•
Measured phase-to-phase voltage V
AB
(
VAB measured
)
•
Measured phase-to-phase voltage V
BC
(
VBC measured
)
•
Measured phase-to-phase voltage V
CA
(
VCA measured
)
•
Calculated phase-to-phase voltage V
AB
(
VAB calculated
)
•
Calculated phase-to-phase voltage V
BC
(
VBC calculated
)
•
Calculated phase-to-phase voltage V
CA
(
VCA calculated
)
•
Calculated voltage V0 (
V0 calculated
)
The selection depends on the corresponding application.
i
i
NOTE
From V7.30 on, the value
VN measured
is no longer provided. If you have selected this value in earlier
versions, you can select the value
V0 calculated
instead after upgrading the configuration to V7.30 or a
later version.
If the function Undervoltage protection with any voltage is used in a 1-phase function group, the param-
eter
Measured value
is not visible.
Parameter: Threshold
•
Default setting
(_:571:3) Threshold
=
80 V
Specify the
Threshold
(pickup threshold) for the specific application.
Depending on the
Measured value
, the
Threshold
is set either as
measured voltage
or as a
phase-
to-phase
variable.
i
i
NOTE
If the function is used in a Voltage-current 1-phase function group connected to the 1-phase voltage
measuring point with the voltage type
VN broken-delta
, you set the threshold value based on the
equivalent zero-sequence voltage.
Calculate the equivalent zero-sequence voltage V
0 equiv. sec
from the measured voltage V
N sec
with the
following formula:
You can find more information about the
Matching ratio Vph / VN
cation and Setting Notes for Measuring Point Voltage 3-Phase (V-3ph)
Parameter: Operate delay
•
Default setting
(_:571:6) Operate delay
=
3 s
The
Operate delay
must be set for the specific application.
Parameter: Dropout ratio
•
Recommended setting value
(_:571:4) Dropout ratio
=
1.05
The recommended set value of
1.05
is appropriate for most applications. To achieve high measurement preci-
sion, the
Dropout ratio
can be reduced to 1.02, for example.
Parameter: Current-flow criterion
•
Recommended setting value
(_:2311:101) Current-flow criterion
=
on
Protection and Automation Functions
7.17 Undervoltage Protection with Any Voltage
SIPROTEC 5, High-Voltage Bay Controller, Manual
821
C53000-G5040-C015-9, Edition 11.2017
Summary of Contents for 6MD85
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