Development and Validation of a Combined Horizontal-Vertical Seismic Isolation System for High-Voltage-Power Transformers

Keywords: Earthquake engineering, seismic isolation, damping, vertical ground motion, vertical isolation, power transformers

Abstract: This report presents the development and validation of a practical three-directional seismic isolation system for use in high-voltage power transformers, although the technology could  easily be transferred to building applications. Characteristics of the developed system are: (a) it is a modular extension of a horizontal seismic isolation system consisting of triple Friction Pendulum isolators currently used for power transformers, (b) it consist of two separate systems, one to achieve horizontal seismic isolation and the other to achieve vertical seismic isolation, © the horizontal system is highly flexible in order to achieve a high degree of seismic isolation but subject to constraints on displacements for serviceability of the equipment, (d) the vertical system is able to support the weight of the equipment with limited deflection in order to meet serviceability requirements and compactness, (e) all components of the system are readily available from reputable manufacturers, and (f) all components of the system are passive and highly reliable.