A diode has been developed at Sandia National Laboratories containing gallium nitride that could protect power grids from overvoltages.
The all-rounder among semiconductors: gallium nitride (GaN) is proving its potential in more and more fields in the electronics industry. This compound, made up of the technology metal gallium and nitrogen, enables high power density in tiny spaces, for example in microchips, chargers and mobile phone applications. A new device developed by Sandia National Laboratories in the USA now also demonstrates that GaN can protect the power grid from overload. A team of scientists there has built a GaN diode that can conduct an amazingly high voltage of 6,400 volts in ultra-fast time. By comparison: power sockets in Europe deliver a standard mains voltage of 230 volts, in the USA it is 110 to 120 volts.
In a statement issued by the research institution, it is claimed that the new device is “a significant step towards protecting the nation’s electric grid from an electromagnetic pulse”. By this they mean short-term electromagnetic pulses that can be triggered by natural phenomena such as solar flares or human impact such as a nuclear detonation. Electromagnetic pulses generate enormous voltages in fractions of a second, which in the worst case could lead to months-long power interruptions. Jack Flicker, a Sandia electric grid resiliency expert, is well aware that there are already protective devices in the power grid that can react to pulses within a millionth of a second – to divert lightning strikes, for example. However, with electromagnetic pulses, surges can occur within a matter of ten billionths of a second – a significantly shorter period of time. Gallium nitride offers great advantages over other semiconductor materials such as silicon because it is able to react so quickly, explained Bob Kaplar, head of a Sandia research group on semiconductor devices. GaN can also withstand huge voltages and currents.
The scientists now want to develop a device that is able to operate at up to 20,000 volts, offering protection against voltage surges, since most grid distribution electronics operate at around 13,000 volts. Kaplar believes that the device could also be used in other areas beyond power grid protection. Transformers, power converters/rectifiers or charging infrastructure for electric cars, for example, could become more efficient.
The production and test results were published in the journal IEEE Transactions on Electron Devices.
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