ABB RELION 670 Series Technical Manual page 1257

1MRK 502 066-UUS B
If the objective of synchronization is to achieve a relative time within the substation and if no
station master clock with minute pulse output is available, a simple minute pulse generator can be
designed and used for synchronization of the IEDs. The minute pulse generator can be created
using the logical elements and timers available in the IED.
The definition of a minute pulse is that it occurs one minute after the last pulse. As only the flanks
are detected, the flank of the minute pulse shall occur one minute after the last flank.
Binary minute pulses are checked with reference to frequency.
Pulse data:
• Period time (a) should be 60 seconds.
• Pulse length (b):
•
•
• Magnitude (c) - please refer to section
Deviations in the period time (a) larger than 50 ms will cause TSYNCERR.
IEC05000251 V1 EN-US
Figure 631: Binary minute pulses
The default time-out-time for a minute pulse is two minutes, and if no valid minute pulse is
received within two minutes a SYNCERR will be given.
If contact bounce occurs, only the first pulse will be detected as a minute pulse. The next minute
pulse will be registered first 60 s - 50 ms after the last contact bounce.
If the minute pulses are perfect, for example, it is exactly 60 seconds between the pulses, contact
bounces might occur 49 ms after the actual minute pulse without effecting the system. If contact
bounce occurs more than 50 ms, for example, it is less than 59950 ms between the two most
adjacent positive (or negative) flanks, the minute pulse will not be accepted.
Binary synchronization example
An IED is configured to use only binary input for time synchronization, and a valid binary input is
applied to a binary input card. The HMI is used to tell the IED the approximate time, and the
minute pulse is then used to synchronize the IED. Minute pulse means that each pulse occurs one
minute after the previous pulse, so the first pulse is not used at all. The second pulse will probably
be rejected due to 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
Technical manual
Minimum pulse length should be >50 ms.
Maximum pulse length is optional.
a
b
c
"Binary input module (BIM)".
en05000251.vsd
Section 21
Basic IED functions
M11346-74 v5
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