Siemens 6MD85, Manual

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Parameter Value Description
phase-to-phase
If you want to monitor the voltage range, keep
phase-to-phase
as the
default setting. In this case, the function will not pick up on ground faults.
Siemens recommends the measured value
phase-to-phase
as the
default setting.
phase-to-ground
Select the
phase-to-ground
setting if you want to detect voltage unbal-
ances and overvoltage conditions caused by ground faults.
Parameter:
Threshold
,
Pickup factor
•
Default setting
(_:3) Threshold
=
110.000 V
•
Default setting
(_:101) Pickup factor
=
1.10
The stage picks up when the measured voltage value exceeds the pickup value
Threshold
×
Pickup
factor
.
Depending on the
Measured value
, the
Threshold
is set either as phase-to-phase quantity or as phase-to-
ground quantity.
With the
Pickup factor
parameter, you modify the pickup value. To avoid a long-time operate delay after
pickup when the measured value is slightly over the threshold, Siemens recommends using the default
setting.
Specify the
Threshold
(pickup threshold) and
Pickup factor
for the specific application.
Parameter:
Pickup mode
•
Recommended setting value
(_:182:101) Pickup mode
=
1 out of 3
With the
Pickup mode
parameter, you define whether the protection stage picks up if all 3 measuring
elements detect the overvoltage condition (
3 out of 3
) or if only 1 measuring element detects the over-
voltage condition (
1 out of 3
).
Parameter Value Description
1 out of 3
Select the setting for protection applications or for monitoring the voltage
range.
Siemens recommends
1 out of 3
as the default setting. This reflects how
the function behaved in previous generations (SIPROTEC 4, SIPROTEC 3).
3 out of 3
Select this setting when using the stage to disconnect from the power
system (in the case of wind farms, for example).
Parameter:
Charact. constant k
,
Charact. constant α
,
Charact. constant c
•
Default setting
(_:102) Charact. constant k
=
1.00
•
Default setting
(_:103) Charact. constant α
=
1.000
•
Default setting
(_:104) Charact. constant c
=
0.000
With the parameters
Charact. constant k
,
Charact. constant α
, and
Charact. constant c
,
you define the required inverse-time characteristic curve.
Parameter:
Time dial
•
Default setting
(_:105) Time dial
=
1.00
With the
Time dial
parameter, you displace the characteristic curve in the time direction.
As usually, there is no time grading for voltage protection and therefore no displacement of the characteristic
curve, Siemens recommends leaving the
Time dial
parameter at
1.00
(default setting).
Parameter:
Additional time delay
•
Default setting
(_:106) Additional time delay
=
0.00 s
Protection and Automation Functions
7.13 Overvoltage Protection with 3-Phase Voltage
792 SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017