An approach to seismic evaluation of electrical substations

Southern California Edison Company has been involved in research and development to provide a firm basis for seismic design requirements and practices for substation facilities. These efforts have resulted in the attainment of a better understanding of the seismic withstand characteristics of Edison´s substation facilities as well as design changes for the seismic improvement of shunt capacitor racks and circuit breakers. A close liaison has been maintained with consultants and academic personnel throughout the current seismic testing program resulting in the development of analytical and testing techniques for the seismic design of equipment and structures. This has enabled Edison to increase their understanding of seismic methodology. The following paper outlines the approach which Edison has taken towards research into improved testing and analytical methods in order to establish more precise and economical means of verifying the seismic withstand requirements of substation equipment and structures. The concept of dynamic rating for substation apparatus and structures is also introduced.