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Publication Date


Date of Final Oral Examination (Defense)


Type of Culminating Activity

Thesis - Boise State University Access Only

Degree Title

Master of Science in Civil Engineering


Civil Engineering

Major Advisor

Arvin Farid, Ph.D


Yang Lu, Ph.D.


Travis Soppe, M.S.


In seismic zones, the electrical grid is at risk due to the vulnerability of large power transformers’ insulating bushings, which can experience dramatic seismic amplification. Identifying cases where this risk exists is critical if we are to mitigate against potentially expensive, extensive, and long-lasting power outages following significant seismic events. This thesis aims to make progress toward developing an improved understanding of the conditions leading to these large amplifications and, thereby, better equip engineers and civil servants to deploy measures aimed at protecting the public. Through dynamic analysis using the finite-element method, five case studies are investigated, which point to several patterns: (i) first, dynamic coupling of transformers and their insulating bushings is a significant concern; (ii) the primary modal-frequency relationship between the transformer tank and its high-voltage bushings affects the recommended design details for minimization of bushing amplifications; and (iii) many large transformer designs are susceptible to excessive amplification of seismic loading to the bushings, and therefore system dynamics should always be considered when evaluating these designs for their seismic withstand capabilities.