b'Robust Insulation for ResilientImproving temperature tolerance of the electrical insulation used in Transformers against antransformers will increase the electrical grid resilience against geomagnetic Electromagnetic Pulse ordisturbances and electromagnetic pulses.Geomagnetic Disturbance P ower transformers, a vital grid component, are vulnerable to premature failure during and after geomagnetic disturbances that cause elevated temperatures and voltage excursions that compromise internal insulation. Current state-of-the-art insulations use organic polymers or micro-fibers imbedded in a temperature sensitive binding matrix for structural stability, which limits the thermal tolerance. A new very high-temperature tolerant insulation is needed. This research investigated novel insulation materials with enhanced thermal TOTAL APPROVED AMOUNT:properties using engineered silica fibers fabricated via electrospinning. These unique $1,412,440 over 3 years electrospun submicron silica fibers were converted into prototype felt insulation for PROJECT NUMBER:use in new compact transformers for the electrical grid and specialty applications 18P37-033 and to provide greater resilience against temperature excursions and overvoltage during a geomagnetic disturbance.PRINCIPAL INVESTIGATOR: Bjorn Vaagensmith Mats composed of silica fibers ranging in diameter from 0.164.12 m were fabricated with thicknesses up to 200 m. These mats were resilient to temperature stresses up to CO-INVESTIGATORS: 1100C (heated for 1 hour), electrical resistivity of 1.81014 -cm, and break down Gorakh Pawar, INL voltages of 6.5 MV/m (for a dry test). Molecular dynamic simulations indicated that the Jesse Reeves, INL molecular bonds begin to break apart at a significantly increased rate around 677COLLABORATOR: 727C. These results approached or exceeded the original goals to survive temperatures University of Utah up to 450C, electrical resistivity of 1015 -cm and a break down voltage of 10 MV/m. Increasing the mat density increased the electrical resistivity to 2.61014 -cm, and further research has the potential to achieve 1015 -cm.Conversely, the tensile strength of the mats was three orders of magnitude weaker (500 kPa) compared to commercial insulation products, such as Kraft paper (50 MPa). After the sol-gel cured for several months, the tensile strength increased to 15 MPa. Alternative fabrication methods were explored to increase the tensile strength; more research is needed to reach the goal.Examples of silica fiber mats developed under this research.112'