Parameter: Threshold add-on stabiliz.
•
Default setting (_:11041:128) Threshold add-on stabiliz. = 2.00
The Threshold add-on stabiliz. parameter allows you to set the pickup value for the additional stabili-
zation. Due to the selected method of measurement, a setting value of 2.00 is practical. The additional stabili-
zation range is limited by the parameters Threshold add-on stabiliz. and Slope 1.
Parameter: Time of add-on stabiliz.
•
Default setting (_:11041:129) Time of add-on stabiliz. = 0.30 s
As orientation for the setting value, you can use the operate time of the external feeder protection. Addition-
ally, take into account the break time of the circuit breaker. Thus, the following calculation rule results:
t
Z rest.
≥ t
off,ext protection
+ t
off,circuit breaker
The default value is a practical value. You must adapt the value appropriately to use. The value 0 deactivates
the detection of external faults.
Parameter: Crossblk. time add-on st.
•
Default setting (_:11041:130) Crossblk. time add-on st. = 0.30 s
The additional stabilization acts separately on each phase. However, it can be extended to block all phases.
Siemens recommends the activation of the crossblock function with a corresponding setting of the time. The
set time must be identical to the time that is set for the duration of the additional stabilization.
Protection Stage I-DIFF Fast
The task of this protection stage is the fast detection of high-current internal short circuits (see also I-DIFF Fast
Differential Protection Function, Page 1054). For this reason, the protection stage must always be activated.
Parameter: Threshold
•
Default setting (_:11071:3) Threshold = 7.5 I/Irated,obj
Siemens recommends that the threshold value is set greater or equal to the starting current.
Protection Stage I-DIFF Unrestrained
The task of this protection stage is the fast detection of high-current internal faults (see also I-DIFF Unre-
strained Differential Protection Function, Page 1057).
Parameter: Threshold
•
Default setting (_:18002:3)Threshold = 10.0 I/Irated,obj
Use the description of the protection stage I-DIFF fast (Protection Stage I-DIFF Fast, Page 1066) to set the
threshold value.
Settings
Addr.
Parameter C Setting Options Default Setting
General
_:11041:1 I-DIFF:Mode
•
off
•
on
•
test
off
_:11041:2 I-DIFF:Operate & flt.rec.
blocked
•
no
•
yes
no
_:11041:6 I-DIFF:Operate delay 0.00 s to 60.00 s 0.00 s
7.8.5
Capacitor Bank Protection
7.8 Differential Protection for Capacitor Banks
1066 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
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