Seismic response of transformer-bushing systems

Substations are critical components in a power system. Performance of substations during past earthquakes has not been satisfactory and many key components such as transformers and porcelain bushings have sustained significant damage. Recently, several research investigations have been conducted to better evaluate, assess, and qualify seismic performance of critical substation components with emphasis on transformers and porcelain bushings. These studies include both analytical and experimental research. These works have revealed that understanding the seismic interactions among key equipments of a substation (transformers, porcelain bushings, foundation, and interconnecting elements) is critical to proper assessment of seismic performance of substations and in qualification of equipment. Due to weight limitations, shaking table tests of transformers are not feasible. Finite-element analysis, however, provides a suitable platform to assess their seismic performance and to evaluate their effect on the response of other important components such as bushings. This paper will present development of finite-element models and will discuss dynamic time history analyses results for several transformer-bushings systems.