scope:

This Specification describes the functional and performance requirements for communication services used to convey teleprotection information. This includes communication requirements for unit protection, direct transfer trip systems, permissive under-reach, blocked over-reach and DAR control signalling.

The part of the teleprotection system which is covered by this Specification is shown in Figure 1. The Specification covers inter-substation communication only.

The Specification defines the teleprotection requirements for the following types of channel:

(a) Four wire, voice frequency presented channels (non power- line carrier)

(b) Digitally presented channels. The overall context of this specification in relation to the complete documentation suite is explained in NGTS 3.24.3.