Date of Award
Master of Science in Civil Engineering - (M.S.)
Civil and Environmental Engineering
M. Ala Saadeghvaziri
William R. Spillers
This study focuses on means to reduce the seismic hazard for transformer-bushing systems and different issues of the response and rehabilitation of transformers. The primary means of seismic mitigation investigated is the use of the Friction Pendulum System (FPS) bearings to seismically isolate transformers. This is done by developing a finite element model representing the behavior of FPS bearings and implementing this model on to ADINA finite element package for further use in analytical studies. This model is used to study the behavior of isolated primary-secondary systems and the effects of parameters like different FPS radii or vertical excitations. Also studied are the effects of isolation on forces applied to the foundations and the corresponding design of foundations compared to the commonly used fixed-base forces. Further, the interaction of transformer-bushings with interconnecting equipment in the substation is studied and corresponding graphs indicating the amount of required slack in connecting cables are presented. Finally, the behavior of internal components of transformers under seismic excitation has been studied. Possible failure and damage modes are identified and a model is developed and analyzed to assess damage risk.
Hashemi Nezhad Ashrafi, Seyed Ali, "Issues of seismic response and retrofit for critical substation equipment" (2003). Theses. 647.