced with new units which have lead times of 12 months or more." With demand for power growing even faster than the grids themselves, modern networks are sprawling, interconnected, and stressed to the limit-a recipe for trouble, according to the National Academy of Sciences: "The scale and speed of problems that could occur on have the potential to impact the power system in ways not previously experienced."Ī large-scale blackout could last a long time, mainly due to transformer damage. This has turned power grids into giant antennas for geomagnetically induced currents. Since the beginning of the Space Age the total length of high-voltage power lines crisscrossing North America has increased nearly 10 fold. Credit: North American Electric Reliability Corporation and the US Dept. ![]() Growth of the High Voltage Transmission Network and annual electric energy usage in the United States over the past 50 years. A 2009 report by the North American Electric Reliability Corporation (NERC) and the US Department of Energy concluded that modern power systems have a "significantly enhance vulnerability and exposure to effects of a severe geomagnetic storm." The underlying reason may be seen at a glance in this plot: While many utilities have taken steps to fortify their grids, the overall situation has only gotten worse. A similar series of "Halloween storms" in October 2003 triggered a regional blackout in southern Sweden and may have damaged transformers in South Africa. The storm damaged transformers in Quebec, New Jersey, and Great Britain, and caused more than 200 power anomalies across the USA from the eastern seaboard to the Pacific Northwest. This actually happened in Quebec on March 13, 1989, when a geomagnetic storm much less severe than the Carrington Event knocked out power across the entire province for more than nine hours. Powerful GICs can overload circuits, trip breakers, and in extreme cases melt the windings of heavy-duty transformers. These magnetic vibrations induce currents almost everywhere, from Earth's upper atmosphere to the ground beneath our feet. When a coronal mass ejection (a billion-ton solar storm cloud) hits Earth's magnetic field, the impact causes the field to shake and quiver. The troublemaker for power grids is the "GIC" – short for geomagnetically induced current. "We believe we can zero in on specific transformers and predict which of them are going to be hit hardest by a space weather event." "Solar Shield is a new and experimental forecasting system for the North American power grid," explains project leader Antti Pulkkinen, a Catholic University of America research associate working at NASA's Goddard Space Flight Center. The sun rises behind high-voltage power lines in North America.Ī new NASA project called "Solar Shield" could help keep the lights on. ![]()
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