Seismic Response Of Substation Equipment with Porcelain Components Seismic Response of Substation Equipment with Porcelain Components

Abstract

The performance of equipment and structures during earthquake depends on their configuration, strength of construction, ductility and their dynamic properties. Lightly damped structures having one or more natural modes of oscillation within the frequency band of ground excitation may experience considerable amplification of forces, component stresses and deflections. Substation equipment comes under this category. The satisfactory operation of substation during and after an earthquake depends on the survival, without malfunction, of many diverse type of equipment. Individual equipment needs to be properly engineered. In addition, their anchorages and interconnections need to be well designed.Porcelain components are identified as most vulnerable parts against earthquake vibrations than any other components of the substation. In this research, substation equipment are divided into three categories based on the length of porcelain cylinders/components and bushings. i.e., short, medium and long porcelain insulator components. Electrical equipment are mounted on support structure or on Transformer tanks. Support structure and Transformer tank amplify the ground acceleration at the base of porcelain components.Dynamic characteristics of substation equipment are calculated by carrying out shake table experiments and finite element analysis. Assumptions are introducedin finite element modeling of equipment with respect to internal components like coil windings, metering equipment, insulating oil etc., are appropriately lumped at respective nodes to reduce the complexity involved in modelling non structural components. Basic validation of finite element models of substation components have been done with shake table experiments. Results of shake table experiments and finite element analyses are compared well with the less difference. The research concentrated towards identifyingexact earthquake ground motion amplification at the base of the porcelain components. At the same time discussions are presented on ground motion amplification of equipment with respect to recommendations available in International standards like IEEE-693-2005.