The device – an ultrfast diode – represents a significant step towards protecting the nation’s electric grid from an electromagnetic pulse (EMP), say the scientists. The researchers say that their ultimate goal is to provide protection from voltage surges, which could lead to months-long power interruptions, with a device that operates at up to 20,000 volts.

An EMP can be caused by natural phenomena, such as solar flares, or human activity, such as a nuclear detonation in the atmosphere. An EMP causes huge voltages in a few billionths of a second, potentially affecting and damaging electronic devices over large swaths of the country.

如果EMP发生和damage the huge transformers that form the backbone of the electric grid, say the researchers, it could take months to replace them and re-establish power to the affected portion of the nation.

“The reason why these devices are relevant to protecting the grid from an EMP is not just that they can get to high voltage – other devices can get to high voltage – but that they can respond in a couple billionths of a second,” says Bob Kaplar, manager of a semiconductor device research group at Sandia. “While the device is protecting the grid from an EMP, it’s at a very high voltage and thousands of amps are going through it, which is a huge amount of power. A material can only handle so much power for a certain amount of time, but we think the material in our diode has some advantages over other materials.”

研究人员正在努力建造一个diode able to operate at around 20,000 volts, since most grid distribution electronics operate at around 13,000 volts. Diodes are electronic components found in nearly every electronic device and allow electricity to flow in one direction through the device, but not the other – operating somewhat like a one-way regulator valve in plumbing. They can be used to convert AC power into DC power, and in this project, divert damaging high voltage away from sensitive grid transformers.

“In a regulator valve, even if you open that valve all the way, you can’t flow an infinite amount of water through the valve,” says Kaplar. “Similarly, there’s a limit to how much current you can flow through our diode. If the valve on the pipe is closed, if the pressure reaches a certain point, it’ll burst. Analogously, the diode cannot block an infinite voltage. However, our EMP device uses the point at which the diode can no longer block the high voltage, holds the voltage to that ‘pressure,’ shunting the excess current through itself, to the ground and away from the grid equipment in a controlled, non-destructive fashion.”