Siemens SIPROTEC 7SS523 V3.2 Manual page 168

Functions
5.5.2 Setting Notes
BLOCKING MODE
DIFF SUPERV
T-Idiff SUPERV
Id> SUPERV BZ
Id> SUPERV CZ
DIF SUP mode BZ
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The parameter BLOCKING MODE (6305/CU) is used to select the blocking mode of
the busbar and breaker failure protection in the event of
• Measured value errors
• Failure of a bay unit
• Isolator malfunctions (6302/CU)
With setting zone/phase 3-pole or 1-pole blocking is only performed on the protec-
tion zone allocated to the bay unit. If zone-selective blocking is performed on a 1-bay
coupler, both affected protection zones will be blocked.
With setting protection the protection will be blocked completely.
The parameter DIFF SUPERV (6306/CU) is used to activate and deactivate the dif-
ferential current supervision.
With setting ON the differential current supervision will be activated. In normal mode
the differential current supervision must remain ON.
With setting OFF the differential current supervision will be deactivated. The differen-
tial current supervision may be deactivated for testing (e.g. for establishing the char-
acteristic).
The parameter T-Idiff SUPERV (6307/CU) is used to set the delay time for block-
ing or alarm after a pickup of the differential current supervision.
The parameterId> SUPERV BZ (6308/CU) is used to set the threshold I/Ino for se-
lective differential current supervision.
The parameter Id> SUPERV CZ (6309/CU) is used to set the threshold I/Ino for dif-
ferential current supervision in the check zone.
The monitoring limit value should be set as low as possible, generally to the double
maximum differential current in fault-free condition. Please note that due to the fault
characteristic of the current transformers, there usually occur more severe faults un-
der weak-infeed conditions than under rated load.
The parameter DIF SUP mode BZ (6310/CU) is used to set the response of the pro-
tection after pickup of the differential current supervision.
With setting alarm only a pickup of the differential current supervision causes only
an alarm and not a blocking of the protection.
With setting block./release the protection will be blocked for the duration of the
malfunction. Phase- and bus zone-selective blocking is performed if the parameter
BLOCKING MODE (6305/CU) is set accordingly.
With setting blocking the blocking of the affected phase and zone is treated as with
block./release. It differs from the setting block./release in that the protection
is released by an operator input "Reset Id-Block" or a binary input ">Reset Id-
Block" (BI FNo. 6/CU) as soon as the malfunction is eliminated.
7SS52 V4 Manual
C53000-G1176-C182-1