Revision Standard - Active.
Concepts and applications of ac transmission line protection are presented in this guide. Many important issues, such as coordination of settings, operating times, characteristics of relays, mutual coupling of lines, and use of communication channels, are examined. The impact of different electrical parameters and system performance considerations on the selection of relays and protection schemes is discussed. The purpose of this guide is to provide protection engineers with information that helps them to apply relays and other devices to protect ac transmission lines.