Time Synchronization - ABB REF 610 Technical Reference Manual

REF 610 REF 610
5.1.1.8.
22
Feeder Protection Relay
Technical Reference Manual
WARNING
FAULT CODE:
Fig. 5.1.1.7.-3 Warning with numeric code
For fault codes, refer to Section 5.1.18. Self-supervision (IRF) system.

Time synchronization

Time synchronization of the relay's real-time clock can be realized in two different
ways: via serial communication using a communication protocol or via a digital
input.
When time synchronization is realized via serial communication, the time is written
directly to the relay's real-time clock.
Any digital input can be configured for time synchronization and used for either
minute-pulse or second-pulse synchronization. The synchronization pulse is
automatically selected and depends on the time range within which the pulse occurs.
Two detected pulses within acceptable time range are required before the relay
activates pulse synchronization. Respectively, if the synchronization pulses
disappear, the relay takes time that corresponds to the time range of four pulses
before de-activating pulse synchronization. The time must be set once, either via
serial communication or manually via the HMI.
When the time is set via serial communication and minute-pulse synchronization is
used, only year-month-day-hour-minute is written to the relay's real-time clock, and
when second-pulse synchronization is used, only year-month-day-hour-minute-
second is written. The relay's real-time clock will be rounded to the nearest whole
second or minute, depending on whether second- or minute-pulse synchronization is
used. When the time is set via the HMI, the entire time is written to the relay's real-
time clock.
If the synchronization pulse differs more than ±0.05 seconds for second-pulse or ±2
seconds for minute-pulse synchronization from the relay's real-time clock, the
synchronization pulse is rejected.
Time synchronization is always triggered on the rising edge of the digital input
signal. The time is adjusted by accelerating or decelerating the relay's clock. By this
way the clock neither stops nor makes sudden jumps during the time adjustment.
The typical accuracy achievable with time synchronization via a digital input is ±2.5
milliseconds for second-pulse and ±5 milliseconds for minute-pulse
synchronization.
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1MRS755310
A040280