ABB Relion 650 Series Technical Manual page 629

1MRK 511 424-UEN B
Bay control REC650 2.2 IEC
Technical manual
the spike filter. The third pulse will give the IED a good time, and will reset the
time so that the fourth pulse will occur on a minute border. After the first three
minutes, the time in the IED will be good if the coarse time is set properly via the
HMI or if the RTC backup still keeps the time since last up-time. If the minute
pulse is removed, for example, for an hour, the internal time will drift by maximum
the error rate in the internal clock. If the minute pulse is returned, the first pulse is
automatically rejected. The second pulse will possibly be rejected due to the spike
filter. The third pulse will set the time if the time offset is more than 500 ms or
adjust the time if the time offset is small enough. If the time is set, the application
will be brought to a safe state before the time is set. If the time is adjusted, the time
will reach its destination within one minute.
Synchronization via IRIG-B module
The IRIG-B interface to the IED supplies two possible synchronization methods,
IRIG-B and PPS.
IRIG-B is a protocol used only for time synchronization. A clock can provide local
time of the year in this format. The "B" in IRIG-B states that 100 bits per second
are transmitted and the message is sent every second. After IRIG-B there are
numbers stating if and how the signal is modulated and the information
transmitted.
To receive IRIG-B there are two connectors in the IRIG-B module, one galvanic
BNC connector and one optical ST connector. IRIG-B 12x messages can be
supplied via the galvanic interface, and IRIG-B 00x messages can be supplied via
either the galvanic interface or the optical interface, where x (in 00x or 12x) means
a number in the range of 0-7.
"00" means that a base band is used, and the information can be fed into the IRIG-
B module via the BNC contact or an optical fiber. "12" means that a 1 kHz
modulation is used. In this case the information must go into the module via the
BNC connector.
If the x in 00x or 12x is 4, 5, 6 or 7, the time message from IRIG-B contains
information of the year. If the x is 0, 1, 2 or 3, the information contains only the
time within the year, and year information has to be set via PCM600 or local HMI.
The IRIG-B module also takes care of IEEE1344 messages that are sent by IRIG-B
clocks, as IRIG-B previously did not have any year information. IEEE1344 is
compatible with IRIG-B and contains year information and information of the
time-zone.
PPS
An optical PPS signal can be supplied to the optical interface of the IRIG-B
module.
The PPS signal is a transition from dark to light, that occurs 1 second +/- 2 μs after
another PPS signal. The allowed jitter is <2 μs. If jitter is >2 μs a TSYNCERR
signal will be generated.
Section 15
Basic IED functions
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