Siemens 6MD85, Manual

Page: 754 / 1256

Parameter Value Description
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:
Type of character. curve
•
Default setting
(_:12691:108) Type of character. curve
=
IEC normal inverse
The device offers all the usual inverse-time characteristic curves according to IEC and ANSI. Select the
Type
of character. curve
required for your specific application.
Parameter:
Threshold
•
Default setting
(_:12691:3) Threshold
=
1.20 A
Set the
Threshold
and
Type of character. curve
parameters for the specific application.
Note that a safety margin is set between pickup value and threshold value. The stage only picks up at approx.
10 % above the
Threshold
.
Parameter:
Time dial
•
Default setting
(_:12691:101) Time dial
=
1
Use the
Time dial
parameter to displace the characteristic curve in the time direction.
Where no time grading and therefore no displacement of the characteristic curve is required, leave the param-
eter
Time dial
at
1
(default setting).
Parameter:
Reset
•
Default setting
(_:12691:109) Reset
=
disk emulation
You use the
Reset
parameter to define whether the stage drops out according to the dropout characteristic
curve (in accordance with the behavior of a disk emulation = rotor disk) or instantaneously.
Parameter Value Description
disk emulation
Select this setting if the device is coordinated with electromechanical
devices or other devices which perform a dropout after a disk emulation.
instantaneous
Use this setting if the dropout is not to be performed after disk emulation
and an instantaneous dropout is desired instead.
Settings
Addr. Parameter C Setting Options Default Setting
Inverse-T 1
_:12691:1 Inverse-T 1:Mode
•
off
•
on
•
test
off
_:12691:2 Inverse-T 1:Operate &
flt.rec. blocked
•
no
•
yes
no
_:12691:27 Inverse-T 1:Blk. w. inrush
curr. detect.
•
no
•
yes
no
7.8.4.3
Protection and Automation Functions
7.8 Overcurrent Protection, 1-Phase
754 SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017