Protection General
167
7SS52 V4 Manual
C53000-G1176-C182-3
5.9
Protection General
This section summarizes general information required by the SIPROTEC 7SS52 V4
distributed busbar and breaker failure protection.
5.9.1
Current-Controlled TRIP Reset
For a reset of the TRIP command, it must be ensured that the tripped circuit breaker
has actually been opened and that the trip circuit of the bay unit has been interrupted
by the circuit breaker auxiliary contact.
If the trip relay interrupts the tripping current prematurely, its contacts are overloaded
and destroyed.
A TRIP command from the busbar protection is only transmitted to the circuit breaker
of the faulted feeder if the feeder current exceeds the current threshold for TRIP re-
lease
XX13/CU
).
Minimum duration
of TRIP command
The relays for the TRIP command and the transfer trip command are reset if after the
time
(
) the feeder current drops below the threshold
XX18/CU
) or
(
XX19/CU
).
Figure 5-37 Minimum duration of TRIP command
5.9.2
Local Control of the Bay Unit
If you want to ensure that the operating status of the bay units set with the parameter
XX12/CU
) and the function keys
F1
and
F3
cannot be changed in the
bay units, you can block the local control of the bay units with the parameter
).
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