ABB Relion Technical Manual page 679

1MRK 502 048-UUS A
Technical manual
Design of the time system (clock synchronization)
External
synchronization
sources
Disabled
SNTP
IRIG-B
DNP
IEC60870-5-103
ANSI09000210 V1 EN
Figure 300: Design of time system (clock synchronization)
Synchronization principle
From a general point of view synchronization can be seen as a hierarchical structure. A
function is synchronized from a higher level and provides synchronization to lower levels.
Synchronization from
a higher level
Optional synchronization of
modules at a lower level
IEC09000342 V1 EN
Figure 301: Synchronization principle
A function is said to be synchronized when it periodically receives synchronization
messages from a higher level. As the level decreases, the accuracy of the synchronization
decreases as well. A function can have several potential sources of synchronization, with
different maximum errors. This gives the function the possibility to choose the source with
the best quality, and to adjust its internal clock after this source. The maximum error of a
clock can be defined as:
Time tagging and general synchronization
Commu
- nication
Time-
regulator
SW- time
Function
IEC09000342-1-en.vsd
Section 17
Basic IED functions
Protection
Events
and control
functions
ANSI09000210-1-en.vsd
673