ABB RED650 Technical Manual page 786

Section 21
Basic IED functions
780
External
synchronization
sources
Off
LON
SPA
Min. pulse
SNTP
DNP
IRIG-B
PPS
Off
IRIG-B
PPS
IEC16000002 V2 EN-US
Figure 361: Design of the time system (clock synchronization)
All time tagging is performed by the software clock. When, for example, a status
signal is changed in the protection system of a function based on the free running
hardware clock, the event is time tagged by the software clock when it reaches the
event recorder. The hardware clock can thus run independently.
The echo mode of the line differential protection function is based on the hardware
clock. Thus, there is no need to synchronize the hardware clock and the software
clock.
Synchronization of the hardware clock to the software clock is necessary only
when IRIG B 00X with optical fibre, IEEE 1344 is used for differential protection.
The two clock systems are synchronized by a special clock synchronization unit
with two modes, fast and slow. A special feature, an automatic fast clock time
regulator is used. The automatic fast mode makes the synchronization time as short
as possible during start-up. The Fast and Slow settings are also available on the
local HMI.
SyncLostMode is not required to set as Block/BlockonLostUTC when differential
protection is based on ECHO mode.
PTP(IEEE 1588)
Off
On
Time tagging and general synchronization
Slave only
Commu-
Time nication
regulator
(Setting:
SW time
see
Technical
manual)
Time
HW time
regulator
(fast or slow)
converter
Line differential protection RED650 2.2 IEC
1MRK 505 394-UEN A
Protection
Events
and control
functions
Synchronization for differential protection
(Echo mode)
Diff.
A/D
commu-
nication
*IEC 61850-9-2
IEC16000002-2-en.vsdx
Technical manual
Merging
units*