Experimental System Identification of a 63kV Substation Post Insulator and the Development of Its Fragility Curves by Dynamic Finite Element Analyses

Abstract

Electric substations play a great role in electric power systems as the most important lifelines, and post insulators are among the most-used parts in many components of substations. Therefore, realizing the seismic behavior of insulators helps in creating more realistic seismic evaluations of substations, and accordingly, the whole network. In this study, first, various damages to the high-voltage electricity substation insulators during past earthquakes are briefly reviewed. Next, by using the results of a previous experimental study, a 63 kV insulator was modeled using the finite element technique, and by using the accelerograms of 69 earthquakes in 13 PGA categories, the maximum stress values were obtained by time history analyses. Finally, considering an appropriate failure criterion the failure probabilities for all categories were obtained, and the corresponding fragility curves were developed. Results show that a single parameter, particularly PGA, as the hazard index does not lead to satisfactory results for fragility curves.