Reliability of electric power grids under tornadoes

Strong wind disasters, especially tornadoes with high damage scales, constantly cause huge damage to electric power grids (EPGs). In this paper, a concept is presented to quantify the connectivity reliability of EPGs under tornadoes. First, a tornado wind field is established using a modified Rankine vortex model, which is a representative 2D tornado wind field model. Second, fragility models of grid components, including transmission substations, transmission support structures, distribution poles, distribution conductors, and local circuits, are introduced. Third, a Monte Carlo simulation is presented to evaluate the connectivity reliability of EPGs under tornadoes. Finally, the connectivity reliability is verified under different scales and propagation angles of tornadoes by taking an actual EPG in China as a case study. Results show that the connectivity reliability directly correlates with the maximum wind speed and the propagation angle of the tornado, and the EPG experiences severe damage when the tornado exceeds the Enhanced Fujita 3 scale.