Seismic Design Standards for Electric Substation Equipment

IEEE 693 has become a leading seismic design standard for electrical substation equipment primarily among utilities in high seismic hazard areas in North America. For the seismic qualification of switchgear and controlgear, IEC 62271 Part 300 presents an alternative that has been adopted primarily in Europe. The Institute of Electrical and Electronic Engineers (IEEE) and the International Electrotechnical Commission (IEC) have been engaged for many years in efforts to unify their standards for electrical equipment. These efforts are motivated by globalization and a desire to streamline the standards for equipment for the benefit of equipment manufacturers and users alike. This paper compares the key aspects, features, and rationale for the seismic qualification requirements of IEEE 693 and IEC 62271-300. While the overarching objectives of these two standards are the same, i.e., to provide the means for qualifying and procuring seismically rugged substation equipment, the philosophy and methods employed differ somewhat. Preliminary discussions to unify these two standards have begun, but much work remains to be done.