This document specifies standard service conditions, standard ratings, environmental performance requirements,
and testing requirements for communications networking devices and communications ports in
protective relays installed in electric power substations. It does not cover such equipment designed for
operation in other environments, such as office locations. Other than their communications ports, it does
not cover such equipment used in protective relaying applications, for which
IEEE Std C37.90TM-2007 [B8],1,2 IEEE Std C37.90.1TM-2002 [B9], IEEE Std C37.90.2TM-2004 [B10], and
IEEE Std C37.90.3TM-2001 [B11] shall apply.
The purpose of this standard is to define the environmental conditions present in electric power substations
and to establish a common reproducible basis for designing and evaluating communications networking
devices to be installed in those substations. It is a freestanding document, with no normative references to
other standards.