Settings
Addr. Parameter Setting Options Default Setting Comments
8201 TRIP Cir. SUP. ON
OFF
OFF TRIP Circuit Supervision
Information List
No. Information Type of
Informa-
tion
Comments
6851 >BLOCK TripC SP >BLOCK Trip circuit supervision
6852 >TripC trip rel SP >Trip circuit supervision: trip relay
6853 >TripC brk rel. SP >Trip circuit supervision: breaker relay
6861 TripC OFF OUT Trip circuit supervision OFF
6862 TripC BLOCKED OUT Trip circuit supervision is BLOCKED
6863 TripC ACTIVE OUT Trip circuit supervision is ACTIVE
6864 TripC ProgFail OUT Trip Circuit blk. Bin. input is not set
6865 FAIL: Trip cir. OUT Failure Trip Circuit
Monitoring
Broken Wire Detection, Fuse Failure Monitoring
Broken Wire
During steady-state operation the broken wire monitoring registers interruptions in the secondary circuit of
the current transformers. In addition to the hazard potential caused by high voltages in the secondary circuit,
this kind of interruption simulates differential currents to the differential protection, such as those evoked by
faults in the protected object.
The broken-wire monitor scans the transient behaviour of the currents of each phase for each measuring loca-
tion. The instantaneous current values are checked for plausibility. If an instantaneous value does not corre-
spond to the expected value although the other steady-state currents continue to flow, a broken wire is
considered. Moreover it is checked, whether the current decays strongly or drops abruptly to 0 (from > 0.1 ·
Ι
N
), or no zero crossing is registered. At the same time, the currents flowing in other phases must not exceed 2
·Ι
N
.
The protection functions which react on unsymmetrical currents are blocked as well provided they are
assigned to the defective measuring location: the time overcurrent protection for residual current and the
unbalanced load protection. The device issues the message “Broken wire” indicating also the affected phase
and measuring location.
The blocking is released as soon as a current flow is registered again in the appropriate phase of the device
concerned.
The following figure shows the logic of the wire break detection for 3 measuring locations.
2.19.2.3
2.19.2.4
2.19.3
2.19.3.1
Functions
2.19 Monitoring Functions
262 SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
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