NOTE
If the (_:2311:104) Current-flow criterion parameter is deactivated, the device picks up imme-
diately if a missing measuring voltage is detected while the undervoltage protection is active. The param-
eter setting can be changed even when the device has picked up.
Blocking the Stage
In the event of blocking, the picked-up stage is reset. The following blocking options are available for the
stage:
•
Via the binary input signal
>Block stage
from an external or internal source
•
From inside on pickup of the Measuring-voltage failure detection function (see chapter 9.3.2.1 Over-
view of Functions) . The Blk. by meas.-volt. failure parameter can be set so that measuring-
voltage failure detection blocks the stage or does not block it.
•
From an external source via the binary input signal
>Open
of the function block Volt.-transf. c.
b., which links in the tripping of the voltage-transformer circuit breaker. The Blk. by meas.-volt.
failure parameter can be set so that measuring-voltage failure detection blocks the stage or does not
block it.
Application and Setting Notes
Parameter: Method of measurement
•
Recommended setting value (_:8) Method of measurement = fundamental comp.
With the Method of measurement parameter, you define whether the stage uses the fundamental compo-
nent (standard method = default setting) or the calculated RMS value.
Parameter Value
Description
fundamental comp.
Select this method of measurement to suppress harmonics or transient
voltage peaks.
Siemens recommends using this parameter value as the default setting.
RMS value
Select this method of measurement if you want the stage to take harmonics
into account (for example, at capacitor banks). Do not set the threshold
value of the stage under 10 V for this method of measurement.
Parameter: Measured value
•
Recommended setting value (_:9) Measured value = phase-to-phase
With the Measured value parameter, you define whether the stage monitors the phase-to-phase voltages
V
AB
, V
BC
, and V
CA
, or the phase-to-ground voltages V
A
, V
B
, and V
C
.
Parameter Value
Description
phase-to-phase
If you want to detect voltage dips caused by multiphase short circuits, or
generally monitor the voltage range, keep phase-to-phase as the default
setting. 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 or overvoltage conditions caused by ground faults.
Parameter: Threshold, Pickup factor
•
Default setting (_:3) Threshold = 80.000 V
•
Default setting (_:109) Pickup factor = 0.90
6.29.4.2
Protection and Automation Functions
6.29 Undervoltage Protection with 3-Phase Voltage
746 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
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