ABB REB 551-C3*2.5, Installation And Commissioning Manual, Page: 69 / 148

60
Fault tracing Chapter 8
Configuring the 56/64 kbit data
communication modules
Table 4: Summary
2.0.2 Explanation of contents in column 2 of table 42
1. Transmit errors are due to that the terminal cannot send messages via the tele-
communication channel (PCM). The line differential function initiates the send-
ing of one message every 5 ms. If this command can not be executed for 10
consecutive times (= 10 x 5 ms) due to blocked, missing or unsynchronized com-
munication channel, COMFAIL is triggered. For non-consecutive interruptions,
an integration algorithm is used that prolongs the COMFAIL triggering time.
2. Receive errors occur when no expected messages are received. The line differen-
tial function expects to receive one message every 5 ms. If this does not occur 10
consecutive times (= 10x5 ms), COMFAIL is triggered. For non-consecutive in-
terruptions, an integration algorithm is used that prolongs the COMFAIL trigger-
ing time.
No. COMFAIL triggering COMFAIL trigger-
ing time
(Drop-out delay
200 ms) Remark
1 Transmit error
≥
50 ms Messages can not be sent
2 Receive error
≥
100 ms No valid messages received
3 Block differential protection 0 ms Block of the differential protection due to set-
ting changes etc.
4 Remote terminal COMFAIL 0 ms COMFAIL from the remote terminal. For error
no 1, 2, 3, and no 5, 6, 7, 8, 9, 10 the COM-
FAIL is sent in the second consecutive mes-
sage (within 10 ms)
5 Time synchronization error
≥
2 s Problems in the synchronization of internal
differential clock in the differential protection.
The clock refers to the synchronized counters
0-39999
μ
s in each terminal. The clock is
independent of the real time clock in the ter-
minal.
6 Differential clock drift > 0 ms Unacceptable drift of the internal differential
clock in the slave terminal compared to the
internal differential clock in the master termi-
nal (slave- master -slave)
7 Communication channel loop
delay - instantaneous 0 ms Checks if the loop time (slave - master -slave)
in the differential communication channel 31
ms
8 Communication channel loop
delay - time delayed
≥
2 s Checks if the loop time (local - remote- local)
in the differential communication channel 24
ms
9 Abnormal clock deviation 0 ms Internal differential clock deviation (slave-
master - slave)
10 Data flow
Only in version *2.3
0 ms Long time between attempts to send mes-
sages and adjustment of the real time termi-
nal clock . The terminal clock is the real time
clock in the terminal for time tagging of events
etc.