rate of 1.2 kHz for a time interval of at least 1 second and for a maximum of 5
seconds. The recording time is a combination of pre- and post-fault time. The total
recording capability is 5 seconds. There can then be configured 5 records of 1
seconds or a single record of 5 seconds. The recording can be started by a protection
event, by a binary signal change or by any user-defined condition.
Fault records can be transferred locally to a personal computer from the HMI optical
port with the Operating Tool on from the communication interface. When extracted
with the Operating Tool, the fault records are automatically converted into the
standard COMTRADE format. When retrieved from the communication interface,
they can be converted with a utility program. Fault records are stored in non-volatile
memory, so they remain available also after a power failure.
Fault records can be exported and converted with the configuration software. The
transfer of fault records can be done also via the interbay. Fig. 4.6.-1 shows a record
of a cross-country fault in an earth-fault compensated MV system starting with the
earth fault.
A050404
Fig. 4.6.-1 Record of a cross-country fault in MV system
4.7. Time synchronization
REF 542plus is equipped with an internal real-time clock, which is used to time
stamp events. The internal clock is buffered by a special capacitor. In case of a DC
power supply failure, the stored electrical energy in the capacitor ensures continued
operation of the internal clock for at least another two hours. The date and time of
the clock can be set via the HMI control unit.
REF 542plus internal clock can be kept in synchronization with an external clock in
different ways.
When connected to an ABB station automation system, REF 542plus is
synchronized via an interbay bus using the facilities of, for example, SPA protocol
or ABB LON per LAG 1.4 protocol. For connection to third party system the
24
REF 542plusREF 542plus
Multifunction Protection and Switchbay Control
Unit
Technical Reference Manual
1MRS755859
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