Wire Rope Isolators for Seismic Base Isolation

Tall and slender substation equipment is prone to failure under seismic excitations. The consequences of such failure can be devastating and lead to weeks or months of lost power. The IEEE Std 693-2005 ensures that all substation equipment installed in high seismic areas are designed to withstand earthquakes of a severity related to that area. There are numerous ways to increase the seismic strength of substation equipment and this paper will discuss doing so by base isolation, specifically using wire rope isolators (WRIs). It is the purpose of this paper to present a case study in which the Socitec Group provided a WRI base isolation design for a high voltage surge arrester. The simulation results show that the moment at the base of the surge arrester was reduced by 55% when using the Socitec designed WRI base isolation system.