Numerical modeling for the seismic response of interconnected electrical substation equipment

The seismic safety of electrical substations is significantly important for the resiliency of regions prone to earthquakes since they are one of the main components of the power grids. International standards require an additional amount of slackness and terminal forces in the design of such systems to eliminate the effect of the interconnection of the components. Even though the additional slack might be efficient to reduce the terminal forces, some other issues arise from the point of view of electrical engineering related to the phase-to-ground and minimum safety clearances. In this paper, a simplified numerical model is developed and proposed by using commercial structural analysis packages (SAP2000 and Abaqus/CAE) to reproduce the results of an experimental campaign by considering some other parameters which are generally neglected, i.e., bending stiffness of the conductor and varying damping ratio with the slackness of the conductor. In general, the experimental results (mode shapes and response histories) were captured reasonably by the simplified numerical models. The maximum absolute mean relative differences for the displacements and forces were 13.31% and 14.92%, respectively. Hence, the modeling strategy for the interconnected electrical substation equipment might be employed for further analyses, such as the construction of fragility curves.