Application; Theory Of Operation - ABB REC 561 User Manual

ABB Network Partner AB
Version 1.0-00
November 1996
Function:

1 Application

2 Theory of operation

Time synchronisation
Basic
Time-tagging of internal events and disturbances is an excellent help
when evaluating faults. Without time synchronisation, only the events
within the terminal can be compared to one another. With time synchroni-
sation, events and disturbances within the entire station, and even between
line ends, can be compared during an evaluation.
If external time synchronisation is applied, there are two main alterna-
tives. Either the synchronisation message is applied via one of the com-
munication ports (Station Monitoring System (SMS) or Substation
Control System (SCS)) as a telegram message, or a minute pulse, con-
nected to a binary input.
The terminal has its own internal clock with date, hour, minute, second
and millisecond. It has a resolution of 1 ms.
The clock has a built-in calendar for 30 years that handles leap years. Any
change between summer and winter time must be handled manually or
through external time synchronisation. The clock is powered by a capaci-
tor, to bridge interruptions in power supply without malfunction.
The internal clock is used for time-tagging disturbances, events in SMS
and SCS, and internal events.
1MRK 580 135-XEN
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