scope:

This Manual deals with major power system elements-power-generating stations, transmission and distribution lines, substations, system communications and control, and ancillary facilities and functions. The emphasis given to the various elements is strongly related to their earthquake performance. Thus, a large portion of the document is devoted to high-voltage substations, as this is where most power system damage has been concentrated. Where existing practices, even though they may not be well defined, have performed well (as, for example, in power generating plants), recommendations will be limited to those areas where damage has been observed.

This Manual is meant to identify practices that have yielded either good or poor performance and to suggest mitigation methods. Seismic design criteria are determined by the utilities. Guidance for design criteria for substation structures are contained in ASCE's Substation Structure Design Guide (currently being developed). The Institute of Electrical and Electronic Engineers (IEEE) Standard 693-1997, "Recommended Practices for Seismic Design of Substations/' provides guidance for seismic qualification criteria and methods for substation equipment; when given time for its recommendations to find their way into the field, these recommendations should improve the seismic performance of such equipment.