Busbar Protection
107
7SS52 V4 Manual
C53000-G1176-C182-3
5.1.3.7
Transfer Busbar With Inside Transformers
If the protection of the transfer busbar is impossible because of internal transformers
or not required for outside transformers,
PROT TR BUS
(
5401/CU
) is to be configured
with
No
. Then, only the Q7 on the bus coupler side is required to start the transfer op-
eration. With the Q7 installed, the protected zone ends at the last coupling transformer
(T1). All plant components beyond the last coupler CT are now outside the protected
zone of the busbar protection. Therefore, the protected zone of the check zone also
has to be transferred into the coupler (T1).
The following figure shows the correction of the check zone with an unprotected trans-
fer busbar.
Figure 5-14 Transfer operation without transfer busbar protection
1) configured and detected
2) existing but not configured
5.1.3.8
Special Cases of Transfer Busbar Operation
Transfer Busbar
Operation with Sev-
eral Feeders
The transfer operation is usually established for one feeder. For this, a feeder is
connected to the transfer / combination busbar via the coupler. To ensure a flexible
operational management, also several feeders and couplers can be connected
simultaneously to the transfer / combination busbar. The protection behavior depends
on the assembly position of the current transformers. If all the feeders involved
possess external transformers, the transfer / combination busbar can be protected
selectively. Otherwise, the protected zone ends at the current transformer of the
coupler or at the feeder transformer.
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