scope:

This guide provides information of special relevance to the planning, design, testing, installation, operation, and maintenance of gas-insulated substations (GIS) and equipment. This guide is intended to supplement IEEE Std C37.122-1993 .¹

In general, this guide is applicable to all ac GIS from 72.5-800 kV However, the importance of the topics covered varies with circumstances. For example, issues related to advanced field test techniques and very fast transients (VFT) are of particular interest for extra-high-voltage (EHV) GIS (345 kV and above), and are of lesser importance at lower voltage levels.