Siemens 6MD85, Manual

Page: 749 / 1256

Blocking of the Stage
The picked up stage can reset completely via the binary input signal
>Block stage
.
Blocking of the Time Delay
You can use the binary input signal
>Block delay & op.
to prevent the start of the time delay and thus
also tripping. A running time delay is reset. The pickup is reported and a fault is opened.
Blocking of Tripping via the Device-Internal Inrush-Current Detection Function
With the
Blk. w. inrush curr. detect.
parameter, you can block the operate indication of the stage
for a threshold-value violation due to the inrush current. In case of a blocking, the stage picks up. The start of
the time delay and the operate indication are blocked. The function signals this through a corresponding indi-
cation. If the blocking drops out and the threshold value of the stage is still exceeded, the time delay is
started. When complete, the stage generates an operate indication. The blocking can only be set if the central
function Inrush-current detection is effective.
Blocking of tripping with the Inrush-current detection function is possible only if the following conditions
have been met:
•
The central Inrush-current detection function has to be available in another protection function group
with 3-phase current measurement.
•
You have to connect the protection function group with 1-phase current measurement to the protection
function group with 3-phase current measurement. You connect protection function groups in the
DIGSI 5 Project Tree → Name of the device → Function group connections.
Related Topics
7.4.7.1 Description
Application and Setting Notes
Parameter:
Method of measurement
•
Recommended setting value
(_:12661:8) 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:
Threshold
,
Operate delay
•
Default setting
(_:12661:3) Threshold
=
1.200 A
(for the first stage)
•
Default setting
(_:12661:6) Operate delay
=
0.300 s
(for the first stage)
Set the
Threshold
and
Operate delay
parameters for the specific application.
7.8.3.2
Protection and Automation Functions
7.8 Overcurrent Protection, 1-Phase
SIPROTEC 5, High-Voltage Bay Controller, Manual 749
C53000-G5040-C015-9, Edition 11.2017