Siemens 6MD86 - Application and Setting Notes

Influence of Other Functions via Dynamic Settings (Advanced Stage)
If available in the device, the following functions can exert an influence on the overcurrent-protection stage:
•
Automatic reclosing
•
Cold-load pickup detection
•
Binary input signal
The influence of these functions via dynamic settings is described in chapter 7.7.10 Influence of Other Func-
tions via Dynamic Settings.
Application and Setting Notes
Parameter: Directional mode
•
Default setting (_:4891:111) Directional mode = forward
You can use the Directional mode parameter to define the directional mode of the stage.
Parameter Value Description
forward
Select this setting if the stage is to work in forward direction (in the
direction of the line).
reverse
Select this setting if the stage is to work in reverse direction (in the
direction of the busbar).
Parameter: Method of measurement
•
Recommended setting value (_:4891:8) Method of measurement = fundamental comp.
With the Method of measurement parameter, you define whether the stage uses the fundamental
comp. (standard method) or the calculated RMS value.
Parameter Value
Description
fundamental comp.
Select this method of measurement if harmonics or transient current peaks
are to be suppressed.
Siemens recommends using this method as the standard method.
RMS value
Select this method of measurement if you want the stage to take harmonics
into account (for example, at capacitor banks). Consider that aperiodic DC
components present in the secondary circuit are measured and can cause
an overfunction.
For this method of measurement, do not set the threshold value of the
stage to less than 0.1 I
rated,sec
. If currents from more than one measuring
point are added up in the current interface of a function group, the setting
value should not be set lower than 0.1 I
rated,sec
multiplied by the number of
added currents.
Parameter: Directional comparison, Release via input signal
•
Default setting (_:4891:110) Directional comparison = no
•
Default setting (_:4891:112) Release via input signal= no
The parameters Directional comparison and Release via input signal are not visible for the
basic stage.
You can use these settings to define whether the stage is to be used for directional comparison protection.
Directional comparison protection is performed via the
Direction and >Release delay & op. signals.
Parameter Value
Description
no
The stage is not used for directional comparison protection.
7.7.6.2
Protection and Automation Functions
7.7 Directional Overcurrent Protection, Ground
SIPROTEC 5, High-Voltage Bay Controller, Manual 723
C53000-G5040-C015-9, Edition 11.2017