Siemens SIPROTEC 7UT613 series Manual page 396

3 Mounting and Commissioning
Circuit Breaker
Auxiliary Contacts
External Initiation
Conditions
Busbar Trip
396
The circuit breaker auxiliary contact(s) form an essential part of the breaker failure pro-
tection system in case they have been connected to the device. Make sure that the
correct assignment has been checked. Make sure that the measured currents for
breaker failure protection (CTs), the tested circuit breaker, and its auxiliary contact(s)
relate to the same measuring location or side of the protected object.
If the breaker failure protection is intended to be initiated by external protection devic-
es, each of the external initiation conditions must be checked.
In order for the breaker failure protection to be started, a current must flow at least via
the monitored phase. This may be a secondary injected current.
• Start by trip command of the external protection: binary input >CBF Start (No 1431)
in spontaneous or fault annunciations.
• Following initiation the annunciation CBF Pup. external (No 1457) must appear in
the fault annunciations (trip log) or in the spontaneous annunciations.
• With two-stage breaker failure protection, the trip repetition command to the local
circuit breaker is issued after the delay time T1 (address 7015), and the indication
CBF TRIP T1 (No 1492).
• With single- or two-stage failure protection, the trip repetition command to the local
circuit breaker is issued after the delay time T2 (address 7016), and the indication
CBF TRIP T2 (No 1494)
Switch off test current.
If start is possible without current flow:
• Close tested circuit breaker while the disconnectors at both sides are open.
• Start by trip command of the external protection:
Binary input >CBF Start (No 1431) in the spontaneous or fault annunciations.
• Following initiation the annunciation CBF Pup. external (No 1457) must appear in
the fault annunciations (trip log) or in the spontaneous annunciations.
• With two-stage breaker failure protection, the trip repetition command to the local
circuit breaker is issued after the delay time T1 (address 7015), and the indication
CBF TRIP T1 (No 1492).
• With single- or two-stage failure protection, the trip repetition command to the local
circuit breaker is issued after the delay time T2 (address 7016), and the indication
CBF TRIP T2 (No 1494).
Reopen the local circuit breaker.
The most important thing is the check of the correct distribution of the trip commands
to the adjacent circuit breakers in case of breaker failure.
The adjacent circuit breakers are those of all feeders which must be tripped in order
to ensure interruption of the fault current should the local breaker fail. In other words,
the adjacent breakers are those of all feeders which may feed the same busbar or
busbar section as the faulty feeder. In case of a power transformer, the adjacent break-
ers may include the breaker of the lower-voltage side (or any other side) of the trans-
former, if the upper voltage side breaker is to be monitored, and vice versa.
A general detailed test guide cannot be specified because the layout of the adjacent
circuit breakers largely depends on the system topology.
In particular with multiple busbars the trip distribution logic for the surrounding circuit
breakers must be checked. Here check for every busbar section that all circuit break-
ers which are connected to the same busbar section as the feeder circuit breaker
under observation are tripped, and no other breakers.
7UT613/63x Manual
C53000-G1176-C160-2