Shake Table Testing of Voltage and Current Transformers and Numerical Derivation of Corresponding Fragility Curves

Damage to devices installed in electric substations, which have shown vulnerable behaviour under strong earthquakes the last decades, may endanger power delivery emergency phases during and after an earthquake. Within seismic risk assessment of networks, definition fragility functions equipment is paramount. However, current literature availability such models for some specific substation components, including instrument transformers, relatively limited, this being reason behind deployment experimental numerical research endeavour. Two voltage transformers two having different system levels (respectively high HV extra-high EHV ranges) were subjected shake table tests, results used calibrate corresponding 3D developed OpenSees. A number nonlinear dynamic analyses carried out within a multiple-stripe analysis (MSA) framework allowed derivation 16 curves four both stand-alone elevated/supported configurations, considering also soil types. Based on derived curves, one expected experience light or negligible damage due earthquake shaking, owing its resonance frequencies (and hence stiffness), whilst remaining three suffer moderate medium shaking intensities; however, their effect mitigated by presence typically employed supporting column. Comparison against available lent valuable reassurance adequacy methodology reliability curves.