Dynamic behavior of multilayer suspension equipment and adjacent post insulators with elastic‐viscous connections

Abstract

In an electrical substation or converter station, suspension equipment is connected to an adjacent post insulator by a rigid busbar or flexible conductors if the horizontal displacement is significant. In order to investigate the coupling effect between suspension and post equipment connected by a rigid busbar, a scaled-down model based on a multilayer suspended thyristor valve and an adjacent post insulator was tested. Additionally, an analytical model, which took into account the out-of-plane and torsional motion, was established. The test results showed that the damping of the suspended valve approximated to stiffness-proportional damping. The rigid busbar significantly reduced the seismic responses of both the valve and the post insulator by changing the vibration modes and increasing the damping ratio. Based on the analytical model, the rigid busbar connection is recommended for stiff insulators with a low fundamental frequency. A hard soil site, chain connection, low damping ratio, and an appropriate layout all contribute to the advantages of a rigid busbar. A telescopic busbar using additional rotational and axial damping also can improve the system's seismic performance. Rather than automatically installing flexible conductors, it is recommended that equipment parameters be used to determine an appropriate connection type between suspension equipment and an adjacent post insulator.