Inside the Lab That Pushes Supergrid Circuit Breakers to the Limit

Tomorrow’s megavolt transmission lines need breakers that can withstand titanic forces

10 min read
photo of KEMA Laboratories

The Guardian: KEMA Laboratories tests a circuit breaker under extreme conditions to ensure it won't fail when it really matters.

Photo: KEMA Laboratories

Imagine a blazingly hot day in central China, when all the air conditioners in every megacity are running at full blast. Through the remote mountains of Shanxi province, the major transmission lines that carry ultrahigh-voltage electricity to the cities are operating at close to maximum capacity. Heated by the sunshine and the flowing current, the transmission lines sag dangerously close to the treetops. Suddenly the current jumps from line to tree branch, finding the path of least resistance and pouring through the tree into the ground. There's a bright flash as the current ionizes the air.

During this short circuit, the abruptly unleashed current reaches 10 to 20 times its normal level within a blink of an eye. Now the power grid's protection system must act fast. Within milliseconds, protection relays must recognize the fault and command the circuit breakers at both ends of the line to switch off the current, isolating the faulted line. The stakes are high: A sustained short-circuit current can trigger a chain reaction of failures throughout the grid and cause widespread blackouts, severely damaging expensive equipment in the process. The 2003 blackout in northeast North America was set off by a tree's contact with transmission lines in Ohio, which caused a cascade of failures that shut down more than 260 power plants, stopped the flow of 60,000 megawatts throughout the northeast grid, and darkened New York City.

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A Transistor for Sound Points Toward Whole New Electronics

“Topological” acoustic transistor suggests circuits with dissipationless flow of electricity or light

3 min read
Model of a honeycomb lattice

Model of a honeycomb lattice that serves as the basis for a "transistor" of sound waves—whose design suggests new kinds of transistors of light and electricity, made from so-called topological materials. Electrons in a topological transistor, it is suspected, would flow without any resistance.

Hoffman Lab/Harvard SEAS

Potential future transistors that consume far less energy than current devices may rely on exotic materials called "topological insulators" in which electricity flows across only surfaces and edges, with virtually no dissipation of energy. In research that may help pave the way for such electronic topological transistors, scientists at Harvard have now invented and simulated the first acoustic topological transistors, which operate with sound waves instead of electrons.

Topology is the branch of mathematics that explores the nature of shapes independent of deformation. For instance, an object shaped like a doughnut can be deformed into the shape of a mug, so that the doughnut's hole becomes the hole in the cup's handle. However, the object couldn't lose the hole without changing into a fundamentally different shape.

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Taking Cosmology to the Far Side of the Moon

New Chinese program plans to use satellites in lunar orbit to study faint signals from early universe

3 min read
crescent moon
Darwin Fan/Getty Images

A team of Chinese researchers are planning to use the moon as a shield to detect otherwise hard-to-observe low frequencies of the electromagnetic spectrum and open up a new window on the universe. The Discovering the Sky at the Longest Wavelengths (DSL) mission aims to seek out faint, low-frequency signals from the early cosmos using an array of 10 satellites in lunar orbit. If it launches in 2025 as planned, it will offer one of the very first glimpses of the universe through a new lens.

Nine “sister” spacecraft will make observations of the sky while passing over the far side of the moon, using our 3,474-kilometer-diameter celestial neighbor to block out human-made and other electromagnetic interference. Data collected in this radio-pristine environment will, according to researchers, be gathered by a larger mother spacecraft and transmitted to Earth when the satellites are on the near side of the moon and in view of ground stations.

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Electric utility infrastructure habitually falls prey to overgrown Right-of-Way, high winds, and harsh weather. Impactful events causing outages are increasing in frequency, and need to be endured without major disruptions in electric service. This webinar will discuss the application of covered aerial conductor to "harden" the electric utility grid so that unpredictable events don't result in unsustainable outages.


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