Siemens 6MD86 - Application and Setting Notes; Influence of Other Functions Via Dynamic Settings; Description

[loocp3pha-210812-01.vsd, 1, en_US]
Figure 7-71 Part-Logic Diagram on the Influence of Inrush-Current Detection Exemplified by the 1st Defi-
nite-Time Overcurrent Protection Stage
Application and Setting Notes
Parameter: Blk. w. inrush curr. detect.
•
Default setting (_:661:27) Blk. w. inrush curr. detect. = no
Parameter Value
Description
no
The transformer inrush-current detection does not affect the stage.
Select this setting in the following cases:
•
In cases where the device is not used on transformers.
•
In cases where the device is used on transformers and the threshold
value of the stage is set above the maximum inrush current of the
transformer. This, for example, applies to the high-current stage that is
set such according to the short-circuit voltage V
sc
of the transformer
that it only picks up on faults from the high-voltage side. The trans-
former inrush current cannot become larger than the maximum trans-
mittable short-circuit current.
yes
When the transformer inrush current detection detects an inrush current
that would lead to a tripping of the stage, the start of the time delay and
tripping of the stage are blocked.
Select this setting if the device is used on transformers and the threshold
value of the stage is set below the maximum inrush current of the trans-
former. This applies to the overcurrent-protection stage, which is used as a
backup stage with grading time for faults on the undervoltage side of the
transformer.
Influence of Other Functions via Dynamic Settings
Description
The parameters Threshold and Operate delay used for tripping are so-called dynamic settings.
Depending on other functions, the settings of these parameters can be changed dynamically (see
7.4.7.2
7.4.8
7.4.8.1
Protection and Automation Functions
7.4 Overcurrent Protection, Phases
SIPROTEC 5, High-Voltage Bay Controller, Manual 629
C53000-G5040-C015-9, Edition 11.2017