Diode designed to protect grid from EMPsS. Himmelstein | April 14, 2022
A gallium nitride (GaN) diode has been engineered at U.S. Sandia National Laboratories (SNL) to shunt excess electricity within a few billionths of a second while operating at a record-breaking 6,400 V and improve grid protection in the event of an electromagnetic pulse (EMP).
An EMP can occur as the result of solar flares and other phenomena or human activity, causing huge voltages in a few billionths of a second and potentially damaging transformers and other power grid equipment over large areas. The GaN device can handle much greater voltages relative to the capability of available protective components and responds very quickly, making it a good candidate to achieve the fast action needed to protect the grid from an EMP.
The GaN semiconductor was prepared by chemical vapor deposition to produce layers with different electrical properties. The layers are synthesized and assembled in a specific order to produce a device with the required properties. When subjected to high voltage spikes in the laboratory, the researchers measured the electric pulse reflected back from the vertical GaN p-n diode, demonstrating that the device turns on in less than a billionth of a second.
The researchers will next fabricate thicker wafer layers with fewer defects to design a device that operates at 20,000 V. The diode technology described in IEEE Transactions on Electron Devices can find application in smart transformers for the grid, electronic devices to convert electricity from roof-top solar panels into power for household use, and electric car charging infrastructure.