Tag Archives: Physics

The Celestial Shooting Gallery, Part Four: “You Have Nothing to Worry About (click) Worry About (click) Worry About (click)…”

Stability Model of an experimental distribution grid

A stability map of a simple power grid. Each point on this image represents an operating state of a simple power grid consisting of a few generators. Bluish regions constitute stable working states, red unstable and ‘salt-and-pepper’ represent chaotic behavior. One can tune a grid for stability by controlling the phasing of generators and transformers on the grid and such settings suffice for day-to-day operations. It is difficult to decide where, or by how much, abnormalities such as geomagnetic storms might push a system into red, unstable regions, or, worse, salt-and-pepper regions where the system oscillates between states. It is easy to find cases on the map where chaotic regions lie very close to stable regions, indicating that the destabilizing push need not be large at all. James Thorp, Cornell University, published in IEEE Spectrum

People paid to worry about the North American power grid regard geomagnetic storms as “high impact, low-frequency” events, spawning the inevitable acronym: HILF. Low frequency, in that a geomagnetic storm as intense as May 1921, at 5,000 nano-Teslas/minute, or the 1859 Carrington Event, best guess: 7,500 nano-Teslas/minute, might not happen in our lifetimes, the lifetimes of our children, or even our grand children. If signature traces in Arctic ice core samples are correct, these are ‘500 year events.’ When it comes to deciding where to put that preventative maintenance dollar, storm-proofing Oklahoma elementary schools against EF 5 tornadoes seems a far more practical spend than the hardening of electrical grids against a half-theoretical event that might not even happen in 500 years.

What pulls planners up short is the high impact part: the utter god-awfulness of a power grid that crashes and which then can’t boot itself up. There is a self-referential dependency: fixing a dysfunctional power grid requires it to be functional, as key aspects of the manufacturing of transformers need electricity.

Nor can one expect the cavalry to ride in anytime soon, as the vast geographic reach of geomagnetic storms means that one strong enough to take down the North American grid may very likely take down Eurasian grids as well – entire hemispheres could wind up in the toilet, and we only have two hemispheres. That and the statistical variableness to it all: the Carrington 1859 and May 1921 storms, nominally two ‘500 year events’ were, in fact, separated by only sixty-two years.

Where does the buck stop? Continue reading →

Celestial Shooting Gallery, Part Three: When a CME Hits the Atmosphere

Failed GSU transformer at Salem River, NJ

A Generator Step Up (GSU) transformer failed at the Salem River Nuclear Plant during the March 1989 geomagnetic storm. The unit is depicted on the left; some of the burned 22kV primary windings are shown on the right. Though immersed in cooling oil, the windings became hot enough to melt copper, at about 2000 degrees F. John Kappenman, Metatech

Coronal Mass Ejections are mainly charged particles, protons and electrons. When a CME arrives at Earth, the charged protons and electrons come under the influence of the Earth’s own magnetic field, the magnetosphere. Charged particles spin around the lines of magnetic force that comprise the magnetosphere, which diverts most of CME harmlessly around the planet, keeping Earth’s surface tranquil.

If the ejection is large enough, however, it can distort the shape of the magnetosphere, occasionally causing magnetic flux lines to snap and reconnect. When this happens, charged particles leak in and follow the magnetosphere’s flux lines down to the Earth’s ionosphere. There, they strike oxygen and nitrogen molecules and strip them of electrons. These ionized gases glow, giving rise to the ethereal beauty of the auroras around the north and south poles. Unfortunately, these excess charged particles also produce immense electrojets.

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Celestial Shooting Gallery, Part Two: The Physics of Geomagnetic Storms

goddard_cme_earth

On August 31, 2012 a long filament of solar material that had been hovering in the sun’s atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled at over 900 miles per second. The CME did not travel directly toward Earth, but did connect with Earth’s magnetic environment, or magnetosphere, causing aurora to appear on the night of Monday, September 3. The image above includes an image of Earth to show the size of the CME compared to the size of Earth. NASA Goddard Spaceflight Center

Thursday, May 2nd, 2013, a coronal mass ejection (CME) hurled nearly one billion tons of charged particles from the sun’s corona at an outward velocity of one million miles per hour – 270 miles per second.

In less than a half hour, 2,700 virtual Empire State Buildings, 340,000 tons apiece – give or take a few gorillas – erupted from an active region of the Sun’s surface called AR1748, a northern latitude sunspot. AR1748 had just become visible on the western limb of the Sun’s surface when it ejected this mass, so the vast bulk of it hurled outward, not toward us in Libra, but more or less toward Cancer, at right-angles to us. In practical terms, it shot wide of its mark. Still an impressive shot. The CME had been triggered by an M class solar flare, the second largest in a five step scheme (An, Bn, Cn, Mn, Xn; for n a relative magnitude). It had been the largest coronal mass ejection observed thus far in 2013.

And it was still early in the day for AR1748.

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Celestial Shooting Gallery, Part One: The Day We Lost Quebec

Electrojets over N. America

John Kappenman reconstructed the electrojets which formed in the ionosphere late in the March 13, 1989 geomagnetic storm which compromised the Hydro-Quebec power grid in Canada. Concurrently, the eastward jet induced ground currents that severely strained the electrical distribution grid of northern continental United States, resulting in a transformer failure at the Salem Nuclear Power Plant, in New Jersey. Courtesy of Metatech

Nearly a quarter century ago, on March 13, 1989,  a geomagnetic storm led to the collapse of the Hydro-Quebec electrical grid system, which furnishes power to much of the province of Quebec, Canada. So pervasive were abnormal currents, that protective circuit breakers tripped throughout the system, bringing the entire grid to a halt in about one and a half minutes. The grid’s self-protective systems were geared toward local abnormalities happening in particular places. In contrast, ground induced currents created abnormalities everywhere. The good news was that most of the hardware protected itself. The bad news was that six million customers were without power for as long as nine hours, and where transformer damage did occur, outages continued for another week.

Further south, the United States experienced a close shave. A second surge in the March 13 storm generated similar ground induced currents in the northern United States, with large current spikes observed from the Pacific Northwest to the mid-Atlantic states, one spike destroying a large GSU transformer at the Salem Nuclear Power Plant in New Jersey. According to John Kappenman, of the Metatech Corporation “It was probably at this time that we came uncomfortably close to triggering a blackout that could have literally extended clear across the country.”

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